Green Synthesis of Polyurethane Sponge-Grafted Calcium Alginate with Carbon Ink Aerogel with High Water Vapor Harvesting Capacity for Solar-Driven All-Weather Atmospheric Water Harvesting.

Atmospheric water harvesting (AWH) technology is a new strategy for alleviating freshwater scarcity. Adsorbent materials with high hygroscopicity and high photothermal conversion efficiency are the key to AWH technology. Hence, in this study, a simple and large-scale preparation for a hygroscopic compound of polyurethane (PU) sponge-grafted calcium alginate (CA) with carbon ink (SCAC) was developed. The PU sponge in the SCAC aerogel acts as a substrate, CA as a moisture adsorber, and carbon ink as a light adsorber. The SCAC aerogel exhibits excellent water absorption of 0.555-1.40 g·g-1 within a wide range of relative humidity (40-80%) at 25 °C. The SCAC aerogel could release adsorbed water driven by solar energy, and more than 92.17% of the adsorbed water could be rapidly released over a wide solar intensity range of 1.0-2.0 sun. In an outdoor experiment, 57.517 g of SCAC was able to collect 32.8 g of clean water in 6 h, and the water quality meets the drinking water standards set by the World Health Organization. This study suggests a new approach to design promising AWH materials and infers the potential practical application of SCAC aerogel-based adsorbents.

Unveiling the Roles of Alloyed Boron in Hexavalent Chromium Removal Using Borohydride-Synthesized Nanoscale Zerovalent Iron: Electron Donor and Antipassivator.

Nanoscale zerovalent iron synthesized using borohydride (B-NZVI) has been widely applied in environmental remediation in recent decades. However, the contribution of boron in enhancing the inherent reactivity of B-NZVI and its effectiveness in removing hexavalent chromium [Cr(VI)] have not been well recognized and quantified. To the best of our knowledge, herein, a core-shell structure of B-NZVI featuring an Fe-B alloy shell beneath the iron oxide shell is demonstrated for the first time. Alloyed boron can reduce H+, contributing to more than 35.6% of H2 generation during acid digestion of B-NZVIs. In addition, alloyed B provides electrons for Fe3+ reduction during Cr(VI) removal, preventing in situ passivation of the reactive particle surface. Meanwhile, the amorphous oxide shell of B-NZVI exhibits an increased defect density, promoting the release of Fe2+ outside the shell to reduce Cr(VI), forming layer-structured precipitates and intense Fe-O bonds. Consequently, the surface-area-normalized capacity and surface reaction rate of B-NZVI are 6.5 and 6.9 times higher than those of crystalline NZVI, respectively. This study reveals the importance of alloyed B in Cr(VI) removal using B-NZVI and presents a comprehensive approach for investigating electron pathways and mechanisms involved in B-NZVIs for contaminant removal.

Rational design of full-spectrum visible-light-responsive bimetallic sulfide Bi2S3/CoS2 composites for high-efficiency photocatalytic degradation of naproxen and bacterial inactivation.

Photocatalytic water decontamination has emerged as a highly promising technology for efficient and rapid water treatment, harnessing sustainable solar energy as its driving force. In this study, we prepared visible-light active Bi2S3/CoS2 composites for the degradation of naproxen (NPX) and the inactivation of Escherichia coli (E. coli). The homogeneous dispersion of CoS2 was stably integrated with Bi2S3, resulting in a significant enhancement of the specific surface area, efficient utilization of visible light, and effective separation of photogenerated charge carriers. Consequently, this synergistic photocatalytic system greatly facilitated the successful degradation of NPX and the inactivation of E. coli under visible-light irradiation. Compared to the pure Bi2S3 and CoS2 catalysts, the Bi2S3/CoS2 (1:2) composites displayed significantly enhanced photodegradation activity, achieving 96.46% (k = 0.2847 min-1) degradation of NPX within 90 min and maintaining good recyclability with no significant decline after six successive cycles. Additionally, the photocatalytic inactivation of E. coli results indicated that Bi2S3/CoS2 composites exhibited excellent performance, leading to the inactivation of 7 log10 cfu mL-1 of bacterial cells after 150 min of visible-light exposure. Scanning Electron Microscopy (SEM) and K+ ions leakage tests demonstrated that the destruction of the E. coli cell membrane structure resulted in cell death. The outcomes of this work suggest that Bi2S3/CoS2 composites hold significant potential for treating water contaminated with antibiotic and microbial pollutants.

