Zheng Meixia, Lian Fengli, Zhu Yujing, Liu Bo, Chen Zheng, Zhang Yi, Zheng Baodong, Zhang Longtao
Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou, Fujian 350003, China.
College of Food Science, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; China-Ireland International Cooperation Centre for Food Material Science and Structural Design, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China; and Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China E-mail:
Water Sci Technol. 2019 Jan;79(1):165-174. doi: 10.2166/wst.2019.038.
Modified xanthan gum (XG-AM-TTE) was employed as an adsorbent to study the adsorption behavior, thermodynamics and kinetics of crystal violet (CV) from an aqueous solution. Fourier transform infrared spectroscopy analysis indicates that the functional groups present in the adsorbent, such as carboxyl, ester and hydroxyl groups, are included on the external surface of the material, and these groups are potential active sites for interaction with CV. According to X-ray diffraction results, the structure of XG-AM-TTE after CV adsorption became more disordered, and the microstructure change is an indication of effective adsorption of CV to the surface, with CV becoming remarkably dispersed in the adsorbent according to the scanning electron microscopy observations. The adsorption kinetics and adsorption equilibrium were best described by the pseudo-second-order model and Freundlich isotherms, respectively. The thermodynamic parameters, as the Gibbs-free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), indicated that the adsorption is a spontaneous, endothermic and entropy increase process. The maximum adsorption capacity of XG-AM-TTE was 183 ± 12 mg/g, suggesting that XG-AM-TTE is an efficient adsorbent.
采用改性黄原胶（XG-AM-TTE）作为吸附剂，研究其对水溶液中结晶紫（CV）的吸附行为、热力学和动力学。傅里叶变换红外光谱分析表明，吸附剂中存在的官能团，如羧基、酯基和羟基，位于材料的外表面，这些基团是与CV相互作用的潜在活性位点。根据X射线衍射结果，CV吸附后XG-AM-TTE的结构变得更加无序，微观结构的变化表明CV有效地吸附到了表面，扫描电子显微镜观察显示CV在吸附剂中显著分散。吸附动力学和吸附平衡分别用伪二级模型和Freundlich等温线进行了最佳描述。热力学参数，如吉布斯自由能（ΔG）、焓（ΔH）和熵（ΔS），表明吸附是一个自发、吸热和熵增加的过程。XG-AM-TTE的最大吸附容量为183±12 mg/g，表明XG-AM-TTE是一种高效吸附剂。
