Sichuan Provincial Key Laboratory of Universities on Environmental Science and Engineering, MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
Shanghai Key Laboratory of Molecular Catalysis and Innovation Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, MOE Laboratory for Computational Physical Science, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Chemistry, Fudan University, Shanghai 200433, China.
J Hazard Mater. 2023 Aug 5;455:131524. doi: 10.1016/j.jhazmat.2023.131524. Epub 2023 May 15.
This work investigated the activation of peroxymonosulfate by electrochemical (EC) system assisted with Fe(III)-nitrilotriacetic acid (NTA) complex for degradation of persistent naphthenic acids (NAs) under neutral initial pH conditions. As NAs are a complicated mixture, 1-adamantanecarboxylic acid (ACA) was selected as the model NA compound for degradation experiment. The addition of NTA is to chelate with Fe(III), gaining stability under neutral pH condition to facilitate the circulation of Fe(II)/Fe(III) by the electrochemical process to activate PMS. The EC/Fe(III)-NTA/PMS system was explored with applicable pH range of 3-9 and an optimized molar ratio 1: 2 for Fe: NTA. Results of quenching and chemical probe experiment together with results of electron paramagnetic resonance (EPR) analysis revealed the main reactive species of the system, including OH, SO, O and possibly Fe(IV). With the addition of NTA, the yields of OH, SO, O were enhanced. Results of mass spectrometry analysis and DFT calculations indicated the formation of 9 degradation byproducts of ACA via three primary degradation pathways such as hydroxyl substitution, carbonyl substitution, and decarboxylation. Furthermore, the EC/Fe(III)-NTA/PMS system could achieve excellent removal efficiency of ACA with different anions such as Cl, HCO, NO and HPO in the background. The practical applicability of the system was also verified with the high removal of commercial NAs mixture standard. Overall results have indicated the EC/Fe(III)-NTA/PMS system could be utilized for efficient reclamation of authentic oil and gas industrial wastewater under natural pH conditions.
本研究采用电化学（EC）系统辅助三价铁-氮三乙酸（NTA）络合物活化过一硫酸盐（PMS），在中性初始 pH 条件下降解持久性环烷酸（NAs）。由于 NAs 是一种复杂的混合物，因此选择 1-金刚烷羧酸（ACA）作为降解实验的模型 NA 化合物。添加 NTA 是为了与 Fe(III)螯合，在中性 pH 条件下获得稳定性，以促进电化学过程中 Fe(II)/Fe(III)的循环，从而激活 PMS。研究了 EC/Fe(III)-NTA/PMS 体系，其适用 pH 范围为 3-9，Fe:NTA 的最佳摩尔比为 1:2。猝灭和化学探针实验以及电子顺磁共振（EPR）分析结果表明，该体系的主要活性物质包括 OH、SO、O 和可能的 Fe(IV)。添加 NTA 后，OH、SO、O 的生成量增加。质谱分析和密度泛函理论（DFT）计算结果表明，通过羟基取代、羰基取代和脱羧三种主要降解途径，形成了 9 种 ACA 的降解产物。此外，该 EC/Fe(III)-NTA/PMS 体系在背景中存在 Cl、HCO、NO 和 HPO 等不同阴离子时，仍能实现 ACA 的高效去除。该体系的实际应用也通过高去除商业 NAs 混合物标准得到了验证。总之，结果表明该 EC/Fe(III)-NTA/PMS 体系可在自然 pH 条件下有效回收真实的油气工业废水。