Al2O3 encapsulated by calcium alginate as composite for efficient removal of phosphate from aqueous solutions: batch and column studies.

Activated alumina (Al2O3) has been widely used to remove aqueous anionic pollutants such as phosphate for preventing the eutrophication phenomenon. While Al2O3, as a fine powder material, cannot be stably packed into continuous flow treatment, which limits its practical applications. Herein, we proposed a new strategy in which Al2O3 was encapsulated by calcium alginate (CA) to fabricate Al2O3/CA composite, which has relatively large particle size and can be suitable for application in columns. The BET surface area of Al2O3/CA increased to 51.73 m2/g compared with 37.31 m2/g of Al2O3. The maximum adsorption capacity of phosphate on Al2O3/CA was estimated at 1.92-fold compared with that of pure Al2O3 by Langmuir fitting. The main mechanism of phosphate adsorption was the formation of aluminum phosphate precipitation. Moreover, the column studies showed that the adsorption of phosphate on Al2O3/CA was affected by the amount of outer calcium alginate, bed height, influent flow rates and phosphate concentration. This study demonstrated that Al2O3/CA composite has better adsorption capacity and can be used in the dynamic adsorption system as a promising approach for phosphate removal from water.

Enhanced Solar Evaporation Using a Scalable MoS2 -Based Hydrogel for Highly Efficient Solar Desalination.

Interfacial photo-vapor conversion has been suggested as a cost-effective and sustainable technology for seawater desalination. However, the conversion performance was still limited by some drawbacks, like salt accumulation and poor mechanical stability. Herein, a scalable MoS2 -based porous hydrogel (SMoS2 -PH) with good mechanical stability and salt resistance was successfully constructed through a crosslinking foaming polymerization method. With the high porosity (92.63 %), the SMoS2 -PH performed an impressive evaporation rate of 3.297 kg m-2 h-1 and photothermal conversion efficiency of 93.4 % under 1-sun illumination. Most importantly, the SMoS2 -PH could maintain high and stable photothermal properties for 15 days on the surface of seawater. We believe that the excellent salt resistance, the high photothermal conversion efficiency, the ease of scale preparation method and the available commercial MoS2 make the SMoS2 -PH a promising device for full-scale seawater desalination.

The surface plasmon resonance, thermal, support and size effect induced photocatalytic activity enhancement of Au/reduced graphene oxide for selective oxidation of benzylic alcohols.

Reduced graphene oxide (RGO) as an electron-conductive medium and photosensitizer have been widely used to construct efficient RGO/semiconductor photocatalysts for solar energy conversion; however, the role of RGO has been largely underestimated. Herein, the surface plasmon resonance (SPR) effect, thermal effect, support effect, and size effect of Au/RGO are demonstrated to play important roles in enhancing the photocatalytic activity, which has not been considered previously. Au/RGO nanocomposites, synthesized via a facile wet chemistry route, exhibit an excellent visible light photocatalytic performance for selective oxidation of benzylic alcohols. A collection of joint techniques and control experiments have been employed to explain the SPR effect, thermal effect, support effect, and size effect over the Au/RGO photocatalyst. The possible reaction mechanism for the photocatalytic and thermocatalytic selective oxidation of alcohols over Au/RGO has also been discussed.

Decolorization of RhB dye by manganese oxides: effect of crystal type and solution pH.

