Mn/N co-doped biochar-activated persulfate degradation of tetracycline in water

Fresh sweet flag ( Acorus calamus ) biochar (BC) was modified by impregnation pyrolysis, and the ability of the resulting Mn/N-BC material to activate peroxydisulfate (PDS) adsorption and degrade tetracycline (TC) was investigated alongside its reaction mechanism. Under the optimal 1:1:1 BC: N:Mn doping ratio and optimal experimental conditions (2 mM PDS, 1.0 g/L catalyst dosage, pH 7), Mn/N-BC + PDS degraded 93.67% of 20 mg/L TC within 120 min and maintained a removal rate of > 80% after three cycles. Co-doping of two elements provided a large number of active sites for PDS activation. Nitrogen was detected in the form of pyridine N, pyrrole N, and graphite N. Structural defects caused by doping in carbon materials generates 1 O 2 non-free radicals, and loading of Mn breaks the O-O bond in PDS and produces SO 4 • − and •OH free radicals. These reactive substances play a role in degrading TC and other organic pollutants. Following treatment with the developed system, TC solutions exhibited reduced toxicity and potential feasibility for further exploration in water treatment.