Search

• Coagulation/co-catalytic membrane system integrated coagulation, filtration and AOP. • Fe3+ served as both the coagulant for DOM removal and PMS activator. • MoS 2 in catalytic membrane accelerate the redox cycling of Fe species. • Surface-bound radicals enable efficient BPA removal and in-situ membrane cleaning. • The system showed stable performance during 53 h treatment of WWTP effluent. Low-pressure catalytic membranes allow efficient rejection of particulates and simultaneously removing organics pollutant in water, but the accumulation of dissolved organic matters (DOM) on membrane surface, which cover the catalytic sites and cause membrane fouling, challenges their stable operation in practical wastewater treatment. Here we propose a ferric salt-based coagulation/co-catalytic membrane integrated system that can effectively mitigate the detrimental effects of DOM. Ferric salt (Fe3+) serving both as a DOM coagulant to lower the membrane fouling and as a co-catalyst with the membrane-embedded MoS 2 nanosheets to drive perxymonosulfate (PMS) activation and pollutant degradation. The membrane functionalized with 2H-phased MoS 2 nanosheets showed improved hydrophilicity and fouling resistance relative to the blank polysulfone membrane. Attributed to the DOM coagulation and co-catalytic generation of surface-bound radicals for decontamination at membrane surface, the catalytic membrane/PMS/ Fe3+ system showed much less membrane fouling and 2.6 times higher pollutant degradation rate in wastewater treatment than the catalytic membrane alone. Our work imply a great potential of coagulation/co-catalytic membrane integrated system for water purification application. [Display omitted] [ABSTRACT FROM AUTHOR]

• The introduced PAC optimizes the assembly of heterogeneous FeS x on S-ZVI/PAC. • PAC physically adsorbs isolated FeS x allowed chemically assembled FeS x on S-ZVI. • The chemical assembly of FeS x is superior to physical adsorption on S-ZVI. • PAC adsorbs FeS x to obtain electron properties matching its adsorption threshold. Specifically designing the heterogeneous interface in sulfidated zero-valent iron (S-ZVI) has been an effective, yet usually overlooked method to improve the decontamination ability. However, the mechanism behind FeS x assembly remains elusive and the lack of modulating strategies that can essentially tune the applicability of S-ZVI further imposes difficulties in creating better-performing S-ZVI with heterogeneous interface. In this study, by introducing powdered activated carbon (PAC) during S-ZVI preparation, S-ZVI/PAC microparticles were prepared to modulate the assembly pattern of FeS x for the applicability and reactivity of the material. S-ZVI/PAC showed robust performance in Cr(VI) sequestration, with 11.16 and 1.78 fold increase in Cr(VI) reactivity compared to ZVI and S-ZVI, respectively. This was attributed to the fact that the introduced PAC could acquire FeS x to enhance the electron transfer capacity matching its adsorption threshold, thus helping to accommodate the transfer of the reduction center to PAC in S-ZVI/PAC. In optimizing the FeS x allocation between ZVI and PAC, the chemical assembly of FeS x on S-ZVI was superior to physical adsorption. Critically, we found that isolated FeS x in the prepared solution was physically adsorbed by the PAC, allowing chemically assembled FeS x on the S-ZVI. This was achieved by controlling the addition sequence of Na 2 S and PAC, as it effectively controlled the release rate and content of Fe(II) in the preparation solution. S-ZVI/PAC was demonstrated to be extremely effective in simulated wastewater and electrokinetics-permeable reactive barrier (EK-PRB) treatments. Introducing PAC enriches the diversity of sulfidation mechanisms and may realize the universality of the S-ZVI/PAC application scenarios. This study provides a new interface optimization strategy for S-ZVI targeted design towards environmental applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• A Fe-Co dual-atom catalyst with surface area of 1721.71 m2 g−1 is prepared. • Diatomic site shows higher activity than single-atom sites in activating PMS. • Heterogeneous catalytic efficiency outdistances the homogeneous counterpart. • A new surface collision oxidation path is revealed to dominate the catalysis. • Superior activity of dual-atom site comes from the Fe-Co diatomic synergy. Heterogeneous catalysts lag far behind their homogeneous counterparts in activating peroxymonosulfate (PMS) for water decontamination due to the low site intrinsic activity and sluggish mass transfer. The single-atom catalyst can bridge the gap between heterogeneous and homogeneous catalysts, but the difficulty to break scaling relations originating from the site monotony restricts further efficiency upgradation. Herein through modulating the crystallinity of NH 2 -UIO-66, a porous carbon support with ultrahigh surface area (1721.71 m2 g−1) is obtained to anchor the dual-atom FeCoN 6 site, which exhibits superior turnover frequency over single-atom FeN 4 and CoN 4 sites (13.07 versus 9.97, 9.07 min−1). The as-synthesized composite thus outperforms the homogeneous catalytic system (Fe3++Co2+) for sulfamethoxazole (SMZ) degradation, and the catalyst-dose-normalized kinetic rate constant (99.26 L min−1 g−1) exceeds reported values by 1∼2 orders of magnitude. Moreover, only 20 mg of the catalyst can run a fluidized-bed reactor to realize continuous zero discharge of SMZ in multiple actual waters for up to 8.33 h. Unlike all reported reaction routes, the catalysis on the diatomic site follows a new surface collision oxidation path, i.e. the dispersed catalyst adsorbs PMS to generate surface-activated PMS with high potential, which collides with surrounding SMZ and directly seizes electron from it to induce pollutant oxidation. Theoretical calculation indicates that the enhanced activity of FeCoN 6 site stems from the diatomic synergy, leading to stronger PMS adsorption, larger near-Fermi-level density of states and optimal global Gibbs free energy evolution. Overall, this work provides an effective strategy of constructing heterogeneous dual-atom catalyst/PMS process to achieve faster pollution control than homogeneous system, and sheds light on the interatomic synergetic mechanism for PMS activation. [Display omitted] [ABSTRACT FROM AUTHOR]

