MW-Fe^0/H_2O_2体系预处理垃圾渗滤液浓缩液有机物

Enhanced degradation of refractory organics in leachate concentrates by Fe^0/H_2O_2 coupled with microwave irradiation

为探究MW-Fe^0/H_2O_2类芬顿反应对渗滤液浓缩液的效能与机理,探讨了废水初始p H值、Fe^0投加量、H_2O_2投加量、MW功率和反应时间等影响因素对有机物去除效果,通过类比实验对MW-Fe^0/H_2O_2体系处理渗滤液浓缩液中MW辐射的反应机理进行研究,并采用了SEM和XRD技术对反应前后的Fe^0物相变化及催化机理进行了探究.结果表明,在初始p H值为3.0,Fe^0投加量0.5g/L,H_2O_2投加量20m L/L,MW功率400W,反应时间14min时,其COD、UV_(254)以及色度(CN)的去除率分别为58.70%、85.69%和88.30%.类芬顿类比实验说明MW-Fe^0/H_2O_2体系处理后具有较高的有机物去除率和可生化性;紫外-可见光谱表明,Fenton和MW-Fe^0/H_2O_2类芬顿反应均能使废水中有机物的芳香性程度、分子量和缩合度大幅度降低,但MW-Fe^0/H_2O_2类芬顿反应优于其他反应过程;三维荧光光谱显示,MW-Fe^0/H_2O_2类芬顿反应能使渗滤液浓缩液中荧光峰峰位蓝移,说明废水的腐殖质缩合度减小,且分子量大幅降低.与此同时,Fe^0在反应过程中,表面由光滑变得粗糙且被腐蚀为Fe_3O_4和Fe OOH等物质.MW-Fe^0/H_2O_2类芬顿反应的主要机理为芬顿反应及铁氧化物-H_2O_2非均相芬顿反应的高级氧化作用、铁基胶体对有机物的吸附沉淀,而MW的热效应和非热效应加速了以上作用的进行,从而能对渗滤液浓缩液中有机污染物进行快速去除.

To study the effect and mechanism of MW-Fe0/H2O2 Fenton-like process on concentrated leachate,the effects of initial p H,Fe0 dosage,H2O2 dosage,MW power and reaction time on the removal of organic substances were investigated.The phase change of Fe0 before and after reaction and its catalytic mechanism were investigated by SEM micrograph and XRD spectra.Results showed that the removal efficiencies of COD,UV254 and CN were 58.70%,85.69%and 88.30%at initial p H of 3.0,Fe0 dosage of 0.5g/L,H2O2 dosage of 20m L/L,MW power of 400W and reaction time of14min.Comparison of different Fenton-like process indicated that a higher removal efficiency of organic substances and a greater biodegradability were achieved after MW-Fe0/H2O2 Fenton-like process.UV-Vis spectra illustrated that both Fenton and MW-Fe0/H2O2 processes can significantly decrease the aromaticity degree,molecular weight and condensation degree of organic substances in wastewater,however,MW-Fe0/H2O2 process was the most efficient.3D-EEM spectrum demonstrated that the fluorescence peak of concentrated leachate occurred blue-shift in MW-Fe0/H2O2 process,further indicating that condensation degree of humic substances declined and molecular weight remarkably decreased.After MW-Fe0/H2O2 process,the surface of Fe0 changed from smooth to rough and the material was corroded as Fe3O4 and Fe OOH,indicating that the mechanism of MW-Fe0/H2O2 process was Fenton reaction and advanced oxidation effect of heterogeneous Fenton reaction between iron oxide and H2O2,adsorption and precipitation effects of iron based colloid on organic substances.Moreover,thermal and non-thermal effects of MW accelerated the actions mentioned above.Thereby,fast removal of organic pollutants in concentrated leachate was achieved.