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Highlights: [•] Iron bearing clays are efficient catalysts for co-conversion of Cr(VI) and dyes. [•] Molecular oxygen has an insignificant effect on photosensitized reduction of Cr(VI). [•] These iron-bearing clays are stable and reusable for Cr(VI) reduction. [ABSTRACT FROM AUTHOR]

• Novel carbon-supported SnO x -CeO x flow-anodes were introduced in electro-oxidation. • SnO x -CeO x /CB outperformed SnO x -CeO x /GAC and SnO x -CeO x /MWCNTs. • Ce species accelerated the electron transfer from Sn to CB substrate directionally. • The loading of SnO x -CeO x triggered effective ·OH production. • Higher current efficiency and lower energy consumption were achieved. Exploiting electrochemically active materials as flow-anodes can effectively alleviate mass transfer restriction in an electro-oxidation system. However, the electrocatalytic activity and persistence of the conventional flow-anode materials are insufficient, resulting in limited improvement in the electro-oxidation rate and efficiency. Herein, we reported a rational strategy to substantially enhance the electrocatalytic performance of flow-anodes in electro-oxidation by introducing the redox cycle of high-valent metal in a suitable carbon substrate. The characterization suggested that the SnO x -CeO x /carbon black (CB) featured well-distributed morphology, rapid charge transfer, high oxygen evolution potential, and strong water adsorption, and stood out among three kinds of SnO x -CeO x loaded carbon materials. Mechanistic analysis indicated that the redox cycle of Ce species played a key role in accelerating the electron transfer from SnO x to CB directionally and could continuously create the electron-deficient state of the SnO x , thereby sustainably triggering the generation of ·OH. All these features enabled the resulting SnO x -CeO x /CB flow-anode to accomplish a calculated maximum kinetic constant of 0.02461 1/min, a higher current efficiency of 47.1%, and a lower energy consumption of 21.3 kWh/kg COD compared with other conventional flow-anodes reported to date. Additionally, SnO x -CeO x /CB exhibited excellent stability with extremely low leaching concentrations of Sn and Ce ions. This study provides a feasible manner for efficient water decontamination using the electro-oxidation system with SnO x -CeO x /CB. [Display omitted] [ABSTRACT FROM AUTHOR]

