In-situ material synthesis technology achieves efficient removal of heavy metal and levofloxacin combined pollution: The key role of amorphous copper species

Abstract

Introducing persulfate into combined pollution management is crucial for the complete removal of organic pollutants. In this paper, the attapulgite/alkali lignin biochar (ATP/AL) through one-step method to simultaneously adsorb heavy metals and degrade levofloxacin (LEV). The ATP/AL exhibited exceptional removal performance for Cu2+, Cd2+ and Pb2+ with high capacities of 229.90, 472.30 and 492.80 mg/g respectively, while also effectively utilizing the adsorbed Cu2+ for efficient persulfate catalysis. Notably, Cu2+ formed amorphous precipitates on ATP/AL surface acting as an electron donor to generate Cu3+, expediting the activation of PDS. This in turn facilitated persulfate decomposition and significantly increased the removal efficiency of LEV up to 94.92 % within just 5 min. Quenching experiments along with EPR results confirmed that ·OH and 1O2 are the main active species. Furthermore, DFT calculation revealed that the existence of Cu2+ reduced LEV stability and exposed its active sites. The intermediates generated during the degradation process were detected, providing insights into a possible degradation pathway for LEV degradation. Moreover, ATP/AL demonstrated excellent performance in real water treatment applications. This study introduces an innovative approach involving in-situ modification of materials using heavy metals present in combined pollution to realize the simultaneous pollutant removal.