镁掺杂煤基活性炭对亚磷酸的吸附性能研究

Adsorption performance of magnesium-doped coal-based activated carbon for phosphorous acid

为回收草甘膦母液中的亚磷酸,以禾草沟煤为原料,通过KOH活化、热解和金属镁掺杂相结合的方法,制得了镁掺杂的煤基活性炭(Mg-AC)。采用SEM、XRD、TEM、BET、FT-IR以及XPS等对样品的表观形貌、晶体结构、表面官能团和孔结构等理化性质进行分析;考察Mg-AC对亚磷酸的吸附性能,并结合常见的吸附动力学和吸附等温线模型对吸附过程和吸附机理进行探讨。结果表明,Mg-AC的比表面积和孔容分别为896.4 m^(2)/g和0.505 cm^(3)/g,具备良好的孔隙结构。Mg-AC对亚磷酸的吸附能力较AC明显提升,吸附平衡时饱和吸附容量为15.3 mg/g,且具有较宽的pH应用范围(pH为3~10)。Mg-AC对亚磷酸的吸附过程更符合准二级动力学模型(R2=0.991)和Langmuir吸附模型(R2=0.970),表明吸附过程以化学吸附和单分子层吸附为主导。

To recover and remove the large amount of phosphorous acid produced in the glyphosate production industry,a magnesium-doped coal-based activated carbon(Mg-AC)by KOH activation was synthesized with pyrolysis and Mg-doped used Hecaogou coal as raw material.The surface structure,pore structure,composition,and zeta potential of the obtained materials were characterized by SEM,XRD,TEM,BET,FT-IR and XPS,etc.The results showed that the specific surface area and pore volume of Mg-AC were 896.4 m^(2)/g and 0.505 cm^(3)/g,with great pore structure.The adsorption performance of Mg-AC was investigated by adsorption of simulated phosphorous solution.The results indicated that the adsorption capacity of Mg-AC on phosphorous was significantly higher than that of AC and the saturation adsorption capacity was 15.3 mg/g at adsorption equilibrium with a wide pH application range(3~10).Furthermore,the adsorption process of Mg-AC on phosphorous was more consistent with the pseudo-second-order model and the Langmuir model,which indicated that the adsorption process was dominated by chemisorption and monomolecular layer adsorption.