竹炭对糠醛的吸附特性及动边界模型研究

Characteristics of furfural′s adsorbing bamboo charcoal and its mobile boundary model

利用竹子为前躯体热解制得竹炭,以糠醛为吸附质,考察了不同吸附停留时间、糠醛初始质量浓度和吸附温度下竹炭的吸附特性,并用动边界模型积分方程描述其有限浴交换动力学行为,得到了竹炭吸附糠醛的动力学总方程.结果表明:竹炭吸附糠醛的速度控制步骤为颗粒扩散,糠醛初始质量浓度越高,颗粒扩散控制越明显;温度升高,颗粒扩散控制作用减弱;推算出吸附过程的表观反应级数为0.96,表观活化能为3.02kJ·mol-1,说明该吸附过程主要为物理吸附;证实了热解炭的吸附行为与离子交换过程在动力学描述上具有一定的相似性与兼容性.

Bamboo charcoal from pyrolysis was used as an adsorbent to absorb the furfural in the solution.The effects of contact time,initial concentrations of furfural and temperature on the absorptive characteristics of furfural were evaluated and an integrating equation of moving boundary model was used to describe the kinetics.The general kinetical equation was obtained.The results indicate that the dominant procedure is diffusion through particles.The higher the initial concentration of furfural,the strengthen particle diffusion control is.As the temperature increases,the particle diffusion control mechanism is weakened.The apparent reaction order of adsorption is 0.96 and the apparent activation energy is calculated to be 3.02 kJ·mol-1,which indicate that it belongs to physics adsorption.This study is confirmed that the behavior of adsorption and ion exchange process has a certain similarity and compatibility in the kinetic description.