Advanced Water Treatment Technologies Research Articles

Hydrothermal Synthesis of CuO/WO3 Hybrid Bifunctional Composites with Unprecedented Dark Adsorption and Photocatalysis

AbstractThis study presents the synthesis and characterization of Copper Oxide/Tungsten Oxide (CuO/WO3) hybrid bifunctional composites using a hydrothermal approach. X‐ray diffraction (XRD) analysis confirms the successful synthesis of CuO/WO3 hybrids, exhibiting additional peaks corresponding to WO3 phases. Scanning electron microscopy (SEM) images reveal well‐defined, aggregated particles with a nanoscale pattern and uniform distribution of CuO and WO3 throughout the composite. Energy‐dispersive X‐ray spectroscopy (EDX) confirms the stoichiometric composition of CuO/WO3 hybrids. Evaluation of dark adsorption and sunlight‐assisted photocatalysis using methylene blue (MB) dyes shows a remarkable enhancement in efficiency compared to pristine CuO. The CuO/WO3 hybrids exhibit a dark adsorption capacity of 87 % and a photocatalytic degradation efficiency of 95 % under sunlight illumination, outperforming pure CuO. These results underscore the synergistic interaction between CuO and WO3, facilitating efficient pollutant removal. The study elucidates the structural properties and mechanistic insights driving the superior performance of CuO/WO3 hybrid composites, offering promising prospects for advanced water treatment technologies.

Long-term pilot study on advanced treatment of lake water by ultrafiltration / nanofiltration

Advanced water treatment technologies, including ozone biologically activated carbon adsorption (O3-BAC), ultrafiltration (UF), and nanofiltration (NF), are essential for enhancing drinking water quality. O3-BAC and UF excel in pathogen, virus, and by-product removal, while NF promises enhanced contaminant elimination for high-quality water. However, the implementation of combined UF/NF dual-membrane treatment processes in large-scale water treatment facilities using surface water sources like lakes remains relatively novel. The lack of long-term operational data is the main reason for the limited widespread adoption. To address this, two pilot systems were established: one comprising ‘O3-BAC + pressure-driven UF(I) + NF(I) (Route 1 at 6.4m3/h)’, and the other ‘immersed UF(II) + NF(II) (Route 2 at 3.2m3/h)’, undergoing a year-long evaluation. The trials showed that the dual-membrane systems were effective and resistant to interference. Notably, they achieved removal efficiencies exceeding 98 % for turbidity, UV254 absorbance, fluorescence substances, and algae, alongside significant reductions in odor (80 %) and total dissolved solids (TDS) by 30 %. Both membrane systems display promising performance and O3-BAC is recommended as a pretreatment process. Analysis revealed that the primary constituents of membrane fouling on the NF membranes are aluminum silicate, SiO2, CaCO3 particles, and organic pollutants, which are typically formed through interactions between calcium ions and dissolved organic matter (DOM). The most effective cleaning protocol involves acidic-alkaline treatments. This study provides valuable operational insights into advanced treatment processes using dual-membrane combinations for water treatment plants that rely on lake water sources.

Enhancing Ion Separation Efficiency: Janus Charged Nanofiltration Membrane Fabricated via Polyethyleneimine-Manipulated Interfacial Polymerization

This research introduces highly efficient nanofiltration (NF) membranes designed for the effective rejection of both divalent cations and anions, a critical feature for advanced water treatment technologies. We have devised a simple yet adaptable approach for fabricating Janus polyamide (PA) thin-films characterized by dual charges, which exhibit pronounced selectivity towards both mono-/divalent anions and cations. Leveraging a straightforward interfacial polymerization (IP) process, we integrated high molecular weight polyethyleneimine (PEI) within the PA matrix. This strategy ensured the preferential formation of a dense, negatively charged upper layer dominated by piperazine (PIP), while the substantial molecular size of PEI facilitated the emergence of a loose and positively charged lower layer, thus giving rise to a distinctively charged and structurally heterogeneous PA thin-film. Furthermore, the strategic inclusion of PEI inhibits the diffusion of the PIP, thereby promoting the development of nano-wrinkled structures. This structural innovation not only enhances pure water permeance (16.0 L m‒2 h‒1 bar‒1) but also optimizes ion selectivity through the coordination of steric hindrance and Donnan effects. Consequently, the Janus charged NF membranes we developed exhibit exceptional selectivity for mono-/divalent ions, particularly demonstrating remarkable ion selectivity for Cl‒/SO42‒ and Li+/Mg2+ of 102 and 24, respectively. Our findings introduce a pioneering avenue for fabricating NF membranes that proficiently separate mono-/divalent ions, promising significant advancements in water treatment and purification endeavors.

