油茶饼粕活性炭的制备及其对苯酚的吸附动力学研究

Preparation of Activated Carbon with Camellia oleifera Seed-Cake and Its Adsorption Dynamics of Phenol

试验以油茶饼粕为材料,采用磷酸活化法制备活性炭,以苯酚的吸附量来评价其吸附性能,初步考察了活化剂体积分数、活化温度、活化时间和碳化温度对活性炭制备的影响,通过L9(34)正交实验进一步优化油茶饼粕活性炭磷酸活化法制备工艺;并较为深入地探讨了吸附温度和苯酚初始浓度对油茶饼粕活性炭吸附苯酚的动力学差异,采用Langmuir吸附模型对活性炭吸附苯酚溶液的动力学进行了拟合.研究结果表明:活化剂体积分数、活化温度、活化时间和碳化温度等4个单因素对磷酸活化法制备油茶饼粕活性碳均达到了极显著水平;因此,以油茶饼粕为生物原料,在碳化温度300℃下,采用磷酸活化法制备活性炭的最佳工艺为:活化剂体积分数为40%,活化时间为90min,活化温度为600℃;在活性炭对苯酚吸附过程中,随着吸附温度的升高及苯酚初始质量浓度的增加,对苯酚的吸附速率呈下降趋势,并在100min后趋于平衡;且Langmuir吸附模型的准一级动力学速率方程能较好地描述油茶饼粕活性炭对苯酚的吸附过程.

Camellia oleifera seed-cake was used as the raw material to prepare activated carbon with the method of phosphoric acid activation,and the adsorption properties of the product was assessed with phenol adsorption as the standard.A preliminary investigation was made of the effects of activation agent concentration,activation temperature,activation time and carbonization temperature on activated carbon preparation,and an orthogonal test of L9（34）was made to optimize the technology of activated carbon preparation.Langmuir adsorption models were fitted to explore the influences of adsorption temperature and initial phenol concentration on the performance of the Camellia cake-based activated carbon adsorption of phenol.The 4factors of phosphoric acid content,activation temperature,activation time and carbonization temperature were shown to have significant influences on the preparation of Camellia cake-based activated carbon with phosphoric acid activation.The optimum combination of parameters of activated carbon preparation was A1B2C2,that is,activator concentration 40%,activation temperature 600 ℃ and activation time 90min,with the defatted or soap Camellia oleifera seed-cake as the biological raw material and with the phosphoric acid activation method under a carbonization temperature of 300℃.The adsorption rate of the Camellia cake-based activated carbon adsorption on phenol declined with increasing temperature and initial mass concentration of phenol and reached an equilibrium after 100minutes.The process of adsorption of phenol by the Camellia cake-based activated carbon could be well described with the quasi-first-order kinetics rate equation of the Langmuir adsorption model.