College of Construction Engineering, Jilin University, Changchun, 130026, China.
College of Civil Engineering, Taiyuan University of Technology, Taiyuan, 030024, China.
Environ Geochem Health. 2024 Sep 24;46(11):434. doi: 10.1007/s10653-024-02205-x.
The issue of heavy metal pollution is a critical global concern that requires urgent solution. However, conventional heavy metal adsorbents are too costly to be applied in large-scale engineering. In this study, adsorption behavior and mechanism of sintering red mud (RM-A) and bayer red mud (RM-B) for heavy metals were investigated to address the disposal of red mud as industrial waste and remediation of heavy metal pollution. Batch adsorption experiments were conducted to explore the adsorption performances of RM-A and RM-B under various conditions. Characterization of RM-A and RM-B before and after adsorption by XRD, FTIR and SEM-EDX was applied to investigate the specific adsorption behavior and mechanism. Adsorption experiments of both RM-A and RM-B fitted pseudo-second-order kinetic model and Langmuir isotherm model, with estimated maximum adsorption capacity of 21.96 and 25.19 mg/g for Cd, 21.47 and 26.06 mg/g for Cu and 55.47 and 59.65 mg/g for Pb, respectively. Precipitation transformation of calcite was the primary adsorption mechanism for RM-A, whereas ion exchange of cancrinite, surface coordination compounds of hematite and minor precipitation transformation of calcite accounted for the adsorption mechanism for RM-B. Overall, RM-A and RM-B exhibited best adsorption performance for Pb, with RM-B showing greater adsorption capacity attributed to its higher specific surface area. This study compared the adsorption properties of RM-A and RM-B for the first time and demonstrated that both red muds can be effectively applied to remove heavy metals, thereby contributing to the sustainable industrial waste management and resourceful reuse.
重金属污染问题是一个全球性的重大问题，需要紧急解决。然而，传统的重金属吸附剂成本过高，无法在大规模工程中应用。本研究旨在探讨烧结赤泥（RM-A）和拜耳法赤泥（RM-B）对重金属的吸附行为和机理，以解决赤泥作为工业废物的处置问题，并修复重金属污染。通过批式吸附实验，研究了 RM-A 和 RM-B 在不同条件下的吸附性能。采用 XRD、FTIR 和 SEM-EDX 对 RM-A 和 RM-B 吸附前后进行了表征，以探究其具体的吸附行为和机理。RM-A 和 RM-B 的吸附实验均符合准二级动力学模型和 Langmuir 等温模型，Cd 的最大吸附容量估计值分别为 21.96 和 25.19mg/g，Cu 的最大吸附容量估计值分别为 21.47 和 26.06mg/g，Pb 的最大吸附容量估计值分别为 55.47 和 59.65mg/g。RM-A 的主要吸附机制是方解石的沉淀转化，而 RM-B 的吸附机制则包括钙霞石的离子交换、赤铁矿的表面配位化合物以及少量方解石的沉淀转化。总的来说，RM-A 和 RM-B 对 Pb 的吸附性能最佳，而 RM-B 由于具有更高的比表面积，其吸附容量更大。本研究首次比较了 RM-A 和 RM-B 的吸附性能，结果表明两种赤泥均可有效去除重金属，从而有助于可持续的工业废物管理和资源再利用。
