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1
Larsson, Isabelle, and Emma Nilsson. "Drömmen om en effektiv inköpsprocess : ett modeföretags eviga kamp." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20728.
Full textAbstract:
För företag som verkar på den dynamiska och konkurrenskraftiga modemarknaden är den storautmaningen att skapa en hållbar konkurrensfördel för att på ett lönsamt sätt vinna kampen omkunden. Ett viktigt verktyg är en effektiv och flexibel inköpsprocess. Utformningen avinköpsprocessen avgör förmågan att möta den krävande modekundens efterfrågan. Vår studie avseratt undersöka hur inköpsprocessen bör organiseras hos en produktutvecklande modedetaljist för attvara effektiv och kunna möta marknadens förändringar. För att påvisa ämnets praktiska relevans ochförtydliga problematiken används ett fallföretag där kvalitativa empiriska undersökningar har utförts.En inköpsprocess består av olika aktiviteter som tillsammans påverkar processens utfall. Enprocesstyrd verksamhet separerar inte aktiviteterna från varandra utan vill förtydligaberoendeförhållandet mellan dem och skapa ett helhetsperspektiv. En förutsättning för att skapakundvärde är att processens samtliga aktiviteter arbetar med syfte att skapa värde för slutkunden.Inköpsprocessens aktiviteter bör även ha ett tydligt definierat utfall för att överlämningen till nästafas ska ske så effektivt som möjligt. I strävan att säkra kvaliteten på utfallet från varje aktivitet bliransvarsfördelningen inom inköpsprocessen en viktig fråga. En tydlig och balanserad uppdelning avarbetsuppgifter, ansvarsområden och slutgiltig beslutsfattare inom varje aktivitet ökar effektiviteten iprocessen och de interna ledtiderna reduceras.Företag X står inför en omorganisering av deras inköpsprocess då den i dagsläget inte upplevstillräckligt konkurrenskraftig. För att öka processens effektivitet, flexibilitet samt minska de internaledtiderna utförs en omfördelning av arbets‐ och ansvarsuppgifterna. Företagets designers hartidigare ägt allt ansvar över processens beslut, vilket gjort inköpsavdelningens betydelse nästintillobefintlig. Idag arbetar företaget för att öka varje aktivitets‐ och befattningsbetydelse för att säkraprocessens resultat och för att den inte ska, som tidigare, vara beroende av ett fåtal medarbetaresarbete. Genom omorganiseringen ska flera arbetsuppgifter utföras parallellt vilket gjort attöverlämningarna mellan avdelningarna fått en ökad betydelse. Företagets nya inköpsorganisation ärännu i sin uppstartsfas men fördelar och nackdelar kan ändå redan identifieras. Resultatet av denempiriska undersökningen visar på en större andel värdeskapande aktiviteter, en jämnareuppgiftsfördelning och en tydligare gemensam målsättning. Undersökningen påvisar även brister iform av att den tidigare strukturens ansvarsfördelning till mångt och mycket lever sig kvar vilkethämmar effektiviteten. Det saknas, trots identifieringen av överlämningarnas betydelse, tydligariktlinjer om vad överlämningarna ska innefatta och hur dem skall utföras.Vår slutsats är att en processtyrd inköpsprocess är att föredra för en produktutvecklandemodedetaljist. Det faktiska kundvärde som processen har för avsikt att skapa bör styra processensutformning både när det gäller ansvarsfördelning och värdeskapande aktiviteter.For companies that compete in the dynamic and highly compatible fashion market, the greatchallenge is to create a sustainable competitive advantage to be able to win the customer during themost profitable circumstances. An important tool for this ambition is an efficient and flexible buyingprocess. The structure of the buying process determines its requirement and ability to handle thedemanding demands of the fashion customer. Our essay aims to examine how the buying processshould be organized at a product developing fashion retailer to be efficient and able to deal with themarket changes. To make a statement regarding the practical relevance of the chosen theme and toelucidate the complex of problems, we chose to use a company to exemplify in where we carried outqualitative empirical research.A buying process consists of different activities that together have a direct impact at the output ofthe process. A business with a process management doesn’t separate the activities apart, instead itemphasize the interdependence between them and a comprehensive perspective by orientate themin a process. The requirement for creating customer value is for all the activities within the process tobe aware of the customer needs and bear it in mind when performing every single working task. Theactivities of the process should also have a clearly defined output so that the handing over to thenext phase will appear as efficient as possible. With the ambition to secure the output quality foreach activity, the responsibilities within the buying process become an important issue. E clearlydefined and balanced split of working tasks, responsibilities and final decision makers within eachactivity, increases the efficiency of the process and will result in reduced leadtimes.Company X is facing a re‐organisation of their buying process since its current capability doesn’treach a satisfying level of being competitive. To increase the efficiency, flexibility and the internalleadtimes, a redistribution of working tasks and responsibilities are being made. Previously, thedesigners of the firm have had the overall responsibility of the decisions of the process which haveresult in a lack of impact for the buying function. The company is trying to achieve an increasedimportance and impact of each of the activities within the process to secure the result of the outputin which it will not be depending on the work of a few members of the process.In the new structure of the firm’s buying process, the activities within the process are suppose to runparallel which requires hand overs performed with good quality. The new buying process is still in anearly stage but even so, advantages and disadvantages can be identified. The result of the empiricalresearch is showing an increased share of value added activities within the process, a more balancedsplit of working tasks and clearer common objectives from the participating activities and employees.The investigation also shows deficiencies in the new organization regarding the previous structure ofresponsibilities that is still affecting the efficiency in a non‐favorable way. There is also lack of clearguidelines for how the handovers should be performed.Our conclusion is that it’s favourable for a fashion retailer if their buying process has a processmanagement. The process should be designed in both terms of responsibilities and value creationactivities after the real customer value that the process is planning to create.Program: Textilekonomutbildningen
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Giri, Goutam. "Fixed Bed Column Study for Removal of Chromium (VI) from Aqueous Solution by Using Saw Dust(GMELINA ARBOREA)." Thesis, 2009. http://ethesis.nitrkl.ac.in/988/1/10500011_-_FINAL_THESIS.pdf.
Full textAbstract:
The study on performance of low-cost adsorbent such as saw dust of Gmelina arborea (Ghambhari tree) in the removal of Chromium (VI) ion from aqueous solution is performed. The
adsorbent material adopted was found to be an efficient media for removal of Chromium (VI)ion in continuous mode using fixed bed column. A comparative study has also been done on the adsorption capacity of saw dust of different mesh sizes. The column studies were conducted with
a fixed column of diameter 7cms and a bed height of 50cms. The flow rate of solution passing through the adsorbent bed was maintained at a fixed value of 1litre/min. It was found that the metal uptake capacity (amount of removal) of Chromium (VI) ion decreased but the adsorption
capacity (percentage of removal) increased with the decrease in the concentration of chromium (VI) in the initial sample solution. It was also observed that the order of metal uptake capacity & adsorption capacity of saw dust of different ISS mesh size for removal of Chromium (VI) removal was as follows: (-30 +10) > (-50 +30) > (-70 +50) .
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Mondal, T. K. "Phase Equilibrium Modeling in Gas Purification System." Thesis, 2009. http://ethesis.nitrkl.ac.in/1517/1/Mtech-thesis-Tarun.pdf.
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A thermodynamic model based on activity is proposed to correlate and predict the vapour-liquid equilibria of the aforesaid systems. The activity based models render an insight in to the molecular physics of the system; hence accurate speciation of the equilibriated liquid phase becomes a reality besides its prediction ability of solubility of the acid gases over alkanolamine solutions. The activity based model has been developed using extended Debye-Hückel theory of electrolytic solution with short range, non-electrostatic interactions. The vapor phase non-ideality has been taken care of in terms of fugacity coefficient calculated using Virial Equation of State. The equilibrium constants are taken from literature as functions of temperature only. The neutral and ionic species present in the equilibrated liquid phase have been estimated with zero interaction model and incorporated here. The interaction parameters in the activity models are estimated by minimizing the objective function, which is the summation of relative deviation between the experimental and model predicted CO2 partial pressures over a wide range.
The parameter estimation for the phase equilibrium models have been formulated here as a multivariable optimization (minimization) problem with variable bounds. The MATLAB 7.6 optimization toolbox has been used extensively for the present work. ‘fmincon’ function, which is a constrained optimization function uses quasi-Newton and Sequential Quadratic Programming (SQP) methods, has been used here for minimization of the proposed objective functions with variable bounds for both approximate and rigorous modeling. There remains a necessity of refinement of the developed rigorous thermodynamic model in terms of the accurate speciation, i.e., exact determination of the species concentration in the equilibrated liquid phase and use of better optimization algorithm, may be non-traditional one, which will ensure global minima.
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Patel, Sourav. "Preparation and characterization of porous adsorbent for chromium(VI) removal." Thesis, 2010. http://ethesis.nitrkl.ac.in/1772/1/(10600030)cr_removal_2.pdf.
Full textAbstract:
Chromium (VI) compounds are widely used in industry such as electroplating, meal finishing, leather tanning, pigments, etc. In recent years ground water is the main source of domestic water supply. Chromate poisoning cause severe skin disorders allergic dermatitis, liver and kidney damage. Thus chromium causes great public concern. A wide range of separation process has been investigated for the removal of Chromium (VI) from water. Adsorption using activated carbons posed to be the efficient method for removal of Chromium ions from water.
To use carbon as an adsorbent requires activation or surface modification of carbon. Methods like thermal and chemical methods of activation are common, but some problems are associated with them. Electrochemical method as one of the method of surface modification of commercially available activated carbon can be applied. The result is better adsorption of Chromium (VI) ions. The present thesis includes various adsorption techniques. A literature review of adsorption characteristics has been included. Our project work include fabrication of an experimental setup, surface modification (oxidation at anode) in 0.5 M KCl solution at various intensity of currents, and latter comparisons of BET surface area, porosity, FTIR analysis ( for identification of changes in bonds after electrochemical oxidation) and adsorption in spectrophotometer.
