铁碳促进O3/H2O2体系深度处理准好氧矿化垃圾床渗滤液尾水中难降解有机物

构建了铁碳-O_3/H_2O_2体系降解矿化垃圾床渗滤液尾水中有机物,并考察了体系O_3、铁碳及H_2O_2投加量、初始pH值和反应时间对铁碳-O_3/H_2O_2体系处理渗滤液尾水的影响.结果表明,在铁碳投加量为3 g·L~(-1),O_3投加量为9.798 mg·min~(-1),H_2O_2投加量为2 mL·L~(-1),初始pH值为3的条件下,反应10 min后,渗滤液尾水的COD和UV_(245)分别从711.96 mg·L~(-1)、0.19下降至295.04 mg·L~(-1)、0.10.类比实验结果表明,铁碳-O_3/H_2O_2体系对渗滤液尾水有机物具有较高的去除率,且可生化性得到提高(BOD/COD从0.04增加至0.40).紫外-可见和三维荧光光谱显示,废水中难降解有机物转化为小分子有机化合物且腐殖质的分子缩合度降低.最后,采用SEM-EDS、XRD和XPS技术对铁碳-O_3/H_2O_2体系的反应机理进行了解析,发现铁碳-O_3/H_2O_2反应的机理为铁碳微电解反应、铁氧化物-H_2O_2非均相芬顿反应、O_3/H_2O_2、铁碳-O_3非均相的高级氧化作用和铁基胶体对有机物的吸附沉淀作用.研究表明,铁碳-O_3/H_2O_2体系是一种能够有效去除矿化垃圾床渗滤液尾水中难降解有机物的方法.

Degradation of recalcitrant organics in SAARB treatment effluent of landfill leachate by iron-carbon-O3/H2O2 process

The SAARB treatment effluent of landfill leachate (SAARB effluent) was further degraded by iron-carbon-O₃/H₂O₂ process. Firstly, key operational parameters (e.g., ozone dosage, iron-carbon dosage, H₂O₂ dosage, initial pH and reaction time) were investigated in batch experiments, respectively. Results show that after 10 min of iron-carbon-O₃/H₂O₂ treatment, the COD and UV₂₅₄ of SAARB effluent decreased from 711.96 mg·L^-1 and 0.19 AU to 295.04 mg·L^-1 and 0.10 AU, under initial pH 3.0, iron-carbon dosage of 3 g·L^-1, H₂O₂ dosage of 2 mL·L^-1 and O₃ dosage of 9.798 mg·min^-1. In comparison, results of control experiments indicate that a higher removal efficiency of organic substances and a greater biodegradability were achieved after iron-carbon-O₃/H₂O₂ process. In addition, the results of the UV-vis and 3D-EEM analysis confirme that the refractory organics in SAARB effluent had been completely decomposed and transformed into low-molecule organic compounds and as a result, the BOD₅/COD increased from 0.04 to 0.40 with the significant improvement of biodegradability. Finally, the reaction mechanism of the iron-carbon-O₃/H₂O₂ process was proposed according to the results of SEM-EDS, XRD and XPS analysis. It is concluded that iron-carbon-O₃/H₂O₂ process is mainly attributed to (a) micro-electrolysis of Fe-C; (b) heterogeneous Fenton reaction formed by iron-based oxides and H₂O₂; (c) O₃/H₂O₂ process; (d) heterogeneous advanced oxidation of Fe-C catalyzed O₃; (e) adsorption and precipitation effect by iron-based colloids. Therefore, iron-carbon-O₃/H₂O₂ process was proven to be an effective and promising method to handle the SAARB effluent with optimized operation conditions.