High selectivity and effectiveness for removal of tetracycline and its related drug resistance in food wastewater through schwertmannite/graphene oxide catalyzed photo-Fenton-like oxidation

Selectively and effectively for removal of tetracycline (TC) and its related antibiotic resistance gene from food wastewater matrix with high-salt and high COD characteristics is highly desirable. In this work, novel schwertmannite/graphene oxide (SCH/GO) nanocomposites were synthesized through a facile oxidation-coprecipitation method. The SCH/GO nanocomposites were characterized by TEM, XRD, BET, PL, DRS, XPS and FTIR. In the presence of 1 mM H₂O₂, the SCH/GO catalyzed Fenton-like oxidation can thoroughly degrade TC under visible light irradiation, even under nature sunlight, whose second-order kinetic rate constant was about 15 times higher than that of pure SCH. SCH/GO was capable of highly selectively capturing and effectively degrading TC in the presence of similar concentration of Cl⁻, NO₃^-, SO₄^2- and PO₄^3- with that of food wastewater, even at organic matters concentration of 12.5 times than that of TC. At the same time, the removal of total organic carbon (TOC) and chemical oxygen demand (COD) in aforementioned food wastewater in SCH/GO+H₂O₂+Vis system reached 27.3 % and 34.5 % after 60 min, respectively. The inhibition zone experiments authenticated that the removal of drug resistance of bacteria by TC degradation intermediates can be achieved very well without producing secondary contamination in this system.