铁锰氧化物对苯酚氧化降解的实验研究

为了考察铁锰氧化物对酚类污染物的氧化降解能力,采用天然以及合成的铁锰氧化物对苯酚的氧化降解进行对比实验研究。土壤中铁锰氧化物样品分别为天然针铁矿及氧化锰,合成铁锰氧化物样品分别为合成针铁矿及软锰矿。结果表明：苯酚与铁锰氧化物发生氧化还原作用时,还可能与土壤中杂质发生吸附等作用;铁锰氧化物还原反应强度随着反应介质pH值的升高而迅速下降;可用零级反应动力学方程拟合铁氧化物还原溶解反应,针铁矿溶解反应的强度与介质的pH值呈负相关关系;天然针铁矿对酚类污染物的氧化降解能力明显高于合成针铁矿,pH值对天然针铁矿溶解反应影响较大;可用一级指数衰减方程拟合锰氧化物还原溶解反应,锰氧化物溶解反应的强度与介质的pH值呈指数衰减关系;pH值对软锰矿还原溶解反应的影响大于对土壤中氧化锰的影响,pH值越小,影响越显著;对比pH值对铁和锰还原作用的影响发现,在pH=6.5时,锰氧化物仍有较强的氧化性能。

Study on Oxidative Degradation of Phenol by Iron and Manganese Oxides

In order to investigate the ability of oxidative degradation of phenol by iron and manganese oxides,oxidative degradations of phenol by inartificial and synthetic iron and manganese oxides were discussed with the opposite experiments.Iron and manganese oxides in soil included inartificial goethite and manganese oxide,while synthetic iron and manganese oxides included synthetic goethite and pyrolusite.The results showed that phenol and iron and manganese oxides reacted with oxidation-reduction,while phenol and impurity in soil reacted with adsorption;the intensity of reduction reaction of iron and manganese oxides decreased rapidly with the increase of pH value of reaction medium;zero-order reaction kinetics equation was used to fit the reductive dissolution reaction of iron oxide,and the relationship between the intensity of reduction reaction of goethite and pH value of reaction medium was nagetive;oxidative degradation of phenol by inartificial goethite was stronger than that of synthetic goethite,the effect of pH value on the intensity of dissolution reaction of inartificial goethite was significant;one-order reaction kinetics equation was used to fit the reductive dissolution reaction of manganese oxide,and the relationship between the intensity of reduction reaction of manganese oxide and pH value of reaction medium was exponential decay;the effect of pH value on dissolution reaction of pyrolusite was stronger than that on manganese oxide in soil,and the effect was significant with the decrease of pH value;the comparison of the effect of reaction of pH value on iron and manganese indicated that manganese oxide still had strong oxidizing capability when the pH value was 6.5.