BACKGROUND: Organic dye pollution in water has become a major source of environmental pollution. Mn(III/IV) oxides have attracted a great deal of attention to remove organic dye pollutants due to their unique structures and physicochemical properties. Numerous studies have reported the removal of dye by various Mn(III/IV) oxides through catalytic degradation and adsorption. The crystalline structures of manganese oxides and solution pH may exert substantial impact on the removal of dyes. However, few studies have focused on the oxidative degradation of RhB dye using Mn(III/IV) oxides with different crystal structures during a spontaneous reaction. In the present study, three manganese oxides with different crystal type (α-MnO2, ß-MnO2, and δ-MnO2) were prepared by refluxing process to decolorize RhB dye in various pH solutions. RESULTS: The results showed that the decolorization efficiencies of RhB for the three manganese oxides all increase with decrease solution pH. α-MnO2 exhibited highest activity and could efficiently degrade RhB at pH 2-6. The degradation of RhB by ß-MnO2 and δ-MnO2 could be observed at pH 2-3, and only little adsorption RhB on manganese oxides could be found at pH 4-6. The UPLC/MS analysis suggests that the decolorization of RhB by manganese oxides consists of three main stages: (1) cleavage of the ethyl groups from RhB molecular to form Rh; (2) further destruction of -COOH and -CNH2 from Rh to form the small molecular substances; (3) mineralization of the small molecular substances into CO2, H2O, NO3 (-) and NH4 (+). CONCLUSIONS: Overall, these results indicate that α-MnO2 may be envisaged as efficient oxidants for the treatment of organic dye-containing wastewater under acid conditions.

Fabrication and evaluation of Au-Pd core-shell nanocomposites for dechlorination of diclofenac in water.

Nanocomposites with core-shell structure usually exhibit excellent catalytic properties due to unique interfaces and synergistic effect among composites. In this study, Au-Pd bimetallic nanoparticles (NPs) with core-shell structure (Au-Pd cs) by using Au NPs as core and Pd as shell were successfully fabricated and, for the first time, were used to investigate the dechlorination of diclofenac (DCF) at H2 atmosphere in water at room temperature. The degradation products were studied as well by using HPLC/Q-ToF MS/MS. The operational factors such as pH and composition of the Au-Pd cs were also studied. The results showed that nearly 100% of DCF (30 mg L(-1), 50 mL, pH=7) was dechlorinated in 4.5 h by 10 mL of 56 mg L(-1) of Au-Pd cs. Ninety per cent of DCF was degraded in 6.5 h by the mixture of Au and Pd NPs. However, the individual Au NPs had no obvious effect in degrading DCF and the monometallic Pd NPs with comparable concentration only degraded less than 20% of DCF. Furthermore, the reaction mechanism of this catalytic process was studied in detail. It was found that the degradation was a second-order exponential reaction. The two main degradation products were obtained by cleaving the carbon-halogen bond of DCF and this made the degradation products more environmentally friendly.

Microplastics as potential barriers to ultraviolet light emitting diode inactivation of MS2 bacteriophage: Influence of water-quality parameters.

Microplastics have emerged as a concerning contaminant in drinking water sources, potentially interacting with pathogenic microorganisms and affecting the disinfection processes. In this study, MS2 was selected as an alternative for the human enteric virus. The influence of microplastics polyvinylchloride (MPs-PVC) on ultraviolet light emitting diode (UV-LED) inactivation of MS2 was investigated under various water chemistry conditions, such as MPs-PVC concentration, pH, salinity, and humic acid concentration. The results revealed that higher concentrations of MPs-PVC led to the reduced inactivation of MS2 by decreased UV transmittance, hindering the disinfection process. Additionally, the inactivation efficiency of MS2 in the presence of MPs-PVC was influenced by pH, and acidic solution (pH at 4, 5, and 6) exhibited higher efficiency compared to alkaline solution (pH at 8 and 9) and neutral solution (pH at 7). The low Na+ concentrations (0-50 mM) had a noticeable effect on MS2 inaction efficiency in the presence of MPs-PVC, while the addition of Ca2+ posed an insignificant effect due to the preferential interaction with MPs-PVC. Furthermore, the inactivation rate of MS2 initially increased and then decreased with increasing the concentration of humic acid, which was significantly different without MPs-PVC. These findings shed light on the complex interactions between MPs-PVC and MS2 in the UV-LED disinfection process under various water-quality parameters, contributing to drinking water safety and treatment.

