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1
Litynska, Marta, Tetiana Dontsova, Olena Yanushevska e Volodymyr Tarabaka. "Development of iron-containing sorption materials for water purification from arsenic compounds". Eastern-European Journal of Enterprise Technologies 2, n. 10 (110) (30 aprile 2021): 35–42. http://dx.doi.org/10.15587/1729-4061.2021.230216.
Testo completoAbstract (sommario):
The paper is devoted to the development of a method for obtaining and using iron-containing sorption materials for the effective removal of arsenic compounds of different oxidation states from an aqueous medium. It is known that arsenic compounds have a harmful effect on biota due to high toxicity. The paper theoretically and experimentally substantiates the choice of iron-containing materials as the main sorbent material for arsenic compounds removal from the aqueous medium. A series of iron-containing adsorbents, including powder, activated carbon-based granular and suspension sorbents, was synthesized by different methods (heterogeneous and homogeneous precipitation). Experimental studies have confirmed that the adsorption of arsenate ions on iron-containing sorption materials corresponds to the pseudo-second order of the reaction (R2=0.999), which is inherent in adsorption processes. It was determined that oxyhydroxide sorption materials obtained by the homogeneous precipitation demonstrate higher sorption activity (up to 70 mg/g for As(III) and over 70 mg/g for As(V)). It was found that activated carbon-based iron-containing sorption materials showed approximately 2 times lower efficiency than powder iron(III) oxide, iron(III) oxyhydroxide and amorphous iron(III) hydroxide. It was shown that the use of microfiltration membranes is promising for the removal of spent suspension iron-containing sorption materials. Experimental studies have confirmed that the use of the combination “fine-particle iron(III) oxyhydroxide/membrane” allows removing arsenic compounds from contaminated water to the sanitary requirements level (less than 10 μg As/l) and separating effectively the spent fine-particle sorbent from water
2
Dave, Pragnesh N., e Lakhan V. Chopda. "Application of Iron Oxide Nanomaterials for the Removal of Heavy Metals". Journal of Nanotechnology 2014 (2014): 1–14. http://dx.doi.org/10.1155/2014/398569.
Testo completoAbstract (sommario):
In the 21st century water polluted by heavy metal is one of the environment problems. Various methods for removal of the heavy metal ions from the water have extensively been studied. Application of iron oxide nanaparticles based nanomaterials for removal of heavy metals is well-known adsorbents for remediation of water. Due to its important physiochemical property, inexpensive method and easy regeneration in the presence of external magnetic field make them more attractive toward water purification. Surface modification strategy of iron oxide nanoparticles is also used for the remediation of water increases the efficiency of iron oxide for the removal of the heavy metal ions from the aqueous system.
3
Belova, Larisa, Alexandr Zhulin e Olga Sidorenko. "Degassers in drinking water supply". E3S Web of Conferences 135 (2019): 01030. http://dx.doi.org/10.1051/e3sconf/201913501030.
Testo completoAbstract (sommario):
In the Tyumen region, groundwater is widely used for household and drinking water supply, the chemical composition of which is influenced by the increased marshland and peat resistance of soils and, in some cases, the presence of oil and gas-bearing horizons. Underground water typically has a high content of dissolved organic impurities (permanganate oxidability 11.7 - 23.0 mg/dm3), elevated concentrations of free carbon dioxide (20.0 200.0 mg/dm3), hydrogen sulfide (0.20 - 1.95 mg/dm3) and methane (5.3 - 60.0 mg/dm3), dissolved forms of iron (1.14 - 14.00 mg/dm3), manganese (0.02 - 3.80 mg/dm3). Analysis of iron removal plants operation was performed. Analysis of the region's iron removal plants showed that the process of iron removal of water depends on the degree of saturation of water with air oxygen with parallel removal of dissolved gases. Pre-degassing of water with high efficiency degassers is a necessary link of the process chain even when reagent purification techniques are used. Analysis and systematization of existing degassers to remove dissolved carbon dioxide have shown that despite the high-efficiency of some degasser models, they are complex in design and require considerable capital construction and operation costs. There is a need to develop a design not complicated in design, having high degassing efficiency at low economic costs.
4
Hu, Feng Ping, Wei He, Chao Chun Tang e Lv Zhong. "Purification Efficiency Study of Biological Treatment of Iron and Manganese for Groundwater". Advanced Materials Research 599 (novembre 2012): 383–86. http://dx.doi.org/10.4028/www.scientific.net/amr.599.383.
Testo completoAbstract (sommario):
The purification efficiency of biological removal of iron and manganese was probed by pilot tests. In this experiment, the raw water were iron concentration of 0.96~5.56 mg/L, manganese concentration of 0.87~2.38 mg/L, dissolved oxygen of 2~4 mg/L, pH value neutral. In the condition of filter speed of 6 m/h, the average removal rate of iron and manganese reached 97.6% and 90.9% respectively, the effluent concentration of Fe2+ and Mn2+ were keep in below 0.1 mg/L.
5
Zhytsianiou, Barys N., e Lyudmila E. Yordanova. "Backwash water treatment by coagulation in the presence of phosphates at underground water iron removal stations". Vestnik MGSU, n. 4 (aprile 2020): 553–68. http://dx.doi.org/10.22227/1997-0935.2020.4.553-568.
Testo completoAbstract (sommario):
Introduction. The analysis of the present-day condition of water resources has proven the relevance and expediency of developing highly effective backwash water treatment methods to be used at iron removal stations designated for groundwater treatment. In accordance with effective technical regulations, backwash water must be reused. The operation of iron removal stations has proven the inefficiency of backwash water treatment facilities. Water and wastewater treatment companies stop using backwash water treatment facilities and refrain from reusing backwash water. Highly concentrated iron-bearing backwash water is discharged into sewage networks, nearby water bodies or onto the terrain, which means irrational use of high-quality groundwater and environmental pollution with iron compounds.
Materials and methods. The results of experimental research efforts and statistical processing of data on the qualitative and quantitative composition of backwash water at iron removal stations are presented. The chemical nature of the components and the principle underlying the formation of the backwash water composition in the process of groundwater deferrization have been studied. It’s been identified that if backwash water supplied by iron removal stations is treated by sodium phosphate reagent Na3PO4 and aluminum sulphate Al2(SO4)3 as a coagulant, precipitation of iron compounds intensifies, as colloidal particles FePO4 are formed. They have very low solubility, and they are effectively removed by coagulation. It has been theoretically proven and experimentally confirmed that anions H2 PO4– and PO4 3– fformed in the process of hydrolysis of sodium phosphate Na3PO4 help to reduce the electrokinetic charge of the colloidal particle of iron hydroxide Fe(OH)3, and high purification efficiency reaching 99.0–99.9 % is attained by attaching iron compounds to the surface of the colloidal particle of aluminum hydroxide Al(OH)3.
Conclusions. The co-authors have developed a math-and-stats model simulating the backwash water treatment process that employs coagulation in the presence of phosphates. It describes the dependence between the concentration of residual iron, doses of sodium phosphate Na3PO4, aluminum sulphate Al2(SO4)3 and the settling time. A backwash water treatment technology has been developed. It employs coagulation in the presence of phosphates, and it is designated for use at iron removal stations. This technology comprises a chemical plant for sodium phosphate and aluminum sulphate used as a coagulant, a post-treatment filter, and sludge dewatering facilities. The application of this technology enables to reduce iron concentration to 0.05–0.20 mg/l, to reuse backwash water for drinking and other household purposes, or to have this water reused by iron removal stations, this, preventing pollution of water sources with iron compounds.
6
Jordanowska, Joanna, e Monika Jakubus. "Evaluation of Effectiveness Technological Process of Water Purification Exemplified on Modernized Water Treatment Plant at Otoczna". Civil And Environmental Engineering Reports 13, n. 2 (10 dicembre 2014): 49–62. http://dx.doi.org/10.2478/ceer-2014-0014.
Testo completoAbstract (sommario):
Abstract The article presents the work of the Water Treatment Plant in the town of Otoczna, located in the Wielkopolska province, before and after the modernization of the technological line. It includes the quality characteristics of the raw water and treated water with particular emphasis on changes in the quality indicators in the period 2002 -2012 in relation to the physicochemical parameters: the content of total iron and total manganese, the ammonium ion as well as organoleptic parameters(colour and turbidity). The efficiency of technological processes was analysed, including the processes of bed start up with chalcedonic sand to remove total iron and manganese and ammonium ion. Based on the survey, it was found that the applied modernization helped solve the problem of water quality, especially the removal of excessive concentrations of iron, manganese and ammonium nitrogen from groundwater. It has been shown that one year after modernization of the technological line there was a high reduction degree of most parameters, respectively for the general iron content -99%, general manganese - 93% ammonia - 93%, turbidity - 94%. It has been proved, that chalcedonic turned out to be better filter material than quartz sand previously used till 2008. The studies have confirmed that the stage of modernization was soon followed by bed start-up for removing general iron from the groundwater. The stage of manganese removal required more time, about eight months for bed start-up. Furthermore, the technological modernization contributed to the improvement of the efficiency of the nitrification process.
