荔枝皮吸附水中孔雀绿的响应曲面法研究

采用Box-Behnken响应曲面优化设计对荔枝皮吸附去除水中染料孔雀绿（MG）的影响因素（如吸附时间、吸附剂用量、pH值）进行研究，建立了去除率和上述因素之间的二次多项式模型，得到荔枝皮吸附孔雀绿的最佳吸附条件为：温度25℃、吸附时间122.31min、吸附剂用量2.81g/L、pH=6.75、MG浓度为100mg/L，最优条件下荔枝皮对孔雀绿的吸附去除率可以达99.75%。用Langmuir和Freundlich方程对吸附等温线进行拟合，其中Langmuir方程拟合效果最好，其最大吸附量为142.86mg/g，且吸附过程符合假二次动力学模型。此外，热力学结果表明，荔枝皮对孔雀绿的吸附属于自发的吸热过程。结合吸附-解吸循环实验和对吸附的FT-IR表征，表明荔枝皮是一种极具潜力的高效的吸附剂，能有效去除水中的孔雀绿离子。

Study on adsorption of malachite green using litchi pericarps by response surface methodology

The effect of several important parameters on the removal of Malachite Green by litchi pericarps was evaluated using an optimal experimental design based on Box-Behnken Response Surface methodology. The factors included contact time，adsorbent dosage and pH. A quadratic model for predicting the optimum removal conditions was derived，and the obtained optimal parameters were at the temperature of 25℃，contact time of 122.31min，adsorbent dosage of 2.81g/L，pH value of 6.75，MG initial dye concentration 100mg/L. At the optimal conditions，the maximal removal rate of MG reached 99.75%. Langmuir and Freundlich equations were applied to fit the adsorption equilibrium data. The Langmuir isotherm adsoroption model was found to fit the data best and maximum adsorption capacity of MG was 142.86mg/g，and adsorption kinetics conforms to pseudo-second-order model. Additionally，result of thermodynamics measurement suggested that the adsorption processes is spontaneous and endothermic. Finally，the adsorption-desorption cycle and FT-IR were also studied，suggesting the litchi pericarp is a promising and efficient adsorbent for removing MG from water.