Drinking Water Purification Research Articles

Application of bioflocculants produced by Prestia megaterium for drinking water purification

Quality water is a scarce commodity in the developing countries. This paper aims to evaluate the application of bioflocculants produced by Priestia megaterium (accession number: ON184360) for drinking water purification. A total of twenty-four water samples from stream, ponds and wells were collected in sterile containers from four different Local Government Areas of Niger State, Nigeria. Each sample was treated with varying concentrations of bioflocculant and chemical flocculant (0.05, 0.1, 0.15, 0.2 and 0.5 mg L−1). The microbiological and physicochemical characteristics of the treated and untreated water were determined using standard methods. The results show that water samples from stream, ponds and wells treated with the bioflocculant significantly reduced the microbial load and the physicochemical properties of the water reduced to an acceptable limit, which has practical significance for the safety of drinking water in developing countries. The bioflocculant was effective in aggregating suspended particles and thus, proved its potential to be used as alternative flocculant in the drinking water treatment process.

Improving the technology of drinking water purification at the water treatment facilities of the Chernorechensk reservoir during the flood period

The paper considers the natural and technical aspects that contribute to the supply of substandard quality water to the water treatment facilities of the city of Sevastopol during the flood period, which caused repeated shutdown of water treatment facilities. Options for retrofitting the existing water supply and purification scheme are considered, with the determination of the enlarged cost. The paper presents a technological justification for the application of a two-stage sedimentation scheme, which can be implemented within the framework of existing equipment and a small technological re-equipment.

Energy saving analysis for pump-motor set in water purification plant using variable speed drive.

The induction motor is known to be the most reliable motor in the industry and is also the most energy-consuming load worldwide. It is noticeable in some production areas that the use of a high-capacity induction motor is not required at some operating times, and therefore it is important to control the speed of the induction motor to suit the operating requirements and obtain highly efficient performance. This paper presents a case study of a drinking water purification plant that uses a variable speed drive (VSD) as a speed controller for one of its induction motors to drive the pump. The VSD is connected to the motor in question to regulate its speed and maintain the external pressure of the station at an appropriate value that ensures water delivery to all branches of the network. 24-hour power consumption measurements of the respective engine with and without the use of a VSD are studied and analyzed to determine the potential for energy savings. Finally, a case study simulation is presented to compare the simulation results with the actual results.

Emerging Nanomaterials for Drinking Water Purification: A New Era of Water Treatment Technology.

The applications of nanotechnology in the field of water treatment are rapidly expanding and have harvested significant attention from researchers, governments, and industries across the globe. This great interest stems from the numerous benefits, properties, and capabilities that nanotechnology offers in addressing the ever-growing challenges related to water quality, availability, and sustainability. This review paper extensively studies the applications of several nanomaterials including: graphene and its derivative-based adsorbents, CNTs, TiO2 NPs, ZnO NPs, Ag NPs, Fe NPs, and membrane-based nanomaterials in the purification of drinking water. This, it is hoped, will provide the water treatment sector with efficient materials that can be applied successfully in the water purification process to help in addressing the worldwide water scarcity issue.

Fabrication of green xylose-based nanofiltration membrane with enhanced performance and chlorine resistance

Nanofiltration technology has been widely used in drinking water purification due to its excellent permeance and selectivity properties, especially in small molecular solute separation. However, using oxidizing agents in the pretreatment process for fouling control threatens the nanofiltration membrane structure, leading to the deterioration of the separation performance. Herein, we fabricate a polyester nanofiltration membrane utilizing xylose as an aqueous monomer in the interfacial polymerization process. Due to abundant hydroxyl groups and low reactivity of xylose monomers, the polyester membrane possessed a hydrophilic and thin separation layer, which led to high water permeance with the optimal value of 28.7 L·m−2·h−1·bar−1. Possessing highly cross-linking structures and negatively charged surfaces, the fabricated polyester membranes showed an excellent Na2SO4 rejection of up to 95.4 %. In addition, the low electron-donating property of polyester membranes ensured their chemical stability toward active chlorine. This endows relatively stable performance of the polyester membrane after chlorine resistance tests in a wide pH range. This study presents a feasible approach employing green monomers for fabricating nanofiltration membranes with outstanding separation performance and robust chlorine resistance.

