中药渣生物炭对磺胺甲基嘧啶的吸附及机理研究

以传统中药-黄芪废渣为原料，分别在200℃、400℃、500℃、600℃和700℃的厌氧氛围下热解制备生物炭材料（BC200、BC400、BC500、BC600和BC700），并利用BET比表面积分析、FTIR光谱分析、扫描电子显微镜等方法对其进行表征，同时考察不同投加量、吸附时间、初始浓度和pH值下生物炭对磺胺甲基嘧啶的吸附特征.结果表明，随制备温度的升高，生物炭的表面积及吸附性能也显著增加.相比原状黄芪渣（S_BET=0.42m²/g），BC700的BET比表面积（S_BET=155.69m²/g）增大370倍，对磺胺甲基嘧啶的吸附容量增加185倍.BC700对磺胺甲基嘧啶的等温吸附过程符合Langmuir模型（R²=0.9977），最大吸附容量为11.96mg/g，吸附反应过程满足准二级动力学方程（R²>0.994），且为化学吸附.同时随着溶液初始pH值和投加量的升高，生物炭的吸附容量先增大后减小，最佳吸附pH值为4.

Adsorption of sulfamerazine from water by biochar derived from astragalus membranaceus residue

Herb biochar was derived from Astragalus membranaceus residue at five different temperatures: 200℃, 400℃, 500℃, 600℃, and 700℃. The biochars were characterized by SEM, FTIR, and BET techniques. The effects of contact time, initial concentration, dosage, and pH of solution on the adsorption behaviors of the biochars were evaluated, and were preliminarily used to assess the adsorption mechanism of sulfamerazine by biochar. The results showed that surface area, pore volume, and sorption capacity of the biochars increased as the pyrolysis temperature increased. The S_BET values for the natural residue and BC700 were 0.42m²/g and 155.69m²/g, respectively. The S_BET and adsorption capacity were increased about 370-fold and 181-fold. The adsorption kinetics were found to be best represented by the pseudo-second-order kinetic model (R²>0.994). The isotherm sorption behavior is best described by the Langmuir model (R²=0.9977), and the maximum adsorption capacity was observed to be 11.96mg/g. Sulfamerazine adsorption by biochar first increased and then decreased with increasing dosage and pH; the optimum solution pH was 4.