玉米秸秆生物炭对水溶液中Th(Ⅳ)的吸附性能  

On adsorptive property of Th(Ⅳ)from aqueous solution via cornstalk biochar

作　　者：王彦隽 赵婷婷 王维大[2] WANG Yan-jun;ZHAO Ting-ting;WANG Wei-da(Vocational and Technical College of Imnner Mongolia Agricultural University,Baotou 014109,Neimenggu,China;School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,Neimenggu,China)

机构地区：[1]内蒙古农业大学职业技术学院,内蒙古包头014109 [2]内蒙古科技大学能源与环境学院,内蒙古包头014010

出　　处：《安全与环境学报》2020年第6期2375-2382,共8页Journal of Safety and Environment

基　　金：内蒙古自然科学基金项目(2016BS0511);内蒙古科技大学创新基金项目(2016QDL-B08)。

摘　　要：以玉米秸秆为原料,采用厌氧热解法制备生物炭,并采用SEM、EDS、FTIR分析手段对生物炭的物理化学性能进行表征。通过静态吸附试验考察生物炭对水溶液中Th(Ⅳ)的吸附行为,并从动力学和热力学方面对吸附过程进行分析,对吸附机理进行探讨。结果表明,随热解温度升高,BC平均孔径不断增大,孔体积和比表面积也相应增加,且芳香化程度和稳定性增强,有利于其吸附Th(Ⅳ)。红外分析显示,C—C、C O、C C、C—H等基团为BC_(700)吸附Th(Ⅳ)过程中的主要吸附位点。当p H值为4、投加量为1.75 g/L时,BC_(700)对Th(Ⅳ)的去除率达到最高,为99.79%;BC_(700)对Th(Ⅳ)的吸附动力学过程符合准二级动力学模型且吸附过程受颗粒内扩散控制;此外,Freundlich方程能更好地描述等温吸附行为,并且最大吸附容量为20.21 mg/g,。热力学研究表明,吸附吉布斯自由能ΔG^(0)<0,而焓变(ΔH^(0))>0,表明BC_(700)对Th(Ⅳ)的吸附是自发吸热过程,吸附温度升高有利于钍的吸附。生物炭具有较好的重复利用性能。因此,生物炭是一种高效的钍吸附剂,可用于含钍废水的处理和钍污染土壤的修复。Some biochars from maize straw were prepared under a limited oxygen condition.Their physicochemical properties were characterized by scanning electron microscope/energy dispersive spectroscopy(SEM/EDS)and Fourier infrared spectrometer(FT-IR).The adsorption behavior of Th(Ⅳ)on biochar was investigated by conducting a series of batch adsorption experiments.It would be necessary to analyze the adsorption process in terms of thermodynamics and kinetics for a discussion of the adsorption mechanism.The results of our pursuit and discussion indicate that,with the increase of the pyrolysis temperature,the pore structure of BC can also grow up and expand with the increase of the micro-porous formulas.And,furthermore,it is also necessary to discuss the average aperture,the pore volume and the specific surface area,for all of them tend to increase correspondingly,too.And,so,they may also indicate that the BC structure expansion goes also in a direction favorable for the Th(Ⅳ)adsorption.Whereas the BC_(700) has its own adsorption capacity to Th(Ⅳ),the aromaticity of BC_(700) and the removal efficiency of Th(Ⅳ)in the water body,with the increase of temperature,can also be improved in the adsorption process,with the main adsorption sites being C—C,C O,C C,C—H.For instance,when the p H value is 4 and the dosage of BC_(700) is1.75 g/L,it would be possible for the removal rate of Th(Ⅳ)in aqueous to reach the peak ratio by 99.79%.And,the adsorption kinetics analysis may suggest that the adsorption process could be well fitted by the pseudo-second-order model.Then,through the intra-particle diffusion model,the adsorption mechanism can be proven to be of the chemical adsorptive nature.Besides,the Freundlich isotherm can also account for the best explanation ofthe experimental data with the maximum adsorption amount being up to 20.21 mg/g,which is correlated with the multiaperture structure and abundant functional groups of biochar.Further adsorption thermodynamics analysiscan prove that ΔG^(0)<0 and ΔH^(0)>0,which im

关 键 词：环境工程学 钍 生物炭 吸附 热力学 动力学 

分 类 号：X703.1[环境科学与工程—环境工程]