Surface area, pore volume and pore size all decrease with increase in current intensity. A significant loss in porosity and decrease in pore diameter were observed and is due to blockage of pores by formation of functional groups (carboxylic acidic groups, hydroxyl groups, lactonic grops, phenolic group) and aggregation of humic substances. As the intensity of oxidation is increased by increasing the intensity of source current the amount of adsorption also increases. Also it is observed that if the intensity of current is increased from 0.1 Amp to 2.1 Amp, the amount of adsorption increases. But as the current approaches to 2.1 Amp the adsorption amount doesn’t change significantly. Sample oxidized at 2.1 ampere was analyzed in FTIR. In the FTIR spectra it is revealed that in some ranges dip in transmittance was observed. Suitable reasons were found out. This process of activation can be suitably applied for activation of carbon.
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Agarwal, Vinay Kumar. "Stability Study of Important Metal Organic Frameworks (MOFs) and a Review on their Gas Adsorption Properties." Thesis, 2012. http://ethesis.nitrkl.ac.in/3167/1/eThesis_Vinay_Agarwal_108CH008.pdf.
Full textAbstract:
Metal Organic Frameworks (or, MOFs) have shown tremendous potential in adsorptive separation applications and gas storage owing to some of their extraordinary features in terms of specific surface area, pore volume, low to moderate heat of adsorption and fairly uniform pore size distribution. But, the success or failure of any adsorbent material largely depends on their stability in varying experimental conditions. In this work, we have highlighted the synthesis of 3 most versatile MOFs reported till date viz. Cu-BTC (or, HKUST-1), Cr-BDC (or, MIL-101) and Zn-BDC (or, MOF-5). Each of these MOFs after their successful synthesis and characterization were exposed to a regulated environmental conditionto study the effect of moisture sensitivity. Such a study is particularly important since any real time experiment with MOF is bound to come to terms with varying degree of moisture or water vapor, especially when exposed for longer duration. After detailed experimentation we concluded that a controlled exposure to ambient conditions didn’t have a severe effect on MOF’s thermal stability. Cr-BDC was found to be taking up more moisture during the course of time as compared to Cu-BTC and Zn-BDC. The degree of crystallinity appeared to be reduced over the time interval and surface morphology too gets affected.
Moreover, we have carried out a comprehensive review of 3 very important industrially and environmentally important gases viz. H2, CO and CO2 on these three MOF matrices. The reason behind choosing theses gases stems out from the fact that H2 is projected as a future fuel which may very well replace the conventional fossil fuels, both CO2 and CO are the most important green house gases and their emission needs to be effectivelyarrested, mixture of these gases are emitted from various sources e.g. steam reforming of naphtha, partial oxidation of hydrocarbons, metallurgical plants etc. Apart from these facts, physical properties of each of them are quite different. H2 is a non-polar gas whereas CO has a permanent dipole moment and CO2 has a quadrupole moment. Studying the effects of these physical properties could be interesting from a fundamental point of view to understand the adsorption phenomenon. The retrieved experimental data from literature was model fit using standard isotherm models viz. Langmuir, Freundlich, Freundlich-Langmuir, Dual Site Langmuir (DSL) and Virial models. Additionally, a comparative study between simulation data (available in literature) and experimental data (at same conditions)was carried out for a proper validation. CO was selected on the basis of its polarity and CH4 was chosen since it is non-polar. The adsorbent for the study was Cu-BTC.
Our findings are summarized as:
(I) All the isotherm models are not equally efficient in predicting the adsorption behavior in low and high pressure regime. Freundlich-Langmuir model is seen to be the best in explaining the adsorption behavior irrespective of the type of probe or adsorbent surface.
(II) The experimental H2 adsorption data as reported by various researchers varied considerably from lab to lab and H2 adsorption on none of the adsorbents studied in this work satisfies the Department of Energy (DoE) target of 6.5 wt%.
(III) Cr-BDC (or, MIL-101) showed the highest affinity for CO2. This uptake of CO2 is the highest reported till date.
(IV) Although experimental data on CO adsorption on any MOF material is scarce, but still within our review, we have found Cr-BDC to have the highest loading of CO. The higher loading can be attributed to very high surface area (ca. 3000 m2 g-1) for Cr-BDC amongst the studied MOFs.
(V) The comparison of simulation with experimental data of CO and CH4 on Cu-BTC has shown that for polar molecule e.g. CO, simulation data under predicts the experimental data whereas in the higher loading region simulation data over predicts. This is less marked for non-polar gas like CH4. It is worth mentioning that even though there are variations in simulation result predictions with experimental data but still Grand Canonical Monte Carlo (GCMC) simulation is a strong method in predicting experimental excess adsorption data particularly when total pore volume information and single crystal XRD data is available.
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Garg, Deepak. "Adsorptive removal of dyes from aqueous solution using Cu-BTC and Commercial Activated Carbon." Thesis, 2012. http://ethesis.nitrkl.ac.in/3168/1/eThesis_Deepak_Garg_(108CH010).pdf.
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This thesis is dedicated to the liquid phase adsorption of dyes, namely Rhodamine B and Erioglaucine, where they represent the class of a basic and an acid dye respectively. The adsorbents used are Metal Organic Framework (Cu-BTC) and Activated Carbon. The characterization was done for each of the adsorbent. On the one hand, the experimental data did not envisage Cu-BTC as an effective adsorbent for liquid phase adsorption while on the other hand, Activated Carbon showed some encouraging results on the batch experiments conducted on various parameters like effects of adsorbent dose, initial pH and contact time.
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Ranjan, Debesh Kumar. "Preparation of Ceramic Membranes for Effluent Treatment." Thesis, 2013. http://ethesis.nitrkl.ac.in/5373/1/109CH0542.pdf.
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This work highlights the fabrication of ceramic microfiltration membranes using drill mud as the raw material. The raw material was pre-processed and paste casting method was used for fabrication. Three different membranes were successfully fabricated (keeping a standard stoichiometric composition of raw materials and binders) at three different sintering temperatures e.g. 500, 800 and 900oC. Comprehensive characterization techniques viz. scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), BET surface area and Mercury porosimetry were followed to ascertain the nature of the membrane fabrication. The membrane sintered at 900oC, having an average pore size of 18ìm was found best suited for oil-water emulsion studies. A rejection of ca. 38% was observed for this membrane. Another variant of ceramic membrane was fabricated at 900oC with an addition of 25% kaolin. A better rejection of ca. 49% was found for this case which can be attributed to better structural properties of the membrane surface and uniformity in pore size distribution. All the membranes were studied for their regeneration and reusability. A detailed cost analysis was also performed and it was seen that the membranes fabricated were much cheaper than the similar products reported in literature.
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Selsa, H. "Screening of solvents for carbon dioxide absorption in ionic liquids using cosmotherm." Thesis, 2014. http://ethesis.nitrkl.ac.in/5991/1/E-158.pdf.
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Recently room temperature ionic liquids (ILs); called green solvents are emerging as promising candidates to capture due to their wide liquid range, low melting point, negligible vapor pressure, high solubility and reasonable thermal stability. However, these solvents, suffer from a major disadvantage of high viscosities in their unreacted state, which makes them very difficult to handle and transport in an industrial scenario. To make up for this, combining RTILs with conventional solvents like alkanolamines have been proposed.Again, owing to the huge number of possible combinations between cations and anions and blends of the resulted ILS/RTILs with alkanolamines, a solvent screening procedure became essential in narrowing down the solvents/blended solvents with the desired properties. In view of this, various thermophysical and physicochemical properties intended for CO2 absorption were predicted for the ionic liquids as well as their alkanolamine blends using the computational chemistry software “cosmotherm”.Various properties like density, heat capacities, viscosities, conductivity, melting point etc were studied by changing the substituent cation or anion of ILS/RTILs and their combinations with alkanolamines as well.On comparison of the predicted properties, it has been noticed that the anions TF2N and PF6 exhibits the most desirable properties in combination with the solvents MEA, DEA and PE.The screened solvents in this study might be proving their worth on experimental verification.
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Verma, T. "Reactive extraction of acetic acid." Thesis, 2014. http://ethesis.nitrkl.ac.in/6068/1/E-191.pdf.
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Acetic acid is an important carboxylic acid widely used in chemical, pharmaceutical, food and other industries. The growing importance of biological production (fermentation) expressed with new routes and increasing production rates, leads to look for technologies of downstream processing for product separation. The reactive extraction can be used for the recovery of an acetic acid from aqueous solution.The reactive extraction with specific extractant and a proper combination of extractant and diluents provides the higher capacity and selectivity of an acetic acid. The recovery of acetic acid by reactive extraction is studied using an organic solvent such as toluene, petroleum ether and n-hexane. The feed concentration of acetic acid in the aqueous solution ranges in between 0.1 to 0.4 gmol/l. The extraction of acetic acid from aqueous solution (feed concentration 0.4 gmol/lit) with organic solvent gives the distribution coefficient (KD) in toluene, petroleum ether and N-Hexane solvents equal to 1.29, 0.79 and 0.6 respectively. Further, the reactive extraction is carried out with the mixtures of extractant–diluents. The tri-iso-octylamine is used as an extractant. The extraction of acetic acid with 40% of tri-iso-octylamine in an organic solvent shows the highest distribution coefficient for toluene, petroleum ether and n-hexane. These are 3.65, 2.70 and 2.63 respectively. By comparing results, it can be concluded that using the mixtures of extractant–diluents, the extraction is significantly improved.
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Kumar, Balasa Satis. "Fabrication and characterization of kaolin based membrane for catalyst recovery." Thesis, 2014. http://ethesis.nitrkl.ac.in/6432/1/212CH1346-6.pdf.
