Increased photo-catalytic removal of sulfur using titania/MWCNT composite

Titania coating of multi wall carbon nano tube (MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties. The effect of MWCNT/TiO2 mass to volume ratio on adsorption ability, reaction rate and photo-catalytic removal efficiency of dibenzothiophene (DBT) from n-hexane solution was investigated using a 9 W UV lamp. The results show that the addition of nanotubes improves the photo-catalytic properties of TiO2 by two factors; however, the DBT removal rate versus MWCNT content is found to follow a bimodal pattern. Two factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT content. First, large quantities of MWCNTs prevent light absorption by the solution and decrease removal efficiency. By contrast, a low dosage of MWCNT causes recombination of the electron holes, which also decreases the DBT removal rate. The optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 mL of sol.