A Novel G-CN Modified Biogenic Mackinawite Mediated by SRB for Boosting Highly Efficient Adsorption and Catalytic Degradation of Antibiotics in Photo-Fenton Process.

FeS-based nanomaterials are widely used in Fenton-like reaction of antibiotics degradation. However, the problems of poor stability and low reusability limit the catalytic efficiency. Herein, the study ingeniously introduced the g-CN into FeS to synthesize g-CN@biogenic FeS (CN-BF-1) nanocomposite with strong interaction of iron ions and "N-pots" by the mediation of sulfate reducing bacteria (SRB). Results indicated the g-CN accelerated SRB metabolism and improved the mineralization and stability of FeS to well-crystallized mackinawite. The CN-BF-1 can efficiently adsorb and degrade antibiotics compared with FeS and g-CN, and bear a broad pH range which further proved the increase of stability. The toxicity studies showed ciprofloxacin (CIP) degradation solution hardly caused ecotoxicity and induced antibiotic resistance genes, while CN-BF-1 can be regenerated by SRB in this solution with chemical and enzymatic reduction of Fe(III)-mud to achieve efficient CIP degradation (99.9%). Finally, the mechanism part showed that CN-BF-1 can activate HO to form O and •OH which played the main roles in the catalysis process. The work paves the way for a novel approach to intensify iron-based photo-Fenton system in sustainable remediation of antibiotic wastewater, upon which the high-efficiency removal and non-toxic degradation solution of antibiotic contamination are expected.