作者机构：
[Furong Guo; Tingjuan Gao] Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China;School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;[Jiangshan Li] State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;[Shiyu Cao] Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China<&wdkj&>State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China;[Yanbiao Shi; Lizhi Zhang] Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China<&wdkj&>School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
通讯机构：
[Tingjuan Gao; Lizhi Zhang] K;Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China<&wdkj&>School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China<&wdkj&>Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Institute of Environmental & Applied Chemistry, College of Chemistry, Central China Normal University, Wuhan 430079, China
摘要：
Nano zero-valent iron (nZVI) is a promising phosphate adsorbent for advanced phosphate removal. However, the rapid passivation of nZVI and the low activity of adsorption sites seriously limit its phosphate removal performance, accounting for its inapplicability to meet the emission criteria of 0.1 mg P/L phosphate. In this study, we report that the oxalate modification can inhibit the passivation of nZVI and alter the multi-stage phosphate adsorption mechanism by changing the adsorption sites. As expected, the stronger anti-passivation ability of oxalate modified nZVI (OX-nZVI) strongly favored its phosphate adsorption. Interestingly, the oxalate modification endowed the surface Fe(III) sites with the lowest chemisorption energy and the fastest phosphate adsorption ability than the other adsorption sites, by in situ forming a Fe(III)-phosphate-oxalate ternary complex, therefore enabling an advanced phosphate removal process. At an initial phosphate concentration of 1.00 mg P/L, pH of 6.0 and a dosage of 0.3 g/L of adsorbents, OX-nZVI exhibited faster phosphate removal rate (0.11 g/mg/min) and lower residual phosphate level (0.02 mg P/L) than nZVI (0.055 g/mg/min and 0.19 mg P/L). This study sheds light on the importance of site manipulation in the development of high-performance adsorbents, and offers a facile surface modification strategy to prepare superior iron-based materials for advanced phosphate removal.
作者机构：
[Fengjiao Quan; Pengfei Xu; Xiaolan Chen; Wenjuan Shen; Yun He; Jianfen Li] College of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, China;[Falong Jia] College of Chemistry, Central China Normal University, Wuhan 430079, China;[Guangming Zhan] School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
通讯机构：
[Falong Jia] C;College of Chemistry, Central China Normal University, Wuhan 430079, China
摘要：
Nitrate (NO3–) is a widespread pollutant in high-salt wastewater and causes serious harm to human health. Although electrochemical removal of nitrate has been demonstrated to be a promising treatment method, the development of low-cost electro-catalysts is still challenging. In this work, a phosphate modified iron (P-Fe) cathode was prepared for electrochemical removal of nitrate in high-salt wastewater. The phosphate modification greatly improved the activity of iron, and the removal rate of nitrate on P-Fe was three times higher than that on Fe electrode. Further experiments and density functional theory (DFT) calculations demonstrated that the modification of phosphoric acid improved the stability and the activity of the zero-valent iron electrode effectively for NO3– removal. The nitrate was firstly electrochemically reduced to ammonium, and then reacted with the anodic generated hypochlorite to N2. In this study, a strategy was developed to improve the activity and stability of metal electrode for NO3– removal, which opened up a new field for the efficient reduction of NO3– removal by metal electrode materials.
