花生壳和玉米芯生物炭对亚甲基蓝的吸附性能

Adsorption Performance for Methylene Blue on Biochar Derived from Peanut Shell and Corn Cob

  • 摘要: 选择花生壳和玉米芯为原材料分别在700℃和450℃条件下制备生物炭,考察了亚甲基蓝初始浓度、生物炭投加量、温度和pH对生物炭吸附亚甲基蓝的影响,并对吸附动力学和等温吸附特征进行了探讨。结果表明,生物炭投加量的增加使其对亚甲基蓝的吸附量下降,而去除率升高;提高亚甲基蓝初始浓度、反应体系温度和pH均会使生物炭对亚甲基蓝的吸附量增高; 4种生物炭对亚甲基蓝的吸附动力学过程均能被准二级动力学方程很好地拟合(R2=0.992~0.999),吸附过程以化学吸附为主要控制步骤; 4种生物炭对亚甲基蓝的吸附更适合用Langmuir方程描述(R2=0.992~0.995),PSB700、PSB450、CCB700和CCB450对亚甲基蓝的理论最大吸附量Qmax分别为10.247mg/g、6.449mg/g、7.919mg/g和2.860mg/g,吸附能力由大到小为PSB700> CCB700> PSB450> CCB450。

     

    Abstract: Peanut shell and corn cob were used as the raw materials to prepare the biochar under the temperature of700℃ and 450℃ . The effects of various parameters such as initial concentration of methylene blue,biochar dosage,temperature,and pH value on the adsorption of methylene blue were investigated. The characteristics of adsorption kinetics and isotherms of methylene blue on biochar were analyzed. The results showed that increasing dose of biochar caused lower adsorption capacity and higher removal rate of methylene blue. The adsorption capacity of methylene blue on biochar increased with a rise in initial concentration of methylene blue,temperature and pH value. The kinetic data showed that it was fitted well with the pseudo-second order model( R2= 0. 992 ~ 0. 999),suggesting adsorption process was influenced by chemical adsorption. The adsorption data of biochar were well fitted with Langmuir model( R2= 0. 992 ~ 0. 995). The theoretical maximum adsorption capacity of methylene blue on PSB700、PSB450,CCB700,CCB450 were 10. 247 mg/g,6. 449 mg/g,7. 919 mg/g,2. 860 mg/g,indicating the adsorption capacity was in the order of PSB700 > CCB700 > PSB450 > CCB450.

     

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