Impact of Industrial Water Usage on Aquatic Biodiversity in the Yangtze River Delta and Its Economic Valuation

The Yangtze River Delta (YRD), a pivotal economic and ecological region in China, faces significant environmental challenges due to rapid industrialization and urbanization. This paper explores various strategies and technologies aimed at mitigating the adverse impacts of industrial activities on the region’s aquatic ecosystems and biodiversity. We examine the implementation of advanced water treatment technologies, the adoption of sustainable industrial practices, and the enforcement of stringent environmental regulations. Predictive models are discussed as essential tools for forecasting environmental changes and guiding conservation efforts. The paper highlights the importance of an integrated approach involving government, industries, and communities to ensure sustainable development. By adopting these strategies, the YRD can achieve a balance between economic growth and environmental sustainability, serving as a model for similar regions globally.

Synthesis of Fe(III)-g-C3N4 and Applications of Synergistic Catalyzed PMS with Mn(VII) for Methylene Blue Degradation

Refractory organic pollutants pose a great threat to public health in water bodies due to their toxicity and low biodegradability. Developing a method of activating persulfate efficiently and in an environmentally friendly way has become a popular topic of research in current advanced oxidation water treatment technologies. Fe(III)-g-C3N4 was prepared by the calcination method. Fe(III) was anchored on the framework of g-C3N4. The characterization analysis indicated that Fe(III) was successfully loaded on g-C3N4. The best effect for MB degradation was Fe(III)-g-C3N4 (0.1 g/L) dosed with 30 µmol/L KMnO4 for synergistic catalyzed PMS (0.1 g/L), where the degradation rate could reach 95.4%. The optimum temperature for MB degradation was determined to be 10 °C. The optimum pH range of Fe(III)-g-C3N4/Mn(VII) synergistic catalyzed PMS for MB degradation was pH 4.4–6.6 under acidic conditions, and the optimum pH range for MB degradation was pH 8–10 under alkaline conditions. The Fe(III)-g-C3N4/Mn(VII) synergistic catalyzed PMS system was also tested for the degradation of methyl orange and rhodamine b, and good degradation results were obtained with the degradation rates of 87.37% and 84%, respectively. It facilitates the reduction in pollutant emissions, improves water quality and will have a positive impact on the sustainability of the environment.

Unlocking the paracetamol adsorption mechanism in graphene tridimensional-based materials: an experimental-theoretical approach

The omnipresence of emerging contaminants in the aquatic environment is indisputable. These contaminants include chemical substances not removed in traditional water and sewage treatment processes. To ensure the quality of water and healthy aquatic ecosystems, new treatment technologies and materials are essential to effectively control the presence of these contaminants in the aquatic environment. More than that, it is important to know how molecules interact with these new materials. A low-cost alternative currently available is adsorption. Despite this method being widely studied, describing the interaction mechanisms between the materials and the analytes is not usual, limiting the obtainment of more efficient materials. Thus, the objective of this work was to understand, in a theoretical-experimental way, the forms of interaction in the adsorption of the drug paracetamol, widely used worldwide, in materials based on graphene with different chemical and structural properties. For this, kinetic and isothermal experimental studies were carried out using four materials that contemplated different dimensions, pore sizes, and oxidation degrees. In theoretical studies, density functional theory (DFT) simulations were performed to cover quantum details, revealing how paracetamol interacts with different graphene structures. According to theoretical studies, binding energies, binding distances, and charge transfer between oxidized graphene and paracetamol drug are compatible with physical adsorption, strongly dependent on the type and number of functional groups on the graphene surface. These results agree with the experimental data where the highest adsorptions were observed precisely for materials containing a higher proportion of functional groups and where these groups are more available (more porous), with adsorptive capacities reaching 235.7 mg/g. Our findings contribute to scientific knowledge about using graphene structures as an adsorbent material, providing a solid basis for future studies and developing more efficient and advanced water treatment technologies.

