A novel Magnéli-phase Ti9O17-containing anode by controlled reductive decomposition of calcium copper titanate perovskite under hydrogen atmosphere for paracetamol degradation

Abstract

CaCu3Ti4O12 (CCTO) materials show high efficacy in water treatment due to their perovskite structure and exceptional chemical stability. Their combination with electro-oxidation and sulfate-based advanced processes represents a promising approach for water treatment applications. CCTO can be modified through various processes to enhance its activity in water treatment. In this study, CCTO was synthesized using ball milling, and the effects of different sintering treatments were evaluated. The treatment with different atmospheres led to CCTO decomposition. Upon sintering under nitrogen, CCTO broke down into the CaTiO3, Cu2O, and rutile TiO2 phases. Conversely, sintering under hydrogen (CCTOH2) led to the reduction of Cu and TiO2 and the creation of Cu and Magnéli phase Ti9O17. CCTOH2 exhibited the highest electrochemical properties due to the presence of Magnéli phases that enhanced electron transfer and conductivity. The decomposition treatment effect on the water treatment performance was evaluated using an electro-oxidation/peroxymonosulfate system. The results showed that when CCTOH2 membranes were used as anodes, paracetamol was completely removed within 10 min. Toxicity was evaluated using Vibrio fischeri. After 1 h, bacterial luminescence inhibition rate dropped to 0 % (from ∼96 % at 2 min), demonstrating paracetamol degradation into non-toxic compounds. Furthermore, CCTOH2 efficacy was tested in the presence of dissolved and colloidal matter from a laboratory-scale secondary effluent. The results demonstrated consistent efficiency in paracetamol degradation in real water and the additional removal of fluorophores. After demonstrating the efficacy of our CCTOH2 membrane, it is now important to test it in large scale experiments.