7
Jung, Sunyu, e Soon-Ho Park. "Characteristics of iron oxide rust prepared by peracetic acid and its removal of heavy metals in water". E3S Web of Conferences 158 (2020): 04005. http://dx.doi.org/10.1051/e3sconf/202015804005.
Testo completoAbstract (sommario):
Fe2O3 is an especially promising material for water purification as it shows high heavy metal adsorption capacity. However, the high cost of commercial Fe2O3 makes it difficult to be widely used in developing countries. Herein, we probe the heavy metal removal performance of iron oxide rust. Rust was grown on iron nails in a controlled manner using peracetic acid (CH3CO3H), a safe and environment-friendly oxidizer. Arsenic was selected as an example of a heavy metal contaminant in this study. XRD and EDS analysis revealed that the iron oxide prepared with peracetic acid was nearly amorphous Fe2O3. Amorphous iron oxide is reported to show higher reactivity than crystalline iron oxide. The BET specific surface area of prepared Fe2O3 is 71 m2/g, which is larger than that of commercial Fe2O3, and the average pore diameter is 73 Å. Oxidized nails are highly effective for removing heavy metals: about 90% of 1ppm arsenic in water was removed at the residence time of 20 minutes, and the removal rate of 90% is maintained after 10 back-to-back arsenic removal experiments at the same residence time. Iron oxide prepared in this study can remove, per 1 cm2, up to 0.114 mg of arsenic.
8
Nkurunziza, T., J. B. Nduwayezu, E. N. Banadda e I. Nhapi. "The effect of turbidity levels and Moringa oleifera concentration on the effectiveness of coagulation in water treatment". Water Science and Technology 59, n. 8 (1 aprile 2009): 1551–58. http://dx.doi.org/10.2166/wst.2009.155.
Testo completoAbstract (sommario):
Laboratory experiments were carried out to assess the water purification and antimicrobial properties of Moringa oleifera (MO). Hence different concentrations (25 to 300 mg/L) were prepared from a salt (1 M NaCl) extract of MO fine powder and applied to natural surface water whose turbidity levels ranged from 50 to 450 NTU. The parameters determined before and after coagulation were turbidity, pH, colour, hardness, iron, manganese and Escherichia coli. The experiments showed that turbidity removal is influenced by the initial turbidity since the lowest turbidity removal of 83.2% was observed at 50 NTU, whilst the highest of 99.8% was obtained at 450 NTU. Colour removal followed the same trend as the turbidity. The pH exhibited slight variations through the coagulation. The hardness removal was very low (0 to 15%). However, high removals were achieved for iron (90.4% to 100%) and manganese (93.1% to 100%). The highest E. coli removal achieved was 96.0%. Its removal was associated with the turbidity removal. The optimum MO dosages were 150 mg/L (50 NTU and 150 NTU) and 125 mg/L for the rest of the initial turbidity values. Furthermore all the parameters determined satisfied the WHO guidelines for drinking water except for E. coli.
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Szatyłowicz, Ewa, e Iwona Skoczko. "Magnetic Field Usage Supported Filtration Through Different Filter Materials". Water 11, n. 8 (31 luglio 2019): 1584. http://dx.doi.org/10.3390/w11081584.
Testo completoAbstract (sommario):
Currently, methods of water purification and aqueous solutions leading to effective reduction of introduced chemical compounds into water purification systems have become the subject of research. Physical methods have become an alternative, because by subjecting water and aqueous solutions to UV (ultraviolet) radiation or magnetic fields (MF), either ultrasonic or electric, it is possible to influence the change of structure, which results in changes in the properties of water and aqueous solutions. This paper attempts to verify the influence of a weak magnetic field on the removal of iron and manganese compounds in the filtration process on gravel of 1–2 mm granulation, sand of 0.4–0.8 mm granulation, activated alumina and activated carbon. The conducted research proved that MF has a significant influence on the effectiveness of iron and manganese removal from water in the case of alumina, while in the filtration process through other filter materials the effect of MF was small.
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Albrektienė, Ramunė, e Dainius Paliulis. "Investigation of Lead Removal from Drinking Water Using Different Sorbents". Ecological Chemistry and Engineering S 27, n. 1 (1 marzo 2020): 67–82. http://dx.doi.org/10.2478/eces-2020-0004.
Testo completoAbstract (sommario):
AbstractLead is a heavy metal with strong toxic properties. This chemical element is found in wastewater and sometimes in drinking water. The article deals with the removal of lead(II) ions from polluted water using a sorption process to determine the most effective sorbent for the removal of lead(II) ions. Three sorbents were used in the research: clay, sapropel, and iron sludge. All three sorbents investigated reduce the concentration of lead(II) ions in water: clay efficiency was of 65.7–90 %, sapropel of 94.3–100 %, and iron sludge of 84.3–97 %, depending on sorbent type and contact duration. The research has shown that the most effective way to remove lead(II) ions from the test water is sapropel. Using different amounts of sapropel (1, 2, 3, 4, 5, 6 g/dm3 and 0.1, 0.2, 0.4, 0.5, 0.6, 0.8 g/dm3) and different duration of contact (30, 60, 90, 120 and 150 minutes), the concentration of lead(II) ions in the test water after purification did not exceed the permissible values for drinking water (10 μg/dm3), so that the lowest sapropel content of 0.1 g/dm3 can be used for sorption. Lead(II) ions are most effectively removed when contact time is 30 min.
11
Verma, Lal Ji, Pramod Kumar Singh e Saurav Ambastha. "Heavy Metal Removal from Domestic Wastewater Employing Live Eichhornia Crassipes". SAMRIDDHI : A Journal of Physical Sciences, Engineering and Technology 9, n. 01 (25 giugno 2017): 47–50. http://dx.doi.org/10.18090/samriddhi.v9i01.8337.
Testo completoAbstract (sommario):
This study uses naturally growing water hyacinth for wastewater purification system, this is an alternative technique of heavy metal remediation. These plants enhance the removal of pollutants by consuming part of them in the form of the plant nutrients. The vascular plants cultured in such treatment system perform several functions, including assimilation and storing contaminates, transporting O2 to root zone, and providing a substrate for microbial activity, canal containing floating macrophytes. This applies to municipal wastewater, in particular, where treatment units of different size can be applied at the pollution source and consumes less energy for the running. The effectiveness of wastewater purification by different plants was tested on laboratory and pilot scales. The aquatic plants system offers an environmentally friendly and cost effective technology, which have been used for removing Cadmium, Iron and Copper from wastewater. Batch experiments verified that the plants are capable of decreasing all tested indicators for water quality to levels that permit the use of purified water for irrigation, which poses serious problems in various locations throughout the country. It is shown that mixture of wastewater from in front of Gautam Budha University canal/ Greater Noida’s canal wastewater and Galgotias University sewage treatment plants. The removal efficiency of the Cadmium, Iron and Copper is 74.52%, 75.31% and 67.75% in greater Noida’s canal and 73.72%, 74.99 % and 68.37% in Galgotias University’s wastewater respectively.
12
Hongve, D., J. Baann, G. Becher e O. A. Beckmann. "Experiences from Operation and Regeneration of an Anionic Exchanger for Natural Organic Matter (NOM) Removal". Water Science and Technology 40, n. 9 (1 novembre 1999): 215–21. http://dx.doi.org/10.2166/wst.1999.0480.
Testo completoAbstract (sommario):
Anionic exchange is an alternative to traditional drinking water purification processes when the main problem is a high concentration of natural organic matter (NOM) in the raw water. A few treatment plants employing anionic exchange have recently been installed in Norway. Some of these have after some time experienced increasing colour of the processed water. In the present study we show that the resin selectively adsorbs fulvic acid from the water while colloidal aggregates of humic substances and iron, which also contributes to the water colour, are nearly unaffected by the treatment. The treatment efficiency is successively reduced as the resin becomes fouled with iron from the raw water. Resin cleaning with hydrochloric acid had little effect, while treatment with a sodium dithionite solution resulted in full recovery of the treatment efficiency.
13
Karthikeyan, M., e S. Vijayachitra. "A Novel Experimental Study and Analysis of Electrocoagulation Process for Textile Wastewater Treatment using Various Sensors with Integration of IoT Monitoring System". Journal of New Materials for Electrochemical Systems 24, n. 2 (30 giugno 2021): 95–102. http://dx.doi.org/10.14447/jnmes.v24i2.a06.
Testo completoAbstract (sommario):
One of the basic requirements of living beings is water. Due to globalization, industries consume large amount of water and creates shortage of pure water. In addition, they pollute the existing fresh water resources. Therefore, it is essential to design an effective wastewater purification system. Electrochemical method namely, electrocoagulation paves the way for an effective wastewater purification system. This research focuses on the study and analysis of the textile wastewater purification, using electrocoagulation process. This novel experimental study and analysis was carried out using iron, aluminium and mild steel electrodes for batch, modified batch and continuous process respectively. In these electrocoagulation processes, three major parameters such as colour, turbidity and pH were sensed and monitored using IoT. Colour and Turbidity Removal efficiency were also calculated, which gives satisfying results.