High conductive polymer PANI link Bi2MoO6 and PBA to establish “tandem hybrid catalysis system” by coupling photocatalysis and PMS activation technology

In order to design an efficient advanced oxidation system to improve the inherent limitations in removing refractory organic pollutants, we couple photocatalysis and peroxymonosulfate (PMS) activation technology to establish a tandem hybrid catalysis system inspired by series hybrid electric vehicles. Among them, Bi2MoO6, as an electric power source, can be driven by fuel (light) to generate continuous power (electron) input into the prussian blue analogues (PBA) through the transmission shaft polyaniline (PANI), allowing it to respond quickly and continuously activate PMS. Therefore, it exhibits excellent catalytic performance to degrade DC increased by 55%, and the catalytic rate constant k increased by 7 times compared with the PMS alone. Continuous flow experiments are explored to reveal the feasibility of engineering applications. This study provides a new strategy of tandem hybrid catalysis system to drive future advanced water treatment technologies.

Peroxymonosulfate activation by boron doped C3N5 metal-free materials with n → π* electronic transitions for tetracycline degradation under visible light: Insights into the generation of reactive species

Heterogeneous photocatalysis coupled with peroxymonosulfate (PMS) activation is regarded as an advanced water treatment technology for emerging contaminates degradation. We introduce a novel coupling system that integrates PMS with metal-free visible light-driven photocatalysis, utilizing boron doped C3N5 (BCNs), with the objective of swiftly eliminating tetracycline (TC) from wastewater. With commendable traits including a robust response to visible light, n → π* electronic transitions and a narrow bandgap, 3BCN optimized from BCNs, exhibited superior catalytic activity in photocatalysis and PMS activation. In 3BCN/PMS/vis system, the degradation efficiency of TC reached 88.6 % in 120 min, with an observed rate constant (kobs) of 0.0222 min−1 for TC removal. Moreover, in real water matrices including tap water, landscape water and secondary effluent, the 3BCN/PMS/vis system consistently maintained high and stable pollutant removal efficiency. To elucidate the underlying mechanisms, the origins of reactive species (h+, SO4−•, •OH and 1O2) were identified and the enhanced pathways in the PMS-based photocatalytic system were systematically investigated. Based on theoretical calculations, generation pathway of reactive oxygen species involving PMS oxidation and reduction over the region of boron atom neighboring N in BCN was unraveled. The BCN catalyst was employed in a flow-through device to explore its potential in practical application. The results showed that continuous and impressive efficient removal of TC was achieved with over 93 % removal rate during 32 h operation. Our findings underscore the substantial promise of chemical-photocatalysis synergy for environment remediation, offering a feasible approach to optimize the performance of metal-free materials in photo-catalytic oxidation of antibiotics.

Trihalomethanes in developed and developing countries.

The reactions between natural organic matter, anthropogenic contaminants, ions, and disinfectants lead to the formation of disinfection by-products (DBPs) such as trihalomethanes (THMs) in drinking water. The formation of THMs is strongly related to the chlorination of water. The study's central objective was to compare the concentration of THMs in twenty developed and developing countries and their disinfection techniques. The THM concentration in 11 developed and 9 developing countries ranged from 0.5 µg/L (Germany) to 215 µg/L (Russia) and 3 µg/L (China) to 439.2 µg/L (Bangladesh), respectively. The developed country has partially succeeded in reducing THM concentration in drinking water, whereas significant steps are needed in developing countries to reduce the existing high THM concentration. The concentration of THMs in water varies among these countries because of the different water sources, water quality, environmental conditions, and efficiency of water treatment technologies. A meaningful relationship has been observed between the properties of water and the THM formation. The use of chemical disinfectants will result in new forms of DBPs that are undesirable due to their carcinogenic and mutagenic effects on human health. The DBP guidelines by various national and international agencies have helped to control and manage the THM concentration in drinking water. However, these regulatory standards are not continuously monitored. Therefore, the formation of these compounds should be prevented either by removing THMs forming precursors or by using an integrated approach for controlling THM formation by implementing advanced water treatment technology. Extensive research is desirable in domains like THM minimization strategies which are easy to deploy, scalable, and cost-effective.

