School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
UNSW Centre for Transformational Environmental Technologies (CTET), Yixing, Jiangsu Province 214200, China.
Environ Sci Technol. 2021 Oct 5;55(19):13317-13325. doi: 10.1021/acs.est.1c04370. Epub 2021 Sep 20.
Iron oxychloride (FeOCl) has been reported to be a highly efficient heterogeneous Fenton catalyst over a wide pH range. In order to determine the true catalytic performance of FeOCl, we simultaneously quantified the adsorptive and oxidative removal of formate, oxalate, and rhodamine-B (RhB) and the formation of RhB oxidation products at both pH 4.0 and 7.0. FeOCl was found to be a poor Fenton catalyst at either pH, as gauged by the oxidation of formate, oxalate, and rhodamine B and the decomposition of HO, in comparison with ferrihydrite (Fhy), one of the most common Fe-containing Fenton catalysts. The adsorption of target contaminants to FeOCl and homogeneous Fenton processes, induced by dissolved iron, resulted in overevaluation of the catalytic performance of FeOCl, especially for (i) the use of strongly adsorbing target compounds, without consideration of the role of adsorption in their removal and (ii) exceedingly high concentrations of HO to remove trace quantities of target contaminants. Overall, this study highlights that the systematic quantification of HO decomposition, target compound adsorption, and oxidation as well as the concentrations of oxidized products formed are prerequisites for unequivocal elucidation of the catalytic nature and reaction mechanism of solid Fenton catalysts.
氧化铁氯 (FeOCl) 在较宽的 pH 范围内被报道为一种高效的非均相 Fenton 催化剂。为了确定 FeOCl 的真实催化性能，我们同时定量测定了在 pH 4.0 和 7.0 时甲酸、草酸盐和罗丹明 B（RhB）的吸附和氧化去除以及 RhB 氧化产物的形成。与最常见的 Fenton 催化剂之一水铁矿（Fhy）相比，FeOCl 作为甲酸、草酸盐和罗丹明 B 的氧化以及 HO 的分解的指标，在任一 pH 值下均是一种较差的 Fenton 催化剂。目标污染物对 FeOCl 的吸附和溶解铁诱导的均相 Fenton 过程导致了对 FeOCl 催化性能的高估，特别是对于（i）使用强吸附目标化合物，而不考虑吸附在其去除中的作用和（ii）过高浓度的 HO 以去除痕量目标污染物。总的来说，本研究强调了系统地定量测定 HO 分解、目标化合物吸附和氧化以及形成的氧化产物浓度是明确阐明固体 Fenton 催化剂的催化性质和反应机制的前提条件。