14
Świderska-Dąbrowska, Renata, Krzysztof Piaskowski e Paweł K. Zarzycki. "Preliminary Studies of Synthetic Dye Adsorption on Iron Sludge and Activated Carbons". Journal of AOAC INTERNATIONAL 101, n. 5 (1 settembre 2018): 1429–36. http://dx.doi.org/10.5740/jaoacint.18-0060.
Testo completoAbstract (sommario):
Abstract There is great interest in the search for multifunctional waste-based materials that may be applied as environmentally friendly adsorbents. Iron-rich sludge from ground drinking-water treatment plants may be considered a potential adsorbent for various water contaminants. This material is generated during ground water purification because of the excess of metal ions in water (Fe, Mn). In practice, this sludge is frequently disposed of as waste material and, so far, is not commonly applied as the adsorption base. Our research aims to explore the adsorption potential of iron sludge for selected synthetic dyes, including malachite green, ponceau 4R, and brilliant blue FCF. Experimental data were performed using iron sludge collected from the Groundwater Treatment Plant in Koszalin, Poland, and comparing it with adsorption properties of commercial activated carbons (Norit SA Super and Norit CA 1). The kinetics, adsorption isotherms, and temperature influence on the removal of target dyes were investigated and discussed. Preliminary experimental data have revealed that iron sludge can be considered an adsorbent for the removal of cationic dyes.
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Ansone, Linda, Maris Klavins e Linda Eglite. "Use of peat-based sorbents for removal of arsenic compounds". Open Chemistry 11, n. 6 (1 giugno 2013): 988–1000. http://dx.doi.org/10.2478/s11532-013-0229-0.
Testo completoAbstract (sommario):
AbstractIt is important to apply sorbent materials for purification of water from arsenic contamination due to serious arsenic pollution worldwide. We have developed new sorbents based on natural materials that provide a cheap and environmentally friendly alternative. For the first time, peat modified with iron compounds and iron humates were tested for sorption of arsenic compounds. The highest sorption capacity was found in peat modified with iron compounds. We have found that sorption of different arsenic speciation forms was strongly dependent on solution pH, reaction time and temperature. Calculations of the sorption process using thermodynamic parameters indicate the spontaneity of sorption process and its endothermic nature. Sorption kinetics showed that most arsenates are removed within 2 hours, and the kinetics of arsenate sorption on modified peat can be described by the pseudo-second order mechanism.
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Setyowati, Elly, e Indasah Indasah. "Optimization of Local Materials in the Water Purification System as an Effort to Reduce Iron Content in Water Sources “Sumber Lestari” in the Manduro Village, Jombang District". Journal for Quality in Public Health 4, n. 2 (30 aprile 2021): 136–42. http://dx.doi.org/10.30994/jqph.v4i2.201.
Testo completoAbstract (sommario):
Background. Groundwater is the main source of drinking water in many countries around the world. It is an essential source of water for domestic, industrial and agricultural activities. In this research, groundwater was collected from Manduro village, Kabuh district, Jombang city. Iron sometimes referred to as “fly in the ointment” has been one of the most troublesome domestic water contaminants. Various quantities of iron are often present in water because of large amounts of iron present in the soil and because corrosive water will pick up iron from pipes clothing washed in water containing excessive iron may become stained with a brownish colour. Iron deposits may build up in tanks, water heater and pipelines reducing the quantity and quality of water. Iron can be present in several forms, and each form can potentially require a different method of removal. The study aims to develop a cheap and easy technology to reduce the presence of excess iron in groundwater.
Methods. The iron removal system is developed by slow sand filter and selecting coconut husk fibre as the substrate material of filter media. The filter media made from coconut husk fibre 15 cm, plain sand 15 cm, coconut husk fibre 20 cm, plain sand 20 cm, charcoal 15 cm, grave 10 cm and mineral stones 15 cm. The developed technique seemed to be very effective in reducing the iron concentration below 0.3 ppm as required Permenkes RI No. 492/MENKES/PER/IV/2010.
Result. The research result show that filter media could reduce iron content. The efficiency of the filter media in reduce of iron content is about 71 - 96%.
Conclusions. Media filter is effective for reduce iron content in groundwater up to 96% and has fulfilled Permenkes RI No. 492/MENKES/PER/IV/2010
Implication. This method can be applied to people who has the same problem. We can counseling how about made filter media to reduce iron content.
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Orhorhoro, Ejiroghene Kelly, Oghenero Wilson Orhorhoro e Eruero Victor Atumah. "Performance Evaluation of Design AD System Biogas Purification Filter". International Journal of Mathematical, Engineering and Management Sciences 3, n. 1 (3 marzo 2018): 17–27. http://dx.doi.org/10.33889/ijmems.2018.3.1-003.
Testo completoAbstract (sommario):
Biogas purification which is the removal of impurities so as to improve the efficiency of gas produced, ensure the safety of end users and prolong the life of the equipment cannot be neglected. This paper is focused on the design and performance evaluation of AD system biogas purification filter. Three different conceptual designs were generated from possible design consideration, feasibility study and preliminary test and with the help of decision matrix; the best conceptual design was selected from which the purification filter was fabricated. The selected concept for detail design was a transparent polyethene cylindrical purification filter fitted with local iron sponge containing activated charcoal and local potash. The reagents were arranged in this order; local potash for the removal of water vapour and carbon dioxide followed by activated charcoal which serves as a purifying agent for hydrogen sulphide. The results obtained showed reduction in percentage composition of hydrogen sulphide (H2S), carbon dioxide, and water vapour. On the other hand, there was an increase in percentage composition of methane (CH4) which is an indication of improvement in methane production after purification. The outcomes of the results obtained were satisfactory and the combination of local potash and activated charcoal was adequate for biogas purification.
18
Wybieralska, Katarzyna, e Anna Wajda. "Removal of Organic Dyes from Aqueous Solutions with Surfactant-Modified Magnetic Nanoparticles". Polish Journal of Chemical Technology 16, n. 2 (26 giugno 2014): 27–30. http://dx.doi.org/10.2478/pjct-2014-0025.
Testo completoAbstract (sommario):
Abstract The paper presents the results of studies on the possibility of using magnetic nanoparticles modified with selected hydrophobic surfactants for model post-production water purification. Colloidal solutions of iron hydroxide (III) and iron oxide (II and III) were obtained and their particles were subjected to surface modification using surfactants. Thus obtained magnetic fluids were used as active agents in the process of removing selected organic dyes from their aqueous solutions. The effectiveness of the modified compounds was analysed using spectrophotometric methods. It has been shown that the effectiveness of the process depends on the type of surfactant used to modify selected magnetic nanoparticles.
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Heponiemi, Anne, Janne Pesonen, Tao Hu e Ulla Lassi. "Alkali-Activated Materials as Catalysts for Water Purification". Catalysts 11, n. 6 (23 maggio 2021): 664. http://dx.doi.org/10.3390/catal11060664.
Testo completoAbstract (sommario):
In this study, novel and cost-effective alkali-activated materials (AAMs) for catalytic applications were developed by using an industrial side stream, i.e., blast furnace slag (BFS). AAMs can be prepared from aluminosilicate precursors under mild conditions (room temperature using non-hazardous chemicals). AAMs were synthesized by mixing BFS and a 50 wt % sodium hydroxide (NaOH) solution at different BFS/NaOH ratios. The pastes were poured into molds, followed by consolidation at 20 or 60 °C. As the active metal, Fe was impregnated into the prepared AAMs by ion exchange. The prepared materials were examined as catalysts for the catalytic wet peroxide oxidation (CWPO) of a bisphenol A (BPA) aqueous solution. As-prepared AAMs exhibited a moderate surface area and mesoporous structure, and they exhibited moderate activity for the CWPO of BPA, while the iron ion-exchanged, BFS-based catalyst (Fe/BFS30-60) exhibited the maximum removal of BPA (50%) during 3 h of oxidation at pH 3.5 at 70 °C. Therefore, these new, inexpensive, AAM-based catalysts could be interesting alternatives for catalytic wastewater treatment applications.
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Kabir, Anayet, Matthew Dunlop, Bishnu Acharya, Rabin Bissessur e Marya Ahmed. "Polymeric Composites with Embedded Nanocrystalline Cellulose for the Removal of Iron(II) from Contaminated Water". Polymers 10, n. 12 (12 dicembre 2018): 1377. http://dx.doi.org/10.3390/polym10121377.