Detailed organic characterization of process water to evaluate reverse osmosis membrane fouling in industrial wastewater treatment

One of the major waste streams within the oil and gas (O&G) industry is produced and process water generated during hydrocarbon production and treatment, respectively. In gas production facilities, process water typically has lower salinity (i.e., <10,000 mg/L) which present opportunities for these wastewaters to be treated for beneficial reuse applications via advanced water treatment technologies, such as reverse osmosis (RO) membranes. One of the key challenges for RO membranes application to industrial wastewater treatment is fouling which is frequently attributed to the soluble organics present in the water and/or associated with field chemicals. In this study, a detailed organic characterization methodology, using liquid chromatography with organic carbon detector (LC-OCD) was applied to characterize the organics on a real process water collected from industrial wastewater treatment plant at a gas production facility. Additionally, a rigorous bench-scale testing procedure was implemented to assess the performance of a full-scale RO system with and without activated carbon filter (ACF) pretreatment, making this study the first one to apply LC-OCD methodology on real wastewater to evaluate the fouling of RO membranes deployed at an industrial treatment plant. Bench-scale RO results showed that in the absence of ACF pretreatment, a 12 % decline in membrane permeability (from 1.78 to 1.57 L/(m2-bar-h)) was observed, while no permeability decline was measured after ACF treatment. The organic fouling was confirmed by mass balance calculations on the bench scale experiments as well as Fourier Transform Infrared (FTIR) analysis on the membrane coupons. Moreover, LC-OCD analysis showed that the ACF inlet has a TOC concentration of approximately 3.06 mg/L; of those 1.29 mg/L (42 %) are hydrophobic, and 1.77 mg/L (58 %) are hydrophilic. After ACF treatment, the hydrophobic organics decreased to 0.65 mg/L, revealing that the ACF is removing >50 % of hydrophobic organics which are likely responsible for membrane fouling. Bench-scale operational and water quality results were comparable to the full-scale RO performance data validating the lab testing procedure implemented in this study.

In situ polymerization of three-dimensional polypyrrole aerogel for efficient solar-driven interfacial evaporation and desalination

Solar-driven interfacial evaporation (SIE) and desalination is a promising approach to mitigate the scarcity of freshwater resources. Here, a three-dimensional polypyrrole (3D PPy) aerogel was prepared by in situ polymerization of pyrrole to serve as an independent evaporator. The interconnected pore structure and super-hydrophilicity enabled PPy evaporators with rapid water transport to the top interface (< 5 s). The hydrogen interaction between polymer chains and water molecules induced large amount of intermediate water, thereby reducing the evaporation enthalpy of water in PPy aerogels. As a result, the optimized PPy aerogel attained an evaporation rate of 2.90 kg m−2 h−1 and an energy conversion efficiency of 114% under 1 sun irradiation. Moreover, the generated steam can be accelerated by the convection and an evaporation rate as high as 6.10 kg m−2 h−1 was realized at 2.5 m s−1. The rapid water transport also enabled PPy aerogel with high-efficiency of self-salt-discharge and efficient desalination for 3.5 wt% brine under 2.5 m s−1. In the outdoor SIE experiment, the excellent evaporation performance was achieved at 12:40 (7.04 kg m−2 h−1 under 74.2 mW cm−2 of solar intensity and 2.5 m s−1 of convective flow), and the cumulative evaporation of 41.50 kg m−2 for successive 9 h was obtained. After the evaporation of simulated seawater and heavy metal wastewater, the concentration of collected fresh water could be reduced about 2–3 orders of magnitude. This 3D PPy evaporation platform with high light absorption, porous structure, super-hydrophilic property, effective steam diffusion, and excellent salt resistance provides an effective way to develop advanced solar-driven water treatment technology.

