Institute of Polymer and Textile Engineering and Technology, University of the Punjab, Lahore, Pakistan.
Department of Chemistry, University of Lahore, Lahore, 54000, Pakistan.
Environ Res. 2022 Nov;214(Pt 2):113790. doi: 10.1016/j.envres.2022.113790. Epub 2022 Jul 6.
A novel adsorbent was prepared by blending chitosan (CS) and acrylic acid (AA) while using formaldehyde as a cross linker in the form of hydrogel beads. The adsorption properties of these hydrogel beads for the removal of toxic metal ions (Pb and Cd) from aqueous solutions were evaluated. The hydrogel beads have a 3D macro-porous structure whose -NH groups were considered to be the dominant binding specie for Cd and Pb ions. The equilibrium adsorption capacity (q) of beads was significantly affected by the mass ratio of sorbent and sorbate. The percentage removal of Cd and Pb ions was observed to be enhanced with the increase in sorbate concentration. The hydrogel beads maintained good adsorption properties at adsorption-desorption equilibrium. The Langmuir and Freundlich models were used to elaborate the isotherms as well as isotherm constants. Adsorption isothermal data is well explained by the Freundlich model. The data of experimental kinetics is interrelated with the second-order kinetic model, which showed that the chemical sorption phenomenon is the rate limiting step. The results of intraparticle diffusion model described the adsorption process occurred on a porous substance that proved chitosan/Formaldehyde beads to be the favorable adsorbent.
一种新型吸附剂是通过将壳聚糖（CS）和丙烯酸（AA）混合，同时以甲醛的形式作为交联剂形成水凝胶珠而制备的。评估了这些水凝胶珠对从水溶液中去除有毒金属离子（Pb 和 Cd）的吸附性能。水凝胶珠具有 3D 大孔结构，其-NH 基团被认为是 Cd 和 Pb 离子的主要结合种。珠粒的平衡吸附容量（q）显著受吸附剂和吸附质的质量比的影响。随着吸附质浓度的增加，观察到 Cd 和 Pb 离子的去除率增加。水凝胶珠在吸附-解吸平衡时保持良好的吸附性能。Langmuir 和 Freundlich 模型用于阐述等温线和等温线常数。吸附等温线数据很好地解释了 Freundlich 模型。实验动力学数据与二级动力学模型相关，表明化学吸附现象是限速步骤。内扩散模型的结果描述了发生在多孔物质上的吸附过程，证明壳聚糖/甲醛珠是一种理想的吸附剂。
