Abstract The objective of this study was to investigate the possibility of using natural and bacteria-modified Erzurum clayey soil with Methylobacterium extorquens as an alternative to high cost commercial adsorbent materials for the removal of copper from aqueous solution. The copper concentrations in the samples of the polluted river water and CuCl2 solutions treated by the natural and bacteria-modified Erzurum clayey soil (ECS) have been determined by spectrophotometric method. Firstly, the surface of ECS was modified with M. extorquens and surface functionality was increased. Then, the adsorption of Cu (II) from solution phases was studied with respect to varying metal concentration, pH, and temperature and agitation time. The maximum adsorption of Cu (II) for natural and bacteria-modified Erzurum clayey soil was observed at pH: 5.0. At different copper concentrations, copper adsorption analysis was performed on 1 g using clay soil or modified clay soil. Maximum adsorption of Cu (II) was obtained as 45.7 and 48.1 mg g-1 at initial concentration (50 mg/50 mL) and optimal conditions by natural and bacteria-modified clay soil, respectively. The copper concentration was decreased in the substantial amount of the leachates solutions of natural and bacteria-modified clay soil. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of Cu (II) ions. The results showed that modified clay soil had a high level of adsorption capacity for copper ion. The various thermodynamic parameters such as ΔG°, ΔH° and ΔS° were analyzed to observe the nature of adsorption. The structural properties of the natural and bacteria-modified-ECS have been characterized by SEM, FTIR and XRD techniques. Consequently, it was concluded that the bacteria-modified clay soil could be successfully used for the removal of the copper ions from the aqueous solutions.

中文翻译：

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用甲基化杆菌修饰的 Erzurum 粘土去除铜污染的河水和水溶液中的铜

摘要 本研究的目的是研究使用天然和细菌改性的 Erzurum 粘土与 Methylobacterium extorquens 作为替代高成本商业吸附材料从水溶液中去除铜的可能性。用分光光度法测定了经天然和细菌改性的埃尔祖鲁姆粘土（ECS）处理的污染河水和CuCl2溶液样品中的铜浓度。首先，用 M. extorquens 修饰 ECS 的表面并增加表面功能。然后，根据不同的金属浓度、pH 值、温度和搅拌时间研究了溶液相中 Cu (II) 的吸附。在 pH: 5.0 时观察到天然和细菌修饰的 Erzurum 黏性土壤对 Cu (II) 的最大吸附。在不同的铜浓度下，使用粘土或改性粘土对 1 g 进行铜吸附分析。Cu (II) 的最大吸附量分别为 45.7 和 48.1 mg g-1 在初始浓度 (50 mg/50 mL) 和天然和细菌改性粘土的最佳条件下。在大量天然和细菌改性粘土的渗滤液溶液中铜浓度降低。Langmuir 和 Freundlich 等温线用于描述 Cu (II) 离子的吸附行为。结果表明，改性粘土对铜离子具有较高的吸附能力。分析各种热力学参数如ΔG°、ΔH°和ΔS°以观察吸附性质。天然和细菌修饰的 ECS 的结构特性已通过 SEM 表征，FTIR 和 XRD 技术。因此，得出结论，细菌改性粘土可以成功地用于去除水溶液中的铜离子。