Water Treatment Technologies Research Articles

Evaluation of Microplastic Toxicity in Drinking Water Using Different Test Systems

Microplastic pollution poses a significant threat to environmental and human health. This study investigated the toxicological and genotoxic effects of various microplastic types (polystyrene (PS), polyethylene terephthalate (PET), polypropylene (PP), and polyethylene (PE)) on plant and animal models. Aqueous extracts of microplastics in different size fractions (0.175 mm, 0.3 mm, 1 mm, 2 mm, and 3 mm) were evaluated for their impact on barley seed germination and cell division. Results indicated that smaller microplastic fractions exhibited higher toxicity, particularly for PP and PE. Significant reductions in germination rates and root growth were observed, along with increased chromosomal aberrations in barley cells. Furthermore, the migration of formaldehyde, a known toxicant, from microplastics exceeded permissible limits. These findings highlight the potential risks associated with microplastic pollution, particularly in drinking water sources. Future research should focus on the long-term health impacts of microplastic exposure, including carcinogenic potential, and explore the synergistic effects with other pollutants. Stricter regulations on microplastic pollution and advancements in water treatment technologies are urgently needed to mitigate these risks.

Response Surface Methodology: A Review on Optimization of Adsorption Studies

Herein, we reviewed response surface methodology (RSM), a powerful statistical tool widely used in optimizing adsorption processes to remove synthetic dyes, toxic heavy metals, and phenols from wastewater. The widely used RSM models during optimization are the central composite design and Box-Behnken, which are second-order polynomial models. The models give a predictive insight into the number of experimental runs to be carried out. Furthermore, an in-depth overview of RSM and its application in optimizing various adsorption parameters, such as adsorbent dosage, initial pollutant concentration, contact time, and pH is discussed. In addition, RSM enables researchers to efficiently determine the optimal conditions for maximum pollutant removal. Lastly, the findings of this research highlight the potential of RSM as a valuable tool for optimizing adsorption processes and contributing to sustainable water treatment technologies.

Mechanically Induced Green Targeted Conversion of Ammonia Nitrogen to N2: Based on Cavitation Effects and ROS Oxidation.

Addressing the mounting challenge of ammonia nitrogen pollution in aquatic ecosystems necessitates the selective oxidation of ammonia nitrogen to nitrogen gas, a pivotal aspect of eco-friendly nitrogen removal processes. Ultrasound cavitation, renowned for its capacity to generate reactive oxygen species (ROS), has garnered considerable attention in environmental remediation. This study reveals a highly synergistic mechanism in ultrasound coupled stirring (US-ST), establishing optimal coupling conditions through sound field monitoring and quantification of ROS. In comparison to ultrasound treatment alone (US), the sound pressure amplitude significantly increased from ±18 to ±30 kPa in US-ST, markedly reducing the cavitation nucleation threshold and augmenting the steady-state concentration of hydroxyl radicals (HO•) by 13-fold. Further, with appropriate charge transfer conditions enabled by the acoustoelectric characteristics of the passive film on stirring paddles, the concentrations of superoxide (•O2-) and singlet oxygen (1O2) elevated to 9.54 × 10-10 M and 8.43 × 10-13 M, respectively. Under the regulation of 500 rpm stirring vortex, a maximum sonochemical efficiency of 6.5 × 105 mg J-1 was achieved. In the context of domestic wastewater, ammonia nitrogen degradation was achieved through the oxidation and thermal dissociation effects of US-ST. The concentration decreased from 27.5 to 3.4 mg/L after 2 h, with an impressive N2 selectivity of 96.8%. This study elucidates the targeted conversion mechanism of ammonia nitrogen in US-ST, introducing an emerging water treatment technology propelled by mechanical energy.

Sonophotocatalytic degradation of rhodamine B dye using Zr doped ZnO nanoparticles: Kinetic study and toxicity assessment

