芦苇生物炭对亚甲基蓝的吸附特性研究

The Adsorption Research of Biochars Prepared from Common Reed on Methylene Blue

本文选取湿地植物芦苇作为原材料,在不同热解温度下（300~600℃）,利用限氧升温炭化法制备成生物炭,通过元素分析、比表面积测定、红外光谱分析、X射线衍射分析、Zeta电位等方法研究其物理化学特征以及对亚甲基蓝的吸附特性。研究发现,当固液比为6g·L-1时,芦苇生物炭吸附亚甲基蓝的平衡时间为24h,其中,500℃下热解制备的生物炭吸附能力最强,其最大吸附量达到了5.030mg·g-1;当溶液的初始pH升高时,芦苇生物炭对亚甲基蓝的平衡吸附量随之增加并最终趋向稳定,其最佳pH为8~9;当背景溶液中的离子强度增加时,芦苇生物炭对亚甲基蓝的平衡吸附量略有减少,降幅范围为5%~22%;Langmuir等温线模型对吸附数据具有很好的拟合水平（R2〉0.99）,说明芦苇生物炭对亚甲基蓝的吸附为单分子层吸附。

In order to study the adsorption properties of biochars on methylene blue（MB）,common reed is selected from wetland plants to be pyrolyzed into biochars under different temperatures（300~600 ℃）.Physical and chemicalpropertieswere characterized by elemental analysis,specific surface area,Fourier transform infrared spectrum,X-ray diffraction and Zeta potential analysis.And adsorption properties on MBwere detected continuously.In this study,the equilibrium time of MB adsorption was 24 hfor the biochars（the ratio of solid of biochars to absorb MB is 6g·L-1）,while the adsorption capacity of 500℃common reed biochar is the strongest which reached the largest equilibrium adsorption capacity of 5.030mg·g-1.The adsorption capacity of biochars on the removal of MB increased with the initial pH value and it was tending towards balance,while the best initial pH value of solution is 8~9.Besides,the equilibrium adsorption capacity was slightly declining with the increase of ionic strength with the decline range of 5%~22%.The Langmuir isotherm can fit theequilibrium data well（R2〉0.99）,and it describes the absorption of biochars on MB belongs to the monolayer adsorption.