A comprehensive review on LDH-based catalysts to activate persulfates for the degradation of organic pollutants

Abstract

AbstractDegradation of organic contaminants into less toxic substances is the best option to remove these compounds rather than using conventional techniques. The sulfate radical-based-advanced oxidation process is an effective strategy that degrades organic contaminants by activating peroxymonosulfate (PMS). Such a strategy generates singlet oxygen (1O2), hydroxyl ($$^ \bullet \!{{{\mathrm{OH}}}}$$ ∙ OH ), and sulfate ($${{{\mathrm{SO}}}}_4^{ \bullet\! - }$$ SO 4 ∙ − ) radicals. $${{{\mathrm{SO}}}}_4^{ \bullet \!- }$$ SO 4 ∙ − is distinguished by its high oxidation selectivity and activity toward the degradation of organic contaminates compared to other radicals. Various catalysts are employed in PMS activation including layered doubled hydroxides (LDHs), which are characterized by their facile synthesis and high catalytic activity. This review article is the first attempt to compile the recent progress in the degradation of common organic pollutants including aromatic compounds, pharmaceutical residues, and dyes via the PMS activation using LDH-based catalysts. The degradation pathways, reaction parameters’ influence, stability of LDHs, and comparisons between different LDH-based catalysts are investigated in this work.