茶叶水提物和柚皮水提物对Cu^(2+)的吸附动力学研究

Kinetics of Adsorption of Cu^(2+) by Tea Aqueous Extract and Pomelo Peel Aqueous Extract

[目的]研究茶叶水提物和柚皮水提物对Cu2+的吸附动力学。[方法]以茶叶和柚皮的水提物为吸附剂,采用电感耦合等离子体发射光谱(ICP-OES)法对重金属Cu的含量进行检测分析,考察了pH、吸附时间、吸附剂投加量等对水提物吸附Cu2+的影响规律和动力学吸附特征。[结果]试验表明,茶叶水提物和柚皮水提物对Cu的最佳吸附pH为5,吸附平衡时间为6 h,最大吸附量分别为156.55和131.35 mg/g。用化学动力学中的拟一级动力学模型和拟二级动力学模型对吸附动力学曲线进行拟合,发现2种水提物都较符合二级反应规律,相关系数分别为0.990 5和0.995 6。用Langmuir型和Freundlich型等温吸附模型对吸附过程进行拟合,结果表明2种水提物都更符合Langmuir吸附模型,相关系数分别为0.882 7和0.934 2。[结论]研究可为重金属的吸附及检测提供一定的参考依据。

[Objective] To study kinetics of adsorption of Cu2＋ by tea aqueous extract and pomelo peel aqueous extract.[Method] The concentrations of Cu were detected by inductively coupled plasma optical emission spectrometer （ICP-OES） while tea aqueous extract and pomelo peel aqueous extract were as adsorbents.The influence law and dynamics adsorption character of Cu2 ＋ by pH,adsorption time and adsorbents dosage were investigated.[Result] The results showed that the optimum pH was 5,the time of adsorption equilibrium was 6 h.The maximum adsorption capacity of tea aqueous extract was 156.55 mg/g,which was 131.35 mg/g by pomelo peel aqueous extract.Pseudo first order kinetic model and Pseudo second order kinetic model were used to fit kinetic curve.The results concluded that both of the water extracts were more suitable to the second order reaction.And the correlation coefficient of Cu2 ＋ by tea aqueous extract was 0.990 5 as well as 0.995 6 by pomelo peel aqueous extract.Langmuir and Freundlich model were used to fit the isothermal adsorption.The two water extracts were more suitable to Langmuir model.The correlation coefficients of Cu2＋ by tea aqueous extract and pomelo peel aqueous extract were 0.882 3 and 0.934 2.[Conclusion] The study can provide reference basis for adsorption and detection of heavy metals.