Abstract

Remediation of hexavalent chromium with conventional chemical and physical methods is a costly process, while replacing some critical steps in physiochemical remediation with self-sustaining bioremediation agents are expected to be cost-effective and environmentally friendly implementation. In this study, a microalga isolated from a freshwater stream receiving treated textile wastewater was identified up to its molecular level and investigated its ability to tolerate and remove hexavalent chromium from extremely acidic conditions under different temperatures. The ability of microalgae to tolerate and remove Cr(VI) was investigated by growing it in BG11 media with different pH (1, 2, 3 & 7), amended with several concentrations of Cr(VI) and incubated under different temperatures for 96 hrs. Microalga was identified as Chlorella vulgaris and found that the isolated strain has a higher hexavalent chromium removal potential in extremely acidic conditions than in neutral pH conditions at 25 °C. In contrast, its Cr(VI) removal potential is significantly influenced by the pH and temperature of the growth medium. Furthermore, it exhibited a permanent viability loss at extreme acidic conditions (pH 1 − 3) and prolonged exposure to the higher chromium content. The microalga investigated will be a highly useful bioagent in hexavalent chromium remediation in high acidic conditions.

摘要

用传统的化学和物理方法修复六价铬是一个昂贵的过程，而用自持生物修复剂代替物理化学修复中的一些关键步骤预计将具有成本效益和环境友好的实施。在这项研究中，从接受处理过的纺织废水的淡水流中分离出的一种微藻被鉴定到其分子水平，并研究了它在不同温度下从极端酸性条件下耐受和去除六价铬的能力。通过在具有不同 pH 值（1、2、3 和 7）的 BG11 培养基中生长微藻来研究微藻耐受和去除 Cr(VI) 的能力，用几种浓度的 Cr(VI) 进行修正并在不同温度下孵育 96 小时. 微藻被鉴定为Chlorella vulgaris并发现分离的菌株在极端酸性条件下比在 25 °C 的中性 pH 条件下具有更高的六价铬去除潜力。相反，它的 Cr(VI) 去除潜力受到生长培养基的 pH 值和温度的显着影响。此外，它在极端酸性条件（pH 1-3）下表现出永久性的活力丧失，并长时间暴露于较高的铬含量。所研究的微藻将是高酸性条件下六价铬修复中非常有用的生物制剂。