State Key Laboratory Base for Eco-Chemical Engineering in College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, 266042, China.
First Institute of Oceanography, Ministry of Natural Resources of the People's Republic of China, Qingdao, 266061, Shandong, China; Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266200, Shandong, China.
Chemosphere. 2021 Apr;269:129436. doi: 10.1016/j.chemosphere.2020.129436. Epub 2020 Dec 27.
P-cresol is a highly toxic phenolic pollutant in coal chemical wastewater. The effective removal of p-cresol is of great significance to the ecological environment. In this study, the degradation of p-cresol by the Fe(III)-EDDS/HO Fenton-like reaction modified by Mn was investigated. The results showed that the removal rate of p-cresol could be significantly increased by the addition of Mn under neutral and weakly alkaline conditions (pH 6.5-8.5). Acidic conditions (pH 3.5) were not conducive to the Fenton-like reaction. This is because a neutral or weakly alkaline environment is conducive to Mn-EDDS complex formation, which can produce O to accelerate the reduction of Fe(III), and the efficiency of p-cresol degradation through a Fenton-like reaction catalyzed by the Fe(III)-EDDS complex is significantly improved. In addition, the degradation of EDDS through ·OH was reduced by O, which maintained and stabilized the Mn-EDDS complex and Fe(III)-EDDS complex. Under neutral conditions, the optimal dosage of Fe(III) is 0.7 mM, and the optimal molar ratios are EDDS/Fe(III) = 1: 1, Mn/Fe(III) = 1: 1, and HO/Fe(III) = 15: 1. The addition of free radical clearance isopropanol and CHCl proved that ·OH was the main active substance in the p-cresol degradation process.
对甲酚是煤化工废水中一种高毒性的酚类污染物。有效去除对甲酚对生态环境具有重要意义。本研究采用 Mn 改性的 Fe(III)-EDDS/HO 类 Fenton 反应对其进行降解。结果表明，在中性和弱碱性条件下（pH 6.5-8.5），添加 Mn 可以显著提高对甲酚的去除率。酸性条件（pH 3.5）不利于类 Fenton 反应。这是因为中性或弱碱性环境有利于 Mn-EDDS 配合物的形成，从而可以产生 O 来加速 Fe(III)的还原，并且通过 Fe(III)-EDDS 配合物催化的类 Fenton 反应，对甲酚的降解效率显著提高。此外，O 还原了 EDDS 经·OH 产生的降解，从而维持和稳定了 Mn-EDDS 配合物和 Fe(III)-EDDS 配合物。在中性条件下，Fe(III)的最佳用量为 0.7 mM，最佳摩尔比为 EDDS/Fe(III)=1:1、Mn/Fe(III)=1:1 和 HO/Fe(III)=15:1。添加自由基清除剂异丙醇和 CHCl 证明了·OH 是对甲酚降解过程中的主要活性物质。
