Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China; Collaborative Innovation Center of Water Pollution Control and Water Security in Karst Area, Guilin University of Technology, Guilin 541004, China; College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China.
Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, Guilin University of Technology, Guilin 541004, China; Collaborative Innovation Center of Water Pollution Control and Water Security in Karst Area, Guilin University of Technology, Guilin 541004, China; College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China.
Int J Biol Macromol. 2023 Jan 1;224:156-169. doi: 10.1016/j.ijbiomac.2022.10.112. Epub 2022 Oct 18.
Iron modified chitosan/coconut shell activated carbon (Fe/CSCC) composite bead is synthesized to remove Cr(VI) and is characterized to reveal the influencing factors and reaction mechanism. Results show that the adsorption capacity (Q) of Cr(VI) increases with the increase of iron loading, contact time (t), Cr(VI) initial concentration (C), and temperature (T), but decreases with the increase of pH, and mass and volume ratio (m/v). After 0.1 mol FeCl modification, the removal efficiency of Cr(VI) by Fe/CSCC reaches as high as 97.25 % at pH = 3, m/v = 1.0 g/L, t = 2880 min, C = 25 mg/L, and T = 25 °C. The coexisting ions of SO, HPO, and Ca lead to the decrease of Q by 7.82, 5.05, and 5.50 mg/g, respectively, and the inhibition effect increases with their increasing concentrations. Fe/CSCC adsorption for Cr(VI) is an endothermic spontaneous process, and a chemical and monolayer adsorption, which is better fitted to a pseudo-second-order kinetic. The fitted maximum Q is 64.49 mg/g by using the Langmuir model. Moreover, after five cycles of regeneration, the Q value only drops about 3.46 mg/g. Characterization analysis of BET, XRD, FTIR, XPS, and SEM-EDS indicates that Cr(VI) is mainly adsorbed by Fe/CSCC through electrostatic attraction and complexation, which is related to the -COOH and - NH groups, and Fe - O groups, respectively.
铁改性壳聚糖/椰子壳活性炭（Fe/CSCC）复合珠粒被合成以去除 Cr(VI)，并对其进行了特性分析以揭示影响因素和反应机制。结果表明，Cr(VI)的吸附容量 (Q) 随铁负载量、接触时间 (t)、Cr(VI)初始浓度 (C) 和温度 (T) 的增加而增加，但随 pH 值、质量和体积比 (m/v) 的增加而降低。经过 0.1 mol FeCl 改性后，Fe/CSCC 对 Cr(VI)的去除效率在 pH = 3、m/v = 1.0 g/L、t = 2880 min、C = 25 mg/L 和 T = 25°C 时高达 97.25%。SO、HPO 和 Ca 的共存离子分别导致 Q 降低 7.82、5.05 和 5.50 mg/g，且抑制效果随其浓度的增加而增加。Fe/CSCC 对 Cr(VI)的吸附是一个吸热自发过程，是化学和单层吸附，更符合拟二级动力学。通过 Langmuir 模型拟合得到的最大 Q 值为 64.49 mg/g。此外，经过五次再生循环，Q 值仅下降了约 3.46 mg/g。BET、XRD、FTIR、XPS 和 SEM-EDS 的特征分析表明，Cr(VI)主要通过静电吸引和络合作用被 Fe/CSCC 吸附，这与-COOH 和-NH 基团以及 Fe-O 基团有关。