Testo completoAbstract (sommario):
The exponential increase in heavy metal usage for industrial applications has led to the limited supply of clean water for human needs. Iron is one of the examples of heavy metals, which is responsible for an unpleasant taste of water and its discoloration, and is also associated with elevated health risks if it persists in drinking water for a prolonged period of time. The adsorption of a soluble form of iron (Fe2+) from water resources is generally accomplished in the presence of natural or synthetic polymers or nanoparticles, followed by their filtration from treated water. The self-assembly of these colloidal carriers into macroarchitectures can help in achieving the facile removal of metal-chelated materials from treated water and hence can reduce the cost and improve the efficiency of the water purification process. In this study, we aim to develop a facile one-pot strategy for the synthesis of polymeric composites with embedded nanocrystalline cellulose (NCC) for the chelation of iron(II) from contaminated water. The synthesis of the polymeric composites with embedded nanoparticles was achieved by the facile coating of ionic monomers on the surface of NCC, followed by their polymerization, crosslinking, and self-assembly in the form of three-dimensional architectures at room temperature. The composites prepared were analyzed for their physiochemical properties, antifouling properties, and for their iron(II)-chelation efficacies in vitro. The results indicate that the embedded-NCC polymeric composites have antifouling properties and exhibit superior iron(II)-chelation properties at both acidic and basic conditions.
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Wu, Yi, Jun Dai, Qiong Wan, Guobin Tian e Dongyang Wei. "Purification of Urban Sewage River Using a Biological Aerated Filter with Sponge Iron and Ceramsite Mixed Fillers". Advances in Civil Engineering 2020 (27 dicembre 2020): 1–10. http://dx.doi.org/10.1155/2020/8862903.
Testo completoAbstract (sommario):
Filler plays an important role in biological sewage treatment technology. In the purification of urban sewage river, the single sponge iron filler is easy to harden. The combination of sponge iron and ceramsite can hinder the hardening and improve the removal efficiency. In this paper, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the fillers. The removal efficiency experiments were carried out through the self-designed biological aerated filter (BAF) reactor with sponge iron and ceramsite mixed fillers, and the microorganisms attached to the surface of the biological fillers were qualitatively and quantitatively identified through 16S rDNA. The results indicate that the presence of Fe3O4, Fe2O3, Fe3C, and Fe2CO3 in sponge iron determines that sponge iron has strong reducibility and provides electrons for efficient denitrification. NaAlSi3O8 in ceramsite filler plays a significant role in phosphorus adsorption. In #3, #4, and #5 reactors (the mass ratios of sponge iron and ceramsite were 1 : 1, 3 : 1, and 1 : 3, resp.), the removal efficiencies of mixed fillers are good on chemical oxygen demand (COD), total phosphorus (TP), and nitrogen (N), and the more the ceramsite fillers in the reactors are, the higher the microbial abundance and diversity are. The mixture of sponge iron and ceramsite can be used to purify urban sewage river. A scientific basis to purify the polluted water body of urban rivers in situ is thus provided.
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Hatva, T. "Treatment of Groundwater with Slow Sand Filtration". Water Science and Technology 20, n. 3 (1 marzo 1988): 141–47. http://dx.doi.org/10.2166/wst.1988.0092.
Testo completoAbstract (sommario):
The purification process and techniques of the slow sand filtration method for treatment of groundwater was studied on the basis of pilot plant and full scale tests and studies of waterworks, to obtain guidelines for construction and maintenance. The purification process consists in general of two principal phases which are pre-treatment and slow sand filtration. Both are biological filters. The main purpose of the pre-treatment is to reduce the iron content of raw water, in order to slow down the clogging of the slow sand filters. Different types of biofilters have proved very effective in the pre-treatment phase, with reduction of total iron from 50 % to over 80 %. During the treatment, the oxidation reduction conditions gradually change becoming suitable for chemical and biological precipitation of iron, manganese and for oxidation of ammonium. Suitable environmental conditions are crucial in the oxidation of manganese and ammonium which, according to these studies, mainly occurs in slow sand filters, at the end of the process. Low water temperature in winter does not seem to prevent the biological activities connected with the removal of iron, manganese and ammonium, the chief properties necessitating treatment of groundwater in Finland.
23
Joshi, Mahesh Kumar, Hem Raj Pant, Han Joo Kim, Ni Na Liao, Jun Hee Kim, Bishnu Kumar Shrestha, Chan Hee Park e Cheol Sang Kim. "Hydrothermally Synthesized Magnetically Separable RGO Supported Nanocomposite for Water Purification". Advanced Materials Research 1088 (febbraio 2015): 540–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1088.540.
Testo completoAbstract (sommario):
Wastewater containing dyes and microbial bodies has attracted global attention because of the harmful effects on aquatic environment and human health. A considerable amount of dyes are present in the industrial effluents due to the loss during the processing of industrial products. The purpose of this study was to syntheses the composite particle for the effective removal of dyes and microbial bodies from aqueous solution. For this purpose, RGO supported nanocomposite was prepared using hydrothermal treatment of aqueous solution containing graphene oxide (GO), aqueous solution of silver nitrate and ferrous chloride tetrahydrate, and ethanol as precursor. Transmission electron microscopy, Raman spectroscopy, and X-ray diffraction indicated the formation of RGO supported silver doped iron oxide nanocomposite. As synthesized nanocomposite was highly effective for the adsorption of methylene blue and reduction of p-nitrophenol in aqueous solution, and also had high antibacterial capacity. The composite synthesis protocol is a simple and efficient to produce a unique composite for environmental remediation.
24
Sablii, Larisa, Obodovych Oleksandr, Vitalii Sydorenko e Mykola Korenchuk. "Increase in the efficiency of removal of iron ions from wastewater by aquatic plant ‘Lemna minor‘". Acta Periodica Technologica, n. 50 (2019): 210–19. http://dx.doi.org/10.2298/apt1950210s.
Testo completoAbstract (sommario):
Wastewater from food production enterprises could have significant concentrations of total iron that must be decreased. Aquatic macrophytes, for example ?Lemna genera?, have a high potential for iron ions removal, but kinetics and treatment parameters should be qualified. The aim of the work is to increase in the efficiency of removal of iron ions from wastewater in the process of biological wastewater treatment using ?Lemna minor? and to determine rational parameters of the treatment (biomass, process duration, hydraulic load). The kinetics of the removal of iron ions from the water was studied in the batch mode of a biological reactor operation under various biomass quantities. Verification of the obtained rational parameters of the process was carried out under continuous mode conditions. The results obtained from the kinetics of the batch mode the bioreactor operation process indicate an increase in the degree of removal of ferrous ions from wastewater from 61.0% to 91.7% with an increase in the plant biomass concentration from 8 mg/L to 25 mg/L during the wastewater treatment process of 24 hours. The rational parameters of removal of iron ions from wastewater in the batch mode of the bioreactor operation are determined: biomass of duckweed is 25 mg/L; the treatment process duration is 8 hours; the hydraulic load is 0,126 L/(h?L). The purification effect was 89.8%.
25
Paneysar, Joginder Singh, Stephen Barton, Sudeshna Chandra, Premlata Ambre e Evans Coutinho. "Novel thermoresponsive assemblies of co-grafted natural and synthetic polymers for water purification". Water Science and Technology 75, n. 5 (21 dicembre 2016): 1084–97. http://dx.doi.org/10.2166/wst.2016.599.
Testo completoAbstract (sommario):
Water contamination and its purification are a global problem. The current approach to purify water is reduction of impurities to acceptable levels. One of the ways to achieve this is by use of water-soluble polymers that extract organic and metallic contaminants, from water. This paper presents a blend of composite polymers that eliminates both the contaminants simultaneously by the principle of adsorption at lower critical solution temperature. These composite polymers have been synthesized by grafting poly(N,N-diethylacrylamide), poly(N-isopropylacrylamide) and poly(N-vinylcaprolactam) on-to the natural polymer chitosan or its derivatives, giving smart graft polymeric assemblies (GPAs). One of the graft polymers, GPA-2, exhibits excellent adsorption properties able to remove metal ions like cadmium, cobalt, copper, lead, iron and also organic impurities like chlorophenol and phthalic anhydride. Studies reveal that 6 mg/ml GPA-2 is able to effect a 100% removal of organic impurities – chlorophenol (50 ppm) and phthalic anhydride (70 ppm) – from water, while complete removal of the heavy metal ions (Cu+2, Co+2 and Cd+2) together at 30 ppm concentration has been achieved with 7.5 mg/ml GPA-2. The reduction in level of impurities along with recyclability and reproducibility in the elimination spectrum makes these assemblies promising materials in water treatment.
26
Mälkki, E. "On the Utilization of Biological Methods in Groundwater Treatment". Water Science and Technology 20, n. 3 (1 marzo 1988): 129–32. http://dx.doi.org/10.2166/wst.1988.0090.
Testo completoAbstract (sommario):
Biological water treatment has been used for more than a century. The processes involved, however, have not been optimally utilized, since knowledge about their character and significance has been insufficient. As conventional water purification techniques developed, the use of biological processes remained in the background until a few decades ago. However, at the moment several biological treatment methods are in use to remove iron and manganese from groundwater, and the future looks promising. The same methods can be used to improve numerous other water quality parameters, e.g. to oxidize reduced nitrogen compounds into nitrates. Biological removal of nitrate, too, will be a future water treatment method.