Laboratory-scale column study for remediation of TCE-contaminated aquifers using three-section controlled-release potassium permanganate barriers.

A laboratory-scale study with a sand column was designed to simulate trichloroethylene (TCE) pollution in the aquifer environment with three-section controlled-release potassium permanganate (CRP) barriers. The main objective of this study was to evaluate the feasibility of CRP barriers in remediation of TCE in aquifers in a long-term and controlled manner. CRP particles with a 1:3 molar ratio of KMnO4 to stearic acid showed the best controlled-release properties in pure water, and the theoretical release time was 138.5 days. The results of TCE removal in the test column indicated that complete removal efficiency of TCE in a sand column by three-section CRP barriers could be reached within 15 days. The molar ratio of KMnO4 to TCE in the three-section CRP barriers was 16:1, which was much lower than 82:1 as required when KMnO4 solution is used directly to achieve complete destruction of TCE. This result revealed that the efficiency of CRP for remediation of TCE was highly improved after encapsulation.

La-MOFs in situ loaded Al2O3 particles for effective removal of phosphate in water: characterization, application potential analysis, and mechanism.

Excessive phosphorus in water would cause eutrophication and deterioration of the ecological environment. Herein, the La-MOFs/Al2O3 composite was successfully prepared by the in situ hydrothermal synthesis method for granulation, which was conducive to exerting the phosphate adsorption capacity and facilitating practical application. The materials were characterized by SEM, EDX, XRD, BET, FTIR, and Zeta. In addition, the adsorption performance of La-MOFs/Al2O3 was evaluated through adsorption kinetics and isotherms, showing that the Langmuir adsorption capacity was 16.34 mgP·g-1 (25 °C) and increased with the water temperature. Moreover, the batch influence experiments of intimal pH, adsorbent dosage, coexisting ions, and stability tests were performed to analyze the potential for practical applications and verified through the natural micro-polluted water samples from Houxi River and Bailu Lake (China). The results indicated that the La-MOFs/Al2O3 was suited to a wide pH range of 4 to 10 and the phosphate removal efficiency remained above 70% after continuous use for four times, exhibiting excellent stability. It also had excellent selectivity in the presence of SO42-, Cl-, NO3-, and HCO3-, only decreased to 70.24% at high HCO3- ion concentration of 60 mg/L, respectively. And the La-MOFs/Al2O3 had excellent adsorption of total phosphorus, phosphate, and organic phosphorus in the actual river and lake water and completely removed dissolved phosphorus. Finally, a phosphate adsorption mechanism model involved in electrostatic interaction and ligand exchange was proposed. Therefore, La-MOFs/Al2O3 could be considered to be an excellent phosphorus adsorbent for application in the actual water environmental remediation.

3D-Printed MOFs/Polymer Composite as a Separatable Adsorbent for the Removal of Phenylarsenic Acid in the Aqueous Solution.

