Constructing Tandem Fenton‐like Reaction Systems Based on Structure Adaption to Boost Water Contaminant Mineralization Efficiency

Abstract Mineralization of emerging contaminants by using advanced oxidation processes (AOPs) is a desirable option to ensure water safety, but still challenged by the excessive chemical and/or energy input. Here, we conceptually proposed the tandem reaction system (TRS) of different reactive oxygen species (ROS) based on structure adaption of target contaminants. To construct a model TRS, we first realized highly selective generation of three classical ROS ( 1 O 2 , HO⋅ and SO 4 ⋅ − ) by peroxymonosulfate activation in an electrochemical Fenton‐like system, where three replaceable Fe‐centered cathodes were rationally designed as electronic mediator. The 1 O 2 +SO 4 ⋅ − ‐TRS exhibited nearly 100 % mineralization of sulfamethoxazole (SMX), whereas only 34.2 %, 56.2 % and 60.8 % for each of the single 1 O 2 /HO⋅/SO 4 ⋅ − ‐AOP systems. Mechanism exploration of SMX degradation in TRS evidenced that the initial reaction with 1 O 2 selectively destructed the sulfonamide bridge of SMX to form p ‐aminobenzenesulfonic acid, which will be vulnerable to sequent SO 4 ⋅ − attack to facilitate mineralization. Successful extendibility of 1 O 2 +SO 4 ⋅ − ‐TRS to other sulfonamide antibiotics and 1 O 2 +HO⋅‐TRS to phenolic and arylcarboxylic compounds, as well as the demonstration of 1 O 2 +SO 4 ⋅ − ‐TRS in treatment of three actual pharmaceutical wastewaters strongly support that TRS is a powerful and sustainable strategy to enhance the mineralization of emerging contaminants in water.