Domain-limited thermal transformation preparation of novel graphitized carbon-supported layered double oxides for efficient tetracycline degradation.

The resource utilization of industrial lignin to construct high-performance catalysts for wastewater treatment field is pioneering research. Herein, the novel graphitized carbon-supported CuCoAl-layered double oxides (LDOs-GC) were successfully designed by the domain-limited thermal transformation technology using sodium lignosulfonate (LS) self-assembled CuCoAl-layered double hydroxides as the precursor. The optimized LDOs-GC catalyst owned the excellent tetracycline (TC) degradation of 98.0% within 15 min by activated peroxymonosulfate (PMS) under optimal conditions (20 mg/L catalyst, 1.5 mM PMS, 30 mg/L TC). The density of metal ions in the catalyst and the synergistic interaction between graphitized carbon (GC) and metal ions played a major role in TC degradation. Based on a comprehensive analysis, the TC degradation in LDOs-GC/PMS system was proved to be accomplished by a combination of free radicals (SO and HO) and non-radicals (O). Meanwhile, the possible degradation pathways of TC were proposed by the analysis of TC degradation intermediates and a comprehensive analysis of the rational reaction mechanism for TC degradation by LDOs-GC/PMS system was also performed. This work provides a new strategy for developing novel high-performance catalysts from industrial waste, while offering a green, cheap and sustainable approach to antibiotic degradation.