Study On Catalytic Degradation Of Phenolic Wastewater In BPA Production Via Supercritical Water Oxidation

Supercritical water oxidation is a newly-developed, highly-effective technologyfor the treatment of organic components of aqueous wastewater, which has attractedmore and more attention from the researchers. The unique properties of supercriticalwater make organic compounds react rapidly and totally with oxygen. In this paper,the catalytic supercritical water oxidation of phenolic wastewater from bisphenol Aplant was investigated.MnO₂ was used as a catalyst, and the optimum conditions of catalyst preparationwere chosen as follows: molding pressure 600MPa, agglutinating agent content1.5wt% and sintering temperature 400℃.The experimental results show that MnO₂ greatly enhances both the conversionof phenolic wastewater and that of total organic carbon (TOC) compared withnon-catalytic oxidation, exhibiting a high activity and stability.The experimental results indicate that the conversion of the organic componentsand TOC is improved with the increase of reaction temperature, reaction pressure,residence time and the multiple of oxygen excess. The influences of both reactiontemperature and residence time on the organics and TOC conversion are higher thanthat of reaction pressure and the multiple of oxygen excess.The optimization experiment show that no phenol and toluene is detected in theproducts at the condition of 480℃,26MPa,the multiple of oxygen excess 15 andresidence time 2.8s, and the TOC concentration is 25.4 mg/kg, all of which have metthe discharge demand of GB8978-1996.The kinetics of catalytic supercritical oxidation of phenolic wastewater wasinvestigated. Opitimization method is used to correlate the experimental data and theresulting power-law rate expression is:2r = 9 .32×10⁴ exp(-5.74×10⁴/RT)[TOC]^0.60[O]^0.44...