木质素生物炭磺酸对水中阳离子染料的吸附性能与机制  

Adsorption effects and mechanisms of cationic dyes in aqueous solution by sulfuric lignin-biochar

作　　者：苗耀文 陈晓填 麦冠辉 余林[1] 麦裕良 陈佳志 MIAO Yao-wen;CHEN Xiao-tian;MAI Guan-hui;YU Lin;MAI Yu-liang;CHEN Jia-zhi(School of Chemical Engineering and Light Industry,Guangdong University of Technology,Guangzhou 510006,China;Guangdong Provincial Key Laboratory of Industrial Surfactant,Institute of Chemical Engineering,Guangdong Academy of Sciences,Guangzhou 510665,China)

机构地区：[1]广东工业大学轻工化工学院,广东广州510006 [2]广东省工业表面活性剂重点实验室广东省科学院化工研究所,广东广州510665

出　　处：《应用化工》2021年第12期3280-3285,3292,共7页Applied Chemical Industry

基　　金：国家自然科学基金项目(21703042);广东省科学院建设国内一流研究机构行动专项(2019GDASYL-0301002,2019GDASYL-0104023);广东省科技计划项目(2017A070701018);广东省科技计划项目(2017B030314137)。

摘　　要：以木质素磺酸钠(LS)为原料,采用浓硫酸一步氧化碳化的方法在60℃和210℃下分别制备了木质素生物炭磺酸SLBC-60和SLBC-210。SLBC-60磺酸基、羧基和酚羟基含量分别为1.66,1.40,4.41 mmol/g,而SLBC-210磺酸基、羧基和酚羟基含量分别为0.34,3.22,5.41 mmol/g。对比评价了它们对亚甲基蓝(MB)的吸附效果,结果显示,在pH=1~10溶液中,SLBC-60对MB保持高吸附量(>463.9 mg/g)和高去除率(>91.9%),而SLBC-210对MB吸附量<231.5 mg/g、去除率<45.8%,结合生物炭结构和Zeta电位分析,这可能与SLBC-60富含磺酸基官能团及其在pH=1~10溶液中表面均富集负电荷有关;优化pH、吸附剂加入量、吸附时间等参数,得到SLBC-60对MB、罗丹明B和孔雀石绿饱和吸附量分别为755.1,926.1,1008.2 mg/g,且吸附性能不受一价金属离子影响。此外,SLBC-60对MB的吸附等温线符合Langmuir模型(R^(2)=0.9989),吸附动力学符合准二级动力学方程(R^(2)=0.9995),说明该吸附以单层化学吸附为主。因此,改性制备的木质素生物炭磺酸可作为高效的阳离子染料吸附剂,有望应用于印染废水治理。Functional lignin-biochars with rich sulfonic and carboxyl groups were produced via a facile simultaneous oxidization-carbonization of lignosulfonate by using 96%sulfuric acid at 60℃and 210℃,signed as SLBC-60 and SLBC-210.SLBC-60 contained 1.66 mmol/g of sulfonic groups,1.40 mmol/g of carboxyl groups and 4.41 mmol/g of phenolic hydroxyl groups,while SLBC-210 contained 0.34 mmol/g of sulfonic groups,3.22 mmol/g of carboxyl groups and 5.41 mmol/g of phenolic hydroxyl groups.Their adsorption capabilities of methylene blue(MB)were separately estimated in the aqueous solution at pH from 1 to 10.The results showed that SLBC-60 had higher adsorption capability for MB(adsorption capacity>463.9 mg/g,removal efficiency>91.9%)than that of SLBC-210(adsorption capacity<231.5 mg/g,removal efficiency<45.8%).Combined with their structures and Zeta potentials,the high adsorption capacity of SLBC-60 may be related to its rich sulfonic acid groups and the enrichment of negative charges on the surface in the solution of pH 1~10.The saturated adsorption capacity of SLBC-60 for MB,rhodamine B and malachite green are respectively 755.1,926.1,1008.2 mg/g after optimizing the conditions of pH,adsorbent addition,adsorption time.The adsorption capacity is not affected by mono-valent metal ions.In addition,the study of the adsorption mechanism of MB on SLBC-60 showed that the adsorption isotherm fitted the Langmuir model(R^(2)=0.9989)and the adsorption kinetic fitted the pseudo-second order kinetic equation(R^(2)=0.9995),indicating that the adsorption was dominated by mono-layer chemical adsorption.Therefore,these sulfonic functional lignin-biochars can be used as efficient adsorbents for cationic dyes and are expected for the treatment of dyeing wastewater.

关 键 词：木质素 生物炭 阳离子染料 吸附 含氧官能团 

分 类 号：TQ424[化学工程] X703[环境科学与工程—环境工程]