乙二酸四乙酸二钠盐改性枸杞杆生物炭对亚甲基蓝吸附性能  

Methylene Blue Adsorption Properties of Modified Wolfberry Biochar with EDTA-2Na

作　　者：任艳娇 徐荣声 王萍 孙冬 耿万东 张海永[3] REN Yan-Jiao;XU Rong-Sheng;WANG Ping;SUN Dong;GENG Wan-Dong;ZHANG Hai-Yong(Xinhua College of Ningxia University,Yinchuan 750021,China;Chemistry and Chemical Engineering College,North Minzu University,Yinchuan 750021,China;Chemistry and Environmental Engineering College,China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]宁夏大学新华学院,银川750021 [2]北方民族大学化学与化工学院,银川750411 [3]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《应用化学》2024年第7期1035-1046,共12页Chinese Journal of Applied Chemistry

基　　金：2021年宁夏大学新华学院重点科研项目(No.21XHKY02);2023年宁夏回族自治区高等学校科学研究项目(No.NYG2024230);2024年宁夏大学新华学院科研项目(No.24XHKY13)资助。

摘　　要：以H_(3)PO_(4)为活化剂,通过高温炭化法将宁夏枸杞杆制备成生物质活性炭(CP),并利用乙二酸四乙酸二钠盐(EDTA-2Na)对其进行表面改性,得到氮掺杂活性炭(CPE)。利用比表面积分析(BET)、X射线衍射仪(XRD)、X射线光电子能谱分析仪(XPS)、傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜(SEM)技术手段研究其表面微观形貌和化学结构特性,阐明了EDTA-2Na的改性机理和CPE对亚甲基蓝的吸附机制。结果表明:EDTA-2Na的掺杂可以有效调控生物炭的孔结构和官能团,显著提升了生物炭的比表面积、孔结构和活性吸附位点。EDTA-2Na改性后的生物炭CPE(比表面积(816.47 m^(2)/g)、总孔体积(0.4925 cm^(3)/g)和平均孔径(2.41 nm))参数明显优于CP(比表面积(241.45 m^(2)/g)、总孔体积(0.1280 cm^(3)/g)和平均孔径(2.12 nm))的微观结构,表面形成较稳定的氨基(—NH—、—NH_(2)—)和吡咯结构氮,构成了对亚甲基蓝有较好吸附效果的活性表面生物质碳材料CPE。常温中性条件下,CPE对MB的最大吸附量为658.8 mg/g,较未进行N掺杂的生物碳CP(吸附量为358.2 mg/g)吸附率提升了83.92%。CPE对MB的等温吸附过程符合Langmuir模型(R^(2)=0.9896),吸附动力学符合准二级动力学模型(R2=0.99997),吸附过程主要以单分子层化学吸附为主,循环使用性能较好。Biomass activated carbon(CP)was prepared from Ningxia Wolfberry stalk by high temperature carbonization method with H_(3)PO_(4)as activator,and the surface modification was carried out by EDTA-2Na to obtain nitrogen-doped activated carbon(CPE).X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR)and scanning electronic microscopy(SEM)were used to study the surface morphology and chemical structure of EDTA-2Na,to elucidate the modification mechanism of EDTA-2Na and the adsorption mechanism of methylene blue on CPE.The results showed that doping EDTA-2Na can effectively regulate the pore structure and functional groups of biochar,and significantly improve the specific surface area,pore structure and active adsorption site of biochar.The parameters of CPE(specific surface area(816.47 m^(2)/g),total pore volume(0.4925 cm^(3)/g)and average pore size(2.41 nm)of biochar modified by EDTA-2Na were significantly better than those of CP(241.45 m^(2)/g)and total pore volume(0.1280 cm^(3)/g)and average pore size(2.12 nm),and stable amino(—NH—,—NH_(2)—)and pyrrole structure nitrogen were formed on the surface,which constituted the active surface biomass carbon material CPE with good adsorption effect on methylene blue.Under normal temperature and neutral conditions,the maximum adsorption capacity of CPE for MB was 658.8 mg/g,which increased the adsorption rate by 83.92%compared with that of biological carbon CP(adsorption capacity 358.2 mg/g)without N doping.The isothermal adsorption process of CPE for MB was consistent with Langmuir model(R^(2)=0.9896),and the adsorption kinetics was consistent with quasi-second-order kinetic model(R^(2)=0.99997).The adsorption process was mainly monolayer chemisorption.It has good recycling performance.

关 键 词：枸杞杆 H_(3)PO_(4)活化 乙二酸四乙酸二钠盐 亚甲基蓝吸附 

分 类 号：O643[理学—物理化学]