Добірка наукової літератури з теми "Ferric Order Parameters - Ferroelasticity"

The adsorption mechanisms for model hydrocarbons, 4-nitrophenol (PNP), and naphthalene were studied in a coagulation-based process using a ferric sulfate–lime softening system. Kinetic and thermodynamic adsorption parameters for this system were obtained under variable ionic strength and temperature. An in situ method was used to investigate kinetic adsorption profiles for PNP and naphthalene, where a pseudo-first order kinetic model adequately described the process. Thermodynamic parameters for the coagulation of PNP and naphthalene reveal an endothermic and spontaneous process. River water was compared against lab water samples at optimized conditions, where the results reveal that ions in the river water decrease the removal efficiency (RE; %) for PNP (RE = 28 to 20.3%) and naphthalene (RE = 89.0 to 80.2%). An aluminum sulfate (alum) coagulant was compared against the ferric system. The removal of PNP with alum decreased from RE = 20.5% in lab water and to RE = 16.8% in river water. Naphthalene removal decreased from RE = 89.0% with ferric sulfate to RE = 83.2% with alum in lab water and from RE = 80.2% for the ferric system to RE = 75.1% for alum in river water. Optical microscopy and dynamic light scattering of isolated flocs corroborated the role of ions in river water, according to variable RE and floc size distribution.

The effect of zinc sulfate and ferric sulfate on the pyrolysis process of lignin was studied at three different heating rates by using the thermogravimetric analysis technique. It was found that the pyrolysis of pure lignin is barely affected with the change of heating rates between 10 to 100 °C/min, which is unexpected because of the kinetic nature of pyrolysis. The pyrolysis kinetics of this major component of biomass was studied by using three fitting methods: the differential method with reaction order model n, the isoconversional method, and the distribution of activation energies model, DAEM. The best fit, which allowed calculating acceptable kinetic parameters, was obtained using the last method. The results show the influence of the catalysts and the heating rate on the lignin pyrolysis processes in the presence of the sulfates under study, which is confirmed by obtaining different kinetic parameters. The results suggest that zinc sulfate and ferric sulfate change the kinetic mechanism of lignin pyrolysis.

In order to nondestructively characterize chemical forms of ferric hydroxides in weathered rock, charge-coupled device type visible microspectroscopy was applied to brown stains produced in weathered granite surfaces. The combination of visible microspectra and color parameters ( a* and b*) was effective in examining chemical forms of ferric hydroxides in the analytical area. Color parameters in an a*– b* diagram of the brown stains, mostly lying between goethite and ferrihydrite trends, indicated that the brown stains contain ferrihydrite or hematite in addition to goethite. Similarity of the visible microspectra of the brown stains and their first derivatives to those of goethite or ferrihydrite suggests that goethite and/or ferrihydrite are the main weathering products of the granite. Occurrence of ferrihydrite as well as goethite in the brown stains implies that crystallization of ferrihydrite to goethite might be hindered during the granite weathering. This fact suggests the possibility of toxic metal retention in ferrihydrite by its long-term persistence during water–rock interactions at the earth's surface.

Significant concerns have been raised over the presence of antibiotics including sulfadimethoxine (SDMO) in aquatic environments. This study investigated the removal capability and mechanism involved in the removal of SDMO by hydrous ferric oxides (HFO). Results showed that SDMO removal was highly pH and ionic strength dependent. The pseudo-first-order model fitted well the kinetic results, and the value of the calculated activation energy for SDMO adsorption onto HFO was 8.6 kJ mol−1. Adsorption isotherms at varied temperatures were well described by the Langmuir model. Thermodynamic parameters (change in enthalpy > 0, change in entropy > 0, and change in Gibbs free energy < 0) calculated from the temperature-dependent sorption data revealed spontaneous and endothermic process. The exchange of the surface hydroxyl groups of HFO and the negative anions of SDMO− and the electrostatic interaction between the positively charged surface of HFO and the deprotonated imino (–N−–) accounted for the uptake of SDMO by HFO.

The goal of this study was to assess the sustainability of a modified cellulose nanofiber material for the recovery of precious gold from chloride solution, with a special focus on gold recovery from acidic solutions generated by cupric and ferric chloride leaching processes. TEMPO-oxidized cellulose nanofiber in hydrogel (TOCN), dry (H-TOCN, F-TOCN) and sheet form (S-TOCN) was examined for gold adsorptivity from chloride solution. Additionally, this work describes the optimum conditions and parameters for gold recovery. The data obtained in this investigation are also modeled using kinetic (pseudo first-order and pseudo second-order), isotherm best fit (Freundlich, Langmuir and Langmuir-Freundlich), and thermodynamic (endothermic process) parameters. Results demonstrate that high levels of gold removal can be achieved with TEMPO-oxidized cellulose nanofibers (98% by H-TOCNF) and the interaction characteristics of H-TOCN with gold suggests that other precious metals could also be efficiently recovered.