This study investigates sonophotocatalysis for the oxidation of Rhodamine B (RhB) dye using Zr doped ZnO nanoparticles. The synthesized nanoparticles were characterized by scanning electron microscope, Fourier-transform infrared, X-ray diffraction, Brunauer Emmett-Teller, thermogravimetric analysis, and photoluminescence. The hybrid sonophotocatalysis system achieved 98.73 ± 1.25% degradation of RhB under the conditions: RhB dye concentration = 10 ppm, 4 wt% of Zr doped ZnO = 0.1 g, reaction temperature = 30 °C, time = 60 min, pH = 7. A kinetic model was developed to predict the efficiency of RhB degradation through intrinsic elementary chemical reactions. The high coefficient of determination (R2 = 0.96) indicates the model's prediction accuracy in describing the degradation kinetics of RhB within sonophotocatalysis system. The electrical energy per order (EEO) analysis demonstrated that US + UVC + 4 wt% of Zr doped ZnO significantly reduced EEO (1055 kWh m−3 order−1). The synergy index for this combination was approximately 1.60, demonstrating a significant synergistic effect. Density Functional Theory (DFT) studies were utilized to propose the most probable degradation pathway, identifying reactive sites and potential byproducts. The simulations revealed the central carbon atom (1C site) as highly susceptible to radical attacks, indicating potential decolorization pathways such as N-de-ethylation, chromophore cleavage, and ring opening. Toxicity assessments of both the parent dye and its intermediates were conducted using ECOSAR (Ecological Structure Activity Relationship) to evaluate their ecological impacts. The combination of experimental results and kinetic modeling and simulations offers a deep understanding of RhB degradation complexities, driving advancements in sustainable water treatment technologies.

Evaluation of pilot-scale drinking water treatment trains using a panel of bioassays

ABSTRACT Chemical water quality monitoring is increasingly complemented with bioassays. In this study, the performance of drinking water treatment technologies was evaluated with bioassays. CALUX reporter gene bioassays and the Ames fluctuation bioassay for mutagenicity were used to analyze the responses of raw feed water with and without a spiking mixture of organic contaminants in five different pilot-scale water treatment trains applying advanced oxidation processes, reverse osmosis and filtration with (biological) activated carbon for the preparation of drinking water. In general, CALUX responses in the spiked feed water were in the same range as in the unspiked feed water, indicating that spiking did not significantly elevate the activity measured in the feed water. This observation was in line with a calculation of the combined additive behavior of the spiking mixture using bioactivities of the spiked chemicals in analog bioassays from ToxCast. This calculation gave no indication of a measurable response in the bioassays to be expected by the spiking, except for oxidative stress. Responses in the Ames fluctuation assay in most feed water were in some cases increased by AOP and mostly removed by active concentrations. The bioassay responses demonstrate the removal of emerging chemicals with different mechanisms of action by different water treatment technologies.

Catalyst Activation of Peroxymonosulfate for Reactive Species Generation and Organic Pollutant Degradation: A Mini Review

This review focuses on the application and mechanisms of peroxymonosulfate (PMS) in advanced oxidation processes (AOPs). It clarifies the significance of PMS in degrading organic pollutants, highlighting its high efficiency in treating persistent contaminants, such as antibiotics. The review details the roles and mechanisms of various catalysts, including single-atom catalysts, metal oxides, non-metal oxides and their composites, as well as metal-organic frameworks (MOFs), in activating PMS. It emphasizes the influence of catalyst surface active sites on both radical and nonradical activation pathways. Key factors affecting PMS activation efficiency, such as PMS concentration, pH value, coexisting ions, and temperature, are examined to underline the importance of optimizing these parameters for effective reaction conditions. By synthesizing existing research, the review not only illustrates the extensive application potential of PMS in AOPs but also identifies future research challenges and directions. This provides a theoretical foundation and technical support for developing efficient, economical, and sustainable water treatment technologies.

Turning Corn Stalk Trashes into a Photothermal Agent for Interfacial Solar Water Evaporation for Sustainable Water Purification

Biomass‐based photothermal materials have a higher photothermal conversion efficiency and contribute significantly to improved solar water evaporation systems. This work aims to transform corn stalk (CS) trash into efficient photothermal materials with centralized and less‐contact area water supply systems to achieve enhanced interfacial heat accumulation. We successfully synthesized cornstalk biochar synthesized via pyrolysis to maintain the environmental concern and is deposited onto a scalable, and cost‐effective (<1$) polyurethane foam (triangle shape, where the tip plays the wick and centralized water supply). The detailed characterizations validate the porous structure of CS biochar‐coated PU foam (CSB@PU), and enhance interfacial heat accumulation up to 47.8 °C under 1 kW m−2 solar irradiation which is endowed via thermal management of polystyrene foam (PS). This reproducible interfacial heat accumulation and sustainable evaporator bestow a water evaporation rate of up to 1.38 kg m−2 h−1, and solar‐to‐vapor conversion efficiency (84%) under one sun which is more efficient than other biomass‐derived evaporators. Inductively coupled plasma‐optical emission spectroscopy analysis validates the reductions of primary (Na+, K+, Mg2+, and Ca2+) and heavy metal ion (Fe3+, Hg2+, Cd2+, and Pb2+) concentrations in condensate, insights the potential of CSB@PU to advance the water treatment technologies.