Removal of arsenic from aqueous solution using magnetic biochar derived from Spirulina platensis

Arsenic contamination in surface waters and groundwater affects millions of people on a daily basis. Oxidation of As(III) to less toxic As(V) is a widely used strategy to enhance the removal of As from solution. This study developed and evaluated a Fe-modified biochar (FeSP600). Spirulina platensis (SP) is one of the most promising microalgae because of its physicochemical properties and potential applications. The high N content of SP may affect the physicochemical properties of the biochar, which could be used as an inherent N source for N doping biochar by carbonization. After Fe modification, the formed Fe species and N-containing components of SP were used to introduce pyridinic N, which can be coordinated with Fe to form Fe-N. We demonstrated that the formed Fe species (Fe0, Fe2+ and Fe3+) and the defective structures in FeSP600 could act as active sites for surface catalytic reactions. FeSP600 not only had magnetic properties but also could effectively remove As from an aqueous solution. These properties were attributed to the release of Fe2+ and the reactive oxygen species (ROSs) generated by the γ-Fe2O3 particles on the crystalline defect structure. As(III) and As(V) removal were affected by the initial pH values. The removal efficiencies for As(III) increased from 57.2 % to 94.9 % as the pH increased from 3 to 9, whereas that for As(V) decreased from 80.1 % to 46.8 %. The presence of coexisting ions either completely (PO43−) or partially (Cl−, CO32− and SO42−) inhibited As removal. The removal of As(V) depended on electrostatic interactions, but As(III) removal was a complex process, including both oxidation and surface adsorption, as the ROSs were able to oxidize As(III) to As(V). Our study demonstrates that FeSP600 has properties that are beneficial for the removal of As(III) and As(V) from aqueous environments. The findings of this study have potential for real-world application in treating As-contaminated water sources, particularly in improving drinking water purification systems in developing countries. More importantly, an assessment of the impact of FeSP600 usage on aquatic ecosystems is required to ensure the safe application of this technology. Therefore, developing methods for mass production of FeSP600 is essential for the commercialization of this technology, necessitating process engineering studies in this area.

New fibrous carboxyl cation exchangers for sorption cations of heavy and non-ferrous metals from water

New fibrous carboxyl cation exchangers FIBAN were synthesized by the method of graft copolymerization to polypropylene staple fibers of acrylic acid and various bifunctional comonomers (divinylbenzene – DVB, ethyleneglycoldimethacrylate – EGDM, methylene-bis-acrylamide – MBAA). Sorption properties of the fibers towards cations of heavy and non-ferrous metals (Cо2+, Ni2+, Zn2+, Cd2+, Cu2+ и Pb2+) were studied on the model solutions in the dynamic regime. The dynamic activity of the crosslinked sorbents towards Cu2+ and Pb2+ ions is higher compared to fibrous analogues FIBAN Х-1, FIBAN Х-2, FIBAN К-6М, FIBAN К-5, VION КN-1. The best sorbent for lead ions between the crosslinked fibers is the fiber with EGDM. The fiber with MBAA has a higher affinity towards the cations of Ni2+, Zn2+, Cd2+ and Cа2+, which increases with the increasing of the degree of crosslinking by MBAA. Studying the fibers by the methods of Fourier-transform IR-spectroscopy, scanning electron microscopy, analyzing of the chemical oxygen demand in water extracts and determination of the equivalent moisture capacity coefficient coefficient demonstrated that the crosslinking by MBAA provides a stable structure of the sorbent. The high stability of the crosslinked structure combined with the high ion exchange capacity near 7 mEq/g and dynamic activity towards the cations of Pb2+, Zn2+, Cd2+ и Cа2+ makes the fibrous carboxyl sorbent with MBAA safe and perspective for drinking water purification.