Full textAbstract:
In this project work, Kaolin was the primary raw material for membrane fabrication. Various additives/binders were also used based on their suitability and effectiveness in imparting special properties e.g. mechanical strength and dispersion properties for homogeneity to the final or finished membrane. During membrane preparation with various stoichiometric compositions of ingredients, it was observed that higher percentages of kaolin didn’t result into membranes with good flexural strength whereas increasing the % of red-mud enhanced the mechanical strength quite considerably e.g. 10.11 MPa (membrane F), 18.93 MPa (membrane G) and 12.04 MPa (membrane H) respectively. Methanol permeation studies showed that the average steady state flux was highest for membrane G (ca. 4.23×10-4 m3 m-2 sec-1). The fabricated membranes were undergone catalyst recovery study in a batch membrane module. In this work, Cu-BTC (or, HKUST-1 or, MOF-199), a well-known Metal Organic Framework (MOF) was selected as the potential catalyst. Several cycles (or batches) were carried out inside the membrane module and it was observed that membrane G performed better than the rest and a recovery percentage of ca. 61% was noted after 3 cycles before the membrane pores were completely choked. Membrane de-fouling and regeneration studies were carried out in detail using back-washing treatment inside the module itself and ultra-sonication techniques for preparing the membranes for next round of operations.
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Palai, Ashis. "Analysis of Essential Oil Content Obtained from Plant Materials Using Steam Distillation." Thesis, 2015. http://ethesis.nitrkl.ac.in/6793/1/2015_BT_Ashis_111CH0081.pdf.
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An expansive number of materials contain Essential Oils with broad bioactvities. Recognizing the significance of plant and its restorative quality, Essential Oil was extracted utilizing Steam Distillation technique. In this venture Steam Distillation was utilized to concentrate oil from distinctive plant materials like eucalyptus leaf, curry leaf, hibiscus leaf, marigold blossoms, rose blooms, orange peels and so forth. Examination has affirmed hundreds of years of down to earth utilization of vital oils, and we now realize that the 'fragrant drug store' contain mixes with an amazingly expansive scope of biochemical effects. Fundamental oils are accepted to speak to the very substance of odour and flavour. The recuperation of Essential Oil from the crude organic beginning material is essential since the nature of the oil is enormously impacted amid this step. There is a mixed bag of strategies for acquiring unstable oil from plant. Steam distillation technique was discovered for systems of the extraction of key oil from plants as legitimate distiller will protect the first characteristics of the plant. The distillation was led in Clevenger apparatus where bubbling, gathering and decantation was finished. Examination of Essential oil had been done utilizing Gas Chromatography-Mass Spectrometer, which gives evaluates Essential Oil subjectively and quantetatively. Volume of Oil acquired had been changed with respect to temperature and heating
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Raman, R. Shashank V. "Preparation and Characterization of Activated Carbon from Waste Food Packaging Polymers." Thesis, 2015. http://ethesis.nitrkl.ac.in/6865/1/PREPARATION_Raman_2015.pdf.
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The two of the major challenges which we are facing in the modern era are the management of the waste plastics and the waste water from the industries. Water pollution is one of the major challenges faced by the environmental engineers today due to toxic metal releases from various industries. Among various technologies, adsorptive removal of these toxins by the usage of activated carbon as the adsorbent is more promising and economical as it is known for its high adsorption capacity. The preparation of activated carbon from waste food packaging polymers, which is about 35% of the total plastic waste accumulated, would not only reduce the voluminous quantities of plastic but also help in water treatment. A relatively new technique, Hydrothermal Carbonization (HTC), was used for the carbonization of the raw material instead of the traditional carbonization process. A pressure vessel was fabricated for HTC and the temperature set at 235 degrees celcius and the holding time was 15 hours. After processing the „hydrochar? with benzene to remove ash, dirt and iron rust (if there) it was activated with 1 M KOH for a period of 10 hours and subsequent drying for 5 days under the temperature 70 degrees celsius. Proximate analysis, Field Emission Scanning Electron Microscope (FESEM), Iodine Number, Fourier Transform Infrared Spectroscopy (FTIR), and Methylene Blue Number were the characterization techniques implemented. It was observed that the methylene blue number was high indicating the presence of high percentage of mesopores content.
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Mallick, Sabyasachi. "Reactive Extraction of Butyric Acid Using Tri-Octyl Amine in Decanol." Thesis, 2015. http://ethesis.nitrkl.ac.in/6940/1/Reactive_Mallick_2015.pdf.
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The application of reactive extraction for the separation of butyric acid from its aqueous solution is a relatively new technique. It has many uses in different industries, and currently there is a great interest in using it as a precursor to biofuels. Research works are available on equilibrium study of the reactive extraction of butyric acid where aliquat-336 and tri-butyl phosphate were used as the reactive extractant. But no one has used TOA as the extractant, and nowhere study on the kinetic behaviour of reactive extraction of butyric acid has been done. Also the detailed study on the effect of temperature on the Butyric acid-TOA- Decanol system is unavailable. The present research work has focused on the reactive extraction of butyric acid from its aqueous solution using Tri-Octyl-Amine (TOA) in the active diluent decanol. Equilibrium and kinetic studies was performed at very low concentrations of butyric acid in water viz. 0.05M to 0.3M at 250C, 300C, 350C and 400C. The effect of temperature on the extraction equilibrium and kinetics was considered. In the equilibrium study, the complexation constant (KE(1:1) ) was evaluated and the type of complex formed was also determined. The distribution coefficient (KD) and extraction efficiency (E%), were determined. In the kinetic study, the order of the reaction (n), the rate constant (k) and the mass transfer coefficient (KL) were found from the experimental data. Extraction efficiency (E%) of 98% and distribution coefficient (KD) of 49 has been achieved at 400C. The order of the reaction (n) has been found to be 1. The mass transfer coefficient (KL) has been found to be 10.77×10-3 cm/min.
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Biswas, Snehasis. "Separation of Chromium (VI) By Bulk Liquid Membrane Technique." Thesis, 2015. http://ethesis.nitrkl.ac.in/7033/1/Separation_Biswas_2015.pdf.
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In this work an attempt has been made for faster extraction and separation of Cr (VI) from its model solution with minimal use of carrier. Studying the effects of various process parameters viz. source and stripping phase concentration and pH on the overall performance of this bulk liquid membrane technique have been a key objective along with the membrane reusability. Aqueous solution of potassium dichromate (K2Cr2O7) was used as the source phase or model contaminant for Cr (VI) ions. 1, 2-dichloroethane was the preferred solvent used as the liquid membrane phase in this work. Aqueous solution of NaOH was found to be the effective stripping phase. Performances of several carriers had been investigated and tri-n-octylamine (TOA) was found to be the most suitable in facilitating the transport mechanism. A comprehensive kinetic study was carried out and the effect of various parameters viz. carrier concentration, feed and stripping phase concentrations and pH were studied. A key objective of this work was to achieve maximum separation of Cr (VI) with minimal carrier concentration and this work successfully reports a removal percentage of ca. 98% of Cr (VI) ions with 0.25 vol. % of TOA within a span of 2 hrs. The transport mechanism was observed to be more effective in the acidic pH range w.r.t the feed phase (ca. pH 1) whereas the optimum stripping phase concentration of NaOH was 0.3 N. Membrane reproducibility study showed that the performance of the liquid membrane remained largely unaffected even after fourfold use.
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Das, Chitra. "Liquid-Liquid Equilibrium Studies on Extraction of Commercially Significant Carboxylic Acids." Thesis, 2015. http://ethesis.nitrkl.ac.in/7990/1/2015_Liquid_Das.pdf.
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Carboxylic acids are commercially very important organic acids and their extraction from fermentation broth can be one of the sources of recycling back these important organic acids.Here, we have worked on two systems: experimental tie-line results and solubility (binodal) curves were obtained for the ternary systems of water + acetic acid + hexanol and water + caproic acid + methyl isobutyl ketone at temperature of 308K and at atmospheric pressure. The concentrations of the components in the equilibrium phases were measured using gas chromatography for hexanol and methyl isobutyl ketone and acid concentration in each phase was determined by titration against NaOH solution. The water concentration was determined using mass balance. Using the equilibrium tie line phase compositions graph was plotted for the ternary systems. Solubility or binodal curves were obtained by joining these tie line phase compositions. The two phase and the one phase region were then determined for the ternary systems. Distribution coefficients and separation factors were calculated for the ternary systems to determine whether the solvents used were suitable for extraction of those specific organic acids from their aqueous phases.
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Negi, Deepika. "Reactive Extraction of Butyric Acid using Tri-Octyl Amine in Decanol." Thesis, 2016. http://ethesis.nitrkl.ac.in/8561/1/2016_MT_214CH1102_Deepika_Negi.pdf.
Full textAbstract:
Reactive extraction is a separation technique using the reaction between extractant and the material to be extracted. The extractant present in the organic phase reacts with the material present in the aqueous phase and the reaction complexes thus formed are solubilized in the organic phase. The application of reactive extraction for separating Butyric Acid (BA) from its aqueous solution is a new technique. Butyric acid (BA, CH3CH2CH2CO2H) also known as butanoic acid, abbreviated as BTA, is a short chain carboxylic acid. It has many important applications in various industries. It can be used as an energy source by converting into butanol by biological conversions. It is anti carcinogenic, as it induces morphological and biochemical differentiation in a range of cells, which leads to concomitant suppression of neoplastic properties and presently it is being used as a precursor to biofuels. It is a promising chemical as it has the potential for future energy needs by converting into butanol through biological transformation. Study of effect of pH on reactive extraction process is essential because pH varies as the process of reactive extraction proceeds. Normally pH of solution containing acid is below pKa values of the respective acid but as the extraction proceeds, due the removal of the acid, pH approaches near 7.0. Thus for reactive extraction process an extractant-diluent combination is required which could recover the acid efficiently at all pHs . Fermentation process usually operates in the temperature range of 305 to 313 K. Thus an extractant is effective only if it operates efficiently in this temperature range. In addition to this, the climate variation, feed and bioreactor conditions makes the study of temperature effect even more important.
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Kella, Tatinaidu. "Synthesis of Zeolite-X from Coal Fly Ash and Its Application in Removal of Methylene Blue Dye." Thesis, 2016. http://ethesis.nitrkl.ac.in/9277/1/2016_MT_TKella.pdf.