Adsorption Removal of Organophosphates from Water by Steel Slag: Modification, Performance, and Energy Site Analysis

Organophosphates are a type of emerging environmental contaminant, which can be removed effectively by adsorption. Here, modified steel slag was examined for its adsorptive performance in the removal of hydroxyethylidene diphosphonic acid (HEDP) from water. Compared to acid (55.3%, maximum removal rate) and base (85.5%) modification, high-temperature modification (90.6%) significantly enhanced steel slag’s adsorption capacity for HEDP, surpassing that of unmodified slag (71.2%). Kinetic analyses elucidated a two-phase adsorption process—initial rapid adsorption followed by a slower equilibrium phase. The results of adsorption energy analysis showed that modified steel slag preferentially occupied the sites with higher energy, which promoted the adsorption. After five regeneration cycles, the adsorption properties of the material were not significantly reduced, which indicates that the material has good application potential. Microscopic and spectroscopic techniques, including SEM-EDS, FTIR, and XPS, were employed to uncover the surface chemistry and structural changes responsible for the enhanced adsorption efficiency. The adsorption mechanism of HEDP on steel slag is a complete process guided by hydrogen bonding interactions, strengthened surface complexation, and optimized ligand exchange. This study advances the sustainable utilization of industrial waste materials and contributes significantly to the development of innovative water treatment technologies.

European approaches to wastewater reuse regulation: A comparison between Spain, Malta and the Netherlands

AbstractWastewater reuse is encouraged and facilitated by legislation and policy across the EU. A recent example is the EU Regulation 2020/741 on minimum requirements for water reuse. This and other regulatory developments have gone hand in hand with an increase in research in technological innovations that facilitate wastewater reuse, including advanced water treatment technologies. Despite these harmonised developments at the EU level, there appear to be large differences across Member States in the volume of reused water, its sources and the purposes of wastewater reuse. These differences are mirrored in the differences in the regulation of wastewater reuse across the European Union. The present paper has two goals. The first is to provide an overview of the regulation of wastewater reuse in three EU Member States, namely, Spain, Malta and the Netherlands. The comparative analysis reveals evidence of variability in the division of roles and responsibilities, substantive provisions on water reuse, and the allocation of costs. The second objective of the paper is to highlight how, even within the boundaries of the theoretical best practices, national regulation can be heterogenous.

Enhancing nanofiltration performance with tannic acid and polyvinyl alcohol interlayers for improved water permeability and selective solute rejection

Global water shortages have significantly intensified the demand for efficient and sustainable water purification technologies. Nanofiltration (NF) plays a crucial role in desalination, providing distinct advantages by removing a variety of pollutants including heavy metals and organic compounds, all while consuming minimal energy. Traditional NF membranes often struggle to balance high rejection with satisfactory permeability. This study advances NF technology by utilizing polysulfone as a durable substrate and introducing tannic acid (TA)-polyvinyl alcohol (PVA) interlayer to enhance structural robustness and functional capabilities of membranes. Through streamlined one-step coating followed by precise interfacial polymerization, this approach optimizes monomer piperazine storage and dispersion on substrate, effectively controlling its diffusion rate, resulting in a thinner polyamide (PA) layer. These strategic enhancements not only lead to a significant increase in permeability to 216.3 L·m−2·h−1·MPa−1 and an impressive rejection for Na2SO4 of 99.04 % but also ensure enhanced long-term operational stability. The innovative TA-PVA interlayer sets new benchmarks for high-performance NF membranes by combining environmental friendliness with cost-effectiveness, making it ideal for large-scale industrial applications. This unique composition promotes sustainability and economic efficiency in water treatment technologies, and underscoring the vast potential for expanding the production and application of advanced NF systems.

Can air nanobubbles improve the swim bladder inflation in developing European perch? A pilot study of advanced water treatment.