Adsorption of organic micropollutants in water: A review of advances in modelling, mechanisms, adsorbents, and their characteristics

The presence of organic micropollutants (OMPs) in water resources poses significant environmental and health risks due to their bioaccumulative and toxic properties. Adsorption technologies offer a promising solution for removing OMPs from water, yet comprehensive information on their development and application is limited. This review examines recent advancements in OMP removal using adsorption technologies, focusing on isotherms, breakthroughs, and kinetics modelling in both batch and column adsorption systems. It explores the mechanisms and characteristics of various adsorbents, highlighting significant progress in synthesizing green, mineral, porous carbon, and nanomaterial adsorbents. These developments aim to enhance properties like surface area, pore structure, surface chemistry, and particle size to optimize OMP adsorption. Despite the existence of accurate models for OMP removal by porous carbons, there is a gap in models for other adsorbents and a research bias toward batch systems. This review underscores the need for more research, particularly in computational simulation, to develop and optimize suitable models for predicting the removal of different OMPs from water via adsorption technologies using novel adsorbents in continuous column adsorption systems, to enhance the practical application of adsorption technologies in drinking water purification.

Flake size-dependent water transport through graphene oxide membranes and rejection of geosmin (GSM) and 2-methylisoborneol (MIB) from drinking water

Water transport through graphene oxide membranes (GOMs) and the rejection of inorganic and organic solutes have been extensively studied. However, the influence of the lateral size of GO flakes on membrane performance remains unclear. Here, we investigate the water permeation and separation performance of GOMs fabricated using various sizes of flakes. The membranes prepared with larger flakes showed higher water flux. Our experiment clearly shows that GOMs consist of both lamellae and void structures. Monte Carlo simulations indicate that water transport through the voids is faster than that through the lamellae in GO membranes. Moreover, the voids are more predominant for the membranes prepared with larger sizes of GO flakes and, hence, higher water flux for larger flake membranes. Additionally, the GOMs prepared with the large flakes effectively rejected more than 98 % of geosmin (GSM) and 2-methylisoborneol (MIB) with high reproducibility and a stable water flux of 1.49 LMH. Our results contribute to a better understanding of the complex structure of GOMs, where the rejection performance of membranes mainly depends on the interlayer space, but the water transport is governed by the voids. Our study also demonstrated the industrial potential of GOMs in drinking water purification technology.

Antibacterial Behavior of Synthesized Silica-Silver Nanocomposite for Drinking Water Purification

Antibacterial Behavior of Synthesized Silica-Silver Nanocomposite for Drinking Water Purification

A Janus membrane with electro-induced multi-affinity interfaces for high-efficiency water purification.

Drinking water with micropollutants is a notable environmental concern worldwide. Membrane separation is one of the few methods capable of removing micropollutants from water. However, existing membranes face challenges in the simultaneous and efficient treatment of small-molecular and ionic contaminants because of their limited permselectivity. Here, we propose a high-efficiency water purification method using a low-pressure Janus membrane with electro-induced multi-affinity. By virtue of hydrophobic and electrostatic interactions between the functional interfaces and contaminants, the Janus membrane achieves simultaneous separation of diverse types of organics and heavy metals from water via single-pass filtration, with an approximately 100% removal efficiency, high water flux (>680 liters m-2 hour-1), and 98% lower energy consumption compared with commercial nanofiltration membranes. The electro-induced switching of interfacial affinity enables 100% regeneration of membrane performance; thus, our work paves a sustainable avenue for drinking water purification by regulating the interfacial affinity of membranes.

Possibilities of Corona Electric Discharge for Deep Purification of Drinking Water from Phenol and Tetracycline

Possibilities of Corona Electric Discharge for Deep Purification of Drinking Water from Phenol and Tetracycline

Carbon-polymer composites for environmental applications

Abstract Carbon polymer nanocomposite is a type of composite material that combines carbon-based materials with polymers and nanoparticles to achieve enhanced properties. These materials are designed to take advantage of the unique properties of each constituent to create a new material with superior performance compared to individual components. Nanocomposites composed of carbon-based polymers are the wonder and novel materials of contemporary research. At the forefront of a more recent scientific revolution, both material science and composite science are involved. Polymer science and nanotechnology are inextricably linked in today’s modern science. The subjects of environmental engineering science and nanotechnology require focused attention since these professions currently offer limited solutions for the increasingly pressing problems of groundwater contaminated with heavy metal and drinking water purification. Carbon polymer composites play a significant role in numerous modern applications due to their excellent electrical, mechanical, chemical, and thermal capabilities. Carbon polymer composites are viewed as desirable candidates for the manufacture of nanocomposite materials due to their nanoscale geometries, high aspect ratio, and specific surface area. Due to the shape-dependent nature of their physical and chemical characteristics as well as their thickness, carbon polymer nanocomposites have demonstrated excellent catalytic activity in organic chemical processes. It has been discovered that the catalytic product from the usage of carbon polymer nanocomposites is of tremendous utility in a variety of sectors, inclusive of material sciences, medicinal, and nutritional for biotechnology. As a result, the demand for carbon nanocomposites has grown quickly and the creation of new preparation techniques elevates a higher level of interaction.

