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研究了玉米叶对水溶液中Pb~(2+)的吸附性能,借助正交和单因素试验探讨各因素对吸附率的影响,利用红外光谱研究吸附机理,并采用Langmuir、Freundlich和Temkin模型对吸附数据进行拟合。结果表明:金属初始质量浓度和体系pH值是影响吸附的重要因素;玉米叶吸附铅离子的最佳pH值为5.0,金属质量浓度和吸附剂投加量最佳比值为80 mg/L:0.170 g,在25℃时玉米叶对铅离子的吸附较快,180min后达到吸附平衡;吸附数据更加符合Freundlich和Femkin等温吸附模型,由Langmuir等温吸附模型可知玉米叶最大吸附量为103.266mg/g,吉布斯自由能△G°为负值,该过程吸热且自发进行。红外光谱分析表明,参与作用的官能团为羟基、羧基、酰胺或脂肪族C—X(X代表Cl、Br、I)。
The effects of corn leaf on the adsorption of Pb 2+ in aqueous solution were studied. The effects of various factors on the adsorption rate were investigated by means of orthogonal and single factor experiments. The adsorption mechanism was studied by infrared spectroscopy. Langmuir, Freundlich and Temkin models were used to determine the adsorption of Pb 2+. Data fitting. The results showed that the initial concentration of metal and the pH value of the system were the important factors affecting the adsorption. The optimal pH value for the adsorption of lead ions on maize leaf was 5.0, and the optimal ratio of metal mass concentration and adsorbent dosage was 80 mg / L: 0.170 g at 25 ℃, the adsorption of Pb 2+ by maize leaf is faster and the adsorption equilibrium is reached after 180 min. The adsorption data are more in accord with the Freundlich and Femkin isotherm model. The maximum sorption amount of maize leaves is 103.266 mg / g by Langmuir isotherm model, Gibbs free energy △ G ° is negative, the process endothermic and spontaneous. Infrared spectroscopy showed that the functional groups involved were hydroxyl, carboxyl, amide or aliphatic C-X (X represents Cl, Br, I).