Application of the sulfur-siderite composite filler: A case study of augmented performance and synergistic mechanism for low C/N wastewater treatment in constructed wetland

The urgent need to achieve sustainable development goals and address global climate change calls for innovative solutions in advanced low-carbon water treatment technologies. In this study, constructed wetlands (CWs), a sustainable and multifunctional wastewater treatment technology known for its low cost and energy efficiency, was focused. It was presented a novel approach that employs a sulfur-siderite composite filler in the constructed wetland (SSCF-CW), which demonstrated remarkable removal efficiencies for total phosphorus (TP) ranging from 81.14 % to 98.87 %, nitrate nitrogen (NO3−-N) ranging from 85.23 % to 99.82 %, and total nitrogen (TN) ranging from 91.65 % to 97.01 % in low C/N wastewater treatment. The electron resupply mode of the sulfur and iron cycles plays a pivotal role in enhancing denitrification efficiency. Furthermore, SSCF enhances the resilience of SSCF-CW against shock loadings, providing increased stability and performance with TN removal rate of 2.96 ∼ 3.42 g N·m−3·d−1 while HRT decreased from 48 h to 10 h. Notably, the majority of NO3−-N elimination occurs within the SSCF layer, where Thiobacillus species dominate the denitrification process in SSCF-CW. The introduction of SSCF promotes carbon fixation with the higher relative abundance of DLD gene (5.52 %) in SSCF-CW, benefiting microbial growth and accelerating electron transfer process. Co-precipitation and adsorption pathways in the SSCF layer primarily contribute to TP removal, while iron leaching from SSCF facilitates the formation of iron plaque on roots, establishing an iron reservoir and ensuring bioavailability. These findings highlight the significant potential of SSCF in constructed wetland systems, offering a cost-effective and sustainable low-carbon technology for municipal wastewater treatment.

Unlocking the Potential of Nanobubbles: Achieving Exceptional Gas Efficiency in Electrogeneration of Hydrogen Peroxide.

The electrogeneration of hydrogen peroxide (H2 O2 ) via the oxygen reduction reaction is a crucial process for advanced water treatment technologies. While significant effort is being devoted to developing highly reactive materials, gas provision systems used in these processes are receiving less attention. Here, using oxygen nanobubbles to improve the gas efficiency of the electrogeneration of H2 O2 is proposed. Aeration with nanobubbles is compared to aeration with macrobubbles under an identical experimental set-up, with nanobubbles showing a much higher gas-liquid volumetric mass transfer coefficient (KL a) of 2.6 × 10-2 min-1 compared to 2.7 × 10-4 min-1 for macrobubbles. Consequently, nanobubbles exhibit a much higher gas efficiency using 60% of O2 delivered to the system compared to 0.19% for macrobubbles. Further, it is observed that the electrogeneration of H2 O2 using carbon felt electrodes is enhanced using nanobubbles. Under the same dissolved oxygen levels, nanobubbles boost the reaction yield to 84%, while macrobubbles yield only 53.8%. To the authors' knowledge, this is the first study to investigate the use of nanobubbles in electrochemical reactions and demonstrate their ability to enhance gas efficiency and electrocatalytic response. These findings have important implications for developing more efficient chemical and electrochemical processes operating under gas-starving systems.

Effects of liquor production wastewater discharge on water quality and health risks in the Chishui River Basin, Southwest China

Learning whether the discharge of large amounts of liquor production wastewater in China affects water quality is crucial to maintaining sustainable economic development, especially in the vulnerable eco-environment of the karst area. The present study investigated the relationship between liquor production wastewater and water quality in the Chishui River Basin for the first time and proposes several constructive suggestions. After river remediation, water quality in spring, summer, autumn, and winter in the Chishui River Basin was found to be at an excellent level, with water quality in winter being the best. Worse water quality and higher health risks were found in liquor production areas (Guling County and Renhuai City) in comparison with other areas. The developed structural equation model showed that physicochemical indexes (especially in N and P) have a higher influence on water quality in comparison with the algae community, heavy metals, and environmental factors. Because liquor being a pillar industry in the locality and these factories discharging an enormous amount of wastewater every year, our results show that liquor production wastewater have affected the water quality to some extent in the Guling County and Renhuai City sections of the Chishui River Basin, and fortunately, the health risks were acceptable in 2020. To prevent potential risks, we suggest that a related department should apply a stricter standard to wastewater discharge. Furthermore, law-enforcement departments can encourage enterprises to develop or introduce more advanced water treatment technologies to achieve as much pollution-free discharge as possible. Our other suggestion is to develop a project to cleanly produce mineral water in high-quality water-resource areas along the Chishui River Basin, contributing to the sustainable growth of the shoreside economy.

