Nanyang Environment and Water Research Institute (NEWRI), Nanyang Technological University, CleanTech One, 1 Cleantech Loop, Singapore, 637141, Singapore.
Division of Environmental and Water Resources Engineering, School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore.
Environ Sci Pollut Res Int. 2019 Jan;26(2):1026-1035. doi: 10.1007/s11356-017-8476-9. Epub 2017 Jan 27.
In this study, a BiFeO catalyst with nanoplate morphology was fabricated using a facile hydrothermal method. It was used as a catalyst to activate peroxymonosulfate (PMS) for aqueous sulfamethoxazole (SMX) removal. A comprehensive performance evaluation of the BiFeO/PMS system was conducted by investigating the effects of pH, PMS dosage, catalyst loading, SMX concentration, temperature, and halides (Cl and Br) on the degradation of SMX. The BiFeO/PMS system demonstrated a remarkable catalytic activity with >95% SMX removal within 30 min (conditions: pH 3.8, [BiFeO] = 0.1 g L, [SMX]:[PMS] mol ratio =1:20). It was found that both Cl and Br can lead to the formation of PMS-induced reactive halide species (i.e. HClO, HBrO, and Br) which can also react with SMX forming halogenated SMX byproducts. Based on the detected degradation byproducts, the major SMX degradation pathway in the BiFeO/PMS system is proposed. The SMX degradation by BiFeO/PMS system in the wastewater secondary effluent (SE) was also investigated. The results showed that SMX degradation rate in the SE was relatively slower than in the deionized water due to (i) reactive radical scavenging by water matrix species found in SE (e.g.: dissolved organic matters (DOCs), etc.), and (ii) partial deactivation of the catalyst by DOCs. Nevertheless, the selectivity of the SO towards SMX degradation was evidenced from the rapid SMX degradation despite the high background DOCs in the SE. At least four times the dosage of PMS is required for SMX degradation in the SE to achieve a similar SMX removal efficiency to that of the deionized water matrix.
在这项研究中，使用简便的水热法制备了具有纳米片形态的 BiFeO 催化剂。它被用作催化剂来激活过一硫酸盐 (PMS) 以去除水中的磺胺甲恶唑 (SMX)。通过研究 pH 值、PMS 用量、催化剂负载量、SMX 浓度、温度和卤素 (Cl 和 Br) 对 SMX 降解的影响，对 BiFeO/PMS 体系的综合性能进行了评估。在 30 分钟内，BiFeO/PMS 体系表现出显著的催化活性，超过 95%的 SMX 被去除（条件：pH 3.8，[BiFeO]=0.1 g L，[SMX]：[PMS]摩尔比=1:20）。结果发现，Cl 和 Br 都可以导致形成 PMS 诱导的活性卤化物物种（即 HClO、HBrO 和 Br），这些物种也可以与 SMX 反应，生成卤代 SMX 副产物。根据检测到的降解副产物，提出了 BiFeO/PMS 体系中 SMX 的主要降解途径。还研究了 BiFeO/PMS 体系在废水二级出水 (SE) 中的 SMX 降解情况。结果表明，由于（i）SE 中存在的水基质物种（如溶解有机物 (DOCs) 等）对活性自由基的清除作用，以及（ii）DOCs 对催化剂的部分失活作用，SE 中 SMX 的降解速率相对较慢。然而，尽管 SE 中的背景 DOCs 较高，但 SO 对 SMX 降解的选择性仍得到了证明，SMX 降解速度很快。在 SE 中实现与去离子水基质相似的 SMX 去除效率，至少需要增加四倍的 PMS 用量。
