Abstract
A threshold thermodesorption method, named fast Intermittent TPD (ITPD), was used to study the evolution of CO 2 and CO arising from the decomposition of oxygen groups at the surface of a porous carbon used in the wastewater treatment. Applied to the as-received carbon, CO 2-ITPD provided clear evidence for six values of the apparent activation energy of oxygen group decomposition ( E app ): 139, 168, 206, 237, 270 and 290 kJ mol −1. Corresponding apparent pre-exponential factors ( A app ) were also determined. The data ( E app and A app ) derived from ITPD for the six desorption steps allowed a successful description of the complete TPD profile, considering a Gaussian narrow distribution of E app for each step. CO-ITPD also showed the presence of six (possibly seven) distinguishable steps upon CO thermal desorption and further demonstrated the interest of the fast ITPD technique for studying carbon surface chemistry. The TPD and ITPD profiles of the carbon treated with sodium hypochlorite showed: (i) a sharp increase in the amount of desorbed species, (ii) the prevailing presence of less stable oxygen groups, mainly carboxylic acids, giving rise to CO 2 desorption at low temperature, and (iii) the progressive merging of the desorption steps detectable at low temperature upon increasing surface density of oxygen groups.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.