•  
  •  
 

Corresponding Author

Jiao QU(quj100@nenu.edu.cn);
Ying LU(luy332@nenu.edu.cn)

Abstract

To study the optimal removal condition, adsorption mechanism and comparative analysis of the three typical cationic pollutants, i.e., Zn(II), anionic pollutant Cr(VI) and molecular pollutant sulfamethoxazole (SMX), using self-made upflowed electro-sorption device for adsorptions of above three pollutants by modified activated carbon fiber were researched. The activated carbon fiber (ACF) was modified by hydrochloric acid. The ACF morphology and structure before and after modification were characterized by SEM, BET and FTIR. The characterization results show that the modified ACF had fewer surface impurities than the modified surface and the gully is more obvious, the specific surface area was increased by 22%, while the micropore volume was increased by 5%, and the oxygen-containing functional groups (C-O, C=O) are significantly increased. Using the heavy metal ions (Zn(II), Cr(VI)) and the antibiotic Sulfamethoxazole (SMX) in water as the target pollutants, the adsorptions of ACF after hydrochloric acid modification on the target pollutants (static adsorption and electro-sorption) were studied. The effects of concentration, pH and applied voltage on adsorptions were investigated. The results showed that when the ACF dosage was 5 g, voltage was 1.2 V, Zn(II), Cr(VI) and SMX concentrations were 10 mg·L-1, Zn(II) solution pH was 5, the maximum adsorption capacity of Zn(II) adsorbed by ACF was 9.25 mg·g-1, which is 2.15 times of the static adsorption condition; when the pH of Cr(VI) solution was 4, the maximum adsorption amount of Cr(VI) adsorbed by ACF was 8.86 mg·g-1, which is 1.96 times of static adsorption condition; when the pH of SMX solution was 6, the maximum adsorption capacity of ACF to adsorb SMX was 8.32 mg·g-1, which is 1.84 times of static adsorption condition. The kinetic curves for the adsorptions of Zn(II), Cr(VI) and SMX by ACF were consistent with the pseudo-second-order kinetic model, and the adsorption process was chemical adsorption. The Freundlich isotherm model can better describe the adsorption characteristics of ACF on Zn(II), Cr(VI) and SMX, whose adsorption is multi-molecular layer adsorption. ACF was recycled by electrode reverse connection, whose desorption rate was fast and the desorption effect was obvious. After 4 cycles of regeneration, the removal rates of Zn(II), Cr(VI) and SMX by ACF were above 90%, and great regeneration efficiency, which can be reused in practical applications, saving resources.

Graphical Abstract

Keywords

activated carbon fiber, electro-adsorption, Zn(II), Cr(VI), sulphonamide, recycling

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Publication Date

2019-12-28

Online Available Date

2018-09-30

Revised Date

2018-09-20

Received Date

2018-08-23

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.