采用静置吸附法,以芹菜渣为生物吸附剂,研究了其对Pb2+的吸附作用、吸附过程的影响因素、热力学和动力学行为。结果显示:芹菜渣对Pb2+的吸附率随其粒径的减小而增大;Pb2+初始浓度相同时,吸附率随芹菜渣加入量的增加而增大,芹菜渣加入量相同时,吸附率随Pb2+初始浓度的增加而增大;正交试验得到3因素对吸附效果的影响程度顺序为pH值>时间>温度,最优吸附条件为pH值4、吸附温度50℃、吸附时间5 h;芹菜渣对Pb2+的吸附以单分子层吸附为主,Freundlich吸附等温式能较好的描述其吸附热力学情况;芹菜渣对Pb2+吸附先是快速吸附,吸附时间超过40 min后为慢速吸附,芹菜渣对Pb2+的吸附动力学可以用二级动力学模型描述;对于50 mg/L的Pb2+溶液,芹菜渣为吸附剂时的最佳固液比为15 g/L;芹菜渣对低浓度(≤20 mg/L)Pb2+溶液的吸附效果好于活性炭。

By adsorption,this paper systematically studies adsorption and adsorption mechanism of Pb2+ by celery residue.Experimental results showe that: with the smaller size of celery residue,Pb2+ adsorption rate is increased.Under the same Pb2+ initial concentration,with the addition of more celery residue,Pb2+ adsorption rate is increased.Under the same addition amount of celery residue,with the addition of Pb2+ initial concentration,adsorption rate is also increased.Orthogonal tests show that: the optimum adsorption conditions for the wastewater pH is 4,the temperature is 50 ℃ and soaking time is 5 hour.The influence order of 3 factors is pH,soaking time and temperature.Celery residue on Pb2+ adsorption with single molecule layer absorption dominant,and adsorption isotherm is fit to Freundlich adsorption isotherm.The adsorption rate for celery residue to Pb2+ is quick at the beginning,and then becomes slowly after 40min.Second kinetic model better describes the adsorption kinetics of celery residue.The best s/l radio of Pb2+(50 mg/L) adsorption by celery residue is 15 g/L.In the low concentration of Pb2+ solution(≤20 mg/L),the adsorption of celery residue is better than activated carbon.