Novel Pilot-Scale Photocatalytic Nanofiltration Reactor for Agricultural Wastewater Treatment

Nowadays, the increased agro-industrial activities and the inability of traditional wastewater treatment plants (WWTPs) to eliminate recalcitrant organic contaminants are raising a potential worldwide risk for the environment. Among the various advanced water treatment technologies that are lately proposed for addressing this challenge, the development and optimization of an innovative hybrid photocatalytic nanofiltration reactor (PNFR) prototype emerges as a prominent solution that achieves synergistic beneficial effects between the photocatalytic degradation activity and size exclusion capacity for micropollutant molecules. Both these features can be contemporarily endued to a multitude of membrane monoliths. The physicochemical and the photoinduced decontamination properties of the titania materials were firstly determined in the powder form, and subsequently, the structural and morphological characterization of the obtained titania-modified membrane monoliths were accomplished. The PNFR unit can operate at high water recovery and low pressures, exhibiting promising removal efficiencies against Acetamiprid (ACT) and Thiabendazole (TBZ) pesticides and achieving the recycling of 15 m3/day of real agro-wastewater. The obtained results are very encouraging, demonstrating the integration of titania photocatalysts in a photocatalytic membrane reactor as a feasible technological solution for the purification of agricultural wastewater.

Pilot-scale biofiltration of 1,4-dioxane at drinking water-relevant concentrations

1,4-Dioxane is a drinking water contaminant of emerging concern. Because conventional and many advanced drinking water treatment technologies are ineffective for 1,4-dioxane removal, cost-effective technologies for the removal of 1,4-dioxane at drinking water-relevant concentrations are needed. In this research, a gravity-fed, cometabolic biofiltration system was developed to degrade 1,4-dioxane that was spiked into coagulated, settled surface water at a concentration of ∼10 µg/L. Objectives were to determine whether cometabolic degradation of trace levels of 1,4-dioxane can be sustained using n-butane as primary substrate and whether filter media properties and empty bed contact time (EBCT) affect biofiltration efficiency. A mixed culture of bacteria derived from the Cape Fear River basin and previously enriched using isobutane served as inoculum for biologically active filters. Two granular activated carbons (GACs) with different grain sizes and one carbonaceous resin were used as attachment media, and n-butane served as the primary substrate for biologically active filters. Non-inoculated controls with the same media were evaluated in parallel to distinguish between biological and adsorptive removals of 1,4-dioxane. For the duration of the pilot study (>3 months), 1,4-dioxane was degraded in inoculated biofilters receiving n-butane. In control filters containing larger and smaller grain GAC, 1,4-dioxane broke through completely within 750 and 1250 bed volumes, respectively, corresponding to 15 to 30 days of operation at an EBCT of 30 min. 1,4-Dioxane removal increased with increasing EBCT in all biologically active filters. At an EBCT of 30 min, the biologically active GAC filter containing the larger-grain GAC removed on average 87% of 1,4-dioxane at pseudo steady-state. When the hydraulic loading rate was decreased to achieve an overall EBCT of 60 min, 1,4-dioxane was removed to <1 µg/L in the biologically active GAC filter containing the larger-grain GAC. Activity-based labeling showed the presence of catalytically active monooxygenases in backwash water from biologically active filters that degraded 1,4-dioxane. Amplicon sequencing results showed that while taxa shifted after the initial inoculation of biologically active filters, taxa in biologically active filters remained more similar to the inoculum than those in the non-inoculated control filters. Overall, results of this research demonstrate that cometabolic degradation of 1,4-dioxane at trace levels is possible for extended periods of time in inoculated biofilters that receive n-butane as primary substrate.

