Solar vapor generation has presented great potential for wastewater treatment and seawater desalination with high energy conversion and utilization efficiency. However, technology gaps still exist ...for achieving a fast evaporation rate and high quality of water combined with low‐cost deployment to provide a sustainable solar‐driven water purification system. In this study, a naturally abundant biomass, konjac glucomannan, together with simple‐to‐fabricate iron‐based metal‐organic framework‐derived photothermal nanoparticles is introduced into the polyvinyl alcohol networks, building hybrid hydrogel evaporators in a cost‐effective fashion ($14.9 m−2 of total materials cost). With advantageous features of adequate water transport, effective water activation, and anti‐salt‐fouling function, the hybrid hydrogel evaporators achieve a high evaporation rate under one sun (1 kW m−2) at 3.2 kg m−2 h−1 out of wastewater with wide degrees of acidity and alkalinity (pH 2–14) and high‐salinity seawater (up to 330 g kg−1). More notably, heavy metal ions are removed effectively by forming hydrogen and chelating bonds with excess hydroxyl groups in the hydrogel. It is anticipated that this study offers new possibilities for a deployable, cost‐effective solar water purification system with assured water quality, especially for economically stressed communities.
Abundant biomass, konjac glucomannan, and iron‐based metal–organic framework‐derived solar absorbers are introduced into poly(vinyl alcohol) networks to build cost‐effective hybrid hydrogel evaporators (HHEs). With a total materials cost of $14.9 m−2, HHEs achieve a high evaporation rate of 3.2 kg m−2 h−1 under one sun with effective removal of heavy‐metal ions and anti‐salt‐fouling functions.
The vacuum-UV radiation of water results in the in situ generation of hydroxyl radicals. Low-pressure mercury vapor lamps which emit at 185 nm are potential sources of VUV radiation. The scope of ...this article is to give an overview of the application of VUV radiation at 185 nm for water treatment including the transformation of inorganic and organic water constituents, and the disinfection efficiency. Another focus is on the generation of ozone by VUV radiation from oxygen or air and the application of the produced ozone in combination with VUV irradiation of water in the VUV/O3 process. The advantages and limitation of the VUV process at 185 nm as well as possible applications in water treatment are outlined.
Interfacial materials with special wettability have become a burgeoning research area in materials science in the past decade. The unique surface properties of materials and interfaces generated by ...biomimetic approaches can be leveraged to develop effective solutions to challenging environmental problems. This critical review presents the concept, mechanisms, and fabrication techniques of interfacial materials with special wettability, and assesses the environmental applications of these materials for oil–water separation, membrane-based water purification and desalination, biofouling control, high performance vapor condensation, and atmospheric water collection. We also highlight the most promising properties of interfacial materials with special wettability that enable innovative environmental applications and discuss the practical challenges for large-scale implementation of these novel materials.
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Membrane separation is one of the most effective strategies for water treatment. However, problems such as poor emulsion separation performance, single function and easy membrane ...fouling limit its application in dealing with complex wastewater. The synergistic treatment technology of adsorption and visible light catalysis is an efficient and environment-friendly method to degrade organic pollutants. Here, we report a simple method to fabricate Zeolitic Imidazolate Framework-8/Graphene oxide/Polyacrylonitrile (ZIF-8/GO/PAN) nanofibrous membranes and their multifunctional treatment capacity for complex wastewater. The construction of superhydrophilic and underwater superoleophobic surface structure has achieved excellent emulsion separation performance (with a maximum flux of 6779.66 L m-2h−1), visible light photocatalytic degradation (with an efficiency of 96.5% in 90 min) and antibacterial properties. Moreover, the fibrous membrane also shows good biosafety, and will not have toxic effects on aquatic organisms. These excellent performances endow this membrane with great potential in complex wastewater purification.
Industrial development, energy production and mining have led to dramatically increased levels of environmental pollutants such as heavy metal ions, metal cyanides and nuclear waste. Current ...technologies for purifying contaminated waters are typically expensive and ion specific, and there is therefore a significant need for new approaches. Here, we report inexpensive hybrid membranes made from protein amyloid fibrils and activated porous carbon that can be used to remove heavy metal ions and radioactive waste from water. During filtration, the concentration of heavy metal ions drops by three to five orders of magnitude per passage and the process can be repeated numerous times. Notably, their efficiency remains unaltered when filtering several ions simultaneously. The performance of the membrane is enabled by the ability of the amyloids to selectively absorb heavy metal pollutants from solutions. We also show that our membranes can be used to recycle valuable heavy metal contaminants by thermally reducing ions trapped in saturated membranes, leading to the creation of elemental metal nanoparticles and films.
The goal of this project was to remove iron from drinking water using a new electrocoagulation (EC) cell. In this research, a flow column has been employed in the designing of a new ...electrocoagulation reactor (FCER) to achieve the planned target. Where, the water being treated flows through the perforated disc electrodes, thereby effectively mixing and aerating the water being treated. As a result, the stirring and aerating devices that until now have been widely used in the electrocoagulation reactors are unnecessary.
The obtained results indicated that FCER reduced the iron concentration from 20 to 0.3 mg/L within 20 min of electrolysis at initial pH of 6, inter-electrode distance (ID) of 5 mm, current density (CD) of 1.5 mA/cm2, and minimum operating cost of 0.22 US $/m3. Additionally, it was found that FCER produces H2 gas enough to generate energy of 10.14 kW/m3.
Statistically, it was found that the relationship between iron removal and operating parameters could be modelled with R2 of 0.86, and the influence of operating parameters on iron removal followed the order: C0>t>CD>pH. Finally, the SEM (scanning electron microscopy) images showed a large number of irregularities on the surface of anode due to the generation of aluminium hydroxides.