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Fly ash is an industrial by product which is generated by combustion of coal. During the combustion minerals partially melt to form fly ash particles which is heavy burden on the land because of dumping. The present concern over fly ash is to convert value added products such as zeolite type of materials on proper treatment. Fly ash is having silica, alumina in core and glass phase is on the surface which is more soluble in the alkaline phase to form aluminosilicate gel, so that fly ash having the potential to form zeolite type of material. In the present study, synthesized zeolite X type of material from coal based fly ash. Synthesized zeolite X was characterized by various techniques such as X-ray diffraction (XRD) analyzer, scanning electron microscope (SEM) and BET analysis. Surface area of the zeolite, pore volume, pore radius of the synthesized zeolite was measured and it has been found that synthesized zeolite having mesoporous pores. The synthesized zeolite using as adsorbent in the removal of methylene blue dye from the aqueous solution. The wastewater containing dyes, generated by the textile, printing and papermaking industries, pose major hazard to the environment and the public health. The influences of five dominant parameters of pH, temperature, time, initial dyes concentration, and adsorbent mass on dyes adsorption were investigated for synthesized zeolite X (from fly ash), Commercial zeolite (13X) and Raw fly ash. The percentage of dye removal was mathematically described as a function of experimental parameters and was modeled through central composite design (CCD). According to the predicted experiments, optimum conditions of 10, 32.7°C, 47.87 min, 50 ppm, and 0.25 g, for pH, temperature, time, initial dyes concentration, and adsorbent mass were resulted, respectively for synthesized zeolite X as adsorbent and the maximum dye removal percentage obtained 82. Optimum conditions of 10, 27.08 °C, 54.13 min, 50 ppm, and 0.66 g, for pH, temperature, time, initial dyes concentration, and adsorbent mass were resulted for raw fly ash as adsorbent and the maximum dye removal percentage obtained 42.66. Optimum conditions of 10, 46.96 °C, 32.61 min, 50 ppm, and 0.25 g, for pH, temperature, time, initial dyes concentration, and adsorbent mass were resulted for commercial zeolite (13X) as adsorbent and the maximum dye removal percentage obtained 64.02. Among these three adsorbents, synthesized zeolite gave the maximum percentage of dye removal.
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Satapathy, Mitra. "Development of Durable Superhydrophobic Polymer Composite Coatings for Self-Cleaning and Oil-Water Separation Applications." Thesis, 2017. http://ethesis.nitrkl.ac.in/9360/1/2017_MTR_MSatpathy_614CH3002.pdf.
Full textAbstract:
In current work, SiO2 nanoparticles embedded linear low density polyethylene (LLDPE) superhydrophobic coatings on glass and filter paper substrates were fabricated using dip-coating and solution casting technique techniques. Porosity of SiO2 nanoparticles coupled LLDPE superhydrophobic coatings was also varied using non-solvent (ethanol) by employing phase separation method. Surface morphology, water contact angle, self-cleaning, oil-water separation, and water-repellency of coatings were characterized. Furthermore, the stability of these coatings was also evaluated by conducting thermal, chemical and mechanical stability tests at perturbation conditions. Along with, comparative studies of porous and non-porous LLDPE/SiO2 coatings on their performances were presented in the current work. By creating porosity and/or embedding SiO2 nanoparticles in to LLDPE matrix, superhydrophobicity is achieved with water contact angle of 170° and sliding angle of 3.8°. Their superhydrophobic property is also maintained after annealing in temperature range from 40 to 120 °C. Water jet impact test reveals the excellent water repellent nature of coatings. Non-porous coatings exhibit more stability in pH range from 4 to 9 than porous coatings. By abrasion test with micro-fiber cloth and tape peeling tests, it is observed that porous coatings are more durable than non-porous coatings. Additionally, waterdrop impact dynamics for the superhydrophobic coatings were also studied. Further, efficiency and reusability of coated filter papers to remove oil from oil-water mixture were also characterized. Coatings show their excellent oil-water separation application with 99.9% oil recovery. Coatings also exhibit the excellent self-cleaning property. These aforesaid coatings have great industrial applications.
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Kumar, Abhishankar. "Adsorption of methane on activated carbon by volumetric method." Thesis, 2011. http://ethesis.nitrkl.ac.in/2817/1/ADSORPTION_OF_METHANE_ON_ACTIVATED_CARBON_BY_VOLUMETRIC_METHOD_merged.pdf.
Full textAbstract:
The adsorption characteristics of methane on granular activated carbon were measured over the temperature range of (293 to 323) K and at pressures up to 900 psi using a volumetric measurement system. The surface of activated carbon has been modified with copper oxides and sliver in order to improve the adsorption capacity of methane. The results indicate that the adsorption capacity can be marginally improved by doping small amount of metal oxides The adsorption data were fitted to different isotherm models and the result shows that DA are able to predict data correctly at all temperature . The isosteric heat of adsorption, which is concentration- and temperature-dependent, is extracted from the data.
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Hazra, Deveshree. "Hazard Identification and Risk Assessment and Formulation of Safety Report of Blast Furnace Deveshree." Thesis, 2018. http://ethesis.nitrkl.ac.in/9549/1/2018_MT_216CH2109_DHazra_Hazard.pdf.
Full textAbstract:
The project topic focuses on safety and welfare of the workers working in and around hazardous and risky environment. Numerous accidents take place each day and many workers lose their life just because the prescribed safety norms are not followed properly. It is the responsibility of management to ensure that all employees are properly trained and receive the necessary tools and guidelines to work safely.
This project aims to enhance the safety performance at shop floor and achieve the company‟s target of zero accident in Blast Furnace by identification of different hazards and calculating the risks associated to various activities.
Hazard identification and risk assessment (HIRA) is a collective term that encompasses all activities involved in identifying hazards and evaluating risk at workplace to make certain that risks to employees, the equipment, or the environment are consistently controlled within organization‟s risk tolerance and a Safety Report provides updates on safety indicators, including accidents and risk factors.
A number of hazards have been identified and the risks associated to the hazards have been noted. Assessment of risks has been done by using matrix method and risks have been classified according to the severity of its occurrence. After analysing all the data gathered, we have made possible recommendations to ensure safe working of blast furnace.
This project will certainly help the organisation to minimise losses due to any accident. Analysis of accident data to find reportable, non-reportable and first-aid on the basis of unfit period has been noted. The results of this analysis will be valuable to find out the consequences on emergency situation that may occur. We have also suggested various mitigation measures that will be efficient to avoid accidents in future.
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Das, Adya. "A Study on Evaluation of Indigenous Microbial Consortium for Enhanced Decolorization of Textile AZO Dyes and Feasibility for Simultaneous Bioelectricity Generation in A Microbial Fuel Cell." Thesis, 2016. http://ethesis.nitrkl.ac.in/8427/1/2016-PhD-ADas-511CH110.pdf.
Full textAbstract:
Extensive use of synthetic azo dyes in various colored industries and the proven toxic and aesthetic effect of these dyes and their degradation metabolites on environment makes the proper treatment of these colored effluent essential before discharging them into the outside waterbodies. Biological treatment methods are taking attention now-a-days as it is proven to be the cheap, eco-friendly and highly efficient treatment method for dye effluent in industrial scale as compared to the other available treatment methods. Organisms isolated from contaminated regions are believed to be more efficient in treatment of any xenobiotic and recalcitrant compounds as they are acclimatized to the toxic effect of the pollutants.
The present work emphasises on decolorization and degradation of different textile azo dyes (Reactive green-19 (RG-19), Remazol navy blue (RNB), Reactive Red-198 (RR-198) and a synthetic dye mixture (SDM) comprising of these three dyes using bacteria isolated from textile industry effluent. Three bacterial strains showing highest dye decolorization capacity were screened and identified as Bacillus pumilus HKG212 (GenBank Accession Number: KJ741252.1), Zobellella taiwanensis AT1-3 (GenBank Accession Number: FJ999669.1) and Enterococcus durans GM13 (GenBank Accession Number: KC213474.1) using 16s rRNA molecular analysis tool. Bacillus pumilus HKG212 was found to show highest decolorization capacity among the three isolates achieving 89% decolorization for RG-19, 95% decolorization for RNB and 94% decolorization for RR-198 dye within 24hr of incubation. However, all the three strains were found to be highly tolerant to higher dye concentrations achieving 80-95% decolorization for three model dyes in a wide range of dye concentration (i.e 50 mg/L to 1000 mg/L). Effect of different physico-chemical parameters on decolorization efficiency of the isolates revealed that, ambient temperature, neutral to slightly alkaline pH and static or anaerobic incubation condition favours the growth and decolorization potential of the organisms....
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S, Dinesh. "Development and Characterization Of Pellet Activated Carbon from New Precursor." Thesis, 2011. http://ethesis.nitrkl.ac.in/2401/1/The_Final_Thesis.pdf.
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Coconut shell was used as a precursor for the production of activated carbon. The substrate was initially physically activated for determination of optimum temperature of production. However on comparison with various chemical activations, zinc chloride activation produced the best results. Preliminary tests determine the inefficiency of epoxy resins as binders. Later concentrated sugarcane juice was used as an adhesive for pellet formation. On activation of these pellets, enhanced surface properties (better than powder activated carbon using same procedures) are obtained. The characteristics of the pellet activated carbon were studied through various tests and analysis. The iodine number of the pellet activated carbon was determined to be 1100 mg/g and had a yield of 36.95%. However the powder activated carbon had an iodine number of only 1020 mg/g. The adsorption study of the pellet activated carbon hence provides evidence for better activity and surface area than commercial activated carbon. It also determines a suitable application of Methane gas storage by adsorption on this pellet activated carbon at high pressure.
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Jain, Garima. "Removal of copper and zinc from wastewater using chitosan." Thesis, 2013. http://ethesis.nitrkl.ac.in/5310/1/211CH1258.pdf.
