State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Water Res. 2023 Nov 1;246:120678. doi: 10.1016/j.watres.2023.120678. Epub 2023 Sep 29.
Nonradical electron transfer process (ETP) in peroxomonosulfate (PMS) based advanced oxidation processes (AOPs) is regarded promising for selective degradation of organic contaminants in water, however, the subjective modulation strategy and the definitive mechanistic elucidation of ETP are still lacking. Herein, we proposed a heretofore unreported yet efficient ETP indution approach by construction of polar electrical field on biochar via nonmetallic elements co-doping. Physicochemical characterizations and density functional theory (DFT) calculations verified the electronegativity difference among boron, nitrogen, and sulfur elements bestowed robust local electric fields on biochar surface (BC-BNS), which effectively enhanced the adsorption complexation and charge transfer between biochar and PMS. Compared to the other single-doped or co-doped biochar, BC-BNS exhibited superior catalytic performance of PMS activation for degradation of atrazine (ATZ) (k=0.036 min), as well as various kinds of electron-rich organics. The remarkable catalytic degradation capacity was further verified in various aqueous matrices and background factors, representing the excellent selectivity. Analysis of contribution from reactive oxygen species and electrochemical testing together substantiated the role of polar electric fields in facilitating the modulation from singlet oxygen (O) to ETP as a prevailing mechanism. DFT calculations and apparent interactions revealed the dissociation of S-O bond was thermodynamically favored within this potent localized electric field, which further induced the cleavage of OO bond and ultimately promoted the dual electron transfer between ATZ and PMS. The superiority of BC-BNS/PMS system was further validated with the low ecotoxicity caused by enhanced dechlorination, the low energy consumption, and the long-term effectiveness. The novel modulation principle and atomic-level mechanism exploration gave suggestions for advancing ETP-dominated AOP to remove recalcitrant contaminants during water treatment and restoration.
过一硫酸盐（PMS）基高级氧化工艺（AOPs）中的非自由基电子转移过程（ETP）被认为是水中有机污染物选择性降解的有前途的方法，然而，ETP 的主观调控策略和明确的机理阐明仍然缺乏。在此，我们通过非金属元素共掺杂在生物炭上构建极性电场，提出了一种迄今为止尚未报道但有效的 ETP 诱导方法。物理化学特性和密度泛函理论（DFT）计算证实了硼、氮和硫元素之间的电负性差异在生物炭表面（BC-BNS）上赋予了强大的局部电场，这有效地增强了生物炭和 PMS 之间的吸附络合和电荷转移。与其他单掺杂或共掺杂生物炭相比，BC-BNS 表现出了优越的 PMS 活化催化性能，用于降解莠去津（ATZ）（k=0.036 min）以及各种富电子有机物。在各种水基质和背景因素中的卓越催化降解能力进一步得到了验证，表现出了优异的选择性。活性氧物种的分析和电化学测试共同证实了极性电场在促进从单线态氧（O）到 ETP 的调制中的作用，这是一种主要的机制。DFT 计算和明显的相互作用表明，在这种强大的局部电场内，S-O 键的解离在热力学上是有利的，这进一步诱导了 OO 键的断裂，并最终促进了 ATZ 和 PMS 之间的双重电子转移。BC-BNS/PMS 体系的优越性还通过增强脱氯引起的低生态毒性、低能耗和长期有效性得到了验证。新的调控原理和原子级机制探索为推进以 ETP 为主导的 AOP 在水处理和修复过程中去除难降解污染物提供了建议。