Swim bladder inflation (SBI) is a fundamental step in larval development for both physostome and physoclist fish species. Failure of the SBI triggers higher energy expenditures of the individual, which negatively affects swimming ability, growth rate, feeding efficiency, susceptibility to predation, and survival rate. In aquaculture, the SBI failure is caused by different factors including: (a) water contamination with oil increasing the surface water tension and preventing the larvae from gulping air bubbles for inflation, and (b) bacterial aerocystitis of the swim bladder caused by gulped organic debris. Hence, novel and effective water treatment technologies such as nanobubbles can be employed in aquaculture to reduce the risk of low SBI. In the present study, we compared conventional water treatment, i.e. surface spray combined with skimmers with air nanobubbles either alone or in combination, on the SBI of European perch larvae. In the control, no water treatment technology was employed. All treatments showed higher SBI efficiency compared to the control. The control group showed the lowest percentage of swim bladder-inflated individuals associated with low body weight (BW). The highest BW and SBI efficiency was recorded with the combination of surface skimmer, spray, and nanobubbles. The current study offers the first investigation of the nanobubbles' effect on SBI promotion in larvae of European perch and gives motivation for future optimizations.

MoS2–CdS Composite Photocatalyst for Dye Degradation: Enhanced Apparent Quantum Yield and Reduced Energy Consumption

AbstractThis study investigates the visible light‐assisted photocatalytic degradation of rhodamine B (Rh B) dye using MoS2–CdS nanocomposite. Two crucial operational parameters, illumination time and the weight ratio of MoS2 to CdS, are systematically examined. Approximately, 91.9% of Rh B solution with a concentration of 10 mg/L is degraded by the MoS2–CdS photocatalyst under 60 min of illumination, with a photocatalyst dosage of 0.5 g/L. The results are consistent with a pseudo‐first‐order kinetic model, wherein the degradation rate constant of CdS increases fourfold after amalgamation with MoS2. The formation of the composite with MoS2 results in 1.72 times increase in the apparent quantum yield and 3.15 times decrease in the electrical energy consumption per order of CdS nanorods under similar experimental conditions. The investigation also comprehensively explores the reactive species responsible for Rh B degradation under visible light in the presence of MoS2–CdS photocatalyst. This analysis confirms that both hydroxyl and superoxide anion radicals play a dominant role in Rh B degradation. These findings underscore the potential practical applications of MoS2–CdS nanorods in eco‐friendly water treatment technologies, offering efficient and sustainable solutions to contemporary environmental challenges.

Improved ultrafiltration performance through dielectric barrier discharge/sulfite pretreatment: Effects of water matrices and mechanistic insights

The feasibility of utilizing a dielectric barrier discharge (DBD)/sulfite-ultrafiltration system was investigated in various real water bodies, aiming to clarify the mechanism behind alleviating membrane fouling while synchronously degrading perfluorooctanoic acid (PFOA) during the treatment process of Yangtze River water. The results demonstrated that the DBD/sulfite pretreatment exhibited remarkable rates of membrane flux mitigation (>84.10%) and efficient degradation rates of PFOA (>85.13%), which decreased with increasing pH from 3.0 to 11.0. The presence of anions, cations, and natural organic matter slightly hindered the membrane fouling mitigation and PFOA degradation by quenching free radicals; however, the addition of SO42− had a negligible impact. The mitigation of membrane fouling was attributed to the significant involvement of various radicals, including hydroxyl radical (•OH), sulfate radical (SO4•−), electron (e−/eaq−), su-peroxide anion radicals (•O2−), and other radicals such as SO3•−, exhibiting respective contributions of 33.25%, 28.49%, 20.56%, 11.32%, and 6.39% in a synergistic redox effect. The pretreatment effectively reduced standard blocking and cake filtration fouling mechanisms by creating a sparse fouling layer on the membrane surface while increasing its roughness. Additionally, the main active species that played a significant role in the degradation of PFOA were identified as SO4•−, •OH, and eaq−. These species contributed approximately 43.63%, 24.39%, and 20.65% respectively to the degradation process. By employing mass spectrometry and density functional theory, a proposed pathway for PFOA degradation was established, effectively reducing the toxicity associated with its degradation byproducts. This study provides innovative insights into membrane-based water treatment technologies that effectively tackle both membrane fouling mitigation and PFOA degradation.

