State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Nanjing 210023 , P. R. China.
Research Center for Environmental Nanotechnology (ReCENT) , Nanjing University , Nanjing 210023 , P. R. China.
Environ Sci Technol. 2019 May 7;53(9):5319-5327. doi: 10.1021/acs.est.9b00745. Epub 2019 Apr 12.
Toxic metals are usually present as organic complexes in high-salinity effluents from various industries. The efficient removal of such metal complexes is an imperative but still challenging task due to their stable structure and high mobility. Herein, we propose a new strategy to remove Cu-carboxyl complexes from high-salinity water by using a commercially available nanocomposite HZO-201, i.e., nanohydrated zirconium oxide (HZO) confined inside anion exchanger D201. In contrast to D201 and a cation exchanger D001, which both adsorb Cu-citrate negligibly, HZO-201 exhibits preferable adsorption toward Cu-citrate (∼130 mg Cu/g-Zr) at high salinity (1.5 wt % NaCl). On the basis of scanning transmission electron microscopy energy-dispersive spectrometry (STEM-EDS), attenuated total reflection Fourier transform infrared (ATR-FTIR), and X-ray photoelectron spectrometry (XPS) analysis, the formation of ternary complex among Cu(II), citrate, and the embedded nano-HZO is evidenced to be responsible for the removal of Cu-citrate. The exhausted HZO-201 can be regenerated with a binary HCl-NaCl solution for repeated use for 5 cycles without capacity loss. Fixed-bed adsorption demonstrates that HZO-201 column is capable of producing ∼1150 bed volume (BV) clean water (<0.5 mg Cu/L) from simulated high-salinity wastewater, whereas only ∼10 BV and ∼60 BV was produced for the D001 and D201 columns, respectively. Furthermore, HZO-201 shows excellent removal of Cu(II) complexes with three other carboxyl ligands (oxalate, tartrate, and succinate).
有毒金属通常以各种工业高盐废水中的有机络合物形式存在。由于其稳定的结构和高迁移性，有效去除这些金属络合物是一项必要但仍然具有挑战性的任务。在此，我们提出了一种从高盐水中去除 Cu-羧基络合物的新策略，即使用市售纳米复合材料 HZO-201（即纳米水合氧化锆（HZO）限域在阴离子交换剂 D201 内）去除 Cu-羧基络合物。与仅略微吸附 Cu-柠檬酸盐的 D201 和阳离子交换剂 D001 不同，HZO-201 在高盐度（1.5wt%NaCl）下对 Cu-柠檬酸盐（∼130mgCu/g-Zr）表现出更好的吸附性。基于扫描透射电子显微镜能量色散谱（STEM-EDS）、衰减全反射傅里叶变换红外（ATR-FTIR）和 X 射线光电子能谱（XPS）分析，Cu（II）、柠檬酸盐和嵌入的纳米 HZO 之间形成三元络合物被证明是去除 Cu-柠檬酸盐的原因。用过的 HZO-201 可以用二元 HCl-NaCl 溶液再生，重复使用 5 次而不会损失容量。固定床吸附表明，HZO-201 柱能够从模拟高盐废水中生产约 1150 床体积（BV）的清洁水（<0.5mgCu/L），而 D001 和 D201 柱分别仅生产约 10BV 和约 60BV。此外，HZO-201 对三种其他羧基配体（草酸盐、酒石酸盐和琥珀酸盐）的 Cu（II）络合物也具有出色的去除效果。
