苜蓿生物炭对磺胺甲恶唑的吸附机理研究

Mechanism of adsorption of sulfamethoxazole by alfalfa biochar at different pyrolysis temperatures

该文以紫花苜蓿为原料,分别在600℃、700℃和800℃下热解制备生物炭,研究其对水溶液中磺胺甲恶唑的吸附机理。通过元素分析、FTIR、BET、XRD等方法对制备的生物炭进行表征,探究了热解温度、环境温度、初始抗生素浓度、溶液pH值、离子强度以及离子类型等对磺胺甲恶唑吸附的的影响,应用吸附动力学和吸附等温线研究生物炭对磺胺甲恶唑的吸附行为。结果表明,生物炭对磺胺甲恶唑的吸附性能随着热解温度的升高而升高,BC800具有最优异的吸附性能,环境温度、初始抗生素浓度、溶液pH值、离子强度以及离子类型等对磺胺甲恶唑的吸附具有显著影响。吸附过程遵循拟二级动力学方程,等温吸附实验符合Langmuir方程,主要吸附过程为自发吸热的化学吸附,最大吸附量可达到47.88 mg·g^(-1)。根据该文研究,苜蓿在800℃下产生的生物炭是一种吸附容量好、性能较优的环境友好型吸附剂,对去除废水中的磺胺甲恶唑抗生素具有潜在价值。

In this study,alfalfa was chosen as raw materials to prepare biochars(BC600,BC700 and BC800)at 600℃,700℃and 800℃.For the removal of sulfamethoxazole from aqueous solution.The biochar was characterized by scanning electron microscopy(SEM),elemental ananlysis,Fourier transform infrared(FTIR)spectroscopy and X-ray diffraction(XRD).The influence of different factors such as pyrolytic temperature,pH value,ionic strength and types,initial concentration and reaction temperature on the removal of sulfamethoxazole from solutions by biochars were investigated.Moreover,the adsorptive behavior of sulfamethoxazole by biochar was investigated using adsorption kinetics and isotherms.The result showed that the adsorption capacity of biochars for sulfamethoxazole was elevated with increase in the pyrolytic temperature.The biochar prepared at 800℃had the best adsorption properities.Biochar dosages,solution pH,ionic strength,and adsorption time had significant effects on the adsorption of sulfamethoxazole by biochars.The adsorption kinetics and isotherms of sulfamethoxazole onto biochars were all fitted to pseudo-second order models and to a Freundlich equation.The adsorption process was mainly controlled by chemical reaction,and the adsorption process was spontaneous and endothermic.These resluts demonstrated promise of alfalfa pyrolysised at 800℃as an effective and environmentally friendly sorbent for removing sulfamethoxazole from wastewater with high adsorption capacity and cost effectiveness.