화학공학소재연구정보센터
Journal of Hazardous Materials, Vol.279, 141-147, 2014
Quick and efficient co-treatment of Zn2+/Ni2+ and CN- via the formation of Ni(CN)(4)(2-) intercalated larger ZnAl-LDH crystals
The wide use of metal electroplating involving CN- necessitates the cost-effective treatment of both CN and metals (Zn, Cu, Ni etc.). In this research, we developed a novel strategy - Ni2+-assisted layered double hydroxide (LDH) precipitation - to simultaneously remove aqueous CN and Zn/Ni metals. The strategy is to convert CN-/Zn(CN)(4)(2-) to Ni(CN)(4)(2-) first, and then to quickly precipitate Ni(CN)(4)(2-)/CN- into LDH crystals. The conversion has been clearly evidenced by the change of CN characteristic FTIR bands of Zn-CN solution before and after adding Ni(NO3)(2). The intercalation and efficient removal of CN have also been confirmed through the formation of LDH crystals XRD and SEM. In particular, a set of optimized experimental factors has been obtained by investigating their effects on CN removal efficiency in the simulated tests. Remarkably, over 95% CN were removed with high removal efficiencies of metals. Our results thus suggest that the current strategy is a quick, efficient and promising way to simultaneously treat both Ni and metals/CN rich electroplating wastewaters. (C) 2014 Elsevier B.V. All rights reserved.