摘要
煤质腐植酸是低阶煤中的一种天然芳香族聚合物,具有高碳含量、松散的海绵质地、资源丰富、成本低廉等特性,是制备活性炭的新型碳前驱体。本工作以褐煤提取的腐植酸为前驱体,采用化学活化法制得腐植酸基活性炭,研究其对亚甲基蓝的吸附性能。利用扫描电子显微镜、BET比表面仪、傅里叶红外光谱仪对活性炭的物理化学性质进行表征。考察了溶液pH、吸附剂用量、初始浓度、温度和离子强度对活性炭吸附性能的影响。结果表明,腐植酸基活性炭具有大的比表面积(2370.21 m^(2)/g)、丰富的孔结构以及含氧官能团,有利于亚甲基蓝的吸附。Langmuir模型能够准确地描述活性炭对亚甲基蓝的吸附行为,根据Langmuir等温模型拟合,298 K时活性炭对亚甲基蓝的最大吸附量为970.87 mg/g。对比不同前驱体制备的活性炭亚甲基蓝的吸附性能,由腐植酸制备的活性炭对亚甲基蓝表现出明显良好的吸附性能。伪二级动力学模型更能描述亚甲基蓝在活性炭上的吸附。活性炭对亚甲基蓝的吸附是自发的吸热过程。经过五次循环使用,吸附量有所减小,但去除率均达到了93%以上,活性炭循环使用性能良好。
Coal humic acid is a natural aromatic polymer in low-rank coal and has the characteristics of high carbon content,loose sponge texture,abundant reserves and low cost,etc.,which makes it a new carbon precursor for the preparation of activated carbon.In this paper,humic acid-based activated carbon was prepared by chemical activation method using humic acid extracted from lignite as precursor,and its adsorption performance on methylene blue was studied.The physical and chemical properties of the activated carbon were characterized by scanning electron microscopy,BETsurface spectrometer and Fourier transform infrared spectrometer.The effects of solution pH,adsorbent dosage,initial concentration,temperature and ionic strength on the adsorption performance of activated carbon were investigated.The results show that the humic acid-based activated carbon had a large specific surface area(2370.21 m^(2)/g),rich pore structure and oxygen-containing functional groups,which were beneficial to the adsorption of methylene blue.The Langmuir model was more suitable to describe the adsorption behavior of activated carbon on methylene blue.According to the Langmuir isotherm model fitting,the maximum adsorption capacity of activated carbon on methylene blue at 298 K was 970.87 mg/g.Compared with the adsorption properties of activated carbon methylene blue prepared from different precursors,the activated carbon prepared from humic acid showed obviously good adsorption properties for methylene blue.The pseudo-second-order kinetic model could better describe the adsorption of methylene blue on activated carbon.The adsorption of methylene blue by activated carbon was a spontaneous and endothermic process.After 5 cycles of recycling,the adsorption capacity of activated carbon on methylene blue has decreased,but the removal rate of activated carbon in the recycling reached more than 93%,indicating that the recycling performance of activated carbon was good.
作者
侯金瑛
董宪姝
马晓敏
樊玉萍
姚素玲
HOU Jinying;DONG Xianshu;MA Xiaomin;FAN Yuping;YAO Suling(College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《材料导报》
CSCD
北大核心
2023年第22期73-79,共7页
Materials Reports
基金
国家自然科学基金国际(地区)合作与交流项目(51820105006)
山西省自然科学基金面上基金项目(201901D111075)
山西省留学回国人员科技活动择优资助项目。
关键词
褐煤
腐植酸基活性炭
吸附
亚甲基蓝
lignite
humic acidbased activated carbon
adsorption
methylene blue
