改性生物炭对Cr(Ⅵ)的吸附特性研究

Adsorption Characteristics and Mechanism of Modified Biochar to Cr(Ⅵ)

通过硝酸铁浸渍改性制备改性芦苇生物炭,研究改性生物炭(FeBC500)和原始生物炭(BC500,BC,biochar)对Cr(Ⅵ)的吸附性能,利用扫描电子显微镜(SEM)、比表面积及孔径分析仪(BET)、傅里叶转换红外光谱(FT-IR)、X射线光电子能谱仪(XPS)和Zeta电位等测试技术对材料进行表征并进一步探究吸附机理.结果表明,酸性条件下改性前后生物炭对Cr的吸附效果更优;与BC500相比,FeBC500提高了Cr(Ⅵ)还原为Cr(Ⅲ)的能力,改性后Cr(Ⅵ)的去除率由68.68%提高至94.52%,主要原因是Fe^(3+)作为电子穿梭体增强了生物炭和Cr(Ⅵ)之间的电子传递作用.改性前后生物炭对Cr(Ⅵ)的吸附过程符合Freundlich方程和准二级动力学方程,表面吸附过程主要为化学多层吸附.

Modified reed biochar was prepared by impregnation modification with ferric nitrate,and the adsorption performance of modified biochar(FeBC500)and original biochar(BC500)on Cr(Ⅵ) was studied,using scanning electron microscope(SEM),specific surface area and pore size analysis Test techniques such as BET,Fourier Transform Infrared Spectroscopy(FT-IR)and Zeta potential characterize the material and further explore the adsorption mechanism.The results show that the adsorption effect of biochar on Cr(Ⅵ) before and after modification is better under acidic conditions;FeBC500 improves the ability of Cr(Ⅵ) to be reduced to Cr(Ⅲ) compared with BC500,and the modified Cr(Ⅵ) The removal rate increased from 68.68%to 94.52%,mainly because Fe^(3+)acts as an electron shuttle to enhance the electron transfer between biochar and Cr(Ⅵ).The adsorption process of biochar on Cr(Ⅵ) before and after modification accords with Freundlich equation and quasi-second-order kinetic equation.The surface adsorption process is mainly chemical multilayer adsorption.