On a direct course to the aldehyde: Hydrosilylation catalyzed by a well‐defined N‐heterocyclic‐carbene–iron complex under UV irradiation enabled the selective reduction of esters to aldehydes (see scheme; Bn=benzyl, Mes=mesityl). The low catalyst loading and very mild reaction conditions make this chemoselective transformation a promising alternative to the reduction of esters with diisobutylaluminum hydride.

The direct reduction of carboxylic acids to disilylacetals was achieved through a manganese catalyzed hydrosilylation reaction in the presence of triethylsilane under mild conditions, at r.t. and under UV irradiation (350 nm). The aldehydes were obtained in good to excellent yields after acidic hydrolysis.

Recovery of nutrients and energy from municipal wastewater has attracted much attention in recent years; however, its efficiency is significantly limited by the low-strength properties of municipal wastewater. Herein, we report a pilot-scale forward osmosis (FO) system using a spiral-wound membrane module to concentrate real municipal wastewater. Under active layer facing feed solution mode, the critical concentration factor (CCF) of this FO system was determined to be 8 with 0.5 M NaCl as draw solution. During long-term operation at a concentration factor of 5, (99.8 ± 0.6)% of chemical oxygen demand and (99.7 ± 0.5)% of total phosphorus rejection rates could be achieved at a flux of 6 L/(m2 h) on average. In comparison, only (48.1 ± 10.5)% and (67.8 ± 7.3)% rejection of ammonium and total nitrogen were observed. Cake enhanced concentration polarization is a major contributor to the decrease of water fluxes. The fouling also led to the occurrence of a cake reduced concentration polarization effect, improving ammonium rejection rate with the increase of operation time in each cycle. This work demonstrates the applicability of using FO process for wastewater concentrating and also limitations in ammonium recovery that need further improvement in future.

Removal of recalcitrant anthropogenic contaminants from water calls for the development of cost-effective treatment technologies. In this work, a novel electrochemical membrane filtration (EMF) process using a conducting microfiltration membrane as the cathode has been developed and the degradation of sulphanilic acid (SA) examined. The electrochemical degradation of SA in flow-by mode followed pseudo-first-order kinetics with the degradation rate enhanced with increase in charging voltage. Hydrogen peroxide as well as oxidants such as HO and Fe(IV)O were generated electrochemically with HO found to be the dominant oxidant responsible for SA degradation. In addition to the anodic splitting of water, HO was formed via a heterogeneous Fenton process with surface-bound Fe(II) resulting from aerobic corrosion of the steel mesh. In flow-through mode, the removal rate of SA was 13.0% greater than obtained in flow-by mode, presumably due to the better contact of the contaminant with the oxidants generated in the vicinity of the membrane surface. A variety of oxidized products including hydroquinone, p-benzoquinone, oxamic acid, maleic acid, fumaric acid, acetic acid, formic acid, and oxalic acid were identified and an electrochemical degradation pathway proposed. These findings highlight the potential of the cathodic EMF process as an effective technology for water purification.

Methylation of secondary amines was achieved using dimethyl carbonate or diethyl carbonate as the C1 source under the catalysis of well-defined half-sandwich iron complexes bearing an N-heterocyclic carbene ligand. The reaction proceeded under mild conditions in the presence of hydrosilanes as the reductants, and the amines were obtained with good to excellent isolated yields.

Inability to remove low-molecular-weight anthropogenic contaminants is a critical issue in low-pressure membrane filtration processes for water treatment. In this work, a novel electrochemical ceramic membrane filtration (ECMF) system using TiO@SnO-Sb anode was developed for removing persistent p-chloroaniline (PCA). Results showed that the ECMF system achieved efficient removal of PCA from contaminated waters. At a charging voltage of 3 V, the PCA removal rate of TiO@SnO-Sb ECMF system under flow-through mode was 2.4 times that of flow-by mode. The energy consumption for 50% of PCA removal for TiO@SnO-Sb ECMF at 3 V under flow-through mode was 0.38 Wh/L, much lower than that of flow-by operation (1.5 Wh/L), which was attributed to the improved utilization of the surface adsorbed HO· and dissociated HO· driven by the enhanced mass transfer of PCA toward the anode surface. Benefiting from the increased production of reactive oxygen species such as O, HO, and HO· arising from excitation of anatase TiO, TiO@SnO-Sb ECMF exhibited a superior electrocatalytic activity to the SnO-Sb ECMF system. The degradation pathways of PCA initiated by OH· attack were further proposed, with the biodegradable short-chain carboxylic acids (mainly formic, acetic, and oxalic acids) identified as the dominant oxidized products. These results highlight the potential of the ECMF system for cost-effective water purification.

International audienc

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