Extremely efficient mineralizing CN^- into N₂ via a newly developed system of generating sufficient ClO^○/Cl₂^○- and self-decreasing pH

作者：Tian, Lei; Yin, Meng-Ying; Zheng, Ling-Ling; Chen, Ying; Liu, Wen; Fan, Jie-Ping^*; Wu, Dai-She; Zou, Jian-Ping^*; Luo, Sheng-Lian

来源：Separation and Purification Technology, 2023, 309: 123021.

DOI：10.1016/j.seppur.2022.123021

• Electrocatalysis
• Advanced oxidation processes
• Cyanide
• Mineralization
• Nitrogen

IIn the presence of the difficulties pertinent to the selective oxidation of cyanide and the high-efficient hydrolysis of cyanate, the mineralization of cyanide into nitrogen could not be realized during the traditional processes. Herein, a novel system of electrocatalysis coupled with ultraviolet-based advanced oxidation processes (UV/EC/ PS, PS: persulfate) is developed, exhibiting astonishingly high activity and selectivity for cyanide mineralization. The achieved results reveal that adequate active-chlorine species (ClO circle/Cl-2(circle-)) are generated due to the synergistic effects of electrocatalysis and advanced oxidation processes and these are high-selective for cyanide mineralization. Concurrently, induced by the interconversion between active species, the pH value in the UV/EC/PS system vigorously lessens from 11.5 to 3.3 at a rate of 1.1 x 10(-2) min(-1), hugely speeding up the hydrolysis of cyanate intermediates. The results display that PS plays a pivotal role in the formation of ClO circle/Cl-2(circle-) and the selfreduction of pH value in the UV/EC/PS system. Under the action of ClO circle/Cl-2(circle-) and self-decreased pH value, 0.25 mM of ferricyanide is thoroughly mineralized into nitrogen within 80 min and no HCN evolves. Additionally, the UV/EC/PS system exhibits exceptional feasibility for the practical purifications of cyanide-containing wastewater (CCWW). This study aims to give new insights into developing technologies associated with the mineralization treatment of CCWW.

• 单位
  北京大学; 南昌航空大学; 南昌大学