27
Wolthoorn, Anke, Erwin J. M. Temminghoff e Willem H. van Riemsdijk. "Effect of synthetic iron colloids on the microbiological NH4+ removal process during groundwater purification". Water Research 38, n. 7 (aprile 2004): 1884–92. http://dx.doi.org/10.1016/j.watres.2003.12.026.
Testo completo
28
Papciak, Dorota, Andżelika Domoń, Alicja Puszkarewicz e Jadwiga Kaleta. "The Use of Chalcedonite as a Biosorption Bed in the Treatment of Groundwater". Applied Sciences 9, n. 4 (21 febbraio 2019): 751. http://dx.doi.org/10.3390/app9040751.
Testo completoAbstract (sommario):
The conducted laboratory tests allowed determination of the efficiency of removing ammonium nitrogen, iron, and manganese in the biofiltration process on chalcedonite beds. The process of water purification was carried out by a single- and two-stage biofiltration method with gravitational and anti-gravitational flow. The study examined the extent to which chemical activation of the bed with potassium manganese (VII) affects the course of the nitrification process and the rate of biofilm formation. The obtained test results indicate that two-stage biofiltration, with initial chemical activation at the first stage of biofiltration, is an effective method for purifying waters with an abnormal content of ammonium nitrogen with simultaneous removal of iron and manganese. Activation of the bed had an effect on, among other things: biofilm formation time, efficiency of removing manganese (II) ions, and oxygen consumption in the biofiltration process. Due to the longer maturation time of the activated bed, the normative value of ammonium nitrogen (< 0.39 N-NH4+) was obtained on the 23rd day of the operation of the filters, and in the non-activated bed on the 14th day. The method of bed preparation did not affect the efficiency of removal of iron compounds.
29
Palacios Hinestroza, Hasbleidy, Hilary Urena-Saborio, Florentina Zurita, Aida Alejandra Guerrero de León, Gunasekaran Sundaram e Belkis Sulbarán-Rangel. "Nanocellulose and Polycaprolactone Nanospun Composite Membranes and Their Potential for the Removal of Pollutants from Water". Molecules 25, n. 3 (6 febbraio 2020): 683. http://dx.doi.org/10.3390/molecules25030683.
Testo completoAbstract (sommario):
A composite membrane based on polycaprolactone (PCL) and cellulose nanofibers (CNF) with different compositions was prepared using the electro-spinning method, with the objective of developing organic membranes with good mechanical properties to remove contaminants from water. Water is a resource of primary importance for life and human activities. In this sense, cellulose obtained from agave bagasse and polycaprolactone nanofibers was used to prepare membranes that were tested by filtering tap water. The membranes obtained presented a porosity and structure on a nanometric scale. The water quality variables evaluated after filtration with the PCL/CNF membranes showed 100% turbidity removal, 100% conductivity, and heavy metal removal of the order of 75% to 99% for iron and chromium. CNF comprises biowaste derived from tequila production, and it has added value. Electro-spun CNF and PCL membranes can be applied as a “green” and eco-friendly filtration system for water purification.
30
Rabajczyk, Anna, Maria Zielecka, Krzysztof Cygańczuk, Łukasz Pastuszka e Leszek Jurecki. "Nanometals-Containing Polymeric Membranes for Purification Processes". Materials 14, n. 3 (21 gennaio 2021): 513. http://dx.doi.org/10.3390/ma14030513.
Testo completoAbstract (sommario):
A recent trend in the field of membrane research is the incorporation of nanoparticles into polymeric membranes, which could produce synergistic effects when using different types of materials. This paper discusses the effect of the introduction of different nanometals such as silver, iron, silica, aluminum, titanium, zinc, and copper and their oxides on the permeability, selectivity, hydrophilicity, conductivity, mechanical strength, thermal stability, and antiviral and antibacterial properties of polymeric membranes. The effects of nanoparticle physicochemical properties, type, size, and concentration on a membrane’s intrinsic properties such as pore morphology, porosity, pore size, hydrophilicity/hydrophobicity, membrane surface charge, and roughness are discussed, and the performance of nanocomposite membranes in terms of flux permeation, contaminant rejection, and antifouling capability are reviewed. The wide range of nanocomposite membrane applications including desalination and removal of various contaminants in water-treatment processes are discussed.
31
Shtepa, V., N. Zaiets e D. Alekseevskiy. "The use of electrolysis processes in reagent-free water treatment: removal of hydrogen sulfur, organic iron, synthetic surface-active substances". Energy and automation, n. 2(54) (22 giugno 2021): 52–68. http://dx.doi.org/10.31548/energiya2021.02.052.
Testo completoAbstract (sommario):
The use of electrotechnical equipment refers to reagent-free methods and makes it possible to simplify the automation schemes for facilities for removing pollutants from aqueous solutions. The article substantiates the approaches and structural diagrams of a reagent-free water purification unit based on the use of electrolysis processes. During the research, the processes of oxidation of pollutants were analyzed when a block of electrochemical action on aqueous solutions was used during processing. A diaphragm cell with an inactive membrane volume of 3.5 liters was used to implement the appropriate reagent-free method for removing pollutants from aqueous solutions. The solution of scientific and practical problems is shown: removal of hydrogen sulfide from water from a well before feeding it to the technological lines of a dairy plant; purification of waste water from an enterprise for the production of gelatinous products from organic iron and related pollutants; reduction of waste water pollutants of a cosmetology enterprise, with a focus on destructive effects on synthetic surfactants. Based on the analysis of the results and treatment modes of three aqueous solutions, the structure of the block of reagent-free electrolysis treatment of aqueous solutions is substantiated. As a result of experimental studies, the prospects of electrical equipment have been confirmed. The reagent-free method will simplify the automation schemes for facilities for removing pollutants from aqueous solutions - accordingly, increase the reliability of such computer-integrated solutions. Further research should be directed to the substantiation, creation and parameterization of mathematical models of combined electrotechnological water treatment complexes. Key words: environmental safety, electrotechnological complex, waste water, reagent-free method, electrolysis processes
32
Kvartenko, Oleksandr, Larysa Sabliy, Nataliya Kovalchuk e Andriy Lysytsya. "The use of the biological method for treating iron containing underground waters". Journal of Water and Land Development 39, n. 1 (1 dicembre 2018): 77–82. http://dx.doi.org/10.2478/jwld-2018-0061.
Testo completoAbstract (sommario):
AbstractThe use of the biological method is promising for treating underground waters from iron compounds. Iron bacteria used in the process are widely spread in weak acidic and neutral underground waters containing iron ions (II), dissolved carbon dioxide and minimum concentrations of oxygen. The relevant direction of present-day biotechnology is the use of iron bacteria for treating underground waters. The goal of this research is to compare the efficiency of using the biological method for treating underground iron containing weak acidic and neutral waters under different conditions. As the test-objects, Gallionella and Lepthotrix iron bacteria were used. The sedimentation of bio-minerals was obtained from the washout waters of the biological deironing station. Calcium soda was used as an additional source of inorganic carbon for bacteria. As a result of the studies it is established that the use of the non-reagent method gives the possibility to achieve only 80% efficiency in removing iron compounds while the use of sodium carbonate results in increasing efficiency up to 93%. To determine the contribution of biological purification of ground water from iron compounds, the bacteria were inhibited with the preparation of polyhexamethylene guanidine (PHMG) chloride. It was found that inhibition of Gallionella and Lepthotrix led to the reduction of 50% of the iron removal effect. The mechanism was developed of inhibiting the process of iron bacteria metabolism by PHMG (polyhexamethylene guanidine). The new technology of arranging a block-module station for treating underground waters is proposed.
33
Ikhlaq, Amir, Rida Fatima, Umair Yaqub Qazi, Rahat Javaid, Asia Akram, Sami Ibn Shamsah e Fei Qi. "Combined Iron-Loaded Zeolites and Ozone-Based Process for the Purification of Drinking Water in a Novel Hybrid Reactor: Removal of Faecal Coliforms and Arsenic". Catalysts 11, n. 3 (12 marzo 2021): 373. http://dx.doi.org/10.3390/catal11030373.
Testo completoAbstract (sommario):
This study was carried out to provide a novel solution to treat drinking water at household levels, specifically removing arsenic (As) and faecal coliforms (microbes). In the current investigation, a synergistic iron-loaded zeolites and ozonation process (O3/Fe-ZA) was used for the first time in a modified batch reactor to remove coliform bacteria and arsenic in tap water. Moreover, the study utilizes the human health risk assessment model to confirm the health risk due to As intake in drinking water. The risk assessment study revealed a health risk threat among the residents suffering from the adverse effects of As through its intake in drinking water. Furthermore, the results also suggested that the O3/Fe-ZA process significantly removes faecal coliforms and As, when compared with single ozonation processes. Additionally, the ozone dose 0.2 mg/min and Fe-ZA dose of 10 g (in the O3/Fe-ZA process) gives the maximum removal efficiency of 100% within 15 min for faecal coliform removal. In 30 min, the removal efficiency of 88.4% was achieved at the ozone dose of 0.5 mg/min and 93% removal efficiency was achieved using 10 g Fe-ZA for the removal of As in the O3/Fe-ZA process. Hence, it was concluded that the O3/Fe-ZA process may be regarded as an effective method for removing faecal coliforms and As from drinking water compared to the single ozonation processes.
