Quaternary nitrogen activated carbons for removal of perchlorate with electrochemical regeneration

Positively charged nitrogen functional groups were introduced onto the surface of granular activated carbon (GAC), and these increased perchlorate anion removal from drinking water sources. Nitrogen functionalization involved three treatment steps: (1) introducing oxygen groups onto the GAC, (2) inc...

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Bibliographic Details
Published in:Carbon (New York) 2014-07, Vol.73, p.1-12
Main Authors: Byrne, Timothy M., Gu, Xin, Hou, Pin, Cannon, Fred S., Brown, Nicole R., Nieto-Delgado, César
Format: Article
Language:English
Subjects:
Activated carbon
Adsorbents
Bituminous
Charging
Chemistry
Cross-disciplinary physics: materials science
rheology
Electrochemistry
Exact sciences and technology
Fullerenes and related materials
diamonds, graphite
Functional groups
General and physical chemistry
Materials science
Media
Perchlorates
Physics
Regeneration
Specific materials
Surface chemistry
Surface physical chemistry
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Summary:Positively charged nitrogen functional groups were introduced onto the surface of granular activated carbon (GAC), and these increased perchlorate anion removal from drinking water sources. Nitrogen functionalization involved three treatment steps: (1) introducing oxygen groups onto the GAC, (2) incorporating nitrogen groups by thermal treatment in ammonia flow to replace O with N, and (3) quaternerizing pyridine-like groups to create positively charged pyridinium-like groups. Functionalized bituminous GAC provided 6 times more perchlorate removal than its predecessor, pristine bituminous GAC. The conversion of pyridine-like groups (after step 2) to pyridinium-like groups by quaternization (step 3) was confirmed by analysis of the XPS N 1s signals and surface charge analysis. Redox peaks, observed during cyclic voltammetry analysis of the functionalized GAC, evidenced that these nitrogen functional groups were electrochemically active, so that they sorbed perchlorate when they were oxidized, and then desorbed perchlorate when reduced. Moreover, after sorbing perchlorate onto pyridinium-GAC in RSSCTs, the GAC media could be regenerated by electrochemical reduction, and its capacity for perchlorate adsorption was mostly restored. This tailored functionality and redox regeneration of a relatively inexpensive media such as activated carbon could offer novel opportunity to the adsorption industry.
ISSN:0008-6223
1873-3891
DOI:10.1016/j.carbon.2014.02.020