Xanthate, as the primary collector in flotation processes, can accumulate through the food chain and release toxic gases such as CS₂, posing threats to mining ecosystems and public health. While ozone conventional bubbles (OCBs) have been used for oxidation, their low gas-liquid interfacial area and fast buoyancy limit mass transfer and treatment efficiency. In this study, the quantitative relationship between the properties of ozone microbubbles (OMBs) and their degradation efficiency is first evaluated for xanthate-containing mineral processing wastewater using OMBs, in comparison with OCBs. This work focuses on potassium ethyl xanthate (EX) as the target pollutant and constructs an OMBs mass-transfer and reaction system. First, the regulation of bubble micro-physics on ozone steady-state concentration and mass transfer coefficient was elucidated. Then, the in-situ characterization of bubble properties was conducted using FBRM technology, and the role of bubble properties in degradation efficiency was revealed through kinetic parameter fitting. The synergistic mineralization pathway via O₃/·OH was uncovered through product analysis and DFT calculations, and plant experiments were performed to validate biosafety. Results demonstrated that OMBs increased the steady-state ozone concentration by 2.23 times compared to OCBs and enhanced the degradation rate of 50 mg L^-1 EX by 47.22% within 60 minutes, following zero-order kinetics (R²>0.95). The solution chemistry (pH, ion concentration, temperature) directly influenced the degradation rate enhancement by modulating bubble stability. EX was ultimately mineralized into water, CO₂, and SO₄^2-. The germination rate of Chinese cabbage seeds reached 93.3%, and plant height increased by 41.53% compared to the control, confirming the non-toxic nature of the degradation products. This study establishes a closed-loop mechanism of “bubble characteristics–mass transfer enhancement–reaction pathway”, providing a scalable technological solution and theoretical foundation for the green and deep treatment of xanthate-based collectors in mineral processing wastewater.
 

Ethyl xanthate,Ozone microbubbles,Bubble characteristics,Degradation kinetics,Degradation pathway