苹果渣吸附水体中pb2+的研究

采用静置吸附法,以苹果渣为生物吸附剂,研究了其对水体中pb2+的吸附作用、影响吸附过程的因素、吸附过程的热力学和动力学行为.结果显示:苹果渣对pb2+的吸附率随其粒径的减小而增大；pb2+初始质量浓度相同时,吸附率随苹果渣加入量的增加而增大；苹果渣加入量相同时,吸附率随pb2+初始质量浓度的增加而增大.正交试验显示:3种因素对吸附效果的影响程度顺序为pH值＞吸附温度＞吸附时间,最优吸附条件为pH值2.0、吸附温度40℃、吸附时间4 h.Freundlich吸附等温式能较好地描述苹果渣对pb2+的吸附热力学行为,二级动力学模型可描述其吸附动力学行为；吸附过程先是快速吸附,60 min后变为慢速吸附；对于60 mg/L的pb2+溶液,苹果渣为吸附剂时的最佳固液比为12 g/L.

STUDY ON BIOSORPTION OF Pb2+ IN WATER BY APPLE RESIDUE

In this paper,we studied the adsorption effect,the factors and the thermodynamic and kinetic behaviors of Pb 2+ in water by using apple residues as a biosorbent.The results showed that the adsorption rate increased as the particle size of the apple residue decreased;the adsorption rate increased as the addition amount of the apple residue was increased when the initial mass concentration of Pb 2+ was constant;and the adsorption rate increased as the initial mass concentration of Pb 2+ was increased when the addition amount of apple residue was constant. The orthogonal experiments showed that the influence degree of the three factors on the adsorption effect was as follows: pH,adsorption temperature and adsorption time;and the optimum adsorption conditions were pH 2.0, adsorption temperature 40 ℃ and adsorption time 4 hours.Freundlich adsorption isothermal equation could well describe the adsorption thermodynamic behavior of Pb 2+;a second kinetic model could describe the adsorption kinetic behavior;the adsorption process was fast firstly and then turned to slow adsorption after 60 minutes;and the optimum solid-to-liquid ratio was 12 g/L for the Pb 2+ solution with the mass concentration of 60 mg/L.