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/IrO2-RhOx-TiO2/ alpha-PbO2/beta-PbO2 electrode. The electrochemical oxidation experimental results verified the superior electro-catalytic properties of the beta-PbO2 electrode. Accelerated lifetime tests suggested that Ti/IrO2-RhOx-TiO2/ alpha-PbO2/beta-PbO2 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 beta-PbO2 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 Na2SO4 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.

Automated summary

In this study, the ordinary scale inhibitor Amino Trimethylene Phosphonic Acid (ATMP) was successfully degraded using electrochemical oxidation with a beta-PbO2 electrode, which demonstrated superior electro-catalytic properties. The Ti/IrO2-RhOx-TiO2/alpha-PbO2/beta-PbO2 electrode showed a service lifetime of 201 hours under a current density of 40000 A/m(2), significantly longer than other beta-PbO2 electrodes reported by other researchers. The degradation rate and electrical efficiency of ATMP were found to be significantly affected by four major operational parameters, namely electrolyte, current density, initial ATMP concentration, and pH. The degradation mechanism involved direct oxidation, leading to a removal efficiency of 55.11% in Na2SO4 solution and 38.82% in NaCl solution. Two possible degradation pathways of ATMP were proposed, involving the breaking of either C-P or C-N bonds.