Iron and nitrogen modified sludge biochar efficiently activated persulfate for mineralization of sulfamethoxazole in groundwater
Shanhu Wang, Xianrong Meng, Xingyu Yan, Yan Wang, Yuanye Mo, Yonghao Chen, Wei Xu, Weilin Shi
Abstract
In this work, iron-nitrogen co-doped sludge biochar (Fe@N-SBC) was successfully prepared by a facile synthetic method using sludge as a precursor. We investigated the degradation effect of Fe@N-SBC activated peroxodisulfate (PDS) on sulfamethoxazole (SMX), a common antibiotic pollutant in groundwater, and explored its reaction mechanism. The removal of SMX in the Fe@N-SBC /PDS system reached more than 99%, and it could still reach 97.8% in actual groundwater with complex composition. Under the condition of sufficient dosage, the final mineralization of SMX can reach more than 95%, which means that there is no risk of secondary pollution of intermediate products to the environment. The main mechanism for the degradation of SMX by Fe@N-SBC/PDS system is the electron transfer mechanism mediated by the substable [Fe@N-SBC-PDS* ] complex formed on the surface of Fe@N-SBC, followed by the non-radical reaction mechanism dominated by singlet oxygen, and thus it has a wide pH range and strong resistance to ionic interference. The addition of N can significantly reduce the leaching of metal ions in the material, and the leaching amount of Fe in Fe@N-SBC is only 0.1 μg/g, while other toxic and harmful heavy metals are hardly leached. Overall, Fe@N-SBC is an environmentally friendly catalyst with simple preparation, high catalytic activity, wide applicable pH range, strong resistance to ionic interference, and selectivity for electron-rich organics, which has good application prospects in practical groundwater treatment.