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Heavy metals are one of the most toxic materials to the environment. Adsorption is the process which is used for the removal of heavy metals from wastewater. Many researches have been conducted to remove heavy metals using different materials. Various adsorbents have been used to remove different type of heavy metal ions from wastewater especially those that are harmful to mankind. Activated carbons, plant or lignocellulosic wastes, clays and biopolymers are the most common adsorbents used. For this research, chitosan was used as a adsorbent to remove copper and zinc from wastewater. Chitosan, a type of biopolymer, is a good adsorbent to remove the heavy metal ions from wastewater. The synthetic wastewater was prepared in the laboratory to conduct the experiments. Batch experiments were conducted to obtain the optimum conditions for copper and zinc. Effect of parameter like pH, adsorbent dose, contact time, temperature and initial metal ion concentration were also determined. The optimum conditions obtained were 360 min contact time, 200 mg adsorbent dose and pH 5 for copper and 180 min contact time, 200 mg adsorbent dose and pH 7 for zinc. Adsorption behavior could be described using the Langmuir, Freundlich and Temkin isotherm model. Adsorption data was well fitted in Langmuir isotherm model for both metals. The maximum adsorption capacity was found to be 89% for copper and 96.97% for zinc. The kinetics of adsorption could describe using pseudo first order and pseudo second order kinetic model. In all cases the kinetics follows the pseudo second order rate equation. The negative values of ∆G0 and ∆H0 indicate that the process was thermodynamically spontaneous and exothermic in nature.
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Hippale, Santosh Vishwanath. "Di-Octyl Amine Mediated Transport of Lignosulfonate using Bulk Liquid Membrane Technique." Thesis, 2015. http://ethesis.nitrkl.ac.in/6784/1/DI-OCTYL_Hippale_2015.pdf.
Full textAbstract:
Although there are several techniques in vogue to separate organic/inorganic components from contaminated waste water emanating from many sources, liquid membrane techniques have been gaining much attention and acceptability in the research arena owing to their simplicity in operability, high removal efficiency and superior selectivity during the transport process. It is also important to highlight the fact that selecting a carrier suitable for specific applications using liquid membranes is a tedious proposition and it requires a calibrated approach to figure out the suitable one. We proposed a simple bulk liquid membrane (BLM) technique to separate lignosulfonate from its model contaminant. The source phase was an aqueous solution sodium lignosulfonate and the strip phase was NaOH solution. 1, 2-dichloroethane was selected as solvent in the liquid membrane phase. Di-octyl amine was chosen as the carrier for this study primarily due to its amine functionality. A comprehensive 2-phase equilibrium study was followed by 3-phase kinetic study to ascertain and establish various parameters for this unit operation. Effect of manifold parameters like carrier volume %, pH of feed phase, strip and feed phase concentration were studied to find out optimum working conditions. In this BLM ensemble, an extraction lignosulfonate of ca. 98% was achieved from source phase to membrane phase whereas the recovery from membrane phase to strip phase was ca. 75%. The optimum strip phase concentration was found to be 0.5 N and the optimum carrier concentration was 3 vol%. Acidic condition was found to be favouring the transport process where the optimum pH of the feed phase was found to be 2. Finally, the transport mechanism was seen to highly influenced by the stirring conditions and the best results were obtained when all the three phases were stirred simulateously. Membrane reusability study also categorically showed consistent performance during multi-fold use.
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Chand, Sidhant. "Optimization in the Treatment of Spent Pot Lining and Enriching of Its Carbon Percentage by Hydrochloric Acid Leaching." Thesis, 2015. http://ethesis.nitrkl.ac.in/6785/1/OPTIMIZATION_Chand_2015.pdf.
Full textAbstract:
Due to a rise in demand of aluminium, the undesirable production of Spent Pot Lining in the Hall-Heroult process has been increasing side-by-side, owing to added environmental problems. The aim of this project is to optimize the process parameters so as to enrich maximum amount of graphitic carbon from Spent Pot Lining, by using sodium hydroxide followed by hydrochloric acid for the first time. The Taguchi method approach for optimization was adopted and significant process parameters such as temperature, alkali concentration, acid concentration and L/S ratio were optimized. Characterization of the various SPL samples was also done to qualify and quantify the samples, using XRD, SEMEDX, FESEM-EDX, CHNS analysis. The carbon percentage of SPL was increased from 43.39% to 70.44% which was confirmed from the ultimate analysis. From EDX data analysis, the carbon percentage was increased from 33.27% to 86.78%. Alkali concentration contributed 47.27% in the leaching process among the four factors, while acid concentration contributed only 1.02 %. The maximum leaching percentage was found to be 54.11% from experimentation. Finally, the analysis of the leaching capacity of four acids, HClO4, H2SO4, HNO3 and HCl was done graphically and comparisons were made.
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Bishoyi, Newton. "Treatment of Spent Pot Lining by Chemical Leaching Using Nitric Acid for Enrichment of Its Fuel Value and Optimzation of The Process Parameters." Thesis, 2015. http://ethesis.nitrkl.ac.in/7197/1/Treatment_Bishoyi_2015.pdf.
Full textAbstract:
Over the years numerous methods have been suggested for treatment of Spent Pot Lining (SPL)- a waste produced from aluminum industries that has been declared as hazardous by the US Environmental Protection Agency. In this project chemical leaching treatment method was adopted and several process parameters and their dependency on each other were studied. SPL was subjected to caustic leaching followed by HNO3 leaching at different temperature and liquid to solid ratio combinations. Again an optimized set of values was obtained via Taguchi method. The main objective of the optimization methodology was to determine the effect of acid concentration, alkali concentration, temperature and L/S ratio on the leaching percentage in terms of percentage contribution. Alkali concentration contributed 51.80% in the leaching process, whereas acid concentration contributed only 2.61 %. The maximum leaching percentage was found out to be 50.62% by Taguchi optimization. It was concluded that 2.5 M NaOH, 5 M HNO3 concentration, 4.5 L/S ratio and temperature 75 ±1°C was the best combination for the optimum leaching percentage for final treated SPL. The carbon percentage of SPL was increased from 33.27% to 87.31% as confirmed from the elemental composition obtained by Enegry Dispersive X-ray spectroscopy. Again with the help of existing data, an extensive comparison was made to find out the best suitable acid out of HCl, HNO3, H2SO4 and HClO4 for leaching process keeping L/S ratio constant. It was observed that at normal temperatures H2SO4 gave maximum leaching percentage for all values of alkali concentrations. But as temperature was increased from 25°C to 100°C, the leaching percentage obtained by all acids converged slowly to a constant range.
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Mishra, Shreeparna. "Preparation and Characterization of Cassia-4 Hydroxy-Benzoic Acid Resin for Removal of Cr+6 From Contaminated Water." Thesis, 2016. http://ethesis.nitrkl.ac.in/8404/1/2016_M.tech(R)_Smishra_614CH3003.pdf.
Full textAbstract:
The current research emphasizes on removal of Cr+6 from the contaminated water by the preparation of natural resin using cassia gum powder and testing its feasibility to reduce Cr+6in contaminated water. The effects of various process parameters including pH of the solution, amount of resin, initial Cr+6 concentration, contact time etc., on removal efficiency of Cr+6 from the water stream has been studied. The study demonstrates that the prepared natural CHBA resin has potential to remediate Cr+6 from the drinking water. It is observed that using 1g/ml resin 99.26% Cr+6 could be removed from initial concentration 3 ppm at pH 6.8 within 25 min. Experimental data obtained were allowed to fit to various models such as pseudo first order model, pseudo second order, intra particle diffusion, Elovich model. Results indicate that the process of adsorption on Cr+6 was followed by second order kinetic model with R2 value 0.989.Similarly other models of adsorption isotherms such as Langmuir, Freundlich, Temkin were also applied to the data and constants of isotherms were calculated. Cr+6 adsorption on the prepared resin shows good agreement to Freundlich adsorption isotherm model with the regression coefficient of 0.989. Thermodynamics parameter studied that the Positive values of change in enthalpy shows that there is a presence of an energy barrier during the process of adsorption and the process of adsorption follows process of endothermic reaction. The positive values in the change of entropy (∆S) shows good binding capacity of Cr+6 ions for the resin surface and it also increases the uncertainty of the solid solution interaction during the process of adsorption.
RSM experiments were also conducted which showed that the ideal conditions required for Cr+6 adsorption were as per the following: amount of resin as (0.43 g), at pH (6.13) as well as Initial Concentration of (4.53 mg/L) with the value of maximum adsorption is 95.05%. The following results were obtained from the box-behenkn design RSM method with a desirability of 0.989. The Column performances were also evaluated by varying the amount of resin inside the column bed, influent rate of flow with Cr+6 concentrations. Furthermore it was seen that with the expansion in height or depth of the bed, at lower flow rates and at low Cr+6concentration the column performance was good or proved to be better.
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Karnjkar, Yogesh Sanjay. "Extraction and Recovery of Different Dyes Using Green Solvents as a Liquid Membrane Medium." Thesis, 2017. http://ethesis.nitrkl.ac.in/8773/1/2017_MT_YS_Karnjkar.pdf.
Full textAbstract:
In current research work, an attempt has been made for efficient transport of different dye molecules such as Crystal violet (CV) and Congo red (CR) using vegetable oil based bulk liquid membrane technique. A comprehensive kinetic study was carried out and the effect of various parameters viz. carrier concentration, strip phase concentration, stirring speed, temperature were studied. An aqueous solution of CV and CR was used as the feed phase and based on two-phase study acetic acid and sodium carbonate was chosen as the stripping agent for CV and CR respectively. Acidic condition of feed phase solution was proved effective for transport of dye molecule. The liquid membrane was prepared by using vegetable oils such as soybean and sunflower oil for CV and CR, respectively. The fundamental objective of present work is to achieve maximum extent of separation of dye molecule from feed phase with the minimal use of a carrier. This work magnificently achieves >86% extraction and >75% recovery of CV in presence of 1M phenol within 12 hrs, whereas >99% extraction and >76% recovery of CR in presence of 4 % (volume) TOA within 8 hrs. Finally, the study of membrane reusability also showed the consistent performance with 75% fresh and 25% used-membrane.
