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In this study, we demonstrate that Fe(III)-doped g-C 3 N 4 can efficiently activate peracetic acid (PAA) to degrade electron-rich pollutants (e.g., sulfamethoxazole, SMX) over a wide pH range (3−7). Almost ∼100% high-valent iron-oxo species (Fe(V)) was generated and acted as the dominant reactive species responsible for the micropollutants oxidation based on the analysis result of quenching experiments, 18O isotope-labeling examination and methyl phenyl sulfoxide (PMSO) probe method. Electrochemical testing (e.g., amperometric i−t and linear sweep voltammetry (LSV)) and density functional theory (DFT) calculations illustrated that the main active site Fe atom and PAA underwent electron transfer to form Fe(V) for attacking SMX. Linear free energy relationship (LFER) between the pseudo-first-order rates of different substituted phenols (SPs) and the Hammett constant σ+ depicted the electrophilic oxidation properties. The selective oxidation of Fe(V) endows the established system remarkable anti-interference capacity against water matrices, while the Fe(V) lead to the formation of iodinated disinfection by-products (I-DBPs) in the presence of I−. Fe(III)-doped g-C 3 N 4 /PAA system showed excellent degradation efficiency of aquaculture antibiotics. This study enriches the knowledge and research of high-valent iron-oxo species and provides a novel perspective for the activation of PAA via heterogeneous iron-based catalysts and practical environmental applications. [Display omitted] • Nearly 100% Fe(V) was generated in Fe(III)-doped g-C 3 N 4 /PAA process. • A favorable SMX removal was observed over a wide pH range (3−7). • An outstanding anti-interference was exhibited in Fe(III)-doped g-C 3 N 4 /PAA process. • Iodinated disinfection byproducts (I-DBPs) was formed during Fe(III)-doped g-C 3 N 4 /PAA/I− process. [ABSTRACT FROM AUTHOR]

Effective treatment of industrial wastewater containing complex pollutants, such as nitrate (NO 3 --N) and organic pollutants, remains a significant challenge to date. Here, a strain Nocardioides sp. ZS2 with denitrification and degradation of p -nitrophenol (PNP) was isolated and its culture conditions were optimized by kinetic analysis. Hydrophilic sponge carriers were prepared using polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), and chitosan (CS) to construct bioreactors. Furthermore, to further enhance the PNP degradation and denitrification performance of bioreactors, Pseudomonas stutzeri GF2 with denitrification capability was introduced. The results revealed that the removal efficiencies of PNP and NO 3 --N reached 97.9 % and 91.9 %, respectively, when hydraulic retention time (HRT) of 6 h, C/N of 2.0, and pH of 6.5. The bioreactor exhibited stable denitrification performance even with fluctuations in the influent PNP concentration. The potential functional prediction results revealed that the abundance of amino acids, fatty acids, and carbohydrates increased as the influent C/N decreased, reflecting a tendency of the microbial community to adjust carbon source utilization to maintain cell growth, metabolic balance, and resist adverse C/N environments. This research provides new insights into the effective removal of organic pollutants and NO 3 --N in wastewater treatment. [Display omitted] • A novel Nocardioides sp. ZS2 with the ability to remove PNP and NO 3 --N was isolated. • PNP degradation by-products alleviate NO 2 --N accumulation in denitrification process. • A novel hydrophilic sponge biocarrier was prepared by hydroxyaldol reaction. • Dual bacterial collaboration enhanced the removal efficiencies of NO 3 --N and PNP. • The increase in PNP concentration promoted substance transport and metabolism. [ABSTRACT FROM AUTHOR]