蒙脱石改性材料制备及其对低浓度含钴溶液中钴的吸附行为

Research on extracting cobalt from low concentration cobalt-containingleaching solution using modified montmorillonite loaded with sulfur

针对含钴废渣酸浸余液中低浓度Co^(2+)提取困难的问题,采用NaOH和S与蒙脱石混合焙烧的方法制备出硫改性蒙脱石复合材料,用于酸浸余液中Co^(2+)的吸附。对所制备的硫改性蒙脱石复合材料对Co^(2+)的吸附性能进行研究。研究表明,改性后,S被成功地负载在蒙脱石表面,并和Na均匀分布在蒙脱石结构中;在初始Co^(2+)浓度为100μg·L^(-1)、溶液pH值为8、吸附剂用量为3 g·L^(-1)、吸附时间10 h的条件下,硫改性蒙脱石复合材料最大吸附容量为90 mg·g^(-1),Co^(2+)的回收率可以达到95%。此外,对硫改性蒙脱石复合材料吸附Co^(2+)的过程进行研究时发现:该过程符合准二级动力学模型,R2为0.999 0。溶液中的Co^(2+)会以两种方式进入改性蒙脱石中,一是Co^(2+)与S2-以软硬酸碱作用力相结合,二是Co^(2+)会取代蒙脱石层间结构中的Na,从而达到高效提取Co^(2+)的目的。

To address the challenge of extracting low-concentration Co ^(2+)from acidic leachate of cobalt-containing waste residues,a sulfur-modified montmorillonite composite material was prepared using a method involving the mixed calcination of NaOH and S with montmorillonite.This material was employed for the adsorption of Co ^(2+)in the acidic leachate.The adsorption performance of the prepared sulfur-modified montmorillonite composite material for Co ^(2+)was investigated.The study indicates that S is successfully encapsulated into the montmorillonite and is uniformly distributed with Na in the montmorillonite structure.Under the conditions of an initial Co ^(2+)concentration of 100μg·L^(-1),solution pH of 8,the adsorbent dosage of 3 g·L^(-1),and an adsorption time of 10 h,the maximum adsorption capacity of the sulfur-modified montmorillonite composite material is 90 mg·g^(-1),and the recovery rate of Co ^(2+)can reach 95%.Furthermore,the study on the adsorption process of Co ^(2+)by sulfur-modified montmorillonite composite material reveals that the process conforms to a pseudo-second-order kinetic model with an R 2 value of 0.9990.Co ^(2+)in the solution enters the modified montmorillonite in two ways:firstly,through the combination of Co ^(2+)and S 2-via soft and hard acid-base interactions,and secondly,Co ^(2+)replaces Na in the interlayer structure of montmorillonite,achieving efficient extraction of Co ^(2+).