Degradation of tetracycline hydrochloride by sodium percarbonate activated by nitrogen and sulfur co-doped biochar
Nitrogen and sulfur co-doped biochar(NSBC)was prepared from corncob and thiourea,and it was used to activate sodium percarbonate(SPC)to degrade tetracycline hydrochloride(TCH).It was characterized by FTIR and XPS.The effects of various key parameters on the degradation of TCH by NS-BC/SPC were investigated in detail.On this basis,the catalytic mechanism of the system was further ex-plored and its degradation ability was verified.The results indicated that the co-doping of N and S signifi-cantly increased the active functional groups of biochar and enhanced the catalytic ability of NSBC to pro-duce·OH,thus significantly improving the performance of NSBC catalyzing the degradation of TCH com-pared to the original biochar(BC).Under the conditions of NSBC dosage of 0.6 g/L,temperature of room temperature,SPC concentration of 1 mmol/L and TCH concentration of 5 mg/L,the removal rate of TCH reached more than 90%in 70 min,and the change of pH had little effect on the removal of TCH.EPR ex-periments and free radical quenching experiments confirmed that the removal of TCH in the NSBC/SPC system was a synergistic effect of hydroxyl radicals(·OH)and singlet oxygen(1 O2).Inorganic anions and natural organic matter(NOM)had little effect on the degradation of TCH by NSBC/SPC system.The NSBC/SPC system achieved good degradation effects on the other five refractory organics.
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