玉米秸秆皮生物炭制备及其对亚甲基蓝吸附性能研究

Preparation of Corn Stalk Rind Biochar and Its Adsorption Performance for Methylene Blue

以玉米秸秆皮为原料,在自制固定床反应器中快速热解制备生物炭。利用现代测试技术对生物炭进行表征,探究炭化温度(500、550、600、650、700℃)及炭化时间(10、20、30 min)对生物炭产率与物理性质(孔隙结构、官能团和表观形貌)的影响,并通过批量试验探讨生物炭对亚甲基蓝的吸附特性。结果表明,随着炭化温度的升高和炭化时间的延长,生物炭产率下降。当炭化温度为600℃、炭化时间为30 min时,秸秆皮生物炭比表面积和孔容均最大,分别为146.89 m^(2)/g和0.098 m3/g。生物炭对亚甲基蓝的吸附容量和吸附率均随着炭化温度的升高呈先增大后减小趋势,当炭化温度为600℃、炭化时间为30 min时,生物炭对亚甲基蓝吸附容量与吸附率均达到最大,分别为32.57 mg/g和61.07%。生物炭对亚甲基蓝的吸附在180 min内到平衡,准二级动力学模型能更好地描述亚甲基蓝的动力学吸附行为,根据拟合结果,最大吸附量可达37.888 mg/g。这表明直接热解玉米秸秆皮获得的生物炭用于处理印染废水具有很大的潜力。

Using corn stalk rinds as raw materials,biochar was prepared by rapidly pyrolyzing corn stalk rinds in a self-made fixed bed reactor.Using modern testing techniques to characterize biochar,this paper investigated the effects of carbonization temperature(500,550,600,650,700℃)and carbonization time(10,20,30 minutes)on biochar yield and physical properties(pore structure,functional groups and apparent morphology),and the adsorption characteristics of biochar for methylene blue through batch experiments were explored.The results showed that with the increase of carbonization temperature and the extension of carbonization time,the biochar yield decreased.When the carbonization temperature was 600℃and the carbonization time was 30 minutes,the specific surface area and pore volume of corn stalk rind biochar were both the highest,which were 146.89 m2/g and 0.098 m3/g,respectively.The adsorption capacity and adsorption rate of biochar for methylene blue both showed a trend of first increasing and then decreasing with the increase of carbonization temperature.When the carbonization temperature was 600℃and the carbonization time was 30 minutes,the adsorption capacity and adsorption rate of biochar for methylene blue reach their maximum,which were 32.57 mg/g and 61.07%,respectively.The adsorption of biochar for methylene blue reached equilibrium within 180 minutes,and the quasi-secondary kinetic model could better describe the adsorption behavior of methylene blue.According to the fitting results,the maximum adsorption capacity could reach 37.888 mg/g.This indicated that biochar obtained by directly pyrolyzing corn stalk rinds had great potential for treating printing and dyeing wastewater.