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Agarwalla, Ankit. "Extraction and Recovery of Phenol from its Aqueous Solution Using Vegetable Oil as Liquid Membrane." Thesis, 2017. http://ethesis.nitrkl.ac.in/8774/1/2017_MT_A_Agarwalla.pdf.
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In this work an attempt has been made for extraction of phenol from its aqueous solution with minimal use of carrier or no carrier at all. Studying the effects of various parameters such as feed phase concentration, feed phase pH, carrier concentration, strip phase concentration and temperature have been the key objectives along with the effect of salt loading in the transport process. Aqueous solution of phenol (C6H5OH) was used as the feed phase, sunflower oil was the preffered solvent used as the liquid membrane phase in the current work. Aqueous solution of NaOH was found to be the best solvent for the stripping of phenol. Performances of various carriers has been investigated and Trioctyl phosphine oxide (TOPO) was found to be the suitable carrier in facilitating the transport process. The transport mechanism was found to be effective in a low pH of 2 in the feed phase and the equilibrium time was 12 hrs for both presence and absence of carrier. The optimized feed concentration, strip concentration were 100 ppm and 1.25 N for both the cases (with and without carrier). In presence of carrier, when temperature was increased, the extraction and recovery percentages decreased from 94.9 % and 85.2 % at 300C to 56.1 % and 48.69 % at 450C respectively. Whereas in absence of carrier, the extraction and recovery percentages increased from 74.7 % and 74.1 % at 300C to 85.23 % and 84.7 % at 450C. Further increase in temperature upto 500C resulted in decrease in extraction as well as recovery (64.52 % E and 49.38 % R). The presence of inorganic salts in the aqueous phase such as NaCl and KCl, enhances the extraction of phenol.
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Makkitaya, Swarna N. "Study on Reactive Extraction of Butyric Acid Using Suitable Extractant and Diluent." Thesis, 2017. http://ethesis.nitrkl.ac.in/8786/1/2017_MT_SN_Makkitaya.pdf.
Full textAbstract:
Reactive extraction is a separation process using the reactions between extractants and the materials extracted. The extractant in the organic phase reacts with the material in the aqueous phase and the reaction complexes formed are then solubilized in the organic phase. In this reactive extraction, extractants like organophosphorous compounds like tri-n-butyl phosphate (TBP), tri-n- octyl phosphine oxide (TOPO) and aliphatic amines (tri-n-octyl amine (TOA), Aliquat 336, Alamine 336 etc.) have been widely used for the extraction of carboxylic acids. Alcohol, ester and ketones are mainly used as diluents for these extractants as they are viscous in nature. Natural diluents like sunflower oil, castor oil, soybean oil are also used as diluents for the reactive extraction. The application of reactive extraction for the separation of carboxylic acids like butyric acid from its aqueous solution is a relatively new technique. Butyric acid is a five carbon chain carboxylic acid. This acid is generally used in food, pharmaceutical and polymer industries as a raw material. In the present work, attempts were made for the recovery of recovery of butyric acid using Tri -Octyl –Amine (TOA) using decanol as diluent. Effect of temperature is studied in the range of (298-318K) to check the feasibility of the system within given temperature range. Results are discussed in terms of distribution coefficient, loading ratio, equilibrium constant, enthalpy, entropy and free energy. It is observed that as temperature increases, distribution coefficient values decreases. The enthalpy and entropy obtained are negative values states that the reactive extraction of butyric acid is an exothermic reaction.
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Agrawal, Ankit Kumar. "Effect on naphtha yield, overall conversion and coke yield through different operating variables in FCC unit using Aspen-Hysys simulator." Thesis, 2012. http://ethesis.nitrkl.ac.in/3546/1/ankit_final_thesis.pdf.
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Fluid Catalytic Cracking Unit is the pump house of any refinery. Distillation is the initial step in the processing of crude oil and the residue which is coming out from the distillation column enters as the feed in the FCC unit. Gasoline is the main product of the FCC unit and it also produces byproduct which is more olefinic and hence more valuable. Simulation of the fractional distillation has been done to find out the feed composition which is the feed to the riser reactor. The unit was further simulated under the desired specifications to get the naphtha yield and compared with the plant data. Different graphs were plotted by varying feed temperature, flow rate, catalyst to oil ratio and were successfully compared with the modeled data. Further simulation was done with two regenerators and production of SOx was studied. The simulation result concludes that the SOx emission is lesser in case of one regenerator. Two sets of catalyst were chosen and the final yields were compared. Based on the plant requirement different types of catalyst are used. Finally the effect of riser height was studied in one riser and dual riser by keeping the operating parameters to be same and concluded with the fact that naphtha yield increases in case of dual riser.
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Kumar, Vikas. "Extraction and Recovery of Various Wastewater Contaminants Using Liquid Membrane Techniques." Thesis, 2020. http://ethesis.nitrkl.ac.in/10106/1/2020_PhD_VKumar_512CH104_Extraction.pdf.
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This work demonstrates a systematic investigation on extraction and recovery performances of characteristically different species having environmental and industrial importance in Liquid Membrane (LM) transport. The investigated species were: lignosulfonate (LS), congo red (CR) and methylene blue (MB) dyes, hexavalent chromium and curcumin. One major objective of this work was to use renewable vegetable oils as the LM diluent or solvent (green solvents). In a typical bulk liquid membrane (BLM) experiment, detailed 2 and 3 phase studies were carried out for selection of suitable stripping agent, LM solvent, carrier along with estimation of optimum process conditions like carrier concentration, feed phase pH, feed and strip phase concentrations, phase ratios, temperature and stirring rate to maximize the extraction and recovery percentages of the targeted species. Additionally, kinetic estimation of data for individual species in the BLM transport was conducted. Highest extraction (E) and recovery (R) percentages of LS were measured at 92.4 and 75.2 respectively in sunflower oil/tri-n-octylamine (TOA) system using Na2SO4 of solution strength of 0.2 (M) as the stripping medium. 4 vol.% TOA concentration, feed phase pH~2 at 300 rpm stirring speed and 40oC temperature were the optimum manifold conditions with higher rate constants for stripping ( ) than extraction ( ) process, explaining extraction to be the rate determining step. Between %E and %R of two contrastingly different dyes viz. CR (anionic) and MB (cationic), it was observed that the transport of CR was favored using sunflower oil/TOA (4%) system with Na2CO3 (1 M) as effective stripping medium, leading to 99.9 %E and 75.6 %R. Meanwhile, MB reported a 95.2 %E and 92.4 %R using sunflower oil as solvent, phenol as carrier (1 M) and H2SO4 (1.25 M) as stripping medium. Interestingly, CR preferred a highly acidic feed medium (pH~2) whereas MB transport was effective in an alkaline feed condition (pH~12). BLM separation of hexavalent Cr showed maximum 99.2 %E and 94.8 %R using sunflower oil/TOA (2%) as LM medium and CH3COONa (0.2 M) as stripping medium. curcumin’s (or, Curcuma Longa) transport inside the BLM ensemble was most effective using sunflower oil as the diluent, TOA (4%) as carrier and NaOH (0.75 M) as the stripping agent. The overall %E and %R for curcumin was reportedly 99.7 and 96.5 respectively. Equilibrium distribution time for various investigated species were LS (3 h), CR (8 h), MB (8 h), Cr (VI) (2 h) and curcumin (2 h) 2 k 1 k respectively. The estimated values of activation energies for various species during extraction and recovery processes were: (36.85, 54.79 kJ mol-1) for LS, (45.92, 74.05 kJ mol-1) for CR, (25.87, 36.94 kJ mol-1) for MB, (118.71, 90.68 kJ mol-1) for Cr (VI) and (118.83, 109.54 kJ mol-1) for curcumin respectively. Subsequently, transport of LS and Cr (VI) via supported liquid membrane (SLM) was investigated where sunflower oil/TOA was immobilized on the porous network of hydrophobic polytetrafluoroethylene (PTFE) to be used as the membrane medium. LS reported E and R percentages of 90.7 and 64.2 respectively whereas Cr (VI) reported values of 97.6 (%E) and 94.4 (%R). The results were reproducible even after 12th cycle for Cr (VI) with each cycle lasting of 8 h. However, with LS, the results were reproducible upto 2 cycles (each cycle lasting for 12 h). The SLM were found to be stable for 8 (LS) and 15 (hexavalent Cr) experimental runs with 24 and 16 h between each run respectively. The emulsion liquid membrane (ELM) study with Cr (VI) yielded %E of 99.2 with very short (~ 5 min) equilibrium time. MIL-101 (Cr) metal organic framework (MOF) synthesized microwave route reported exceptionally high specific surface area (ca. 3075 m2g-1) and aqueous phase stability and high adsorptive loading for the targeted species viz. LS and CR. Adsorption sweep experiments showed an overall improvement in extraction percentage of LS from 92% (regular BLM study) to ca. 97%. The recovery percentage of LS was decreased from ca. 75% (regular BLM study) to <10% because of adsorption of LS from bulk stripping medium, leading to an increase in concentration gradient across LM-strip interphase. For CR, adsorption sweep had minimal influence in the overall transport vis-à-vis LS. Favorable chemistry of the stripping medium was found to be important for maintaining suitable pH conditions for the success of adsorption sweep process.
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Saleh, Abdullah. "Study Of The Performance Of Batch Distillation Using gPROMS." Thesis, 2011. http://ethesis.nitrkl.ac.in/2625/1/final_Thesis.pdf.
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The detailed dynamic modelling,and simulation of a batch distillation process is presented. The model considers a mixture of 5 components separated in a 20 tray column. Simulations performed in the process modelling tool gPROMS proved that the model gives a very accurate description of the process behaviour. Overall, gPROMS proved to be a powerful tool for solving problems of large scale models of great complexity such as the batch distillation process. One of the reasons for this is its ability to model and handle discontinuities of the types that very often occurs in chemical processes (for example, when changing the reflux ratio during a distillation operation). As with any other chemical process, the modelling of batch distillation requires the accurate consideration of physical properties in order to model the thermodynamics of the process in an accurate manner.
