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Breaking hydrogen bond in metal free carbon nitride (CN) to increase peroxymonosulfate (PMS) adsorption for surface-mediated electron transfer has been challenging. Herein, we incorporated N−C N monomer into CN to break hydrogen bond by the introduction of polyvinylpyrrolidone (PVP). The developed nonradical oxidation system achieved selective decomposition of highly hydrophilic contaminants and efficient removal of chemical oxygen demand (58.0%), total phosphorus (88.1%), ammonia nitrogen (100.0%) and total nitrogen (67.8%) from the secondary effluent in a continuous flow reactor. This was attributed to that the breakage of hydrogen bond accelerated the redistribution of electron densities at C and N sites, leading to an increase in the adsorption energy of N site to PMS. This promoted the formation of PVP/CN-PMS* complex for the selective and efficient removal of organics and inorganics. This work provided a new perspective for the selective and long-term treatment of practical wastewater. [Display omitted] • Surface-mediated electron transfer system was constructed by breaking hydrogen bond. • The effect of hydrogen bond in carbon nitride on PMS activation pathway was revealed. • PVP/CN/PMS/vis system selectively remove highly hydrophilic contaminants. • The efficient and continuous flow treatment of practical wastewater was achieved. [ABSTRACT FROM AUTHOR]

• Fe-POM NP/porous and ultrathin g-C 3 N 4 nanosheet with rich N defect was fabricated. • Various emerging pollutants were almost completely removed by 45Fe- POM/CNNS-N vac. • Impact of N vacancies on ROS degradation mechanism was investigated. • Degradation pathways and products toxicity were given via theoritical calculation. Surface defect engineering has been suggested as an effective strategy to enhance photo-Fenton degradation performance. However, the underlying impact mechanism remains unknown. This study precisely constructed an efficient photo-Fenton catalyst through self-assembly of Fe-polyoxometalates nanoparticles on porous and ultrathin g-C 3 N 4 nanosheets with nitrogen vacancies (Fe-POM/CNNS-N vac). These nitrogen vacancies promoted photo-Fenton reaction rate constant for tetracycline hydrochloride (TCH) from 0.0950 to 0.1520 min−1 under visible light irradiation. Scavenging experiments and characterization results indicated that nitrogen vacancies could accelerate Fe(III)/Fe(II) conversion for OH and 1O 2 generation, and directly regulate electronic structure for O 2 − generation. The possible degradation pathways of TCH were interpreted using experimental results and frontier electron density calculations. The results indicated that holes (h+) were responsible for ring-opening and 1O 2 /OH/O 2 − contributed to demethylation, deamination, and further mineralization. This study provides novel insight for the design of highly efficient catalysts with nitrogen vacancies for the removal of emerging pollutants. [ABSTRACT FROM AUTHOR]

The design of suitable catalyst is the bottleneck in the photo-assisted Fenton-like reaction system. Here we constructed a S-scheme heterojunction consisted of CuO and Cu doped ZnO using Cu-ZIF-8 as precursor. The as-prepared composite catalyst possesses outstanding catalytic activation performance and broad-spectrum degradation capacity. To clearly fit and describe the overall reaction, a pseudo-third-order kinetic model was developed based on the second-order peroxymonosulfate (PMS) consumption and first-order methylene blue removal. The catalyst/visible light/ PMS composite reaction system provides remarkable mineralization and anti-interference ability, and is environmental friendliness. The interaction of Cu/Zn bimetallic sites realized the effective utilization of PMS, accelerated the PMS activation and promoted the formation of the highly oxidative SO 5 •−. Overall, this work provides new systematic insights on PMS activation by Cu/Zn bimetallic oxide S-scheme heterojunction and is of significance for sewage purification. [Display omitted] • A S-scheme heterojunction was constructed by using Cu-ZIF-8 as precursor. • The as-prepared CuZnO-3 exhibited superior catalytic activation capability. • A pseudo-third-order kinetic model was developed involving the reacted MB and PMS. • The CuZnO-3/vis/PMS reaction system was evaluated to be environmentally friendly. • The catalytic activation mechanism of Cu/Zn bimetallic sites was proposed. [ABSTRACT FROM AUTHOR]