School of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 10049, China.
Guangzhou Institute of Chemistry, Chinese Academy of Sciences, Guangzhou 510650, China.
Molecules. 2021 Mar 22;26(6):1785. doi: 10.3390/molecules26061785.
Chitosan is a kind of biodegradable natural polysaccharide, and it is a very promising adsorber material for removing metal ions from aqueous solutions. In this study, chitosan-based magnetic adsorbent CMC@FeO was synthesized by a one-step method using carboxymethyl chitosan (CMC) and ferric salts under relatively mild conditions. The FeO microspheres were formed and the core-shell structure of CMC@FeO was synthesized in the meantime, which was well characterized via SEM/TEM, XRD, VSM, FT-IR, thermo gravimetric analysis (TGA), XPS, size distribution, and zeta potential. The effects of initial arsenic concentration, pH, temperature, contact time, and ionic strength on adsorption quantity of inorganic arsenic was studied through batch adsorption experiments. The magnetic adsorbent CMC@FeO displayed satisfactory adsorption performance for arsenic in water samples, up to 20.1 mg/g. The optimal conditions of the adsorption process were pH 3.0, 30-50 °C, and a reaction time of 15 min. The adsorption process can be well described by pseudo-second-order kinetic model, suggesting that chemisorption was main rate-controlling step. The Langmuir adsorption model provided much higher correlation coefficient than that of Freundlich adsorption model, indicating that the adsorption behavior is monolayer adsorption on the surface of the magnetic adsorbents. The above results have demonstrated that chitosan-based magnetic adsorbent CMC@FeO is suitable for the removal of inorganic arsenic in water.
壳聚糖是一种可生物降解的天然多糖，是一种很有前途的从水溶液中去除金属离子的吸附剂材料。在这项研究中，通过一步法在相对温和的条件下使用羧甲基壳聚糖（CMC）和铁盐合成了基于壳聚糖的磁性吸附剂 CMC@FeO。形成了 FeO 微球，同时合成了 CMC@FeO 的核壳结构，通过 SEM/TEM、XRD、VSM、FT-IR、热重分析（TGA）、XPS、粒径分布和zeta 电位进行了很好的表征。通过批量吸附实验研究了初始砷浓度、pH 值、温度、接触时间和离子强度对无机砷吸附量的影响。磁性吸附剂 CMC@FeO 在水样中对砷表现出令人满意的吸附性能，最高可达 20.1 mg/g。吸附过程的最佳条件为 pH 3.0、30-50°C 和 15 min 的反应时间。吸附过程可以很好地用伪二阶动力学模型来描述，表明化学吸附是主要的速率控制步骤。Langmuir 吸附模型提供的相关系数远高于 Freundlich 吸附模型，表明吸附行为是磁性吸附剂表面的单层吸附。上述结果表明，基于壳聚糖的磁性吸附剂 CMC@FeO 适用于去除水中的无机砷。