34
Pipíška, Martin, Simona Zarodňanská, Miroslav Horník, Libor Ďuriška, Marián Holub e Ivo Šafařík. "Magnetically Functionalized Moss Biomass as Biosorbent for Efficient Co2+ Ions and Thioflavin T Removal". Materials 13, n. 16 (16 agosto 2020): 3619. http://dx.doi.org/10.3390/ma13163619.
Testo completoAbstract (sommario):
Microwave synthesized iron oxide nanoparticles and microparticles were used to prepare a magnetically responsive biosorbent from Rhytidiadelphus squarrosus moss for the rapid and efficient removal of Co2+ ions and thioflavin T (TT). The biocomposite was extensively characterized using Fourier transformed infrared (FTIR), XRD, SEM, and EDX techniques. The magnetic biocomposite showed very good adsorption properties toward Co2+ ions and TT e.g., rapid kinetics, high adsorption capacity (218 μmol g−1 for Co and 483 μmol g−1 for TT), fast magnetic separation, and good reusability in four successive adsorption–desorption cycles. Besides the electrostatic attraction between the oxygen functional moieties of the biomass surface and both Co2+ and TT ions, synergistic interaction with the –FeOH groups of iron oxides also participates in adsorption. The obtained results indicate that the magnetically responsive biocomposite can be a suitable, easily separable, and recyclable biosorbent for water purification.
35
Fadeev, A. B., E. N. Kuzin, N. E. Kruchinina, T. I. Nosova e E. V. Kostyleva. "Estimation of the Efficiency of Methods for Electroplating Wastewater Purification from Ammonium-Tartrate Copper (II) Complexes". Herald of the Bauman Moscow State Technical University. Series Natural Sciences, n. 5 (92) (ottobre 2020): 97–108. http://dx.doi.org/10.18698/1812-3368-2020-5-97-108.
Testo completoAbstract (sommario):
Wastewater purification from heavy metal compounds is a complex and urgent task. One of the main sources of pollution of the environment with ions of heavy metals is the wastewater, i.e., washing, of the electro-plating processes. Complex electrolytes based on copper compounds are stable in a wide pH range and, when released into water, cannot be removed by the traditional methods, such as neutralization and precipitation. The study estimated the efficiency of various methods of physicochemical water purification for removing complex ammonia-tartrate copper (II) complexes from water. Findings of research show that titanyl sulfate is most effective in water purification using coagulants. The efficiency of purification with the use of titanium compounds reaches 85 %, which is on average 30--40 % higher than when using traditional coagulants based on aluminum or iron compounds. Electrocoagulation processes make it possible to effectively remove complex copper compounds from water due to a combination of the processes of organic component oxidation and coagulation with iron salts. It was found that advanced oxidation processes, which are based on the reaction with a hydroxyl radical, using hydrogen peroxide, i.e., Fenton processes, make it possible to purify wastewater from copper compounds by 99.9 %. Despite the high efficiency, it is advisable to use adsorption processes only at the stage of additional water purification from previously coagulated and oxidized pollutants
36
Kulikova, A. A., Yu A. Sergeeva, T. I. Ovchinnikova e E. I. Khabarova. "Formation of mine water composition and analysis of treatment methods". Mining informational and analytical bulletin, n. 7 (20 giugno 2020): 135–45. http://dx.doi.org/10.25018/0236-1493-2020-7-0-135-145.
Testo completoAbstract (sommario):
Formation of mine water inflow compositions is discussed, and the methods of mine water treatment are described. Mine water has different chemistry depending on hydrological, geological and geotechnical factors, as well as on depth of mining. Formation of mine water on higher horizons takes place under the influence of oxidation processes, while reduction processes are typical of lower levels. With an increasing depth, hydrocarbonate water changes into carbonate-sulfate and sulfate-hydrocarbonate water. The main pollutants of mine water are identified, the methods of mine water treatment are reviewed, the criteria of application of mine water treatment methods are specified, and the advantages and disadvantages of the methods are described. In terms of the Kirov Mine, the structure of mine water treatment facilities is considered. It is found that equipment included in the process flow chart ensure good removal of various size suspended solids from water and partially remove iron ions (when its oxidation goes to an insoluble form). However, some heavy metals remain in mine water. This fact is proved by the background concentrations observed in the places of mine water discharge in the Inya river. In the Inya water river, some contaminants exceed MAC, namely, total iron, manganese, copper, ion nitrite, etc. The authors describe the treatment methods and equipment used in coal mines in Kuzbass. There is a wide range of mine water treatment methods, but the technologies in application mainly reduce to mechanical purification which enables efficient removal of suspended solids, oil products, bacterial pollution and, partly, iron. In compliance with the requirements to mine water treatment quality, mines should modernize treatment facilities and introduce new advanced technologies, i.e. provide an integrated solution of the mine water treatment problem, and should anticipate usability of treated mine water and dregs.
37
Weidner, Ewelina, e Filip Ciesielczyk. "Removal of Hazardous Oxyanions from the Environment Using Metal-Oxide-Based Materials". Materials 12, n. 6 (20 marzo 2019): 927. http://dx.doi.org/10.3390/ma12060927.
Testo completoAbstract (sommario):
Scientific development has increased the awareness of water pollutant forms and has reawakened the need for its effective purification. Oxyanions are created by a variety of redox-sensitive metals and metalloids. These species are harmful to living matter due to their toxicity, nondegradibility, and mobility in aquatic environments. Among a variety of water treatment techniques, adsorption is one of the simplest, cheapest, and most effective. Since metal-oxide-based adsorbents poses a variety of functional groups onto their surface, they were widely applied in ions sorption. In this paper adsorption of harmful oxyanions by metal oxide-based materials according to literature survey was studied. Characteristic of oxyanions originating from As, V, B, W and Mo, their probable adsorption mechanisms and comparison of their sorption affinity for metal-oxide-based materials such as iron oxides, aluminum oxides, titanium dioxide, manganium dioxide, and various oxide minerals and their combinations are presented in this paper.
38
Zeng, Huiping, Can Yin, Jie Zhang e Dong Li. "Start-Up of a Biofilter in a Full-Scale Groundwater Treatment Plant for Iron and Manganese Removal". International Journal of Environmental Research and Public Health 16, n. 5 (27 febbraio 2019): 698. http://dx.doi.org/10.3390/ijerph16050698.
Testo completoAbstract (sommario):
In recent years, biological purification technology has been widely developed in the process of iron and manganese removal from groundwater. The cultivation and maturation of the biological filter layer are key for biological iron and manganese removal processes. The time needed for maturation varies significantly with the water quality, filter and filter media conditions and operation parameters; sometimes it takes only one or two months, sometime more than half a year. In this paper, the feasibility of adopting an intermittent operation for the cultivation of biofilter was investigated with productive filters in a groundwater treatment plant, and the comparative test of the filter column was conducted. The results showed that the intermittent operation had little effect on the cultivation of the biofilter because dissolved oxygen would be gradually exhausted during the filter-suspension process, making the filter layer anaerobic, thus possibly inhibiting the growth and reproduction of IMOB (Iron and Manganese Oxidizing Bacteria). At the same time, the test shows that when the mature biological filter needs the suspension operation, the emptying method should be considered to avoid the destruction of the biological layer.
39
Veréb, G., V. E. Gayır, E. N. Santos, Á. Fazekas, Sz Kertész, C. Hodúr e Zs László. "Purification of real car wash wastewater with complex coagulation/flocculation methods using polyaluminum chloride, polyelectrolyte, clay mineral and cationic surfactant". Water Science and Technology 80, n. 10 (15 novembre 2019): 1902–9. http://dx.doi.org/10.2166/wst.2020.008.
Testo completoAbstract (sommario):
Abstract In the present study, real car wash wastewater was purified by different coagulation/flocculation methods. As coagulant, polyaluminum chloride (‘BOPAC’), conventional iron(III) chloride, iron(III) sulfate, and aluminum(III) chloride were used, while as flocculant non-ionic and anionic polyelectrolytes were investigated. The effects of added clay mineral (Na-bentonite) and cationic surfactant (hexadecyltrimethyl ammonium bromide – ‘HTABr’) were also investigated. The use of BOPAC was significantly more effective than conventional coagulants. Extra addition of clay mineral was also beneficial in relation to both the sediment volume and sedimentation speed, while polyelectrolyte addition enhanced further the sedimentation. Moreover, the simultaneous addition of HTABr significantly enhanced the color removal efficiency due to the successful in-situ generation of organophilic bentonite. In summary, the application of 100 mg L−1 Na-bentonite with 20 mg L−1 Al3+ (from BOPAC) and 0.5 mg L−1 anionic polyelectrolyte resulted in the efficient reduction of the turbidity (4–6 NTU), the COD (158 mg L−1) and the extractable oil content (4 mg L−1) with efficiencies of 98%, 59%, and 85%, respectively. By applying organophilic bentonite in high concentration (500 mg L−1) with identical concentrations of BOPAC and anionic polyelectrolyte, significant color removal (5 times lower absorbance at λ = 400 nm) and 27% lower sediment volume were achieved.
