School of Chemical Engineering, University of Science and Technology Liaoning, Anshan, China; Université de Limoges, EA 4330 Groupement de Recherche Eau Sol Environnement, 123 Avenue Albert Thomas, 87060, Limoges, France.
Université de Limoges, EA 4330 Groupement de Recherche Eau Sol Environnement, 123 Avenue Albert Thomas, 87060, Limoges, France.
Environ Res. 2024 Jun 1;250:118440. doi: 10.1016/j.envres.2024.118440. Epub 2024 Feb 13.
Ferrihydrite is an effective adsorbent of chromate and arsenate. In order to gain insight into the application of ferrihydrite in water treatment, macroporous alginate/ferrihydrite beads, synthesized using two different methods (internal and encapsulation processes), were used in this work. The properties of the ferrihydrite were assessed using various techniques, including X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) theory, and zetametry. The results showed that the specific surface area of the ferrihydrite was 242 m/g, and the PZC was pH8. The kinetic and isotherm adsorption properties of the ferrihydrite were evaluated in this study. The results indicate that the pseudo second-order and Freundlich models accurately describe the kinetic and isotherm adsorption properties of chromates and arsenates. For chromate removal, ferrihydrite exhibited a relatively high adsorption capacity (40.7 mg/g) compared to other adsorbents. However, the arsenate adsorption capacity of MFHB-SI (140.8 mg/g) was shown to be the most optimal. The internal synthesis process was suitable for arsenate retention due to the resulting arsenate precipitation. The competitive adsorption analyses indicated that the presence of chromate does not limit the adsorption of arsenate. However, the presence of arsenate almost completely inhibits the adsorption of chromate when the arsenate concentration is above 50 mg/L, due to the precipitation reaction of arsenate.
水铁矿是铬酸盐和砷酸盐的有效吸附剂。为了深入了解水铁矿在水处理中的应用，本文使用了两种不同方法（内部分散法和包埋法）合成的大孔海藻酸钠/水铁矿珠来进行研究。采用 X 射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、BET 理论和动电测定法等多种技术对水铁矿的性质进行了评估。结果表明，水铁矿的比表面积为 242 m/g，等电点（PZC）为 pH8。本文还评估了水铁矿的动力学和等温吸附特性。结果表明，准二级和 Freundlich 模型能够准确描述铬酸盐和砷酸盐的动力学和等温吸附特性。对于铬酸盐的去除，水铁矿表现出相对较高的吸附容量（40.7 mg/g），优于其他吸附剂。然而，MFHB-SI（140.8 mg/g）对砷酸盐的吸附容量最佳。由于内部分散法合成的水铁矿会发生砷酸盐沉淀，因此该方法更适合用于砷酸盐的保留。竞争吸附分析表明，铬酸盐的存在并不限制砷酸盐的吸附。然而，当砷酸盐浓度高于 50 mg/L 时，由于砷酸盐的沉淀反应，砷酸盐几乎完全抑制了铬酸盐的吸附。
