El Bakouri Hicham, Usero José, Morillo José, Ouassini Abdelhamid
Department of Chemical and Environmental Engineering, University of Seville, 41092 Seville, Spain.
Bioresour Technol. 2009 Sep;100(18):4147-55. doi: 10.1016/j.biortech.2009.04.003. Epub 2009 May 5.
The adsorption behavior of drin pesticides from aqueous solution onto acid treated olive stones (ATOS) was investigated using stir bar sorptive extraction and gas chromatography coupled with mass spectroscopy. The effects of sorbent particle size, adsorbent dose, contact time, concentration of pesticide solution and temperature on the adsorption processes were systematically studied in batch shaking sorption experiments. Maximum removal efficiency (94.8%) was reached for aldrin (0.5 mg L(-1)) using the fraction 63-100 microm of ATOS (solid/liquid ratio: 1 g L(-1)). Experimental data were modeled by Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The Freundlich isotherm model (R(2)=0.98-0.99) fitted the equilibrium data better than the Langmuir and D-R isotherm models, with low sum of error values (SE=1.4-9.2%). The mean adsorption free energy derived from the D-R isotherm model (R(2)=0.95-0.99) showed that the adsorption of drin pesticides was taken place by weak physical forces, such as van der Waals forces and hydrogen bonding. The calculated thermodynamic parameters, DeltaH, DeltaS and DeltaG prove that drin pesticides adsorption on ATOS was feasible, spontaneous and exothermic under examined conditions. The pseudo first order, pseudo second order kinetic and the intra-particle diffusion models were used to describe the kinetic data and rate constants were evaluated.
采用搅拌棒吸附萃取和气相色谱-质谱联用技术，研究了水溶液中狄氏剂类农药在酸处理橄榄石（ATOS）上的吸附行为。在批量振荡吸附实验中，系统研究了吸附剂粒径、吸附剂用量、接触时间、农药溶液浓度和温度对吸附过程的影响。使用63-100微米粒径的ATOS（固液比：1 g L(-1)），对艾氏剂（0.5 mg L(-1)）的去除效率最高可达94.8%。实验数据采用朗缪尔、弗伦德里希和杜宾宁-拉杜舍维奇（D-R）等温线模型进行拟合。弗伦德里希等温线模型（R(2)=0.98-0.99）比朗缪尔和D-R等温线模型更能拟合平衡数据，误差值总和较低（SE=1.4-9.2%）。由D-R等温线模型（R(2)=0.95-0.99）得出的平均吸附自由能表明，狄氏剂类农药的吸附是通过范德华力和氢键等弱物理力发生的。计算得到的热力学参数ΔH、ΔS和ΔG证明，在研究条件下，狄氏剂类农药在ATOS上的吸附是可行的、自发的且放热的。采用伪一级、伪二级动力学和颗粒内扩散模型来描述动力学数据，并评估了速率常数。
