Effective treatment of cyanide containing coking wastewater by catalytic ozonation with a novel ruthenium-supported catalyst

Biological treatment of coking wastewater for organic and cyanide compounds required extensive hydraulic retention times and prolonged startup periods. This study introduces a novel Ru, Ag, Mn loaded activated carbon (RuAgMn-AC) catalyst for catalyst ozonation, significantly enhancing the removal of the cyanide and organic compounds. In synthetic coking wastewater (SCW), RuAgMn-AC exhibits a high removal efficiencies, achieving 76.5% for chemical oxygen demand (COD) and 89.1% for cyanide in 30 min of reaction. Electron paramagnetic resonance (EPR) analysis, combine with radicals quenching experiments revealed that hydroxyl radicals (•OH), superoxide radicals (O2•−), and singlet oxygen (1O2) were the dominant reactive oxygen species (ROS) responsible for pollutant degradation. Moreover, the analysis of intermediate products revealed a gradually pH decreased from 10 to 5 during the reaction process, during which cyanide and cyanate were formed and eventually decomposed into nitrogen gas or ammonium. In addition, the catalytic ozonation with RuAgMn-AC effectively removed 91% of cyanide and 87.8% of COD from real coking wastewater (RCW) and maintained a stable removal efficiency after multiple batch cycles. Our study presents a promising solution for removing organic compounds and cyanide from coking wastewater compared to recent literatures. © 2024 Elsevier Ltd