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Chaluvadi, Suresh. "Studies on Dry and Wet Torrefaction of Sugarcane Bagasse to Maximize the Recovery of Sugars and Bioethanol Yield." Thesis, 2021. http://ethesis.nitrkl.ac.in/10327/1/2021_PhD_SChaluvadi_511CH104_Studies.pdf.
Full textAbstract:
Biomass size disruption is a key operation in the process of ethanol production from lignocellulosic materials since enzymatic saccharification of carbohydrate polymers occurs at the molecular level. Various pretreatments of biomass have been extensively studied for the production of sugars and ethanol. However, torrefaction was less explored in the production of sugars. Dry and wet torrefaction techniques have been employed for the production of solid biofuels for many years. Torrefaction technique has been used widely in increasing energy density, hydrophobicity, grindability, enhancing pore structure, and reducing the cost of transportation. In this work, the effect of dry torrefaction of sugarcane bagasse on the production of sugars and ethanol was studied. Moreover, the optimizations of acid (HCl, H2SO4, H3PO4, and HNO3) and alkali (NaOH, KOH, and NH3OH) impregnated sugarcane bagasse (SB) torrefaction were conducted using response surface methodology. Statistically significant models that can predict yields of total reducing sugars were generated. The dry and wet torrefaction experiments of SB were performed at temperatures of 160 °C, 180 °C, 200 °C and 220 °C and residence times of 20 min, 40 min, and 60 min. The sugarcane bagasse pretreated via dry torrefaction at 200 °C for 20 min was observed to produce the highest glucose yields of 199.62 mg g-1 of biomass (dry basis) after saccharification. Furthermore, the pretreated SB under anaerobic fermentation with supplementation of cysteine hydrochloride was noticed to produce ethanol yield up to 81.85 mg g-1 of biomass (dry basis). Moreover, the ethanol yield represents a 19.34% increase for SB when compared with ethanol yields of untreated biomass fermented under anaerobic conditions with cysteine hydrochloride supplement. Moreover, cysteine hydrochloride supplementation enhances ethanol yields through anaerobic fermentation. The crystallinity and chemical nature of biomass materials were analyzed by SEM, XRD, and FTIR. The sulfuric acid impregnated biomass torrefaction using model generated optimized conditions viz temperature (220 °C), sulphuric acid concentration (0.63%w/w) and residence time (10 min) has produced the highest amount of sugars up to 705 mg g-1 of biomass (dry basis) and ethanol up to 320 mg g-1 of biomass (dry basis).
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Kumar, Akash. "Adsorptive removal of Rhodamine B (dye) using low cost adsorbents." Thesis, 2013. http://ethesis.nitrkl.ac.in/4650/1/211CH1259.pdf.
Full textAbstract:
Dyes are widely used in several industries like textile, dyeing, paper and pulp, tannery, paint industries etc. and these are emitting to environment in the form of liquid effluent, which is a matter of global concern. Their classification can be done based on their usage, group and solubility. Various treatment processes used for the removal of dyes include adsorption, microbial degradation, wet air oxidation, ion exchange etc. Low cost adsorbents are available option for dyes removal from aqueous effluents. However, high cost of commercial adsorbents like activated carbon and others, material are losses during their usage, but by regeneration pose can be a best utilization of costlier adsorbent. Four different adsorbents were self-prepared in laboratory from Aegle marmelos (Bael) Shell, abrus precatorius seed, azadirachta indica (neem) seed and Mahua seed, which are all raw biomass. The adsorbents were characterized for BET surface area, point of zero charge, CHNS, TGA, SEM, FTIR etc. Rhodamine B (RhB) basic dye, removal from the wastewater using adsorbents, activated mahua seed carbon(AMC) and activated neem seed carbon(ANC) among four self-prepared adsorbents. Here batch studies were conducted to evaluate the effect of adsorbent dose, contact time, pH, initial concentration at 25 0C.The equilibrium adsorption data of RhB (dye) on adsorbent were analysed by the Langmuir, Freundlich and Temkin isotherm models. The isotherm data were well described by the Freundlich isotherm model. Pseudo-first-order, pseudo-second-order models were used to analyze the kinetic data obtained at different concentrations. The adsorption kinetics was well described by the pseudo-second-order kinetic model. For RhB-AMC and RhB-ANC system maximum adsorption capacity were found to 39.683 mg/g and 15.152 mg/g respectively at 650C.Adsorption experiment has carried out to show that maximum adsorption and it observed in acidic medium for AMC and basic medium for ANC.
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Rebbavarapu, Sandhyarani. "Simultaneous Production of Antimicrobial Agent (2- hydroxyacetohydrazide) and Phenol Degradation Via Microbial Technology." Thesis, 2020. http://ethesis.nitrkl.ac.in/10174/1/2020_PhD_SRebbavarapu_512CH1006_Simultaneous.pdf.
Full textAbstract:
Toxic pollutants of varying anthropogenic sources have been showing adverse effects on growth and survival of biological systems. Microorganisms play a vital role in the biotransformation of these toxic pollutants to less complex chemical compounds which can be used in various industrial applications. These organisms have been evolved to degrade pollutants in different metabolic pathways, and some of them have adapted to consume these chemicals as either growth supplements or elemental sources. The identification and investigation of such organisms is a great challenge and will be beneficial for recycling of pollutants to useful products, thereby reducing the need for expensive substrates. Phenol degrading organisms were effectively isolated from petroleum-contaminated soil. Based on their resistivity to phenol up to 1500 mg l-1, the bacterial strains were isolated as R1, R2, R3, R4, and R5. Morphological studies showed that most of these organisms as Grampositive, rod-shaped, and aerobic. These five isolated organisms showed maximum similarity with Pseudomonas stutzeri NCG1, Bacillus flexus strain MS14-1, Bacillus thuringiensis strain 2PR56-10, Bacillus anthracis strain IHB B 18197, and Bacillus thuringiensis strain Bt 2 based on 16S rRNA sequencing. Preliminary experimental conditions such as pH, temperature, aeration, inoculum age, and inoculum volume were studied for maximum phenol degrading organisms along with the mixed culture. Under optimized conditions, Gram-negative P. stutzeri (Genbank Ac. No. MG230258) showed the maximum capability to degrade phenol up to 81.8% at 500 mg l-1 initial concentration within 84 h.
Moreover, phenol degradation by Pseudomonas stutzeri was optimized using response surface methodology (RSM) for various parameters viz. pH, temperature, phenol concentration, and yeast extract concentration. Optimized conditions of pH, temperature, and yeast extract concentration were used to determine the kinetic parameters of phenol degradation using various models. The analysis of kinetic data suggests that the Haldane substrate inhibitory model can be used to fit experimental data. Additionally, phenol tolerant Pseudomonas stutzeri produced cis, cis-muconic acid, which is a metabolic intermediate signifying the organism followed ortho pathway. Pseudomonas stutzeri also exhibited antimicrobial activity against Gram-positive bacteria like Bacillus cereus (MTCC 430), Bacillus subtilis (MTCC 1133), etc. The culture medium of Pseudomonas stutzeri containing various metabolites was analyzed using Gas chromatography-mass spectrometry (GCMS), and 2-hydroxyacetohydrazide (HAH) was found to be active antimicrobial substance in the culture medium after 72 h of fermentation. The organism P. stutzeri is capable of producing HAH in the culture medium supplemented with 500 mg l-1 of phenol.
The HAH was purified using silica gel column chromatography by subsequent collection of fractions, and the purified HAH was analyzed using Fourier transform infrared spectroscopy (FTIR). Additionally, the concentration of HAH present in the culture medium was assayed using HPLC and found to be 357 μg ml-1. The action of HAH against B. subtilis (MTCC 1133) was determined using tunneling electron microscopy (TEM) analysis. The minimum inhibitory concentration (MIC) of the HAH was found to be 40 μg ml-1 against B. subtilis (MTCC 1133). The optimum parameters for the production of HAH and degradation of phenol were determined using strain improvement techniques. The resultant strain obtained from strain improvement was employed in a 2-liter batch reactor for phenol degradation and HAH production simultaneously.
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Sriram, Sangeetha. "Fabrication of liquid-repellent Coatings on Cellulosic and Glass Surfaces for Various Industrial Applications." Thesis, 2021. http://ethesis.nitrkl.ac.in/10265/1/2021_PhD_SSriarm_514CH1003_Fabrications.pdf.
Full textAbstract:
One of the foremost fascinating properties of materials in nature is the superhydrophobic and self-cleaning abilities of various insect wings and plant leaves. Superhydrophobic/Ultrahydrophobic surfaces exhibit high water repellence, and oleophobic surfaces resist the wetting of liquids which have low surface tension than water. The present research work focuses on surface modification of numerous types of substrates like cellulose-based materials (e.g., filter paper, cotton fabric) and glass substrates by creating superhydrophobic/superoleophobic and superliquiphobic coatings for the different types of applications such as self-cleaning, oil-water separation, biodegradation, stain-resistance, anti-bio adhesion, and transparency. Silica nanoparticles, polymers, and silanes are starting materials are used to produce superhydrophobic coatings by different synthesis techniques such as solution-casting, dip coating, immersion, etc. To optimize the synthesis process, the material variables such as the concentration of polymer, silanes, and nanoparticles are being varied. The process parameters, like immersion time and ambient temperature, are also being needed to vary.
In this thesis, the superhydrophobic coating was developed on the filter paper surface by using polymethyl methacrylate-co-ethyl acrylate polymer (PMMA) /silica nanoparticles (SiO2) by employing the solution-casting technique. The superhydrophobic filter paper was developed by the solution-casting method using hexadecyltrimethoxysilane (HDTMS)/ SiO2 nanoparticles. The superhydrophobic and superliquiphobic cotton fabric was fabricated with Carnauba wax (C.wax)/HDTMS/SiO2 nanoparticles composite. Superhydrophobic/superoleophobic coating on filter paper surface and superhydrophobic coating on glass surface were fabricated using sol-gel of PMMA, 1H, 1H, 2H, 2H, perfluorooctyltrichlorosilane (PFOTS), and SiO2 nanoparticles by employing the dip-coating technique. The prepared superoleophobic/superliquiphobic surfaces were able to repel liquids with surface energy as low as 27 mN/m.
