摘要
以壳聚糖为接枝骨架、丙烯酸为单体制备了一种具有三维网状结构的水凝胶(CTS-g-PAA),结合扫描电镜和傅里叶变换红外光谱对CTS-g-PAA进行了结构及组成表征。在此基础上,系统研究了CTS-g-PAA对水环境中左氧氟沙星(Levofloxacin,Lev)的吸附效果。结果表明,CTS-g-PAA具有利于吸附的海绵状三维结构。当Lev初始质量浓度为50mg/L、CTS-g-PAA对Lev的吸附在pH值为3. 0时效果最佳,吸附量达到32. 35 mg/g。此外,CTS-g-PAA可在30 min内快速吸附Lev,准二级动力学方程和Freundlich模型适于描述该吸附过程。在吸附过程中,CTS-g-PAA与Lev之间的静电引力占据主导地位,这种作用可进一步通过离子强度对吸附过程的影响加以印证。
The present paper is aimed at making an investigation of such influential parameters on the adsorption capacity as the pH value range from 2. 0 to 9. 0,and the ionic strength( ion species of Na+ and Ca2+),the contact time( from 1 min to 180 min),the adsorbate concentration range from 10 mg/L to 600 mg/L,at the temperature from 293 K to 323 K. In the paper,we have prepared a non-toxic and biocompatible hydrogel by taking chitosan( CTS) as the grafted backbone and acrylic acid( AA) as the functional monomer. For the research convenience,we have marked the resulting hydrogel as CTS-g-PAA and determined its morphological structure and functional group composition via the electronic scanning microscope( ESM) and Fourier transform infrared( FTIR) spectrum jointly. Subsequently,we have managed to take CTS-g-PAA as an adsorbent to remove the levofloxacin( Lev),one of the synthetic fluoroquinolone antibiotics,from the water through a batch of experiments. The results of our experimental research reveal that the sponge-like 3D structure of CTS-g-PAA can help to facilitate the adsorption possess.When the initial concentration of Lev is 50 mg/L,the CTS-gPAA shows the best adsorption efficiency at pH = 3. 0,and the optimal adsorption capacity is determined to be 32. 25 mg/g.Moreover,the CTS-g-PAA has been proven to be able to absorb Lev promptly within 30 min at the 3 different concentration levels,with the pseudo-second-order equation being suitable for the experiment data analysis. Furthermore, when compared to the Redlich-Peterson model,the Freundlich model that represents the heterogeneous adsorption can fit for describing the adsorption isotherms. The thermodynamic parameters of ΔH and ΔS are calculated to be-2. 367 × 105 J/mol and -931. 2 J/( mol·K),respectively,suggesting that such an adsorption process is exothermic and the lower temperature is more favorable for this process.During the adsorption process,the electrostatic attraction between negatively charged -COO-groups within CTS-g-PAA and positively charged Le
作者
郑易安
王宁芬
肖伟龙
牛碧慧
ZHENG Yi-an;WANG Ning-fen;XIAO Wei-long;NIU Bi-hui(Gansu Key Laboratory for Environmental Pollution Prediction and Control,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2019年第5期1719-1726,共8页
Journal of Safety and Environment
基金
国家自然科学基金项目(21477135)
甘肃省自然科学基金项目(17JR5RA205)
兰州大学中央高校基本科研业务费专项资金项目(lzujbky-2019-95)
关键词
环境工程学
水凝胶
壳聚糖
左氧氟沙星
吸附
environmental engineering
hydrogel
chitosan
levofloxacin
adsorption
