Effect of ozonation on the activated carbon surface chemical properties and on 2-mercaptobenzothiazole adsorption

Benzothiazoles are organic compounds that may produce negative environmental impact when released into watercourses. In particular, 2-mercaptobenzothiazole (MBT) are known to be toxic and hard to biodegrade. Activated, carbon adsorption and ozonation have been identified as suitable treatment for those contaminants. However, there is some controversy about the effect of carbon surface chemical composition on the MBT adsorption. This paper focuses. on this issue and presents experimental adsorption isotherms for MBT on Filtrasorb-400 activated carbon treated with different ozone doses. The activated carbon surface chemical properties were assessed by acid/basic neutralization, temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and the point of zero charge (pH(PZC)). Results show that ozone treatment modified the oxygenated groups on the activated carbon surface, increasing the concentration of acid groups, and reducing the pH(PZC). Finally, ozone treatment led to a significant reduction of the carbon's MBT adsorption capacity, due to the increase in polar hydrophilic groups.