Electrochemical degradation of microcystin-LR in high-pH and high-DOC waters using a novel Au/Ni-MOF anode

Microcystin-LR (MC-LR), a potent cyanotoxin produced during harmful algal blooms, poses serious threats to drinking and recreational waters, particularly under alkaline and organic-rich conditions where many treatment processes fail. This study demonstrates electrochemical degradation of MC-LR using a gold-decorated nickel metal-organic framework (Au/Ni-MOF) anode. At 5 mA cm^-2 in phosphate buffer, the anode achieved 71% removal of 20 ppb MC-LR with a pseudo-first-order rate constant of 0.0053 min^-1 and low energy consumption (0.41 kWh m^-3). Notably, degradation kinetics were enhanced under bloom-relevant conditions, with a 5.2-fold increase in rate at elevated pH and dissolved organic carbon (DOC). Reactive oxygen species (ROS) analysis confirmed hydroxyl radicals as the dominant oxidant. The Au/Ni-MOF anode exhibited robust performance in real water matrices, achieving complete MC-LR removal in tap water within 30 min at 0.32 kWh m^-3. These results demonstrate the potential of MOF-based electrodes for energy-efficient electrochemical oxidation of cyanotoxins in chemically complex waters.