废羊毛对三价铬离子络合物的吸附研究

Study on adsorption of waste wool on trivalent chromium ion complexes

选取磺基水杨酸钠、柠檬酸和草酸作为配体与Cr^(3+)配位,然后用剥鳞的废弃羊毛吸附该络合物。对该吸附过程建立了适当的模型,描述了其吸附行为,对吸附机理进行了探究。采用Langmuir及Freundlich吸附等温线模型对试验数据进行拟合,结果表明Cr^(3+)的吸附行为以Langmuir等温吸附为主;吸附动力学表明拟二级动力学方程能较好地描述Cr^(3+)的吸附行为;热力学参数表明Cr^(3+)的吸附为可自发进行的吸热反应,升温有利于反应的进行;Cr^(3+)络合物的红外光谱表明,配体中草酸根的配位能力最强;剥鳞废弃羊毛吸附前后的红外光谱表明,吸附是静电结合以及络合作用的结果;最后废羊毛对三种配体吸附效果评定为柠檬酸-铬络合物>草酸-铬络合物>磺基水杨酸-铬络合物。

Citric acid and oxalic acid were chosen as ligands to coordinate with Cr~＋, and then the com- plex was adsorbed by scraped wool. A proper model was established for the adsorption process. The adsorp- tion behavior was described and the adsorption mechanism was discussed. The adsorption data were fitted by Langmuir and Freundlich adsorption isotherm equation, the result proved that the Langmuir adsorption iso- therm was the main adsorption behavior of Cr3＋. The adsorption kinetics data showed that the pseudo sec- ond-order equation could well describe the adsorption behavior. The thermodynamic parameters showed that the adsorption of Cr3. was a spontaneous endothermic reaction, increasing temperature was conducive to the reaction. The infrared spectroscopy of Cr3＋ complex showed that the coordination ability of oxalate was the strongest. The infrared spectroscopy of waste wool before and after adsorption indicated that adsorption was the result of the electrostatic binding and complexation. Finally, the adsorption of waste wool to three kinds of ligand was evaluated as citric acid-chromium complex〉oxalic acid-chromium complex〉sulfosalicylic acid-chro- mium complex.