Metal-organic frameworks (MOFs) are emerging as advanced nanoporous materials to remove phenylarsenic acid, p-arsanilic acid (p-ASA), and roxarsone (ROX) in the aqueous solution, while MOFs are often present as powder state and encounter difficulties in recovery after adsorption, which greatly limit their practical application in the aqueous environments. Herein, MIL-101 (Fe), a typical MOF, was mixed with sodium alginate and gelatin to prepare MIL-101@CAGE by three-dimensional (3D) printing technology, which was then used as a separatable adsorbent to remove phenylarsenic acid in the aqueous solution. The structure of 3D-printed MIL-101@CAGE was first characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and thermogravimetry and differential thermogravimetry (TG-DTG). The octahedral morphology of MIL-101 (Fe) was found unchanged during the 3D printing process. Then, the adsorption process of MIL-101@CAGE on phenylarsenic acids was systematically investigated by adsorption kinetics, adsorption isotherms, adsorption thermodynamics, condition experiments, and cyclic regeneration experiments. Finally, the adsorption mechanism between MIL-101@CAGE and phenylarsenic acid was further investigated. The results showed that the Langmuir, Freundlich, and Temkin isotherms were well fit, and according to the Langmuir fitting results, the maximum adsorption amounts of MIL-101@CAGE on p-ASA and ROX at 25 °C were 106.98 and 120.28 mg/g, respectively. The removal of p-ASA and ROX by MIL-101@CAGE remained stable over a wide pH range and in the presence of various coexisting ions. The regeneration experiments showed that the 3D-printed MIL-101@CAGE could still maintain a more than 90% removal rate after five cycles. The adsorption mechanism of this system might include π-π stacking interactions between the benzene ring on the phenylarsenic acids and the organic ligands in MIL-101@CAGE, hydrogen-bonding, and ligand-bonding interactions (Fe-O-As). This study provides a new idea for the scale preparation of a separatable and recyclable adsorbent based on MOF material for the efficient removal of phenylarsenic acid in the aqueous solution.

Recycling Graphite from Spent Lithium Batteries for Efficient Solar-Driven Interfacial Evaporation to Obtain Clean Water.

Solar-driven interfacial evaporation technology is regarded as an attracting sustainable strategy for obtaining portable water from seawater and wastewater, and the recycle of waste materials to fabricate efficient photothermal materials as evaporator to efficiently utilize solar energy is very critical, but still difficult. To this purpose, graphite recovered from spent lithium-ion batteries (SLIBs) was realized using a simple acid leaching method, and a reconstructed graphite-based porous hydrogel (RG-PH) was subsequently fabricated by crosslinking foaming method. The incorporation of reconstructed graphite (RG) improves the mechanical characteristics of hydrogels and the light absorption performance significantly. The evaporation rate of optimized RG-PH can constantly reach 3.4278 kg m-2 h-1 for desalination under a one solar irradiation, and it also showed the excellent salt resistance in various salty water. Moreover, RG-PH has a strong elimination of a variety of organic contaminants in wastewater, including the typical volatile organic compound of phenol. This research shows the potential application of flexible and durable solar evaporators made from waste materials in purifying seawater and wastewater, not only contributing to carbon neutrality by recycling graphite from SLIBs, but also ensuring the cost-effectiveness harvest of solar energy for constantly obtaining clean water.

Current advances in the detection and removal of organic arsenic by metal-organic frameworks.

Arsenic (As) is a highly toxic heavy metal and has been widely concerned for its hazardous environmental impact. Aromatic organic arsenic (AOCs) has been frequently used as an animal supplement to enhance feed utilization and prevent dysentery. The majority of organic arsenic could be discharged from the body and evolve as highly toxic inorganic arsenic that is hazardous to the environment and human health via biological conversion, photodegradation, and photo-oxidation. Current environmental issues necessitate the development and application of multifunctional porous materials in environmental remediation. Compared to the conventional adsorbent, such as activated carbon and zeolite, metal-organic frameworks (MOFs) exhibit a number of advantages, including simple synthesis, wide variety, simple modulation of pore size, large specific surface area, excellent chemical stability, and easy modification. In recent years, numerous scientists have investigated MOFs related materials involved with organic arsenic. These studies can be divided into three categories: detection of organic arsenic by MOFs, adsorption to remove organic arsenic by MOFs, and catalytic removal of organic arsenic by MOFs. Here, we conduct a critical analysis of current research findings and knowledge pertaining to the structural characteristics, application methods, removal properties, interaction mechanisms, and spectral analysis of MOFs. We summarized the application of MOFs in organic arsenic detection, adsorption, and catalytic degradation. Other arsenic removal technologies and conventional substances are also being investigated. This review will provide relevant scientific researchers with references.