• Reports suggest that people are continuously ingesting aflatoxins from water. • Legislation disregards the global issue of aflatoxins' presence in water. • High degradation rates were achieved by gamma and UV irradiations, and ozone. • Aflatoxins were efficiently absorbed by minerals, durian peel and activated carbon. • There is still a long way to go before decontamination methods can be implemented. Aflatoxins are highly carcinogenic metabolites produced by some Aspergillus species and are the most prevalent mycotoxins. Although aflatoxins are commonly synthesized during fungal colonization in preharvest maize, cereals, and nuts, they can be transported by rainfall to surface water and are a common toxin found in wastewater from some food industries. Here, the occurrence of aflatoxins in bodies of water is reviewed for the first time, along with the decontamination methods. Aflatoxins have been detected in surface, wastewater and drinking water, including tap and bottled water. The specific sources of water contamination remain unclear, which is an important gap that must be addressed in future research. Two main kinds of decontamination methods have been reported, including degradation and adsorption. The best degradation rates were observed using gamma and UV irradiations, oxidoreductases and ozone, while the best adsorption abilities were observed with minerals, polyvinyl alcohol, durian peel and activated carbon. Synthetic polymers could be used as membranes in pipes to remove aflatoxins in water flows. Although most decontamination methods were screened using AFB 1 , the other commonly found aflatoxins were not used in the screenings. Overall, the occurrence of aflatoxins in water could be a significant emerging public health concern largely ignored by local and international legislation. Numerous advances have been reported for the decontamination of aflatoxins in water; however, there is still a long way to go to put them into practice. [ABSTRACT FROM AUTHOR]

• A Janus electrified ceramic membrane (ECM) with dual electrodes was fabricated. • ECM activated peroxymonosulfate by singlet oxygenation and electron transfer. • Peroxymonosulfate/ECM filtration showed high-efficiency water decontamination. • Janus ECM surpassed single-sided ECM at energy efficiency and contaminants removal. Electrified ceramic membranes (ECMs) achieve high water decontamination efficiency mainly through implementing in situ radical-mediated oxidation in membrane filtration, whereas ECMs leveraging non-radical pathways are rarely explored. Herein, we demonstrated a Janus ECM realizing ultra-efficient micropollutant (MP) removal via electro-activating peroxymonosulfate (PMS) in a fast, flow-through single-pass electro-filtration. The Janus ECM features two separate palladium (Pd) functionalized electrocatalytic reaction zones engineered on its two sides. We confirmed that the PMS/electro-filtration system induced non-radical pathways for MP degradation, including singlet oxygenation and mediating direct electron transfer (DET) from MP to PMS. Under the design of the ECM featuring dual electrocatalytic reaction zones in the ceramic membrane intrapores, the Janus ECM showed over one-fold increase in micropollutant removal rate as 94.5% and lower electric energy consumption as 1.78 Wh g−1 MP in the PMS electro-activation process, as compared with the conventional ECM assembly implementing only half-cell reaction. This finding manifested the Janus ECM configuration advantage for maximizing the PMS electro-activation efficiency via singlet oxygenation intensification and direct usage of cathode for DET mediation. The Janus ECM boosted the PMS electro-activation and water decontamination efficiency by enhancing the convective mass transfer and the spatial confinement effect. Our work demonstrated a high-efficiency PMS electro-activation method based on electro-filtration and maximized the non-radical mediated PMS oxidation for MP removal, expanding the ECM filtration strategies for water decontamination. [Display omitted] [ABSTRACT FROM AUTHOR]