High-performance Ti/IrO2-RhOx-TiO2/α-PbO2/β-PbO2 electrodes for scale inhibitors degradation

The extensive evaporation-induced aggregation of scale inhibitors in the wastewater of recirculating cooling systems causes severe environmental pollution . In this study, Amino Trimethylene Phosphonic Acid (ATMP), an ordinary scale inhibitor, was degraded via electrochemical oxidation using a multi-layered Ti/IrO 2 -RhO x -TiO 2 /α-PbO 2 /β-PbO 2 electrode. The electrochemical oxidation experimental results verified the superior electro-catalytic properties of the β-PbO 2 electrode. Accelerated lifetime tests suggested that Ti/IrO 2 -RhO x -TiO 2 /α-PbO 2 /β-PbO 2 possesses a service lifetime of 201 h under a current density of 40000 A/m 2 , which is 3.4–100.5 times as long as other β-PbO 2 electrodes reported by other researchers. Four major operational parameters, namely electrolyte, current density, initial ATMP concentration, and pH, were discovered to significantly affect the ATMP degradation rate and electrical efficiency. The direct oxidation mechanism predominated in the degradation process of ATMP, achieving a 55.11% and 38.82% removal efficiency in Na 2 SO 4 and NaCl solutions, respectively. In addition, two possible degradation pathways of ATMP were proposed: induced by the breaking of either C-P or C-N bonds.