Chemical Engineering Department, School of Engineering, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2021;56(3):289-302. doi: 10.1080/10934529.2020.1871268. Epub 2021 Jan 14.
Galvanizing industries generate large amounts of effluents rich in toxic and carcinogenic chromium(VI) species. Effective and sustainable treatments are required to comply with environmental regulations. This work focused on the development of innovative treatments for Cr(VI) by its removal from a galvanizing industry wastewater (pH = 5.9) containing Cr (78 mg.L) and Zn (2178 mg.L) using the liquid surfactant membranes technique. The membrane phase carrier was Alamine® 336 in Escaid™ 110. For a synthetic solution (Cr(VI) = 353mg.L, pH = 1.5), 99.9% of Cr(VI) was extracted in three stages ([KOH] = 0.27 mol.L). For the galvanizing wastewater, two selective extractions treatments were proposed: (1) 87% of Cr(VI) and 2% of Zn(II) were extracted in a single stage ([HCl] = 0.03 mol.L, [KOH] = 0.6 mol.L); (2) 95.6% of Cr(VI) and practically no zinc were extracted in a single stage ([HCl] = 10mol.L, [HCl] = 5mol.L). In another treatment condition ([HCl] = 2mol.L and [KOH] = 1.2 mol.L), the simultaneous Cr(VI) and Zn(II) extractions (95% and 70%, respectively) were obtained in a single stage and more than 99% of both metals in three stages. This resulted in a depleted feed phase with 0.01 mg.L of Cr(VI), that allows its discharge, according to the Brazilian legislation (≤0.1 mg/L).
镀锌行业会产生大量富含毒性和致癌铬(VI)物种的废水。为了遵守环境法规，需要采用有效的可持续处理方法。本工作专注于通过使用液体表面活性剂膜技术从含有 Cr（78mg·L）和 Zn（2178mg·L）的镀锌工业废水中去除 Cr(VI)来开发去除 Cr(VI)的创新处理方法。膜相载体为 Alamine® 336 在 Escaid™ 110 中。对于合成溶液（Cr(VI) = 353mg·L，pH = 1.5），在三个阶段中提取了 99.9%的 Cr(VI)（[KOH] = 0.27mol·L）。对于镀锌废水，提出了两种选择性萃取处理方法：（1）在单个阶段中提取 87%的 Cr(VI)和 2%的 Zn(II)（[HCl] = 0.03mol·L，[KOH] = 0.6mol·L）；（2）在单个阶段中提取 95.6%的 Cr(VI)和几乎没有锌（[HCl] = 10mol·L，[HCl] = 5mol·L）。在另一种处理条件下（[HCl] = 2mol·L 和 [KOH] = 1.2mol·L），在单个阶段中获得了 Cr(VI)和 Zn(II)的同时提取（分别为 95%和 70%），在三个阶段中，两种金属的提取率均超过 99%。这导致进料相中的 Cr(VI)含量降低至 0.01mg·L，根据巴西法规（≤0.1mg·L）允许排放。
