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以酸性KMnO4为改性剂对麦麸进行改性,制备能够吸附In(Ⅲ)的生物质吸附剂。考察了改性剂中KMnO4与硫酸的浓度对改性效果的影响。改性效果随着KMnO4浓度的升高而提高,使用浓度为25 g·L-1的酸性KMnO4改性的麦麸对In(Ⅲ)有最佳的吸附效果。改性剂中硫酸的浓度对改性效果的影响呈现出先增大后减小的趋势,并且在硫酸浓度为0.3 mol·L-1时,吸附效果最佳。考察了溶液p H值、吸附时间、In(Ⅲ)浓度和温度等因素对改性麦麸吸附In(Ⅲ)的影响。结果表明:在初始p H为2.5的硫酸溶液中,改性麦麸对In(Ⅲ)有很好的吸附效果,且吸附在2 h内基本达到平衡;吸附过程是吸热过程,吸附符合Langumir吸附模型,为单分子层吸附,饱和吸附量能够达到23.65 mg·g-1。分别采用拟一级动力学模型及拟二级动力学模型对吸附动力学数据进行拟合。拟合结果表明拟二级动力学模型能够很好地描述改性麦麸吸附溶液中In(Ⅲ)的过程。动态吸附与洗脱时,流速为1.0 ml·min-1的条件下能够获得良好的效果,对吸附于饱和后的吸附剂上的In(Ⅲ)可用2 mol·L-1的盐酸进行洗脱,洗脱率达到96%。
The wheat bran was modified with acidic KMnO4 as modifier to prepare a biomass adsorbent capable of adsorbing In (Ⅲ). The effect of the concentration of KMnO4 and sulfuric acid in the modifier on the modification was investigated. The modification effect increased with the increase of the concentration of KMnO4. The optimum adsorption of In (Ⅲ) on the KMnO4-modified wheat bran was achieved with a concentration of 25 g · L-1. The effect of the concentration of sulfuric acid in the modifier on the modification effect firstly increases and then decreases, and the adsorption effect is best when the concentration of sulfuric acid is 0.3 mol·L-1. The effects of p H value, adsorption time, In (Ⅲ) concentration and temperature on In (Ⅲ) adsorption on modified wheat bran were investigated. The results showed that the modified wheat bran had a good adsorption effect on In (Ⅲ) in the initial pH 2.5 sulfuric acid solution, and the adsorption reached equilibrium in 2 h; the adsorption process was endothermic and the adsorption was in accordance with Langumir Adsorption model for the monolayer adsorption, saturated adsorption capacity can reach 23.65 mg · g-1. Adopt the first-order kinetic model and the second-order kinetic model to fit the adsorption kinetics data respectively. The fitting results show that the pseudo-second order kinetic model can well describe the process of In (Ⅲ) in the modified wheat bran adsorption solution. In the condition of dynamic adsorption and elution, good effect can be obtained at a flow rate of 1.0 ml · min-1. In (Ⅲ) adsorbed on the saturated adsorbent can be eluted with 2 mol·L-1 hydrochloric acid , Elution rate of 96%.