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•The new EC reactor, FCER, removed 99.6% of 20 mg/L of iron.•Performance of FECR, in terms of iron removal, was modelled with R2 of 0.86.•FECR reduced the need for external mixing and aerating devices.•FCER emits H2 gas enough to produce energy of 10.14 kW/m3.•SEM images showed many dents on the anode due to the production of Al hydroxides.
In recent years, forward osmosis (FO) hybrid membrane systems have been investigated as an alternative to conventional high-pressure membrane processes (i.e. reverse osmosis (RO)) for seawater ...desalination and wastewater treatment and recovery. Nevertheless, their economic advantage in comparison to conventional processes for seawater desalination and municipal wastewater treatment has not been clearly addressed. This work presents a detailed economic analysis on capital and operational expenses (CAPEX and OPEX) for: i) a hybrid forward osmosis – low-pressure reverse osmosis (FO-LPRO) process, ii) a conventional seawater reverse osmosis (SWRO) desalination process, and iii) a membrane bioreactor – reverse osmosis – advanced oxidation process (MBR-RO-AOP) for wastewater treatment and reuse. The most important variables affecting economic feasibility are obtained through a sensitivity analysis of a hybrid FO-LPRO system. The main parameters taken into account for the life cycle costs are the water quality characteristics (similar feed water and similar water produced), production capacity of 100,000 m3 d−1 of potable water, energy consumption, materials, maintenance, operation, RO and FO module costs, and chemicals. Compared to SWRO, the FO-LPRO systems have a 21% higher CAPEX and a 56% lower OPEX due to savings in energy consumption and fouling control. In terms of the total water cost per cubic meter of water produced, the hybrid FO-LPRO desalination system has a 16% cost reduction compared to the benchmark for desalination, mainly SWRO. Compared to the MBR-RO-AOP, the FO-LPRO systems have a 7% lower CAPEX and 9% higher OPEX, resulting in no significant cost reduction per m3 produced by FO-LPRO. Hybrid FO-LPRO membrane systems are shown to have an economic advantage compared to current available technology for desalination, and comparable costs with a wastewater treatment and recovery system. Based on development on FO membrane modules, packing density, and water permeability, the total water cost could be further reduced.
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•Economic analysis of forward osmosis – low pressure reverse osmosis (FO-LPRO) system.•FO-LPRO system has lower costs for producing water compared to SWRO desalination.•FO-LPRO system has a comparable cost to wastewater treatment and recovery system.•Most critical aspect in economic feasibility of FO-LPRO systems is FO module cost.
Persulfate-based nonradical oxidation processes (PS-NOPs) are appealing in wastewater purification due to their high efficiency and selectivity for removing trace organic contaminants in complicated ...water matrices. In this review, we showcased the recent progresses of state-of-the-art strategies in the nonradical electron-transfer regimes in PS-NOPs, including design of metal and metal-free heterogeneous catalysts, in situ/operando characterization/analytical techniques, and insights into the origins of electron-transfer mechanisms. In a typical electron-transfer process (ETP), persulfate is activated by a catalyst to form surface activated complexes, which directly or indirectly interact with target pollutants to finalize the oxidation. We discussed different analytical techniques on the fundamentals and tactics for accurate analysis of ETP. Moreover, we demonstrated the challenges and proposed future research strategies for ETP-based systems, such as computation-enabled molecular-level investigations, rational design of catalysts, and real-scenario applications in the complicated water environment. Overall, this review dedicates to sharpening the understanding of ETP in PS-NOPs and presenting promising applications in remediation technology and green chemistry.
Solar‐driven water purification is considered as an effective and sustainable technology for water treatment using green solar energy. One major goal for practical applications is to improve the ...solar evaporation performance by the design of novel photothermal materials, with optimized heat localization and water transport pathways to achieve reduced energy consumption for water vaporization. Recently, some emerging materials like polymers, metal‐organic frameworks (MOFs), covalent organic frameworks (COFs) and also single molecules were employed to construct novel solar evaporation systems. In this minireview, we present an overview of the recent efforts on materials development for water purification systems. The state‐of‐the‐art applications of these emerging materials for solar‐driven water treatment, including desalination, wastewater purification, sterilization and energy production, are also summarized.
Research on solar‐driven water purification has grown rapidly over the past years and emerging materials such as polymers, MOFs and COFs have been employed in this field recently. This minireview gives an overview of the basic concepts and principles for solar evaporation systems and on the development of novel photothermal materials.
► The membrane biofilm reactor (MBfR) is introduced. ► The fundamental behavior of MBfRs is discussed. ► Current and novel applications are critically reviewed. ► Design and scale-up issues are ...presented. ► Key research needs are provided.
The membrane biofilm reactor (MBfR), an emerging technology for water and wastewater treatment, is based on pressurized membranes that supply a gaseous substrate to a biofilm formed on the membrane’s exterior. MBfR biofilms behave differently from conventional biofilms due to the counter-diffusion of substrates. MBfRs are uniquely suited for numerous treatment applications, including the removal of carbon and nitrogen when oxygen is supplied, and reduction of oxidized contaminants when hydrogen is supplied. Major benefits include high gas utilization efficiency, low energy consumption, and small reactor footprints. The first commercial MBfR was recently released, and its success may lead to the scale-up of other applications. MBfR development still faces challenges, including biofilm management, the design of scalable reactor configurations, and the identification of cost-effective membranes. If future research and development continue to address these issues, the MBfR may play a key role in the next generation of sustainable treatment systems.
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