富微孔型生物炭对2,4-二氯苯酚的吸附性能

ADSORPTION PERFORMANCE OF 2,4-DICHLOROPHENOL ON MICROPOROUS-RICH BIOCHAR

以废弃的杉木屑为原材料,制备出富微孔的生物质炭(简称FWB),以2,4-二氯苯酚(2,4-DCP)为目标污染物,研究了不同吸附条件对FWB吸附2,4-DCP的影响,并利用动力学模型(准一级动力学、准二级动力学和颗粒内扩散模型)、等温吸附模型(Langmuir、Freundlich和Temkin模型)和吸附热力学模型(Van’t Hoff模型)对吸附过程进行拟合,分析其吸附特性;结合SEM-EDS、BET、FTIR、XRD和XPS表征方法分析FWB的基本特性和吸附机理。结果表明:吸附过程符合准二级动力学模型和Freundlich模型,即FWB对2,4-DCP的吸附是以多分子层的化学吸附为主,最大吸附容量为138.05 mg/g,吸附过程为自发的吸热过程;该生物炭拥有较高的比表面积(326.770 m^(2)/g),平均孔径为1.960 nm,总孔容为0.219 mL/g,微孔孔容(0.178 mL/g)占总孔容的81.279%。

In this paper,microporous-rich biomass charcoal(referred to as FWB)was prepared using waste fir wood chips as the raw material,and 2,4-dichlorophenol(2,4-DCP)was used as the target pollutant.The effects of different adsorption conditions on the adsorption performance of 2,4-DCP by FWB were studied,and the kinetic models(quasi-primary kinetics,quasi-secondary kinetics and intraparticle diffusion models),isothermal adsorption models(Langmuir,Freundlich and Temkin models)and the adsorption thermodynamic model(Van’t Hoff model)were used to fit the adsorption process and analyze its adsorption characteristics.The basic characteristics and adsorption mechanism of FWB were analyzed by SEM-EDS,BET,FTIR,XRD and XPS.The results showed that the adsorption process followed the quasi-secondary kinetic model and the Freundlich model,i.e.the adsorption of 2,4-DCP by FWB was based on the chemisorption of multilayers,with a maximum adsorption capacity of 138.05 mg/g.The adsorption process was a spontaneous heat absorption process.The biochar possesses a high specific surface area(326.770 m^(2)/g),and an average pore size of 1.960.The total pore volume is 0.219 mL/g,and the micro-pore volume(0.178 mL/g)accounts for 81.279%of the total pore volume.