马铃薯秸秆生物炭对水中Pb^(2+)的吸附性能研究

Research on adsorption performance of potato straw biochar for Pb^(2+)in water

采用热解法制备马铃薯秸秆生物炭并对其酸改性.用扫描电镜表征了改性前后生物炭微观结构的改变,用傅立叶红外光谱仪分析Pb^(2+)吸附前后生物炭的官能团变化,通过动力学和热力学实验,探讨酸改性马铃薯生物炭对水中Pb^(2+)的吸附性能和机理。结果表明,酸改性后生物炭表面微孔增多,孔径变大,表面官能团增多,其对Pb^(2+)吸附过程更符合Langmuir模型和准二级动力学方程,同时pH显著影响了生物炭对Pb^(2+)的吸附,pH值为4.0时吸附性能最佳。酸改性后的生物炭主要通过表面离子交换、重金属离子与官能团化学交联和阳离子-π作用等化学吸附水中的Pb^(2+)。

The potato straw biochar was prepared by pyrolysis and modified its acidity.The changes in the microstructure of biochar before and after modification were characterized by scanning electron microscopy,and the changes in functional groups of biochar before and after Pb^(2+)adsorption were analyzed by Fourier infrared spectroscopy.The adsorption performance and mechanism of acid modified potato biochar for Pb^(2+)in water were discussed through dynamic and thermodynamic experiments.The results showed that the adsorption process of Pb^(2+)was more consistent with the Langmuir model and quasi-secondary kinetic equation after the acid-modified biochar had more micro-pores,larger pore size,and more functional groups on the surface,while pH significantly affected the adsorption of Pb^(2+)by biochar.The adsorption performance was best at pH 4.0.The acid-modified biochar was mainly used for the chemisorption of Pb^(2+)in water through surface ion exchange,chemical cross-linking of heavy metal ions with functional groups,and cation-πinteraction.