米糠和麦麸生物炭对水中四环素吸附特性研究

Study on Adsorption Characteristics and Influencing Factors of Rice Bran and Wheat Bran Biochar on Tetracycline in Water

为探索高效利用生物质资源制备生物炭去除水体中的抗生素,以常见的米糠和麦麸为原料,在600℃限氧裂解制备成生物炭。通过各种影响因素的单因素实验和常用的表征方法,探讨其吸附四环素的效果和机理。结果显示2种生物炭均有分层分布的微孔结构和较大的比表面积,并含有羟基、酯、醚和芳香官能团。2种生物炭的吸附最优条件为:生物炭剂量均为4 g/L,四环素初始质量浓度为5 mg/L,溶液pH在5~9之间,环境温度25℃,吸附时间32 h,此时2种生物炭对四环素的去除率分别达到95.07%和90.4%。2种生物炭的等温吸附更符合Langmuir等温吸附方程,它们的吸附动力学更符合伪二阶动力学模型。吸附过程主要受控于化学吸附,是吸热反应。

In order to explore the efficient use of biomass resources in antibiotics removal from water, the rice bran and wheat bran were used as raw materials to prepare biochar at 600℃. The effects and mechanisms of tetracycline adsorption were investigated by single factor experiments and common characterization methods. The results show that two kinds of biochar both have a layered structure with abundant micropores, as well as a large specific surface area. And they both contain functional groups like hydroxyl, ester, ether and aromatic. The optimum conditions for the adsorption of two kinds of biochar are biochar dose 4 g/L, tetracycline initial concentration 5 mg/L, solution pH between 5 and 9, temperature 25 ℃ and adsorption time 32 h. The removal rates of tetracycline by two biochar are 95.07% and 90.4%, respectively. The isothermal adsorption of two biochars are more in line with the Langmuir isotherm adsorption equation. The adsorption kinetics could be fitted with pseudo second-order kinetic model well. The adsorption process is mainly owed to hydrogen bond and controlled by chemical adsorption. Moreover the adsorption is an endothermic reaction.