A large number of refractory organics residual in semi-aerobic aged refuse biofilter (SAARB) leachate, ozone/manganese-dioxide (O3/MnO2) process was used to catalytically decompose organics from SAARB treated landfill leachate. Effects of ozone dosage, MnO2 dosage and initial pH on the removal of organic substances and reaction kinetics were investigated. UV-Vis and 3D-EEM tests were applied to investigate the transformation mechanism of recalcitrant organics in O3/MnO2 process. In addition, the phase change of MnO2 before and after reaction and its catalytic mechanism were investigated by SEM, EDS, XRD and XPS. Results showed that when the ozone dosage of 18.92mg/min, initial pH of 3 and reaction time of 20min, compared to the ozone alone treatment, the O3/MnO2 peroxide treatment was significantly improved with 2mg/L MnO2 addition. The removal efficiencies of COD, UV254, and CN by 24.66%, 4.95%, and 12.57%, respectively, and the chromophore was most easily attacked by ozone. UV-Vis spectra and 3D-EEM spectrum were both illustrated that O3/MnO2 process can significantly decrease the aromaticity degree, molecular weight and condensation degree of organic substances in wastewater, which degradation efficiency of benzene ring compounds was improved significantly and also greatly proved biodegradability of leachate effluent. Meanwhile, After O3/MnO2 process, MnO2 has not shown the change of the peak value of the new valence state, and Mn(Ⅳ) played a dominate role in the catalytic process. In order to promote the selectivity of hydroxyl radical and the catalytic performance, indicating that the mechanism of O3/MnO2 process was MnO2 catalyzed O3 to generate hydroxyl radicals and transformed into hydrated manganese dioxide, which changed the physicochemical properties of the catalyst surface.
邓禺南, 陈炜鸣, 罗梓尹, 崔瑜旗, 李启彬. MnO2催化O3处理准好氧矿化垃圾床渗滤液尾水中难降解有机物[J]. 中国环境科学, 2018, 38(11): 4130-4140.
DENG Yu-nan, CHEN Wei-ming, LUO Zi-yin, CUI Yu-qi, LI Qi-bin. Removal of refractory organics from SAARB treated landfill leachate by O3/MnO2 process. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(11): 4130-4140.
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