40
Maina, Irene Wangari, Veronica Obuseng e Florence Nareetsile. "Use ofMoringa oleifera(Moringa) Seed Pods andSclerocarya birrea(Morula) Nut Shells for Removal of Heavy Metals from Wastewater and Borehole Water". Journal of Chemistry 2016 (2016): 1–13. http://dx.doi.org/10.1155/2016/9312952.
Testo completoAbstract (sommario):
Use of nonedible seed pods ofMoringa oleifera(Moringa) tree and nutshells ofSclerocarya birrea(Morula) tree for removal of selected metal ions (lead, cadmium, copper, manganese, iron, zinc, and magnesium) from wastewater and borehole water samples was investigated. Removal parameters such as contact time, pH, temperature, particle size, sorbent dose, and initial metal concentration were optimized. Determination of residual metal ions after employing sorbent was done using flame atomic absorption spectroscopy (FAAS). Using 200 ng synthetic metal ion mixture in 50 mL of water sample, the optimized parameters for Moringa seed pods were 60 min contact time, 1.0 g of sorbent dose, pH 8, 100 μm sorbent particle size, and extraction temp 35°C. While using Morula nutshells, the optimized conditions were 120 min contact time, 2.0 g sorbent dose, pH 8, 100 μm sorbent particle size, and extraction temp of 35°C. The removal efficiency of acid treated sorbents was compared to that of untreated sorbents and it was found to be higher for acid treated sorbents. These nonedible plant parts for Morula and Moringa plants are proposed as a cheap, simple, and an effective alternative for purification of water contaminated with heavy metals.
41
Ikehata, Keisuke, Yuanyuan Zhao, Jingshu Ma, Andrew T. Komor, Nima Maleky e Michael A. Anderson. "A novel photobiological process for reverse osmosis concentrate treatment using brackish water diatoms". Water Supply 18, n. 2 (6 luglio 2017): 594–602. http://dx.doi.org/10.2166/ws.2017.142.
Testo completoAbstract (sommario):
Abstract A unique aqueous silica removal process using naturally occurring diatoms for water reuse and desalination is described. Several strains of brackish water diatoms have been isolated and tested. Among them Pseudostaurosira and Nitzschia species showed promise. Reverse osmosis (RO) concentrate samples from two full-scale advanced water purification facilities and one brackish groundwater RO plant in Southern California have been successfully treated by this process. This new photobiological process could remove aqueous silica, as well as phosphate, ammonia, nitrate, calcium, iron and manganese very effectively. Under non-optimized conditions, 95% of 78 mg·L−1 reactive silica in an RO concentrate sample could be removed within 72 hours. In most cases, addition of nutrients was not necessary because the RO concentrate typically contains sufficient concentrations of macronutrients derived from the source water (i.e., treated wastewater and brackish groundwater). Preliminary characterization of organics indicated that there was no major generation of dissolved organics, which could potentially foul membranes in the subsequent RO process. This new algal process has a strong potential for its application in desalination and water reuse in the United States and around the world.
42
Said, Noresah, Muhammad Nidzhom Zainol Abidin, Hasrinah Hasbullah, Ahmad Fauzi Ismail, Pei Sean Goh, Mohd Hafiz Dzarfan Othman, Mohd Sohaimi Abdullah, Be Cheer Ng, Siti Hamimah Sheikh Abdul Kadir e Fatmawati Kamal. "Polysulfone hemodialysis membrane incorporated with Fe2O3 for enhanced removal of middle molecular weight uremic toxin". Malaysian Journal of Fundamental and Applied Sciences 16, n. 1 (2 febbraio 2020): 1–5. http://dx.doi.org/10.11113/mjfas.v16n1.1464.
Testo completoAbstract (sommario):
Removing middle molecular weight uremic toxin remains as one of the most challenging tasks in hemodialysis. Hence, in this study a high performance polysulfone (PSf) hemodialysis membrane was developed by incorporating iron oxide (Fe2O3) nanoparticles. The PSf/Fe2O3 hemodialysis membrane and pristine PSf membrane were prepared via dry-wet spinning process. The membranes were characterized by scanning electron microscopy, water contact angle, average pore size, and porosity measurements. The biocompatibility profiles of the membranes were also evaluated in terms of protein adsorption and blood coagulation time. Next, the performance of the membranes was determined by measuring pure water permeability (PWP), bovine serum albumin rejection, and removal of various solutes such as urea and lysozyme. The incorporation of Fe2O3 resulted in significant increment of the PWP from 40.74 L/m2/h/bar to 58.6 L/m2/h/bar, mainly due to the improved water transport properties of the membrane. Moreover, the percent removal of urea and lysozyme was reported to be 75.1% and 35.6%, respectively. PSf/Fe2O3 hemodialysis membrane is proven to have a bright prospect for enhanced blood purification process.
43
Stepova, K., L. Sysa e I. Vintonyk. "PURIFICATION OF FE3+ CONTAINING WASTEWATER USING NATURAL SORBENTS". Bulletin of Lviv State University of Life Safety 20 (24 gennaio 2020): 101–5. http://dx.doi.org/10.32447/20784643.20.2019.15.
Testo completoAbstract (sommario):
Abstract. Bentonites in natural or activated forms, i.e. after chemical treatment with acids, have high adsorption properties and are widely used as a natural adsorbent. The increase in the adsorption capacity of bentonite sorbents during heat treatment at 100–200 ° C is caused by the removal of adsorbed and chemical water that leads to an increase in the overall porosity. By thermal and hydrothermal treatments, the properties of natural sorbents can be varied within wide limits, giving them selectivity with respect to certain dissolved substances. It is known that the irradiation of water systems by microwaves leads to their heating, that is, this method of pre-treatment of sorbents combines their hydro-thermal treatment with high-frequency irradiation. The aim of the work is to investigate the process of absorption of iron (III) by bentonite clay under the influence of microwave radiation. The sorption properties of bentonites were studied under static conditions. For comparison purposes, adsorption was performed on natural bentonite under normal conditions without any pre-treatment and under the action of ultra-high-frequency electromagnetic radiation. The Langmuir equation was used to describe the experimental adsorption isotherms. The maximum sorption capacity of the treated sample was found to be 1.66 times higher than that of the untreated one and was 63.7 and 38.3 mg / g, respectively. The sorption equilibrium constant of the irradiated sample is 42% lower than that of the native one. This indicates that the sorption equilibrium under the action of ultra-high frequency radiation comes in 1.7 times faster than under normal conditions. Therefore, compared to the untreated sample, microwave irradiated bentonite has better sorption characteristics for iron (III), so it can be a promising sorbent for the purification of natural and wastewater.
44
Ilic, Nikola, Slavica Lazarevic, Vladana Rajakovic-Ognjanovic, Ljubinka Rajakovic, Djordje Janackovic e Rada Petrovic. "The sorption of inorganic arsenic on modified sepiolite: Effect of hydrated iron(III)-oxide". Journal of the Serbian Chemical Society 79, n. 7 (2014): 815–28. http://dx.doi.org/10.2298/jsc130912017i.
Testo completoAbstract (sommario):
The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.
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Алексеев, С. Е., Е. В. Корса-Вавилова e А. Я. Шмелев. "Estimation of the effectiveness of ozone use in the purification of heavily contaminated water supply sources". Vodosnabzhenie i sanitarnaia tehnika, n. 6 (15 giugno 2021): 8–17. http://dx.doi.org/10.35776/vst.2021.06.01.
Testo completoAbstract (sommario):
Источники питьевого водоснабжения (реки Великая, Волга, Вычегда, Которосль, Лименда, Солда, Северная Двина, Томь и Тура) характеризуются повышенным содержанием органических соединений природного и антропогенного происхождения. Традиционная технология двухступенчатого осветления воды коагулированием в данном случае по своей эффективности не соответствует качеству воды источника, в результате по некоторым показателям питьевая вода периодически не отвечает современным требованиям стандарта. Особенно сложно обеспечивать в питьевой воде предельно допустимые концентрации органических веществ, а также соединений железа, марганца и остаточного алюминия. Для очистки такой воды были изучены дополнительные методы окисления и сорбции. Результаты исследований показали, что предварительное озонирование речной воды и (или) постозонирование воды после фильтров станции водоподготовки повышают эффективность очистки по цветности, мутности, удалению соединений железа и марганца, уменьшают концентрацию остаточного алюминия, улучшают органолептические показатели. Сорбционная очистка с озонированием существенно улучшает качество очищенной воды и позволяет обеспечить допустимый уровень содержания органических загрязнителей в питьевой воде. Sources of drinking water supply (the Velikaia, Volga, Vychegda, Kotorosl’, Limenda, Solda, Severnaia Dvina, Tom’ and Tura rivers) are characterized by increased concentrations of organic compounds of natural and anthropogenic origin. The traditional technology of two-stage water clarification by coagulation in terms of the efficiency, in this case, is not applicable to the quality of the source water; as a result, by some indicators, drinking water periodically does not meet the current standard requirements. It is especially difficult to ensure the permissible maximum concentrations of organic substances in drinking water, as well as of compounds of iron, manganese and residual aluminum. To provide for the purification of such water, additional oxidation and sorption methods have been studied. The research results showed that preliminary ozonation of river water and (or) post-ozonation of water after filtration at a water treatment plant provide for increasing the efficiency of purification in terms of color, turbidity, removal of iron and manganese compounds; for reducing the concentration of residual aluminum, and improving the organoleptic characteristics. Sorption with ozonation significantly improves the quality of treated water and allows to ensure the permissible level of organic pollutants in drinking water.
