In this work, drinking water treatment residuals (WTRs), an iron-rich safety byproducts, was modified via facile reduction calcination and subsequently proved as an effective persulfate (PS) activator for degradation of sulfamethoxazole (SMX). Various parameters affecting SMX degradation efficiency were tested, and the results showed that 80% of SMX (50 μM) was removed within 60 min in the presence of 2.0 mM PS and 0.2 g L⁻¹ modified WTRs at pH 5.3 under ambient temperature. Radical scavenging and electron spin-resonance spectroscopy tests indicated that sulfate radical was a much more powerful active oxygen specie than hydroxyl radical for the SMX degradation in the WTRs/PS system. To understand the proposed activation mechanism, X-ray diffraction and X-ray photoelectron spectroscopy were applied to reveal the change of modified WTRs before and after use. This process confirmed that the activation mechanism was in situ homogenous and heterogeneous reaction simultaneously. Furthermore, liquid chromatography coupled with ion trap time-of-flight mass spectrometry was applied to identify the intermediates of SMX to understand the possible pathway. This work provides a novel value-added reuse approach for WTRs as an efficient and cost-effective heterogeneous activator for PS.

在这项工作中，饮用水处理残留物（WTRs）是一种富含铁的安全副产品，通过简便的还原煅烧进行了改性，随后被证明是降解磺胺甲恶唑（SMX）的有效过硫酸盐（PS）活化剂。测试了影响SMX降解效率的各种参数，结果表明，在存在2.0 mM PS和0.2 g L ^-1的情况下，在60分钟内去除了80％的SMX（50μM）。室温下在pH 5.3时修饰的WTR。自由基清除和电子自旋共振光谱测试表明，对于WTRs / PS系统中的SMX降解，硫酸根比羟基具有更强的活性氧种类。为了理解所提出的活化机理，使用X射线衍射和X射线光电子能谱揭示使用前后WTR的变化。这个过程证实了激活机制是原位的同时发生同质和异质反应。此外，将液相色谱与离子阱飞行时间质谱联用，以鉴定SMX的中间体，以了解可能的途径。这项工作为WTR提供了一种新颖的增值重用方法，将其作为PS的一种高效且具有成本效益的异质活化剂。