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• Atrazine was selectively removed from wastewater with almost 100% detoxification. • Highly specific atrazine recognition relied on halogen bond and hydrogen bond. • Relationship between intermediate and toxicity in atrazine removal was revealed. • Cyanuric acid played an important role in promoting total toxicity elimination. Selective removal of atrazine (ATZ) in wastewater and clarification of the degradation intermediate-toxicity correlation are of great importance. A newly molecularly imprinted, {001} facets-exposed TiO 2 (MI-TiO 2,001) photoanode with strong catalytic and selective ability was designed. ATZ was selectively removed from pesticide wastewater, reaching 1.9 µg L −1, approximately 1/10 of the concentration achieved with nonselective treatment. This selective removal originated from the preferential adsorption and enrichment of ATZ onto MI-TiO 2,001. The highly specific recognition relied on the halogen bond and strong hydrogen bond formed between the Cl atom and triazine ring π orbital of ATZ and the surface -OH group of MI-TiO 2,001 as well as the recognition of MI-TiO 2,001 to the shape and size of ATZ. The specific interaction leads to different accumulations of intermediates. The correlation of intermediate and toxicity was also discussed. Aquatic toxicity was rapidly reduced through the direct dealkylation path, and due to the accumulation of highly toxic 2‑hydroxy-4-ethylamino-6-isopropylamino-s-triazine, there will be transient fluctuations via the dechlorination-hydroxylation path first. The final product was identified as nearly nontoxic cyanuric acid, the selective accumulation of which indicated that there was almost 100% removal of aquatic toxicity and cytotoxicity with only 9.8% removal of total organic carbon. This work provides new insight into the correlation of pollutant degradation intermediates and changes in toxicity. [Display omitted] [ABSTRACT FROM AUTHOR]

• Electrochemical system catalyzes sulfate for in situ generation of SO 4 −. • Synergistic radical generation mechanism at cathode and anode is firstly clarified. • Co 3 O 4 NWs arrays with the fast electron transport to efficiently activate persulfate. • The electrically accelerated circulation of Co(III)/Co(II) sustained the stability. Sulfate-based electrochemical advanced oxidation is of rising importance for pollutant removal, however, adscititious sulfate has adverse effects on water salinity. A novel electrochemical system which could exploit the existed SO 4 2− for in situ generation of SO 4 − was successfully constructed with boron doped diamond (BDD) anode and hierarchical 1D Co 3 O 4 nanowire array cathode. The in situ electrochemical electron paramagnetic spectroscopy and titration were used to study the positive correlation between the increase of sulfate radicals (SRs) and the efficient activation of peroxydisulfate (PDS) by hierarchical 1D Co 3 O 4 nanowire array cathode. Electrochemical impedance and X-ray photoelectron spectroscopy revealed that the efficient activation of PDS by the Co 3 O 4 cathode was derived from the excellent electron transport capability of the 1D nanostructure, and the electric field accelerates the reduction of Co(III). The novel hierarchical 1D Co 3 O 4 nanowire array cathode can completely degrade dibutyl phthalate in 45% less time with 38% less energy compared to a traditional graphite cathode without the requirement of extra chemicals. The possible mechanism of anodic PDS accumulation and cathodic SRs generation was firstly revealed, and this advanced electrochemical oxidation system provides a good reference for the in situ sustainable remediation in sulfate-containing water. [ABSTRACT FROM AUTHOR]

The removal of a class of toxic thiol-containing heterocyclic pollutants from complex water matrices has great environmental significance. In this study, a novel photoanode (Au/MIL100(Fe)/TiO 2) with dual recognition functions was designed for selective group-targeting photoelectrocatalytic removal of thiol-containing heterocyclic pollutants from various aquatic systems. The average degradation and adsorption removal efficiency of 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, and 2-mercaptobenzoxazole were still above 96.7% and 13.5% after selective treatment with Au/MIL100(Fe)/TiO 2 even coexisting with 10-fold concentration of macromolecular interferents (sulfide lignin and natural organic matters) and the same concentration of micromolecular structural analogues. While they were below 71.6% and 3.9% after non-selective treatment with TiO 2. Targets in the actual system were selectively removed to 0.9 µg L−1, which is 1/10 of that after non-selective treatment. FTIR, XPS and operando electrochemical infrared results proved that the highly specific recognition mechanism was mainly attributable to both the size screening of MIL100(Fe) toward targets and Au-S bond formed between -SH group of targets and Au of Au/MIL100(Fe)/TiO 2. •OH are the reactive oxygen species. The degradation mechanism was further investigated via excitation-emission matrix fluorescence spectroscopy and LC-MS. This study provides new guidelines for the selective group-targeting removal of toxic pollutants with characteristic functional groups from complex water matrices. [Display omitted] • Fabrication of a novel Au/MIL100(Fe)/TiO 2 photoanode with dual recognition functions. • Thiol-containing heterocyclic targets were selectively removed from water matrices. • Highly specific recognition relied on the size screening and Au-S bond. • Providing insights for selective removal of toxic group-targeting pollutants. [ABSTRACT FROM AUTHOR]