络合剂强化KMnO_4氧化降解酚类化合物的研究

Ligand-enhanced Oxidation of Phenolic Compounds by Permanganate

研究了磷酸盐、焦磷酸、EDTA等络合剂对KMnO。氧化降解酚类化合物（苯酚、2-氯酚、4-氯酚和2，4-二氯酚）的强化作用。结果表明，在磷酸根浓度为0～50mmol／L、pH值为4．0～9．0的条件下，强化作用随磷酸根浓度的增大或pH的降低而逐渐增强。络合剂通过络合配位作用使得KMnO4氧化降解酚类化合物过程中原位生成的中间价态锰的存活时间延长、稳定性增强，使其氧化能力得到有效利用，从而提高了KMnO4氧化降解酚类化合物的效果；相反，无络合剂存在时，原位生成的中间价态锰会迅速自分解或歧化生成最终稳定态MnO2，其氧化能力难以得到发挥。天然大分子有机物腐殖酸和天然水体由于其络合配位作用，也具有强化KMnO2氧化降解酚类化合物的能力。

The enhancement effects of ligands such as phosphate, pyrophosphate and EDTA on permanganate oxidation of phenolic compounds （phenol, 2-chlorophenol, 4-chlorophenol, and 2,4-dichlorophenol） were investigated. Under the conditions of phosphate 0 to 50 mmol/L and pH 4.0 to 9.0, the enhancement effect is enhanced with the increase of the phosphate concentration or the decrease of pH. In situ formed manganese intermediates during oxidation of phenolic compounds by permanganate can have longer survival time, be excellently stabilized and maximize the oxidation capacity in the pres- ence of ligands, and thus the oxidation effect of phenolic compounds is improved, whereas in the absence of ligands, the in situ formed manganese intermediates can be self-decomposed or be disproportionated to yield stable MnO2, and the oxidation capacity is difficultly fulfilled. Macromolecular humic acid and natural waters, due to their ability to complex metal ions, are also capable of enhancing permanganate oxidation of phenolic compounds.