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Yamaguchi, Natalia Ueda, Andressa Jenifer Rubio e Rosângela Bergamasco. "Activated carbon loaded with manganese and iron for glyphosate adsorption: Kinetics, isotherms and thermodynamic studies". Ambiente e Agua - An Interdisciplinary Journal of Applied Science 14, n. 6 (4 novembre 2019): 1. http://dx.doi.org/10.4136/ambi-agua.2414.
Testo completoAbstract (sommario):
Granular activated carbon was loaded with 0.5% manganese and 1.0% iron (m/m) for glyphosate removal from aqueous solutions. The adsorbent material was characterized by scanning electron microscopy, dispersive energy spectrometry, nitrogen adsorption techniques and zeta potential analyses. Batch studies were performed to investigate the adsorption equilibrium, kinetics mechanisms and to obtain thermodynamic information. Glyphosate adsorption increased with the contact time and achieved equilibrium within 24 h, with a maximum adsorption capacity of 9.19 mg g-1 at 45°C. Batch kinetic experimental data obeyed the pseudo-second-order model with R2>0.99. Adsorption isotherm experiments were carried out at 5, 15, 25, 35 and 45°C. The adsorption isotherms presented a better fitting using the Freundlich model (R2>0.98), indicating a multilayer adsorption of glyphosate. Thermodynamics studies showed that the adsorption of glyphosate onto granular activated carbon loaded with manganese and iron was spontaneous and feasible with negative values of ΔG°, endothermic with ΔH° of 20.924 kJ mol-1 and ΔS° of -73.250 J mol-1 K-1, suggesting a decrease in randomness at the solid–liquid interface between glyphosate and the adsorbent. The experimental results demonstrated that activated carbon loaded with manganese and iron may be an alternative for glyphosate removal in water, wastewater treatment and purification processes.
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Karvelas, Evangelos, Christos Liosis, Lefteris Benos, Theodoros Karakasidis e Ioannis Sarris. "Micromixing Efficiency of Particles in Heavy Metal Removal Processes under Various Inlet Conditions". Water 11, n. 6 (30 maggio 2019): 1135. http://dx.doi.org/10.3390/w11061135.
Testo completoAbstract (sommario):
Water quality problems are a persistent global issue since population growth has continually stressed hydrological resources. Heavy metals released into the environment from plating plants, mining, and alloy manufacturing pose a significant threat to the public health. A possible solution for water purification from heavy metals is to capture them by using nanoparticles in micromixers. In this method, conventionally heavy metal capture is achieved by effectively mixing two streams, a particle solution and the contaminated water, under the action of external magnetic fields. In the present study, we investigated the effective mixing of iron oxide nanoparticles and water without the use of external magnetic fields. For this reason, the mixing of particles and the contaminated water was studied for various inlet velocity ratios and inflow angles of the two streams using computational fluid dynamics techniques. The Navier-Stokes equations were solved for the water flow, the discrete motion of particles was evaluated by a Lagrangian method, while the flow of substances of the contaminated water was studied by a scalar transport equation. Results showed that as the velocity ratio between the inlet streams increased, the mixing of particles with the contaminated water was increased. Therefore, nanoparticles were more uniformly distributed in the duct and efficiently absorbed the substances of the contaminated water. On the other hand, the angle between two streams was found to play an insignificant role in the mixing process. Consequently, the results from this study could be used in the design of more compact and cost efficient micromixer devices.
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Pervez, Md Nahid, Wei He, Tiziano Zarra, Vincenzo Naddeo e Yaping Zhao. "New Sustainable Approach for the Production of Fe3O4/Graphene Oxide-Activated Persulfate System for Dye Removal in Real Wastewater". Water 12, n. 3 (7 marzo 2020): 733. http://dx.doi.org/10.3390/w12030733.
Testo completoAbstract (sommario):
Persulfate (PS)-activated, iron-based heterogeneous catalysts have attracted significant attention as a potential advanced and sustainable water purification system. Herein, a novel Fe3O4 impregnated graphene oxide (Fe3O4@GO)-activated persulfate system (Fe3O4@GO+K2S2O8) was synthesized by following a sustainable protocol and was tested on real wastewater containing dye pollutants. In the presence of the PS-activated system, the degradation efficiency of Rhodamine B (RhB) was significantly increased to a level of ≈95% compared with that of Fe3O4 (≈25%). The influences of different operational parameters, including solution pH, persulfate dosage, and RhB concentration, were systemically evaluated. This system maintained its catalytic activity and durability with a negligible amount of iron leached during successive recirculation experiments. The degradation intermediates were further identified through reactive oxygen species (ROS) studies, where surface-bound SO4− was found to be dominant radical for RhB degradation. Moreover, the degradation mechanism of RhB in the Fe3O4@GO+K2S2O8 system was discussed. Finally, the results indicate that the persulfate-activated Fe3O4@GO catalyst provided an effective pathway for the degradation of dye pollutants in real wastewater treatment.
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Panasyugin, A. S., S. V. Grigor’ev, A. I. Teran, V. N. Anufriev, A. R. Tsyganov e N. P. Masherova. "Extraction from aqueous solutions ions of iron and lead by filter loading, created on the basis of steel melting slag". Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), n. 3 (5 ottobre 2018): 58–62. http://dx.doi.org/10.21122/1683-6065-2018-3-58-62.
Testo completoAbstract (sommario):
The aim of the present paper is investigation of removal of Fe3+ and Pb2+ ions from aqueous media by material on the basis of steel melting slag. It has been established that the process of water purification from Fe3+ and Pb2+ ions by this material proceeds by a mixed mechanism both due to the formation of slightly soluble silicates and also due to the formation of hydroxides. When the filtration rate varies from 2 to 10 column volumes per hour, the percentage of sorption remains within 91,5–99,8%. The most optimal filtration rate is 6 column volumes per hour. Material on the basis of steel melting slag absorbs of Fe (III) up to 5 mg-eq/g and Pb (II) 0.64–1.27 mg-eq/g.
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Vuorinen, A., P. Lahermo e T. Hatva. "The Effect of Fluorine on the Precipitation of Hydrous Iron Oxides from Groundwater Using Re-Infiltration". Water Science and Technology 20, n. 3 (1 marzo 1988): 247. http://dx.doi.org/10.2166/wst.1988.0109.
Testo completoAbstract (sommario):
The behaviour of Fe, Si, Cu, Zn and F was studied in a plant constructed for purification of groundwater from excess Fe, Mn and organic matter by aeration and subsequent re-infiltration at Taivassalo, south-western Finland. The aquifer of the groundwater intake comprises the Laitila rapakivi area and the water has a relatively high F content. The groundwater purification plant consist of two units. In the pre-treatment unit the water was discharged onto a macadam contact filter for aeration, after which it flowed through two clarification basins to the infiltration basin of the re-infiltration unit. Fe oxidized during the treatment and precipitated as hydrous oxides. Precipitates were filtered from water and dried at 20°C, both immediately after sampling and after two year's aging in natural water at 4°C. To clarify the mode of occurrence of the elements the samples were subjected to extraction by 1 M ammonium acetate (NH4Ac) at pH 7.3 for exchangeable and loosely bound elements, at pH 4.8 for loosely bound and sorbed elements, by 1 M hydroxylammonium chloride plus 2 M acetic acid (HX1 - HAc) at 18°C for reducible loosely bound elements and Fe oxyhydroxides, and by HXl-HAc at 80°C for total Fe oxyhydroxide bound F. The precipitates were extracted with NH4Ac (pH 4.8) and HX1-HAc during different time intervals. The F content in water decreased along the flow path but increased during the re-infiltration step. The removal of F from water would obviously be more efficient if the plant arrangements like retention time were more suitable for this purpose. F and Si interacted strongly with Fe in the precipitates, preventing their ordering, and F, Si and Fe correlated well with each other. The loosely bound forms of these elements decreased along flow path and increased during aging of the precipitates. F and Cu were strongly, and Zn less strongly sorbed and scavenged by the precipitates. Owing to the relatively low pH of the raw water (5.74) Ca2+and other cations were not sorbed as was observed at higher pH's (over 7) and Cu and Zn were sorbed instead.