Tian Lei, Chen Peng, Jiang Xun-Heng, Chen Li-Sha, Tong Lin-Lin, Yang Hong-Ying, Fan Jie-Ping, Wu Dai-She, Zou Jian-Ping, Luo Sheng-Lian
National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resource Utilization, Nanchang Hangkong University, Nanchang 330063, China; Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, School of Resources Environmental and Chemical Engineering, Nanchang University, Nanchang 330031, China.
National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resource Utilization, Nanchang Hangkong University, Nanchang 330063, China.
Water Res. 2022 Feb 1;209:117890. doi: 10.1016/j.watres.2021.117890. Epub 2021 Nov 24.
Traditional methods of cyanides' (CN) mineralization cannot overcome the contradiction between the high alkalinity required for the inhibition of hydrogen cyanide evolution and the low alkalinity required for the efficient hydrolysis of cyanate (CNO) intermediates. Thus, in this study, a novel Electro-Fenton system was constructed, in which the free cyanides released from ferricyanide photolysis can be efficiently mineralized by the synergy of •OH and •O. The complex bonds in ferricyanide (100 mL, 0.25 mM) were completely broken within 80 min under ultraviolet radiation, releasing free cyanides. Subsequently, in combination with the heterogeneous Electro-Fenton process, OH and O were simultaneously generated and 92.9% of free cyanides were transformed into NO within 120 min. No low-toxic CNO intermediates were accumulated during the Electro-Fenton process. A new conversion mechanism was proposed that CN was activated into electron-deficient cyanide radical (CN) by OH, and then the CN intermediates reacted with O via nucleophilic addition to quickly form NO, preventing the formation of CNO and promoting the mineralization of cyanide. Furthermore, this new strategy was used to treat the actual cyanide residue eluent, achieving rapid recovery of irons and efficient mineralization of cyanides. In conclusion, this study proposes a new approach for the mineralization treatment of cyanide-containing wastewater.
传统的氰化物（CN）矿化方法无法克服抑制氰化氢逸出所需的高碱度与氰酸盐（CNO）中间体高效水解所需的低碱度之间的矛盾。因此，在本研究中，构建了一种新型的电芬顿系统，其中铁氰化物光解释放的游离氰化物可通过•OH和•O的协同作用有效地矿化。在紫外线辐射下，铁氰化物（100 mL，0.25 mM）中的络合键在80分钟内完全断裂，释放出游离氰化物。随后，结合非均相电芬顿过程，同时产生•OH和•O，92.9%的游离氰化物在120分钟内转化为NO。在电芬顿过程中没有积累低毒的CNO中间体。提出了一种新的转化机制，即CN被•OH活化成缺电子的氰基自由基（CN•），然后CN•中间体通过亲核加成与•O反应迅速形成NO，防止CNO的形成并促进氰化物的矿化。此外，该新策略用于处理实际的氰化物残渣洗脱液，实现了铁的快速回收和氰化物的高效矿化。总之，本研究提出了一种含氰废水矿化处理的新方法。
