壳聚糖/磁性甘蔗渣生物炭复合材料对Cr(Ⅵ)的吸附特性

Adsorption of Cr(Ⅵ) on Chitosan/Magnetic Bagasse Biochar Composite Material

研究了壳聚糖/磁性甘蔗渣生物炭复合材料的制备及从模拟废水中吸附Cr(Ⅵ),采用SEM、FTIR、BET法对普通甘蔗渣和复合材料的结构进行表征。结果表明:壳聚糖/磁性甘蔗渣生物炭复合材料为团状结构,表面有大量微孔,并有许多孔隙穿插其中,化学结构较普通甘蔗渣有较大改变;在废水Cr(Ⅵ)初始质量浓度50mg/L、废水pH=2、反应温度25℃、复合材料投加量8g/L、吸附时间12h条件下,Cr(Ⅵ)吸附去除率为98.7%,最大吸附量为8.7796mg/g;Langmuir等温吸附模型能反映吸附过程,吸附以单层吸附为主可用准二级动力学方程描述,吸附分快速吸附与慢速吸附2个阶段。

The preparation of chitosan/magnetic bagasse biochar composite material and the adsorption of Cr(Ⅵ) from simulated wastewater were studied.The structure of composite materials and original bagasse were characterized by SEM,FTIR and BET.The characterization results show that the chitosan/magnetic bagasse biochar composite material is a cluster structure with a large number of micropores on the surface,and many pores are interspersed among them.The chemical structure has been greatly changed compared to original bagasse.The experimental results show that under the conditions that Cr(Ⅵ) initial concentration is 50 mg/L,pH is 2, reaction temperature is 25 ℃,the dosage of composite material is 8 g/L,adsorption time is 12 h,the removal rate of Cr(Ⅵ) is 98.7% and the maximum adsorption capacity of Cr(Ⅵ) is 8.779 6 mg/g.The Langmuir isotherm adsorption model can better reflect the adsorption process which is mainly monolayer adsorption.The pseudo second order kinetic equation can better fit the adsorption process which can be divided into two stages :fast adsorption and slow adsorption.