Determining the Suitable Location of Constructed Wetland for the Polluted River Water Treatment Based on Analytical Hierarchy Process and Geographic Information System Analysis

The Tukad Badung River is a vital raw water source in Denpasar City and Badung Regency. Concerning the water pollution of the river, water treatment is necessary to manage the water quality. Constructed wetlands are a water treatment technology used for water purification. In this regard, information is essential regarding the appropriate location for the placement of the constructed wetland based on criteria related to the water treatment plant. The research was conducted to determine the suitability level of water treatment locations in the watershed using the Analytic Hierarchy Process method in integration with a Geographic Information System. The Geographic Information System analysis included overlaying steps of the processed and classified data from each criterion: land use, slope, and water pollution index. The Analytic Hierarchy Process method was carried out to obtain the weight of each criterion down to the sub-criteria, which were compiled through interviews with three informants from academic, government, and community representatives. Weight calculations were performed using Expert Choice 11 software to obtain weight values with a consistency ratio of < 0.1. Geographic Information System analysis using the Analytic Hierarchy Process method produces three suitable land types according to the level of suitability for water treatment locations, with constructed wetlands located in the upstream, middle, and downstream parts of the river. Information regarding suitable land is useful for planning the technical design of water treatment plants with constructed wetlands.

Investigating the catalytic and antibacterial behavior of cesium-doped MoO3 nanostructures against methylene blue dye and MDR E. coli with DFT analysis

Water pollution, exacerbated by inadequate water management practices, has compromised the effectiveness of traditional water treatment technologies. The integration of metal oxide-based nanomaterials in treatment systems has the potential to revolutionize the field of wastewater treatment, providing a sustainable and efficient solution to the growing global water crisis. This study focused on the fabrication of hexagonal cesium (Cs) doped MoO3 nanostructures (NSs) for their potential use as catalytic and antibacterial agents. Various structural, optical, and morphological analysis was conducted to examine these NSs. The UV–Vis spectroscopy results showed that as Cs concentration increased, the band gap energies of MoO3 decreased from 3.5 eV to 3.0 eV. The field emission scanning electron microscopy (FESEM) investigation revealed the plate-like structural morphology of MoO3 formed by overlapping one layer onto another. Cs doping effectively inhibited the recombination of photo-generated charge carriers, resulting in a significant reduction in PL peak intensity for Cs-doped MoO3 compared to MoO3. The prepared NS-reduced methylene blue dye in the absence of light under different pH conditions, reaching 86.8% with 2% Cs-doped MoO3. Density functional theory (DFT), utilizing the Heyd-Scuseria-Ernzerhof hybrid (HSE06) method, was employed to model and compute the interactions between methylene blue (MB) and Cs-doped MoO3 during MB adsorption. Bactericidal experiments on multidrug-resistant Escherichia coli showed that the NSs had remarkable antibacterial action, generating an inhibition zone of 9.15 mm at higher doses using 6% Cs-doped MoO3. Consequently, these findings offer potential significance for research in developing and implementing wastewater disinfection systems.

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.

Sucralose and caffeine as chemical indicators of domestic wastewater contamination in the Laurentian Great Lakes Basin.

Surface waters within the basin of the Laurentian Great Lakes are impacted by microbial contamination from municipal wastewater and agricultural runoff, as well as from other sources. In particular, microbial contamination of drinking water is an ongoing problem within many Indigenous communities located in the basin. However, it is difficult to identify the sources of microbial contamination using the traditional monitoring approaches with fecal indicator bacteria, such as total coliforms and Escherichia coli (E. coli). In this study, we evaluated whether surface waters in the basin are contaminated with fecal bacteria of human origin using chemical indicators of domestic wastewater (i.e., caffeine and sucralose) and with Bacteroidales 16S rRNA markers. Study areas included the Grand River watershed within the Lake Erie basin and three nearshore locations within the Great Lakes basin. Two of these sites are sources of drinking water for Indigenous communities. We assessed whether there were relationships between the concentrations of fecal indicator microorganisms and chemical indicators of domestic wastewater at selected study locations. Analysis of genetic markers indicated that about 30% of the Bacteroidales bacteria present at a site in the Grand River were of human fecal origin and the balance were of bovine or general animal origin. The presence of caffeine and sucralose in surface waters indicated that there was upstream contamination by domestic wastewater. However, in the drinking water treatment plant operated by Six Nations of the Grand River, the levels of these chemical indicators and fecal bacteria were reduced by the advanced water treatment technologies. The concentrations of sucralose and caffeine collectively were strongly correlated with the levels of total coliforms in samples from the Grand River (R2 = 0.75) and with levels of E. coli in samples from the Great Lakes basin (R2 = 0.97), but there appeared to be an upper threshold for this relationship. These data indicate that analysis of caffeine and sucralose and genetic markers for strains of Bacteroidales fecal bacteria may be useful tools for identifying the sources of microbiological contamination of surface waters and drinking water.