Investigating the Adsorption of Humic Acid from Water Using CTS/PAM and CTS/PAM/EDTA Adsorbents

In recent decades, reports from around the globe indicate an increase in natural organic matters (NOMs) in surface waters, which has a negative impact on drinking water purification and causes problems such as the taste and color of water, reducing the amount of dissolved oxygen in water, causing membrane fouling in the filtration process, and acting as a precursor for the formation of an antiseptic by-product. This work used the adsorption process to evaluate the elimination of natural organic compounds in aquatic environments. Ethylenediaminetetraacetic acid (EDTA) as a crosslinker for chitosan (CTS) and N, N-methylenebisacrylamide as a crosslinker for polyacrylamide (PAM) were used to prepare humic acid (HA) adsorbents utilizing a two-step procedure. The FTIR spectroscopy proved the EDTA cross-linking agent was effective with the semicrosslinking CTS/PAM hydrogel. CTS/PAM/EDTA double network (DN) hydrogel exhibited a higher HA adsorption capacity (qe = 107.7 mg/g) than CTS/PAM (qe = 59.3 mg/g) at pH = 7 and an initial concentration of 60 mg·L−1 during 60 min. Also, results demonstrate that CTS/PAM/EDTA DN hydrogels showed faster adsorption kinetics than CTS/PAM.

PRODUCTION AND RESEARCH OF SORBENTS FROM FOOD PLANT WASTES FOR WATER PURIFICATION

The article describes the results of research on production of modified types of sorbents based on waste food plants and the possibility of drinking water purification from Ca2+ and Mg2+ ions. Sunflower and buckwheat wastes widely spread in the East Kazakhstan region were selected for production of modified sorbent. Structural features of sunflower and buckwheat shells were studied. It was found that samples of the initial form of buckwheat and sunflower, washed with distilled water, consist of very dense and small micropores. It was found that the surface of the sorbents particles is changed by washing with alcohol solution, with pores and hillocks appearing on the surface of sunflower husk particles. In acid-base-treated sorbents, an increase in the number of macropores and a change in the general morphological structure are observed. As a result of defining the sorption capacity of sorbents produced by acid-alkaline activation, it is on average 0.06 mg/g in iodine and 1.3 mg/g in methylene blue higher than that of medical activated carbon. The results of materials sorption capacity study produced from sunflower husk, sequentially treated with 8.2% hydrochloric acid solution and 16,5% sodium hydroxide solution, indicated effect respect to Ca2+ and Mg2+ ions showed a high purification effect of 98.7% and 95.8%, respectively. The above-mentioned modified sorbent is proposed as a sorption material in the production of filters for drinking water purification.

A novel salt-swelling nanofiltration membranes for drinking water purification: High mineral ions passage and efficient organic removal

BackgroundMunicipal drinking water treatment demands nanofiltration (NF) membranes with high removal efficiency for organics, high passage for mineral ions, and low operating pressure. The development of innovative and loose NF membranes is imperative. MethodsA loose-network-structured NF membrane (L-NF) was synthesized through interfacial polymerization (IP) on a PES substrate by utilizing lysine (with a flexible aliphatic chain) as standalone aqueous phase monomers. The separation performance for typical organics and mineral ions in water, as well as the permeability of the membrane were investigated. Significant findingsThe lysine-based NF membranes exhibit a reversible and appropriate salt-induced swelling effect. The increased salt concentration leads to a significant enhancement of both permeate flux and salt passage, while maintaining unaffected removal efficiency for organics. The optimized membrane (L-NF3), synthesized with a 1 % (w/v) concentration of lysine, demonstrated remarkable retention (>98 %) for organics (humic acid and sodium alginate), while concurrently displaying low retention (5.22 %-16.40 %) for mineral ions (Mg2+ / Ca2+). Furthermore, the salts in the feed led to a substantial improvement in permeate flux (239.61 %-385.70 %) compared to salt-free feed. The Lys-TFC membrane showcased outstanding performance of separation, permeability, and operational stability, underscoring its significant potential in municipal drinking water purification.