Barium titanate BaTiO3 (BTO) - barium hexaferrite BaFe12O19 (BHF) nanocomposite could be as a raw material of multiferroic. Multiferroic is a class of materials with coupled electric, magnetic and structural order parameters that yield simultaneous effects of ferroelectric, ferromagnetism and ferroelasticity in the same material. This material has potential applications in such as spintronic devices and sensors. This work was an earlier research towards formation of multiferroic material. Knowing magnetic properties that will lead to a better understanding of magnetoelectric coupling in multiferroic material is the objective of this research.The samples were BTO and BHF prepared by sol-gel and then were mixed to synthesize composite in bulk system by a conventional techniques in various of weight fraction between BTO : BHF = 1:1 ; 1:2 and 1:3, then samples were sintered at 925°C for 5, 10 and 15 hours for each fraction respectively. Composite phase study was carried out using X-Ray Diffraction (XRD). MPS Magnet Physik EP3 Permagraph L was used to characterize magnetic properties. No residual phases were identified in the XRD analysis for all parameters. The peaks can be only indexed to BaTiO3 and BaFe12O19 phases for all parameters respectively confirming the formation of a BaTiO3-BaFe12O19 composite system. Barium titanate retains its tetragonal structure while barium hexaferrite exhibits hexagonal structure. For weight fraction of BaFe12O19 until 2 parts there is an increase of intrinsic coersive and saturation magnetization value. The maximum values of intrinsic coersive for samples with 5, 10 and 15 hours sintering are of 361.3 kA/m, 359.0 kA/m and 391.6 kA/m respectively and the maximum values of saturation are of 0.1515 T, 0.1516 T and 0.1414 T respectively leading to good characteristics of multiferroic materials.

The iron-modified Dalbergia sissoo sawdust was synthesized by loading iron (III) onto phosphorylated Dalbergia sissoo sawdust via soaking in a ferric salt solution. Batch studies were performed at an initial concentration of 1 mg/l to evaluate the effect of parameters such as pH, equilibrium time, adsorbent dose and concentration of adsorbate. Kinetics and isotherm modeling studies demonstrated that the experimental data best fit a pseudo-first order and Langmuir isotherm model, respectively. The maximum adsorption capacity was found to be 1.33 mg/g for As(III) onto FePDSD suggesting the suitability of chemically modified Dalbergia sissoo sawdust for the adsorptive removal of As(III) from aqueous solution.Journal of Institute of Science and Technology, 2014, 19(1): 150-154

Nanoparticles, by virtue of their amorphous nature and high specific surface area, exhibit ideal pozzolanic activity which leads to the formation of additional C-S-H gel by reacting with calcium hydroxide, resulting in a denser matrix. The proportions of ferric oxide (Fe2O3), silicon dioxide (SiO2), and aluminum oxide (Al2O3) in the clay, which interact chemically with the calcium oxide (CaO) during the clinkering reactions, influence the final properties of the cement and, therefore, of the concrete. Through the phases of this article, a refined trigonometric shear deformation theory (RTSDT), taking into account transverse shear deformation effects, is presented for the thermoelastic bending analysis of concrete slabs reinforced with ferric oxide (Fe2O3) nanoparticles. Thermoelastic properties are generated using Eshelby’s model in order to determine the equivalent Young’s modulus and thermal expansion of the nano-reinforced concrete slab. For an extended use of this study, the concrete plate is subjected to various mechanical and thermal loads. The governing equations of equilibrium are obtained using the principle of virtual work and solved using Navier’s technique for simply supported plates. Numerical results are presented considering the effect of different variations such as volume percent of Fe2O3 nanoparticles, mechanical loads, thermal loads, and geometrical parameters on the thermoelastic bending of the plate. According to the results, the transverse displacement of concrete slabs subjected to mechanical loading and containing 30% nano-Fe2O3 was almost 45% lower than that of a slab without reinforcement, while the transverse displacement under thermal loadings increased by 10%.