A Salt-Resistant and Antibacterial Cu2 ZnSnS4 -Based Hydrogel for High Efficient Photothermal Distillation in Seawater Desalination and Sewage Purification.

Solar steam generation technology (SSGT) using unlimited solar energy is regarded as one of the most promising sustainable technologies to produce clean water. However, most of studies on SSGT simply focus on how to improve salt resistance as well as exclude inorganic and organic pollutants in targeted water, and only very limited studies pay attention to the micro-organisms in the collected water. Herein, one porous Cu2 ZnSnS4 -based photothermal hydrogel (CZTS-PH) with antibacterial properties as well as good salt resistance was successfully prepared. The CZTS-PH was measured with the water evaporation rate as high as 3.249 kg m-2 h-1 and photothermal conversion efficiency of 96.3 % under one sun irradiation. Impressively, owing to the amino groups in the skeleton, CZTS-PH can significantly deteriorate the cell membrane and lead to the death of the Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which ensures its long-term stability photothermal conversion and the safety of clean water. Overall, the admired photothermal conversion efficiency, and the excellent salt resistance and antibacterial performance suggest that CZTS-PH could be a promising full-scale device applied in seawater desalination and water purification.

Recycling Graphite from Spent Lithium Batteries for Efficient Solar-Driven Interfacial Evaporation to Obtain Clean Water.

Invited for this month's cover, the researchers from Huaqiao University and Jilin Jianzhu University. The Cover image shows the use of spent graphite to prepare hydrogels for photothermal evaporation to produce clean water. The Research Article itself is available at 10.1002/cssc.202300845.

Effect of particulate matters on inactivation of bacteriophage MS2 under irradiation above 320 nm.

The inactivation of bacteriophage MS2 under irradiation above 320 nm was investigated, focusing on different solution pH, ionic strength, and Suwannee River natural organic matter (SRNOM) concentrations when solutions contained organic or inorganic particle matters. Inorganic and organic particles were modeled using kaolinite (KAO) and Microcystis aeruginosa (MA), respectively. The results showed that the two types of particles influenced on MS2 inactivation under different conditions. The lower pH contributed to the greater MS2 aggregation within pH range of 3.0 to 8.0, leading to an increasing inactivation rate. The presence of KAO induced reactive oxygen species (ROS) under the action of irradiation above 320 nm, which promoted the inactivation of MS2. By comparison, the [Formula: see text] produced by MA after irradiation promoted the inactivation at pH < 6, whereas when the pH is ≥ 6, the inactivation effect of MS2 was lower than that of particle-free solution because MS2 was no longer aggregated and MA has a shading effect. In the presence of Na+ or Ca2+ cation, irradiation above 320 nm could not effectively inactivate the MS2 under particle-free solution. By comparison, KAO increased the inactivation efficiency as a photosensitizer. With the increase of Ca2+ concentration, MS2 was more easily adsorbed to MA than aggregation. Until Ca2+ concentration reached 20 mM, the inactivation effect in MA solution was enhanced. In the presence of SRNOM, the inactivation effect increased with the increase of SRNOM concentration. When the SRNOM was 20 mM, the inactivation increased in the particle-free solution due to the greater production of [Formula: see text]. Compared with the particle-free solution, the KAO and MA inactivation efficiency was lower.

MWCNT supported V2O5 quantum dot nanoparticles decorated Bi2O3 nanosheets hybrid system: Efficient visible light driven photocatalyst for degradation of ciprofloxacin.

