热改性活性炭吸附甲萘威的性能

在N2保护下采用不同高温对活性炭进行热改性,得到了4种改性活性炭(AC-1至AC-4)。采用气体吸附仪、Boehm滴定、傅里叶变换红外光谱仪(FTIR)对活性炭表面的物化性质进行了表征。通过等温吸附试验考察了改性前后活性炭对甲萘威的吸附性能,确定了最佳改性温度为600℃,探讨了活性炭的吸附能力与其表面物化性质之间的关系。结果表明:热改性使活性炭表面的物化性质发生了改变,活性炭对甲萘威的吸附量与其比表面积、孔容、表面酸性官能团和O元素含量具有显著相关性;活性炭对甲萘威的吸附行为符合准二级吸附动力学方程和Langmuir等温吸附方程,颗粒内扩散模型表明内扩散不是控制活性炭吸附速率的唯一阶段。

On the adsorptive performance of carbaryl onto the activated carbons with the thermal treatment

The paper is aimed to present its methods for preparing four kinds of modified activated carbons under the different temperature conditions to protect the nitrogen atmosphere.For the research purpose,we have examined their surface physicochemical properties in a variety of approaches,such as the application of a gas adsorption analyzer,a Boehm titration,a scanning electronmicroscope (SEM) and the Fourier trans tormed infrared spectroscopy (FTIR).At the same time,we have also done the isothermal adsorption experiments under the conditions with carbaryl being used as the adsorbate.Besides,this paper has also made an exploration of the associated relation between the adsorption power and the physicochemical properties of the activated carbons.The results of the above experimental studies show that the thermal treatment of the activated carbon is in a position to change the physicochemical properties of its surface.For instance,it can promote the decrease of the oxygen content of the carbon surface and the acidic functional groups whereas the surface area and the basic composition of the activated carbons can help to increase themselves significantly,too.Moreover,the SEM analysis indicates that the pore number and volume can be found increased due to the activated carbons expansion with the rising of the temperature.What is more,the analysis results of FTIR experiment prove to be consistent with the results of the Boehm titration.In addition,the adsorption capacity of the activated carbons has been found strongly correlated with their surface area,pore volume,and the surface acidic functional groups while the oxygen content of the surface area and pore volume can help to improve the adsorption capacity of the activated carbons.On the contrary,the acidic functional groups and the oxygen content just behave oppositely.More exactly speaking,the experimental data indicate that the optimal modification temperature should be set up at 600℃.The adsorption behavior of the activated carbons has also been found consistent with the pseudo-second-order kinetic model and that of the Langmuir isotherm.And,finally,the adsorption capacity of all kinds of adsorbents proves to be greater than 8 kJ/mol,signifying that the adsorption process has been dominated by the chemical adsorption.The fitting data of the intraparticle diffusion reveals that the adsorption rate of the activated carbons is not rn()erely controlled in the liquid film diffusion stage.