Barium titanate BaTiO3 (BTO) - barium hexaferrite BaFe12O19 (BHF) nanocomposite could be as a raw material of multiferroic. Multiferroic is a class of materials with coupled electric, magnetic and structural order parameters that yield simultaneous effects of ferroelectric, ferromagnetism and ferroelasticity in the same material. This material has potential applications in such as spintronic devices and sensors. This work was an earlier research towards formation of multiferroic material. Knowing magnetic properties that will lead to a better understanding of magnetoelectric coupling in multiferroic material is the objective of this research.The samples were BTO and BHF prepared by sol-gel and then were mixed in bulk system by a conventional techniques in various of volume fraction between BTO : BHF = 1:1 ; 1:2 and 2:1, then samples were sintered at 925°C for 5, 10 and 15 hours. Composite phase study was carried out using X-Ray Diffraction (XRD). MPS Magnet Physik EP3 Permagraph L was used to characterize magnetic properties. XRD results confirm that composite with volume fraction of BTO : BHF = 1:1 with sintering at 925°C for 5 hours consists only of 2 phases BTO and BHF. There is impurity phase BaFe2O4 beside BTO and BHF phases at samples with volume fraction BTO:BHF = 1:2 and 2:1 for longer sintering. Composite with volume fraction of BTO:BHF = 1:1 for 5 hours sintering has a high value of remanent magnetization 0.081 T and the lowest value of intrinsic coersive 333.6 kA/m leading to good characteristics of multiferroic materials.

The physico-chemical process of coagulation-flocculation is very efficient and economical for the treatment of leachate. The latter can have considerable impacts on the environment. The leachate from the landfill of the city of Mohammedia is characterized by a high COD content which varies between 2200 and 2700 mg/l, a total Kjeldahl nitrogen concentration varying from 1080 to 1405 mg/l while the ammonium content has a concentration varying between 587 and 1410 mg/l. Organic matter is not readily biodegradable (BOD5/COD: 0.2 to 0.13). Metal concentrations ranged from 0.1 to 4.2 mg/l for Cr, 40 to 5 mg/l for Cd, and 0.3 to 0.8 mg/l for lead. For monitoring the leachate treatment, several coagulants and flocculants were used (FeCl3, Al2(SO4)3, Alginate, cationic flocculants, anionic flocculants). In parallel with the monitoring of the physicochemical parameters we followed the production of the volume of the settled sludge over time. Treatment with all coagulants and flocculants used is pH dependent. Ferric Chloride has been shown to be effective at a pH of 6.5 while for Aluminum Sulfate the optimum pH is 5.3. The results showed that coagulation-flocculation by Ferric Chloride and Aluminum Sulfate is very effective in reducing turbidity. This reduction reaches 95 and 98% respectively for FeCl3 and Al2(SO4)3, while the reduction in COD for the two coagulants is around 60%. Organic flocculants alone do not lead to a significant reduction in turbidity and COD, while their combination with coagulants marks a good reduction in pollution. Hydrated iron hydroxides precipitate more easily than flocs formed by aluminum, resulting in more efficient removal of pollutants than that obtained at lower pH values. The order of introduction strongly influences the coagulation flocculation. The optimal doses of the various coagulants and flocculants chosen for the study vary from one reagent to another. FeCl3 remains the most suitable coagulant to further eliminate organic and metal pollution. The cost associated with the treatment using flocculants remains much higher when the flocculant is used in admixture with a coagulant.

The solid particle erosion (SPE) of flow passage is a universal problem in modern high-parameter steam turbines. With the continuous improvement of the working parameters of the steam turbine, the problem of SPE is becoming more serious. This problem is caused by the ferric oxide exfoliations carried by steam from the inner wall of the boiler tube into the steam turbine flow passage, causing the stator blades, the rotor blades, and the shroud to be eroded under impingement and scuffing failure. The SPE cannot only destroy the blade profile, increase the roughness of the blade surface, and affect the aerodynamic performance of the blade, but it can also shorten the maintenance cycle, prolong the maintenance downtime, and even increase the cost for steam turbine maintenance thereby reducing the unit efficiency and safety. In order to simulate SPE in the governing stage of a high-parameter steam turbine, this study adopts the Lagrange method and the Finnie erosion model. The motion characteristics of five different kinds of solid particle, including the solid particle trajectory, are thoroughly analyzed. The regulation of the erosion distribution in the radial and axial directions to the stator and rotor blades is studied to present the mechanism of SPE. Simulated results show that before their collision with the blades, the particles of the small diameters flow with the main stream, and their trajectories are close to the steam streamlines. By contrast, the particles of the large diameters are hardly influenced by the external factors, and their trajectories are close to the straight line. The SPE distribution of the stator and rotor blades varies with the particle diameter. The eroded area in the stator blade is mainly located at the leading edge and the pressure surface, particularly the mid-rear part of the pressure surface, whereas no eroded area can be observed in the suction surface. The small particles greatly affect the erosion distribution of the stator blade. The eroded area in the rotor blade is primarily at the mid-rear part of the pressure surface and the suction surface, which is close to the leading edge. The eroded area takes on a typical slop shape, and the erosion position has an obvious upward trend. The proposed research reveals both the motion characteristics of the solid particles and the distribution regulation of the SPE in the steam turbine flow passage. The analysis results provide references for the governing stage of a high-parameter steam turbine to prevent SPE.

The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.