荔枝皮吸附孔雀绿的性能和机理

Capacity and Mechanism of Litchi Pericarps Adsorbing Malachite Green

采用批量试验方法研究了荔枝皮对水中孔雀绿染料吸附的影响因素(吸附剂剂量、pH值和接触时间)、吸附等温线、吸附动力学和吸附热力学等,并探讨了其吸附机理。结果表明,荔枝皮和改性荔枝皮对孔雀绿的最佳吸附剂用量分别为4和2 g·L-1,最适pH值均为7.0,吸附平衡时间均为120 min;吸附过程均能用Langmuir和Freundlich等温线模型进行很好的描述,且均符合假二次动力学模型。荔枝皮和改性荔枝皮对孔雀绿的最大吸附量分别为72.46和169.49 mg·g-1。此外,吸附热力学试验结果表明,荔枝皮和改性荔枝皮对孔雀绿的吸附均属于自发吸热过程。

Batch assays of litchi pericarps adsorbing malachite green（MG） in water were conducted for exploring its influ- encing factors, such as dosage of adsorbent, pH and duration of exposure, adsorption isotherm, kinetics and thermody- namics, and its mechanism as well. Results show that the optimal dosage of adsorbent for raw litchi pericarps （RLP） and modified litchi pericarps （MLP） adsorbing malachite green was 4 and 2 g ·L-1, respectively, the optimal pH, 7.0, and adsorption equilibrium time, 120 min. The adsorption processes of both RLP and MLP could be well described with the Langmuir and Freundlich isothermal models, and they fitted the pseudo-second-order dynamic model. The maximum MG adsorption capacities of RLP and MLP is 72. 46 and 169. 49 mg·g-1, respectively. Additionally, results of the thermody- namics tests suggest that the MG adsorption processes by RLP and MLP are both spontaneous endothermic ones.