Optimizing natural organic matter removal at the Koka water treatment plant, Ethiopia, using soil–alum composite material

ABSTRACT Conventional water treatment methods often fail to remove natural organic matter (NOM), leading to the formation of harmful disinfection by-products in chlorinated water. This study aimed to develop a synergistic, local soil–aluminum sulfate (alum) composite material to enhance NOM removal from real water samples. Locally derived soil (Chalaltu) samples were collected from selected locations and subjected to thermal treatment at elevated temperatures. The thermally treated soil was then combined with alum at varying mixing percentages to create the composite material. The synthesized composite materials were thoroughly characterized using X-ray diffraction, X-ray fluorescence, scanning electron microscopy, Fourier transform infrared, and Brunauer–Emmett–Teller techniques. The alum-treated soil, obtained through thermal treatment at 500 °C with a mixing ratio of 50%, a dosage of 25 mg/L, and a settling time of 25 min, exhibited impressive removal efficiencies. The composite material increased removal efficiency by 1.5 times for both UV254 absorbance (91.1%) and dissolved organic carbon (90%), while reducing the alum dose by 58% compared to the existing Koka water treatment plant process. Reducing alum usage could lead to cost savings and alleviate concerns about its association with Alzheimer's disease. This technique is essential within the context of water treatment technology.

Fouling of Reverse Osmosis (RO) and Nanofiltration (NF) Membranes by Low Molecular Weight Organic Compounds (LMWOCs), Part 1: Fundamentals and Mechanism.

Reverse osmosis (RO) and nanofiltration (NF) are ubiquitous technologies in modern water treatment, finding applications across various sectors. However, the availability of high-quality water suitable for RO/NF feed is diminishing due to droughts caused by global warming, increasing demand, and water pollution. As concerns grow over the depletion of precious freshwater resources, a global movement is gaining momentum to utilize previously overlooked or challenging water sources, collectively known as "marginal water". Fouling is a serious concern when treating marginal water. In RO/NF, biofouling, organic and colloidal fouling, and scaling are particularly problematic. Of these, organic fouling, along with biofouling, has been considered difficult to manage. The major organic foulants studied are natural organic matter (NOM) for surface water and groundwater and effluent organic matter (EfOM) for municipal wastewater reuse. Polymeric substances such as sodium alginate, humic acid, and proteins have been used as model substances of EfOM. Fouling by low molecular weight organic compounds (LMWOCs) such as surfactants, phenolics, and plasticizers is known, but there have been few comprehensive reports. This review aims to shed light on fouling behavior by LMWOCs and its mechanism. LMWOC foulants reported so far are summarized, and the role of LMWOCs is also outlined for other polymeric membranes, e.g., UF, gas separation membranes, etc. Regarding the mechanism of fouling, it is explained that the fouling is caused by the strong interaction between LMWOC and the membrane, which causes the water permeation to be hindered by LMWOCs adsorbed on the membrane surface (surface fouling) and sorbed inside the membrane pores (internal fouling). Adsorption amounts and flow loss caused by the LMWOC fouling were well correlated with the octanol-water partition coefficient (log P). In part 2, countermeasures to solve this problem and applications using the LMWOCs will be outlined.

Visible-light assisted peroxymonosulfate process for efficient water treatment via Fe-O embedded ZIF-62

The development of efficient and environmentally friendly water treatment technologies is essential for the treatment of emerging pollutants. In this study, a ZIF-62 catalyst embedded with Fe-O was prepared for the visible-light assisted activation of peroxymonosulfate (PMS) to achieve the removal of bisphenol A by coupling photogenerated carriers with the non-radical pathway. The embedding of Fe-O narrowed the bandgap width (reduced from 3.07 eV to 2.37 eV), enhanced the overall photoresponse performance, and improved the segregation of photogenerated carriers. The upward shift of the d-band center contributes to the adsorption of PMS. The embedding of Fe-O improves the BPA removal kinetics by a factor of 15.4 (increased from 0.00391 min−1 to 0.06005 min−1). Surface-activated complexes played a dominant role in the removal of BPA in this system, and photogenerated holes (h+) and singlet oxygen (1O2) were also involved in the removal of BPA. In addition, the system has good pH adaptability (pH = 3 ∼ 11) and good environmental suitability. Toxicity assessment showed that the overall toxicity of the intermediates tended to decrease. This study provides new insights into visible-light assisted activation of PMS.