稻壳生物炭对三氯乙醛的吸附特性研究

Study on Adsorption of Chloral by Rice Husk Biochar

为寻求高效廉价的三氯乙醛吸附剂以及资源化有效利用农业废弃物稻壳的途径,采用限氧控温炭化法将稻壳在300、500和700℃条件下裂解制备生物炭。文章对生物炭结构、元素组成和表面官能团等理化性质进行研究,并用于吸附水中的三氯乙醛,研究了吸附时间、系统温度、初始浓度和pH对生物炭吸附三氯乙醛的影响。结果表明,生物炭对三氯乙醛的吸附动力学过程更满足准二级动力学模型(R>0.9253);等温吸附过程用Freundlich模型能够较好地描述,拟合系数>0.9472。随着制备温度提高,生物炭对三氯乙醛的吸附效果越好;吸附性能与三氯乙醛初始浓度和溶液p H呈正相关。研究显示,稻壳生物炭对三氯乙醛的吸附强度随比表面积和平均孔径的增大而增强。

In order to find efficient and cheap chloral adsorbents and the way of resource utilization of agricultural waste rice husk,the rice husk was decomposed to prepare biochar at 300,500 and 700℃by oxygen-limited temperature-controlled carbonation method.The physical and chemical properties of biochar,such as structure,element composition and surface functional group,were studied and used to adsorb chloral in water.The effects of adsorption time,system temperature,initial concentration and pH on the adsorption of chloral by biochar were studied.The results show that the adsorption kinetics of chloral by biochar is more satisfactory to the quasi-second-order kinetic model(R>0.9253),and the isothermic adsorption process can be well described by Freundlich model,and the fitting coefficient is more than 0.9472.With the increase of preparation temperature,the adsorption effect of biochar on chloral is better,and the adsorption performance is positively correlated with the initial concentration of chloral and solution pH.The results showed that the adsorption strength of chloral on rice husk biochar increased with the increase of specific surface area and average pore size.