Zhu Yingshi, Deng Fengxia, Qiu Shan, Ma Fang, Zheng Yanshi, Lian Ruqian
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, PR China.
J Hazard Mater. 2021 Feb 5;403:123950. doi: 10.1016/j.jhazmat.2020.123950. Epub 2020 Sep 12.
Facing low reactivity/selectivity of oxygen reduction reaction (ORR) in electro-Fenton (EF), N, S atoms were introduced into carbon-based cathode. "End-on" O adsorption was achieved by adjusting electronic nature via N doping, while *OOH binding capability was tuned by spin density variation via S doping. Results showed the optimized N, S co-doped cathode presented a 42.47% improvement of HO accumulation (7.95 ± 0.02 mg L cm). According to density functional theory (DFT), N, S co-doped structure favored the "end-on" O adsorption as adsorption energy dropped to - 2.24 eV. Moreover, O-O/C-O bond lengths variation proved a possibility for *OOH desorption. The elaborated cathode was used in EF for sulfonamides (SAs) decay. A 100% removal rate of sulfadiazine (SDZ), sulfathiazole (STZ) and sulfadimethoxine (SDM) was achieved within 60 min, among which SDZ tended to be degraded easily. Because the absolute hardness (η) of those pollutants is ranked as follows: η> η> η. Degradation pathways were proposed based on the detected byproducts, along with toxicity was evaluated by ecological structure-activity relationship (ECOSAR) program. Results showed that toxic intermediates generated were reduced or even disappeared. EF with N, S co-doped cathode provides a promising process for antibiotics wastewater treatment.
面对电芬顿（EF）中氧还原反应（ORR）的低反应活性/选择性，将N、S原子引入碳基阴极。通过N掺杂调节电子性质实现“端基”O吸附，同时通过S掺杂改变自旋密度来调节OOH结合能力。结果表明，优化后的N、S共掺杂阴极的HO积累提高了42.47%（7.95±0.02 mg L cm）。根据密度泛函理论（DFT），N、S共掺杂结构有利于“端基”O吸附，吸附能降至-2.24 eV。此外，O-O/C-O键长变化证明了OOH解吸的可能性。将精心制备的阴极用于EF中磺胺类药物（SAs）的降解。在60分钟内实现了磺胺嘧啶（SDZ）、磺胺噻唑（STZ）和磺胺二甲氧嘧啶（SDM）100%的去除率，其中SDZ易于降解。因为这些污染物的绝对硬度（η）排序如下：η>η>η。基于检测到的副产物提出了降解途径，并通过生态结构-活性关系（ECOSAR）程序评估了毒性。结果表明，产生的有毒中间体减少甚至消失。具有N、S共掺杂阴极的EF为抗生素废水处理提供了一个有前景的工艺。
