期刊
JOURNAL OF HAZARDOUS MATERIALS
卷 402, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.jhazmat.2020.124084
关键词
Cellulose; Cadmium; Sulfamethoxazole; Complexation-decomplexation-complexation; Co-adsorption
资金
- Key-Area Research and Development Program of Guangdong Province [2019B110207001]
- Guangzhou Municipal Science and Technology Project [201803030001]
- Natural Science Foundation of Guangdong Province [2018A030313363]
- National Natural Science Foundation of China [51508206]
- Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety [2019B030301008]
The study showed that the presence of Cd(II) decreased the adsorption of SMZ due to hydrophilic site competition, while SMZ increased the adsorption of Cd(II) through bridging and electrostatic shielding effects. This inhibitory and synergistic effects were more pronounced in the binary system at a pH of 7.5, indicating a dynamic balance between them depending on the system, pH value, and concentration ratio. DFT results suggested that SMZ coordinated more easily with Cd(II) at sulfonyl oxygen and nitrogen sites, and the cationic bridge of Cd(II) with SMZ mainly occurred in the sequential system, with a complexation-decomplexation-complexation balance in the binary system.
A new self-assembled cellulose (SACS) containing multi-functional amine, carboxyl and hydroxyl groups was successfully obtained through etherification, cross-linking and grafting processes. Then, the adsorption of sul-famethoxazole (SMZ) and Cd(II) onto SACS at pH values of 3, 5.7 and 7.5 was systematically investigated by batch experiments of single, sequential and binary systems, characterization and density functional theory (DFT) calculations. The presence of Cd(II) decreased the adsorption of SMZ because of hydrophilic site competition, while SMZ inversely increased the adsorption of Cd(II), which was attributed to bridging and especially to electrostatic shielding effects; moreover, both the inhibitory and synergistic effects were more obvious in the binary system and at a pH of 7.5. There was a dynamic balance between the inhibitory and synergistic effects that depended on the system, pH value and concentration ratio. DFT results further indicated that SMZ- more easily coordinated with Cd(II) at sulfonyl oxygen and nitrogen sites, and the cationic bridge of Cd(II) with SMZ- mainly occurred in the sequential system. Moreover, a complexation-decomplexation-complexation balance of SMZ- and Cd(II) probably occurred in the binary system.
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