硝酸改性油菜生物炭对四环素的吸附性能研究

Adsorption Performance of Tetracycline on Nitric Acid-modified Rape Biochar

以油菜秸秆为原料制备生物炭并用硝酸进行改性,结合比表面积分析仪、傅立叶红外光谱仪,评价了硝酸改性生物炭理化性质并探究了对四环素的吸附性能。结果表明,生物炭裂解温度越高,比表面积、孔容积越大,生物炭表面羧基、羰基、内酯基逐渐减少;吸附动力学研究表明3种改性生物炭对四环素的吸附容量为34.08～46.61 mg/g,吸附符合准二级动力学受多因素共同影响;采用Freundlich和Langmuir方程对吸附等温模型进行拟合,结果表明Langmuir吸附等温模型能更好拟合吸附过程,该吸附是以单分子层吸附为主;生物炭对四环素的吸附容量随着pH值变化先增大后减小,随着离子浓度的增加而降低。

The biochars prepared from rape straw were modified by nitric acid,then their physicochemical properties were evaluated.Thereafter,the adsorption properties of tetracycline on biochars were investigated.The results showed that with the increase of pyrolysis temperature,the specific surface area and pore volume of biochar get larger,while the carboxyl,carbonyl and lactonyl on the surface of biochar decreased.The adsorption kinetics showed that the adsorption capacity of tetracycline on biochar ranged from 34.08 to 46.61 mg/g,which was in line with the quasi-second-order adsorption kinetics.Both Freundlich and Langmuir equation were used to fit the adsorption isotherm model,the results showed that the Langmuir isotherm model fitted the adsorption process better.With the increase of pH value,the adsorption capacity of biochar for tetracycline first increased and then decreased.Besides,the adsorption capacity decreased with the increase of ion concentration.