柠檬酸改性竹屑吸附亚甲基蓝的动力学和热力学分析

Kinetic and Thermodynamics Analysis of Bio-Sorption of Methylene Blue by Citric Acid Modified Bamboo-Sawdust

为拓宽竹材剩余物的开发应用新途径。以竹屑为原料,柠檬酸为改性剂,制备了柠檬酸改性竹屑吸附剂,以亚甲基蓝(MB)为吸附对象,考察了pH、时间、吸附剂投量及吸附温度等对吸附剂吸附MB效果的影响,并对其吸附动力学和热力学进行了分析。结果表明:溶液pH增大,吸附剂对MB的吸附量增大,pH在5-9间变动,吸附剂对MB吸附量变化不大;染料初始浓度和吸附温度增加,吸附剂对MB吸附能力增强;在吸附120min,吸附达到平衡,吸附动力学过程符合二级动力学模型,吸附热力学过程符合Langmuir模型;在25℃、35℃、45℃时,吸附剂对MB的最大吸附量分别为106.38 mg/g、121.95 mg/g和125mg/g;竹屑吸附剂对MB的吸附过程是一个吸热的自发过程。

To develop new exploiting and utilizing ways for bamboo sawdusts.With bamboo sawdust as raw material,a bio-sorbent was prepared by using critic acid as modification agent,the effect on the adsorption to Mmethyl Blue（MB） by modified bamboo sawdusts were studied,of different adsorption conditions such as solution pH,dose of adsorben,dye con-centration,temperature and so on,the adsorption dynamicsand thermodynamic was analysised then.The adsorption capacity increased when pH increased,when the pH changed range from 5 to 9,the adsorption capacity showed little change;the adsorption capacity rised when MB concentration and temperature rised;the adsorption achieved equilibrium when the time of adsorption was 120min,the pseudo-second model and Langmuir equation were suited to describe the dynamics and thermodynamics;the maximum adsorption capacity was 106.38 mg/g,121.95mg/g and 125 mg/g when the temperature was 25℃,35℃ and 45℃ respectively;the overall adsorption to MB was endothermic and spontaneous.