• Introduction of MOF interlayer resulted in high quality polyamide membrane. • Enhanced performance was achieved by specially designed ceramic-based FO membranes. • Robust water treatment performance was realized under harsh conditions. • Efficient separation was performed for real industrial petrochemical wastewater. Forward osmosis (FO) membrane processes could operate without hydraulic pressures, enabling the efficient treatment of wastewaters with mitigated membrane fouling and enhanced efficiency. Designing a high-performance polyamide (PA) layer on ceramic substrates remains a challenge for FO desalination applications. Herein, we report the enhanced water treatment performance of thin-film nanocomposite ceramic-based FO membranes via an in situ grown Zr-MOF (UiO-66-NH 2) interlayer. With the Zr-MOF interlayer, the ceramic-based FO membranes exhibit lower thickness, higher cross-linking degree, and increased surface roughness, leading to higher water flux of 27.38 L m−2 h−1 and lower reverse salt flux of 3.45 g m−2 h−1. The ceramic-based FO membranes with Zr-MOF interlayer not only have an application potential in harsh environments such as acidic solution (pH 3) and alkaline solution (pH 11), but also exhibit promising water and reverse salt transport properties, which are better than most MOF-incorporated PA membranes. Furthermore, the membranes could reject major species (ions, oil and organics) with rejections ＞94 % and water flux of 22.62−14.35 L m–2 h–1 in the treatment of actual alkaline industrial wastewater (pH 8.6). This rational design proposed in this study is not only applicable for the development of a high-quality ceramic-based FO membrane with enhanced performance but also can be potentially extended to more challenging water treatment applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• E-peroxone efficiently destructed Cr(III) complexes and fully recovered removable cr. • The HO· preferentially attacked Cr(III) site of Cr(III) complexes to form Cr(VI). • E-peroxone enabled significant curtailment of intermediate Cr(VI) to below 0.2 mg/L. • 78.3% and 21.7% of removable cr were separately enriched at ACF cathode and anode. • E-peroxone was capable of recovering cr from authentic electroplating effluent. Available oxidation processes for removing Cr(III) complexes from water/wastewater usually encounter the formation of highly toxic Cr(VI) and the generation of Cr enriched waste sludge, posing challenges on the subsequent disposal. Herein, we achieve efficient removal of Cr(III)-organic complexes and simultaneous recovery of Cr from wastewater with enhanced curtailment of intermediate Cr(VI), by using an electrochemically driven peroxone (i.e., electro-peroxone) process with activated carbon fiber (ACF) electrodes. For Cr(III)-EDTA, electro-peroxone could remove ∼90% total Cr from 11.50 mg/L to 1.20 mg/L and ∼80% total organic carbon, with a strong curtailment of Cr(VI) to less than 0.2 mg/L. Additionally, the process could obtain a complete recovery of the removable Cr, of which 78.3% are enriched at ACF cathode as amorphous Cr(OH) 3 deposits and the remaining 21.7% are adsorbed at the anode, thus avoiding the generation of Cr laden sludge. Mechanism studies show the electro-generated H 2 O 2 reacts with O 3 to generate abundant HO· for decomplexation, which sequentially oxidizes Cr(III) to Cr(VI), and degrades the released EDTA via stepwise decarboxylated process, as confirmed by HPLC analysis. Multiple pathways including electro-reduction, H 2 O 2 reduction and electro-adsorption synergistically curtail and immobilize the formed intermediate Cr(VI). ACF characterizations and continuous 5-cycle experiments substantiate the excellent reusability of the ACF electrodes. Moreover, this process exhibits satisfactory effectiveness to Cr(III) complexed with other ligands (e.g., citrate and oxalate), and complexed Cr(III) in the real electroplating wastewater. We believe this study would provide an efficient and eco-friendly alternative for Cr(III) complexes removal from wastewater. [Display omitted] [ABSTRACT FROM AUTHOR]

With the pollution of perfluoroalkyl substances (PFASs) became increasingly serious, the researches focused on removal of PFASs by adsorption-photocatalysis method has attracted considerable attention. To make the catalyst TiO 2 disperse uniformly as quantum dots onto hydrophobic surface which was liable to attract perfluorooctanoic acid (PFOA), the surfactant sodium dodecyl sulfate (SDS) were used in this work, which not only connected the hydrophilic TiCl 3 to the hydrophobic sulfonated graphene (SG) nanosheets, but also behaved as the molecular template for controlled nucleation and growth of the nanostructured TiO 2. After 3D SG-TiO 2 QD nanosheets were fabricated, a series of 3D SG-TiO 2 QD aerogels were self-assembled by ice-template. TiO 2 uniformly distributed on the surface of SG aerogel at QD size level (2–3 nm) and the size of TiO 2 could be effectively regulated by concentration of SDS. Compared with aggregated TiO 2 material, 3D SG-TiO 2 QD aerogels owned higher adsorption and photocatalytic performance. Benefiting from the hydrophobic surface of 3D SG as well as dispersed TiO 2 QDs, 3D SG-TiO 2 QD could enrich PFOA instantaneously (0.0381/s) and photocatalytic decomposed them effectively (1.898 E−4/s). PFOA degradation by hole and hydroxyl radicals proceeded via a stepwise mechanism. The column made of 3D SG-TiO 2 QD could remove PFOA persistently in cycles of permeation. 3D SG-TiO 2 QD possessed powerful adsorption-photocatalytic decomposition capability of PFOA and steady reusability performance. The present work highlights the individual roles and synergistic effect of TiO 2 QD and 3D SG for effectively removing PFOA. Unlabelled Image • 3D SG-TiO 2 QD aerogels were self-assembled by 3D SG-TiO 2 QD nanosheets. • TiO 2 were uniformly distributed on the surface of 3D SG aerogel at QD size level (2-3 nm). • 3D SG-TiO 2 QD aerogels possessed powerful adsorption-photocatalytic decomposition capability of PFOA, which originated from the individual roles and synergistic effect of TiO 2 QD and 3D SG for effectively removing PFOA. [ABSTRACT FROM AUTHOR]