A novel composite of multiwall carbon nanotube (MWCNT) supported V2O5 quantum dots decorated Bi2O3 hybrid was prepared by the simple wet-impregnation method, and the photocatalytic performance of the prepared samples was investigated against the photodegradation of ciprofloxacin (CIP). Herein, different samples of pristine, V2O5/Bi2O3 and MWCNT@V2O5/Bi2O3 hybrid photocatalyst were prepared and systematically characterized by various physicochemical techniques. The characterization results demonstrated that the introduction of MWCNT can change the energy band gap of V2O5/Bi2O3, and the band energies vary with a constituent of MWCNT@V2O5/Bi2O3 catalyst, in which MWCNT@V2O5/Bi2O3-5 (0.05 g@0.50 g:0.50 g) has the optimal band gap energy of 2.46 eV. The photocatalytic test demonstrates that the MWCNT@V2O5/Bi2O3-5 hybrid composites exhibited enhanced photocatalytic activity in CIP degradation compared to that pure and other photocatalyst and its degradation efficiency did not decrease significantly even after five cyclic experiments. The enhanced photocatalytic activity was due to the formation of heterojunction among MWCNT, V2O5 and Bi2O3, which distinctly improved the separation efficiency of the photogenerated charge carrier, thus increasing the degradation performance. This work gives a new approach to designing an efficient photocatalyst for contaminants degradation.

Inactivation and genome damage of rotavirus and a human norovirus surrogate by monochloramine treatment and sequential application with UV.

The inactivation efficacy by monochloramine for disinfecting gastroenteritis-causing rotaviruses (RV) and Tulane viruses (TV), a surrogate for noroviruses, were evaluated in this study. In addition, the strategies for improving the disinfection efficiency of monochloramine by raising the temperature and sequentially implementing UV irradiation were investigated. The results showed that monochloramine was more effective in the inactivation of TV than RV. Additionally, the inactivation rate constants of RV and TV by monochloramine at 35 °C were improved approximately by 46% and 100%, respectively, compared to those at 25 °C. Moreover, applying UV irradiation before monochloramine enhanced the inactivation efficacy of RV and TV by 63% and 72% compared to monochloramine alone (UV: 6 mJ/cm2, NH2Cl: 60 ppm × min). Furthermore, the synergistic effect was observed during the RV inactivation by the sequential process. Especially, higher than 0.5 log10 reductions of RV VP1 genome contributed to the synergistic effect in sequential treatment, while less than 0.1 log10 reductions of RV VP1 genome were observed during UV alone (13 mJ/cm2) or monochloramine alone (94 ppm × min). The genome damage might be the primary mechanism of generating synergy in sequential treatment for the inactivation of RV. By comparison, no synergistic effect was discovered for the inactivation of TV due to high susceptibility to monochloramine and UV. The findings on the inactivation efficacy and mechanism for improvement will contribute to a wide application of monochloramine for virus inactivation in water treatment and distribution systems.

Removal of phosphate at low concentration from water by porous PVA/Al2O3 composites.

The porous polyvinyl alcohol (PVA)/Al2O3 composite by supporting activated alumina on the cross-linked network of PVA has been successfully prepared and its property for the removal of phosphate in aqueous solution was also evaluated. The structure of the PVA/Al2O3 was examined by scanning electron microscopy. It showed that the activated alumina particles with an average size of 1 µm were evenly dispersed and fixed in the cross-linked network structure of PVA. The effects of adsorption time, solution temperature, pH, initial concentration of phosphate, Al2O3 loading rate, dosage and coexisting ions on the phosphate removal were further studied. The results showed that the highest removal phosphate efficiency of 95% can be obtained with the Al2O3 loading rate of PVA/Al2O3 being 60 wt.% at pH of 4 at 30 °C. The maximum adsorption capacities of PO43- by PVA/Al2O3 suggested by the Langmuir isothermal model was 10.12 mg/g. The adsorption process of phosphate can be fit well with a pseudo-second-order model (R2 = 0.9900). The PVA/Al2O3 composite exhibited a high selective adsorption of phosphate in the presence of commonly coexisting anions except the obvious effect of CO32- in water. Meanwhile, the PVA/Al2O3 composite can be easily separated and recovered due to the granulation of adsorbent. PVA/Al2O3 composite also shows the excellent properties of regeneration and recycling use with the removal efficiency of phosphate was 88.93%, 88.38% and 94.34% after three cycles, respectively. It can be proposed that the PVA/Al2O3 composite is a promising recyclable adsorbent for removing phosphate at low concentration from aqueous solution.