Green Synthesis of Nano-Semiconductor Photocatalysts and their Effectivity for Photo-Oxidation of Organic Pollutants in Wastewater: A Review Study

In recent years, green synthesis of nanoparticles (NPs) has been regarded as preferable and acceptable than chemical approaches, particularly when it applies to pollution control and wastewater treatment. The green synthesis approaches were effectively employed to prepare a huge number of semiconductors photocatalysts, such as TiO2 , WO3 , SnO2 , CeO2 , ZnO, Bi2 O3 , Ag, Na2 SeO3 , ZnCr2 O4 , Nb2 O5 , and so on. Photocatalytic degradation is an advanced water treatment technology that has great potential for the photo-oxidation of various organic pollutants and various types of nano-semiconductors photocatalysts. Plant waste has the potential to be more useful in the green synthesis of metal nanoparticles (NPs) due to their availability, high biodiversity, eco-friendliness, and low cost. This review focuses on the employing of plant extracts in the synthesis of nano-photocatalysts as a cost-effective approach. Our study involves reviewing a huge number of impactful studies that deal with the photooxidation of organic pollutants under light radiation. It was concluded that the utilization of waste plants in the green synthesis of nano-photocatalysts is a low-cost technology, environmentally friendly, and can produce nanoparticles with outstanding efficiency for water pollution remediation. This study encourages the development of new technologies based on reusing plant waste in the synthesis of economic photocatalysts for environmental applications.

Potable Reuse and PFAS

Key Takeaways Per‐ and polyfluoroalkyl substances (PFAS) are concerns in water sources because of their potential health effects, widespread detection, and environmental persistence. Potable reuse guidelines and regulations often include monitoring requirements for contaminants of emerging concern. Advanced water treatment technologies used in potable reuse, primarily reverse osmosis and granular activated carbon, are effective at removing PFAS. Regulatory frameworks for potable reuse and PFAS management are evolving at the same time; each framework needs to consider aspects of the other.

Recent advances in the application of carbon nitrides for advanced water treatment and desalination technology

Carbon nitride (CN) and its different derivatives have received increased research consideration in current materials science because of its extensive range of potential applications in environmental protection. At present, the graphitic CN (g-C3N4), an important two-dimensional layered material, has been used in different areas like energy conversion, photocatalysis, and environmental contamination management. Its derivatives have also drawn huge research attention because of its intrinsic characters of their stable chemical and physical properties, eco-friendly nature, and inexpensive feature. This review focuses on the recent studies discussing the application of CNs for desalination and water treatment. In this study, the membrane-based application, photocatalytic application, adsorption application, and electrode-based application of CNs for water treatment and desalination have been discussed. In the membrane-based application, the use of microporous g-C3N4, microporous C2N, and microporous C3N for desalination (reverse osmosis, forward osmosis, nanofiltration), pervaporation, ultrafiltration, oil-in-water separation, and dye separation have been detailed. Moreover, the photocatalytic degradation of organic pollutants (dyes, pharmaceuticals, etc.) and metal ions by CNs have been examined in detail. Further, the adsorption application of CNs for the adsorption of dyes, metal ions, and surfactants has been studied. It was noted that CN and its different derivatives are suitable candidates as membrane materials, photocatalysts, adsorbents, and electrode materials for their effective application in desalination and water treatment.

Boosting solar-powered interfacial water evaporation by architecting 3D interconnected polymetric network in CNT cellular structure

Photothermal hydrogel, with an inherently modifiable hydrated network, has been widely demonstrated as a promising candidate for efficient water treatment. However, there are still great challenges in architecting abundant interfacial mass transfer channels and avoiding excessive polarity interaction in polymeric hydrogels. Here, a 3D interconnected topological porous hydrogel was proposed to enable cellular carbon nanotube (CNT) structures filled with hydrophilic and thermosensitive nanonetworks via infiltration and crosslinking of polyvinyl alcohol (PVA), polyethyleneimine (PEI) and carbon black particles (CBs). A detailed comparative investigation revealed that hosting with CBs/PVA/PEI polymeric nanonetworks in CNT cellular structures facilitated the interfacial dehydration and the decrease of evaporation enthalpy, confirming that such a novel topological structure leaded to a remarkable increase in hydratable and heatable interfaces. In this regard, the obtained hybrid hydrogel achieved a high water evaporation rate of 3.55 kg m−2h−1 with an efficiency of 92.0 % under 1 sun irradiation, and particularly a superior self-evaporation rate of 0.49 kg m−2h−1 in the dark. More importantly, such hybrid hydrogel demonstrated excellent evaporation performance in weak sunlight and highly humid environments. This work has shed light on new insights to manufacture porous and low-enthalpy photothermal hydrogels for advanced solar-driven water treatment technology.