微波诱导AC/Cu、AC/Fe催化非均相Fenton 反应催化降解垃圾渗滤液

采用活性炭载体负载Cu、Fe为催化剂,在微波诱导作用下,对垃圾渗滤液污染物进行降解。实验结果表明,活性炭负载金属前经适当浓度硝酸浸泡处理后,催化剂对COD去除率提高可超过15%,过高硝酸盐浓度对COD去除有不利影响;催化剂对COD去除率随Cu、Fe金属负载量增加呈先增加后降低的趋势,催化剂对Cu、Fe的最佳负载量分别为质量百分比2.11%和1.12%。对于AC-Cu体系,在初始pH=3,H2O2投加量为4.98×103mg/L,催化剂用量为5.0×103mg/L,420 W功率下微波辐射10 min时,垃圾渗滤液COD去除率可达到84.13%;对于AC-Fe体系,当H2O2投加量为0.33×103mg/L,催化剂AC-Fe用量为2.0×104mg/L,420 W功率下微波作用10 min时,垃圾渗滤液COD去除率为60.16%。分析2种催化剂对COD去除差异的原因,可能是催化剂AC-Cu表面单分子分布的阈值比AC-Fe高。降解液的pH值对AC-Cu体系、AC-Fe体系COD去除影响存在拐点,最高COD去除率点对应的降解液pH值为3。微波辐射功率较低时,体系COD去除率随辐射功率增加而增加;辐射功率较高时,高温下垃圾渗滤液中有机硫化物分解成小分子硫化物,对催化剂活性存在一定抑制作用。

Heterogeneous Fenton reaction for landfill leachate degradation of active carbon/Cu and active carbon/Fe catalysts through microwave induced method

Based on the two catalysts(AC/Cu and AC/Fe) and their heterogeneous Fenton reaction, the activity of the catalysts loaded with Cu and Fe were investigated by carrying out the degradation of landfill leachate in aqueous suspension under microwave induced condition. The results showed that active carbon impregnated with satisfactory concentration of nitric acid before the composite catalysts were prepared could make the COD removal rate of landfill leachate increase by more than 15%. With the increasing of metal loaded on the active carbon, the COD removal rate of landfill leachate by catalyst increased firstly and then decreased. The optimum loading of copper and iron were 2.11 wt%, 1.12 wt%, respectively. As far as AC-Cu system was concerned, the COD removal rate of landfill leachate was up to 84.13% under the certain conditions: initial pH 3, H₂O₂ dosage of 4.98×10³ mg/L, the AC-Cu catalyst dosage of 5.0×10³ mg/L, microwave radiation time of 10 min at 420 W power level. For the AC-Fe system, the COD removal rate of landfill leachate was up to 60.16% under the certain conditions: initial pH 3, H₂O₂ dosage of 0.33×10³ mg/L, the AC-Fe catalyst dosage of 20×10⁴ mg/L, microwave radiation time of 10 min at 420 W power level. The COD removal rate of landfill leachate with catalyst AC-Cu and AC-Fe was different, the reason was that the threshold of single molecule distribution on surfaces of AC-Cu catalyst was higher than that of AC-Fe. Inflection points existed in the changes of COD removal with pH for AC-Cu system and AC-Fe system, and pH was 3 corresponding to the highest COD removal. When microwave radiation power level was low, COD removal increased with microwave radiation power. And the catalytic activity was inhibited with microwave radiation power increasing at high power level, which resulted from the degradation of organic sulfide in landfill leachate, and forming into inorganic sulfur compounds. The COD removal rate of landfill leachate was found to strongly depend on the reaction pH, and the optimum pH was 3 in both systems.