Different structural characterizations viz., the wettability, surface morphology, surface roughness measurement, functionalization of the materials were evaluated. For industrial and practical applications, superhydrophobic surfaces should last under extreme surroundings. So, the stability and durability of these surfaces were widely and systematically inspected under a sequence of extremely harsh conditions. The coatings were assessed at harsh conditions like annealing at high temperatures (40 - 400 °C), irradiation by UV light, and pH resistance at different alkali and acidic conditions (pH 2 - 13), and mechanical durability by performing water-jet, abrasion, sand abrasion, adhesion, and washing (ultra-sonication) tests.
The contact angles were measured, and it has shown more than 170 ° ± 1.5° on all substrates of filter paper, cotton fabric, and glass surfaces. Additionally, the coated samples exhibit excellent self-cleaning, > 96% separation efficiency was studied of oil-water mixtures and emulsion separations in all prepared filter paper samples and cotton fabric. All the filter papers, viz., uncoated, coated, and tested for the separation process, were shown biodegradation. The coated fabrics were shown stain-resistance, anti-bio adhesion (microbial activity) properties. 93% of the transparency was achieved on the coated glass surface. All the results indicate that such types of coatings could also be used for self-cleaning, oil-water separations, stain-resistance, anti-bio adhesion, and transparent coatings at the industrial level applications.
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Kumar, N. "Experimental Studies on Conversion of Waste Polystyrene to Styrene and Liquid Fuel." Thesis, 2010. http://ethesis.nitrkl.ac.in/1630/1/EXPERIMENTAL_STUDIES_ON_CONVERSION_OF_WASTE__POLYSTYRENE_TO_STYRENE_AND_LIQUID_FUEL_(Nitin_Kumar_%2C_Roll_no_10600024).pdf.
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The degradation of waste polystyrene sample was carried out in the temperature range of 450-575 ‘c by both thermal degradation and by catalytic degradation using SILICA-ALUMINA as catalyst. It was found that liquid product yield increases with increasing temperature in both thermal as well as catalytic degradation till 550’c , afterwards liquid product yield starts decreasing with increasing temperature. In second stage to find out optimum polystyrene : silica-alumina ratio for maximum liquid product yield , catalytic degradation of polystyrene was carried out at 550’c in various proportion, i.e. 20:1 , 15:1 , 10:1 , 5:1 and 4:1. It was found that liquid product yield increases with increasing the ratio of catalyst upto 5:1 and afterwards increasing the catalyst ratio has resulted in decreasing the amount of liquid product. It was also found that styrene was the main constituents of liquid product ,about 86 % , in thermal degradation of polystyrene at 550’c while in catalytic pyrolysis done in 5:1 ratio at the same temperature has only 41 % styrene in the liquid product obtained. This study indicates that mechanism of degradation depends on the temperature of degradation as well as amount of catalyst used for degradation.
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Parma, Sandeep. "Preparation and Characterization of Ceramic Microfiltration Membrane using Red Mud as cost effective resource." Thesis, 2013. http://ethesis.nitrkl.ac.in/5381/1/211CH1255.pdf.
Full textAbstract:
This work highlights the fabrication of ceramic microfiltration membranes using Red mud as the raw material. The raw material was pre-processed and paste casting method was used for fabrication. Two different membranes were successfully fabricated: membrane A and membrane B. Membrane A had a regular stoichiometric composition of red mud and binding agents whereas in case of membrane B, a significant percentage of kaolin was added to prop up the membrane matrix. After initial treatments, both the membranes were sintered at high temperatures e.g. 800 and 900oC respectively. Comprehensive material characterization techniques viz. scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), BET surface area analysis, Thermogravimetric analysis (TGA) and Mercury intrusion porosimetry were followed to ascertain the nature of the membrane fabrication and their inherent material properties. The membranes A and B being sintered at 900oC, reported an average pore size of 10 and 6µm respectively. These membranes were found well suited for oil-water emulsion and clarifying raw sugar cane juice studies. A maximum rejection of 53% was achieved with membrane B in oil-water emulsion studies. In sugar cane juice study as well, membrane B performed superior to its counterpart. The performance was reasonably well and membrane B reported 78% of turbidity and 28% of colour removal. In addition to that purity percentage was increased to 1.7 units. All the membranes were studied for their regeneration and reusability. The role of organic solvents was found to be important along with hot water wash. A detailed cost analysis was also performed and it was seen that the membranes fabricated were much cheaper than the similar products reported in literature.
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Varshney, Priya. "Development of Superhydrophobic Coatings on Metallic Surfaces for Industrial Applications." Thesis, 2019. http://ethesis.nitrkl.ac.in/10137/1/2019_PhD_PVarshney_514CH1002_Superhydrophobic.pdf.pdf.
Full textAbstract:
Recently, several superhydrophobic coatings on metallic surfaces have been developed, but they have not achieved great success in developing on commercial scale. Although these coatings have exceptional properties like self cleaning, anti-corrosive, anti-icing, etc., but these coatings cannot be used successfully in industry due to inability of complete mechanical, chemical and thermal stability data. Therefore, the main challenge is to create cheap, excellent adhesively, environmentally safe, durable, regenerative superhydrophobic coatings on various metallic surfaces. In the current work, various superhydrophobic coatings on metallic surfaces (aluminum, steel, copper, and steel mesh) for various industrial applications were synthesized by simple immersion technique.Superhydrophobic coatings on aluminium surfaces were synthesized using two-step and one-step processes. By using two-step process, two different superhydrophobic coatings were prepared using etchants such as KOH and HCl+HNO3 solutions independently and then by immersion in lauric acid solution for lowering surface energy. One-step process was used to synthesize superhydrophobic coating by immersing aluminium sample in a mixture of KOH etchant and lauric acid solution. Superhydrophobic coatings on steel and steel mesh surfaces were synthesized using two-step process. For the fabrication, first roughness was created by immersing in etchant (HCl+HNO3) and then by dipping the roughened surface in lauric acid low surface energy surface was created. Superhydrophobic coatings on copper surfaces were synthesized using two-step and one-step processes. In this case, after the creation of roughness and lowering the surface energy, the same chemicals were used. For each case, effects of process parameters like etching time and immersion time in lauric acid are studied. The result reveals that surface roughness and water contact angle increase with etching and immersion time. After fabrication, mechanical, thermal, and chemical stability tests were performed to identify the operating range. The SEM studies reveal the presence of a rough micropattern on the treated surfaces and the contact angle measurements confirm the superhydrophobicity. The water droplet dynamics study reveals that the water droplet with low impact velocity bounces from the surface. At critical impact velocity, pinning of water droplet is observed. Splashing of water droplet is observed beyond the critical impact velocity. Furthermore, the coated sample remains in floating condition on the water surface for several weeks, showing excellent water-repellent nature. Coated surface bounces off the high speed water jet stream and then still no change in superhydrophobicity is found. This behaviour confirms the excellent mechanical properties of the coatings. In addition to the above, it is observed that mechanical disturbances due to surface bending and repeated folding and de-folding do not have much effect on the superhydrophobicity. Mechanical durability of coatings was also evaluated by performing adhesive tape peeling and sand paper abrasion tests for the confirmation and quantification of the durability of coatings.
In chemical stability test, superhydrophobic nature remains unaffected after several days of immersion in NaCl solution and shows the excellent chemical stability of coating. Thermal stability of coatings was evaluated by annealing samples in temperature range 40 - 250 °C for one-hour period in hot air oven. It is found that superhydrophobicity of most of the coated samples remains unaffected after annealing in temperature range 40 - 140 °C, and this is considered as the excellent thermal stability of coatings. Coatings are found to be fully damaged after 24 hours annealing at 300 °C and superhydrophobicity of surface turns into superhydrophilicity. However, wettability of the surfaces can be restored by simple immersing the samples again in lauric acid solution. The analysis reveals that superhydrophobicity of the coatings is regained.
Self-cleaning property of the fabricated superhydrophobic aluminium, steel, and copper surfaces was studied. Coating shows the excellent self-cleaning property. No accumulation of moisture from air on the cooled superhydrophobic aluminium, steel, and copper surfaces is observed and this asserts the excellent anti-fogging property of coatings. By electrochemical tests, it is demonstrated anti-corrosion property of coating with low corrosion current density and high corrosion potential. For the replication of industrial applications in laboratory, petroleum ether-water and benzene-water mixtures which are oil-water mixtures were successfully separated from each other by a simple filtration method using the superhydrophobic steel mesh with the separation efficiency above 99%. Oil-water separation using the coated steel mesh is simple, fast, and repeatable for at least 10 times. The aforesaid durable and regenerable superhydrophobic metallic surfaces have potential industrial applications.
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Biswas, Ritam. "Removal of methylene blue dye using oil cake (karanja)." Thesis, 2013. http://ethesis.nitrkl.ac.in/5303/1/109CH0468.pdf.
Full textAbstract:
The feasibility of karanjia oil cake as a precursor for the preparation of activated carbon for the removal of methylene blue was investigated. The effect of various factors such as contact time, temperature, solution pH, amount of adsorbent and the initial dye concentration, was studied. The experimental data were analysed by the Freundlich and Langmuir isotherm models. The adsorption isotherm obtained was described accurately by both the isotherms. The maximum removal of methylene blue was found to be 91.62 %.Two simplified kinetic models, pseudo-first-order and pseudo-second-order equation were selected to follow the adsorption processes. Kinetic studies showed that the adsorption followed pseudo-second order kinetic model. The results in the study indicate that the activated carbon prepared from karanjia oil cake could be used for the removal of methylene blue from aqueous solution.