西维因在活性炭及草木灰上的吸附及解吸特性

Adsorption and desorption characteristics of sevin on activated carbon and plant ash

在详细表征活性炭(AC)、草木灰(PA)和沉积物(S)表面性质及化学组成的基础上,研究他们对农药西维因的吸附等温线及吸附和解吸动力学特征.结果表明,化学组成类似,孔隙结构不同的碳吸附剂所遵循的吸附机理不同.介孔分布较多的AC吸附机理复杂,介孔分布较少的PA以线性分配作用为主,AC对西维因的吸附量远大于PA,表面积标化饱和吸附量显示,表面积是影响吸附量的关键因素.AC对西维因的解吸量远小于吸附量,与PA的解吸量相当,PA的解吸量与吸附量相近,且解吸动力学数据均能用准一级动力学方程拟合,说明以分配作用黏附于碳吸附剂上的西维因可能又以分配的形式解吸.沉积物(S)中掺混AC和PA后,对西维因的吸附量增加,解吸量降低,证明AC和PA均具有应用于污染沉积物治理的潜力,但复杂的沉积物体系使得吸附并非简单的叠加.

Surface characteristics and chemical compositions of activated carbon（AC）,plant ash（PA） and sediment（S） were measured.Sorption isotherms,sorption and desorption kinetics of sevin on these 3 sorbents were examined,respectively.Batch experiments showed that the sorption mechanisms of carbonaceous sorbents containing similar chemical compositions and dissimilar pore configurations were different.AC having more mesoporous than PA exhibited complex adsorption process to sevin while PA showed near partition process.The sorption quantity of sevin on AC was significantly higher than on PA.The surface area normalized saturated capacities demonstrated that surface area was crucial factors determining sorption quantities of carbonaceous sorbents.The desorption quantity of sevin on AC was significantly less than the sorption quantity on AC,corresponding to sevin desorption quantity on PA,which was closed to the sorption capacity on PA.Both desorption kinetic data of AC and PA were well fitted by pseudo one-stape dynamics equation.It was indicating that the sevin molecules distributing onto the sorbent surface possibly released by partition model.The sorption capacities of sevin on sediment increased,but the desorption capacities decreased,after adding AC and PA,implying that both AC and PA could be used as sorbent amendments of contaminated sediment.But the sorption in complex sediment environment was not simple superimpose.