基于正交设计葡萄废弃物基生物活化炭的制备及其吸附性能

Preparation of grape peel based biochar by orthogonal design and its adsorption performance

以葡萄皮为原材料,用限氧热解法制备生物炭。通过设计3因素3水平的正交实验,选择出最佳的活化条件进行活化,得到活化生物炭用于吸附实验。考察反应物初始浓度、反应温度和接触时间对吸附的影响规律,并进行分析。由动力学拟合结果,可以得出葡萄皮基生物炭对甲基橙的吸附过程用准二级动力学方程较好拟合,说明生物炭对甲基橙的吸附不是单一的单层吸附过程。颗粒内扩散方程表明颗粒内扩散不是唯一的限速因素,吸附过程由液膜扩散和颗粒内扩散两个过程控制。双室模型表明快吸附反应在吸附过程中起主导作用。用Temkin-Pyzhev模型对等温线进行拟合,表明活化炭对于甲基橙的吸附更倾向于不规则的表面吸附,吸附热力学数据证明吸附反应易发生。

The biochar was prepared by the limited oxygen pyrolysis method using agricultural waste grape peel as raw materials.The best activation conditions were selected for activated biochar through the orthogonal test table of three factors and three levels,and the activated biochar was obtained for adsorption experiment.The effects of initial concentration of reactants,reaction temperature and contact time on adsorption were investigated and analyzed through batch experiments.According to the kinetic fitting results,it could be concluded that the adsorption process of grape peel-based biochar on methyl orange could be well described by the quasi-second-order kinetic equation.It indicated that the adsorption process of activated biochar on methyl orange was not a single monolayer adsorption process.The intraparticle diffusion equation showed that intraparticle diffusion was not the only limiting factor,and the adsorption process was controlled by two processes:liquid film diffusion and intraparticle diffusion.The two-chamber model showed that the fast adsorption reaction played a leading role in the whole adsorption process.The adsorption of methyl orange by activated biochar was well fitted by Temkin-Pyzhev model,which showed that the adsorption of methyl orange by activated carbon was more prone to irregular surface adsorption.The adsorption thermodynamic data proved that adsorption reaction was easy to occur.