Give plastic wastes from the production of hollow fibre membranes a second life

Give plastic wastes from the production of hollow fibre membranes a second life LIFE REMEMBRANCE’s ambition is a demonstrated circular production process of safe and innovative granules and cartridges for drinking water purification from emerging contaminants. The objectives will be achieved through the development of a novel technology based on the recycling of high-value industrial waste, deriving from hollow fibre membranes (HFM) filter production and validated with the collaboration of an internationally recognised utilities company.

Innovative enhancement of electron tunneling synergy in carbon-doped Ta2O5[sbnd]CuO photocatalyst with nematic liquid crystal for safe drinking water

This study focuses on enhancing the photocatalytic properties of carbon-doped Ta2O5CuO (C-Ta2O5CuO) nanocomposites for drinking water purification. The nanocomposites were fabricated by depositing C-Ta2O5CuO onto Nematic Liquid Crystal Polaroid (NLCP) obtained from a discarded laptop monitor, employing the sputter deposition method. The X-ray diffraction (XRD) and High-resolution transmission electron microscopy (HRTEM) determined the nanocomposite thin films' crystallinity and structural properties. The EDX and XPS analyses confirmed the elemental composition and reality of the Cu-incorporated Ta2O5 nanocomposites, respectively. The combination of electron tunneling enhancement provided by the NLCP and graphitic carbon led to exceptional photocatalytic performance. This was particularly evident in the efficient degradation of P-Rosaniline Hydrochloride (PRH) dye in an aqueous medium. C-Ta2O5CuO catalytic activities were estimated at various dye concentrations, repeatability, reusability with time, and kinetics. Coating's stability and long-term activity in photocatalysis reactions were also tested. Additionally, Cu present in the C-Ta2O5CuO and ˙OH radicals exhibited remarkable bactericidal activity. They displayed significant antibacterial efficacy against both gram-positive Escherichia coli (E. coli) and gram-negative Staphylococcus aureus (S. aureus) bacteria. These findings have significant implications for the development of advanced materials with potent photocatalytic and antibacterial properties, holding promise for improving drinking water quality and addressing environmental and health challenges.

Adsorption of Organic Pollutants on Carbonaceous Adsorbents Prepared by Direct Activation of Sweet Cherry Stones.

The main objective of this study was to assess the usefulness of the sweet cherry stones for the production of carbonaceous adsorbents by means of direct physical activation method, using conventional and microwave variant of heating. The adsorbents were characterized in terms of textural parameters, acidic-basic character of the surface, electrokinetic properties and their suitability for drinking water purification. Adsorption tests were carried out against three organic compounds - Triton X-100 (surfactant), bovine serum albumin (protein) and methylene blue (synthetic dye). Depending on the variant of heating applied during activation procedure, the obtained activated biochars differed significantly in terms of the elemental composition, acidic-basic properties as well as degree of specific surface development and the type of porous structure generated. Adsorption tests have showed that the efficiency of organic pollutants removal from aqueous solutions depends significantly not only on the type of the adsorbent and adsorbate applied, but also on the temperature and pH of the system. The sample prepared by microwave-assisted direct activation proved to be very effective in terms of all tested organic pollutants adsorption. The maximum sorption capacity toward Triton X-100, bovine serum albumin and methylene blue reached the level of 86.5, 23.4 and 81.1 mg/g, respectively.

Study on the effect of container tilt on the falling speed of suspended particles in gravity field

The boycott effect is widely used in wastewater purification, drinking water purification, and mixture treatment in industry and manufacturing. In this paper, we analyze the settling velocity of particles in the clear water and suspended zones, and investigate the reasons for the tilting angle of the vessel to accelerate the settling velocity of particles. This paper uses video tracking software to analyze the settling velocity of particles in the experiment and draws conclusions.