摘要
为探索利用食品加工废弃物柚子皮制备一种重金属离子吸附材料的可行性,通过NaOH将柚子皮中甲酯化的羧基水解成羧酸,再利用TEMPO/次氯酸钠/溴化钠体系将柚子皮中C-6位伯羟基氧化成羧酸,制备出一种羧基化柚子皮吸附材料,同时采用FTIR、SEM-EDS和XPS对柚子皮和吸附Cd^(2+)前后的羧基化柚子皮进行表征,研究其吸附机制。结果表明羧基化柚子皮中羧基含量为2.34 mmol/g,是改性前的10.64倍,且可以有效地去除水溶液中Cd^(2+)。羧基化柚子皮吸附Cd^(2+)更符合Langmuir和伪二阶动力学模型,属于单层化学吸附,对Cd^(2+)的最大吸附量为76.16 mg/g,是改性前的5.81倍。羧基化柚子皮中羧基(-COO^(-))是吸附Cd^(2+)的功能性基团,吸附后形成羧酸镉,其中镉以Cd^(2+)的形式存在,与-COO^(-)的配位方式主要是双齿桥式,该吸附过程是一个阳离子(Na^(+)和Cd^(2+))交换的过程。
In order to explore the feasibility of preparing a heavy metal ions adsorption material with food processing waste pomelo peel as raw material,the methyl carboxyl groups in pomelo peel were hydrolyzed into carboxylic acids by NaOH.The C-6 primary hydroxyl groups in pomelo peel were oxidized to carboxylic acids by TEMPO/sodium hypochlorite/sodium bromide system.A carboxylated pomelo peel adsorbent was prepared.FTIR,SEM-EDS and XPS were used to characterize the pomelo peel and the carboxylated pomelo peel before and after adsorption of Cd^(2+)for elucidating the mechanism of its influence.The results show that the carboxyl content in the carboxylated pomelo peel is 2.34 mmol/g,which is 10.64 times greater compared with that before modification.The carboxylated pomelo peel can effectively remove Cd^(2+)from aqueous solution.The adsorption of Cd^(2+)using the carboxylated pomelo peel is more in line with Langmuir model and pseudo-second-order model,belong to single-layer and chemical adsorption.The maximum adsorption capacity of the carboxylated pomelo peel for Cd^(2+)is 76.16 mg/g and 5.81 times that before modification.It could be proved that the carboxyl groups(-COO^(-))contained in the carboxylated pomelo peel are functional groups,which adsorb Cd^(2+)in the solution and form carboxylic acid cadmium.They(-COO^(-))are acting as a bidentate chelate coordinate to Cd^(2+).The process of adsorption of Cd^(2+)using the carboxylated pomelo peel is an exchange process of cations(Na^(+)and Cd^(2+)).
作者
陈尚龙
刘恩岐
赵节昌
陈安徽
刘辉
苗敬芝
CHEN Shanglong;LIU Enqi;ZHAO Jiechang;CHEN Anhui;LIU Hui;MIAO Jingzhi(College of Food and Biological Engineering,Xuzhou University of Technology,Xuzhou 221018,Jiangsu,China;Jiangsu Key Laboratory of Food Resources Development and Quality Safe,Xuzhou University of Technology,Xuzhou 221018,Jiangsu,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2024年第20期283-289,共7页
Materials Reports
基金
江苏省产学研合作项目(BY20221265)。
关键词
羧基
柚子皮
Cd^(2+)
吸附性能
吸附机制
carboxyl group
pomelo peel
Cd^(2+)
adsorption property
adsorption mechanism
