水热氢氧化钾改性花生壳对染料的吸附性能

为了实现花生壳的资源化利用,以氢氧化钾为活化剂,采用水热法制备了改性花生壳吸附剂,并将其用于罗丹明B染料的吸附,旨在达到以废治废的目的。通过正交试验对水热改性温度、时间和改性剂浓度进行优化,采用扫描电子显微镜和傅立叶变换红外光谱对吸附剂进行表征,并考察了吸附剂投加量、初始浓度及p H值对吸附剂吸附性能的影响。结果表明,在水热温度453 K、反应时间10 h、氢氧化钾质量分数2%条件下制备的改性花生壳对罗丹明B的吸附量最高;罗丹明B初始浓度为5 mg·L~(-1)、吸附剂投加量为1.5 g·L~(-1)、吸附时间120 min的条件下,对罗丹明B染料吸附率最高达93.50%。改性花生壳吸附剂对罗丹明B的吸附动力学过程符合伪二级动力学,Langmuir吸附等温方程能更好地描述吸附过程,主要为单分子层吸附,并且吸附热力学参数ΔH0、ΔG0,表明该吸附过程是一个自发吸热过程,以物理吸附为主。

Preparation and adsorption performance of peanut shells based adsorbent by potassium hydroxide-assisted hydrothermal method

In order to realized the resource utilization of peanut shells, a peanut shells-based adsorbent was prepared by potassium hydrox-ide-assisted hydrothermal method, and the adsorption performance of rhodamine B(Rh B)dye was discussed. The modified parameters, such as temperature, duration and concentration of KOH, were optimized by the orthogonal experiment. The characterization of the as-pre-pared adsorbent was investigated using scanning electron microscope(SEM)and Fourier transform infrared spectroscopy(FTIR). The influ-ence of adsorbent dosage, initial concentration and pH of Rh B solutions were investigated. The best adsorption efficiency of Rh B by modi-fied peanut shells was at the condition of the temperature of 453 K, reaction time of 10 h, and the KOH concentration of 2%. The removal efficiency of Rh B was 93.50%under condition of 5 mg·L-1, 1.5 g·L-1 and 120 min, corresponding to the initial concentration of Rh B, the dosage of modified peanut shells, and the adsorption time, respectively. Adsorption kinetics fitting results showed that the adsorption ac-corded with the pseudo-second-order kinetics. Langmuir monolayer adsorption model could be well used to describe the adsorption process. Meanwhile, the adsorption was a spontaneous endothermic process by the results of△H>0 and△G<0, and was mainly consisted with physi-cal adsorption.