Graphitic carbon nitride-immobilized bacterial endospores: Combined adsorptive- and bio-desulfurization of liquid fuels

Desulfurization of thiol compounds, namely dibenzothiophene (DBT) and thiophene (TH) in n-octane was performed by combining the adsorptive and bacterial desulfurization techniques. Graphitic carbon nitride (g-C3N4) pellets were used as an adsorbent for thiol compounds as well as a substrate for the immobilization of bacterial endospores (ES) harvested from active bacterial cells. The integrated approach using ES_g-C3N4 showed an approximately 99% removal of both thiol compounds in 8 h at 30(degrees)C, attributed to the combined effects of adsorption by g-C3N4 and degradation by the ES-transformed bacteria. Bacterial identification and characterization were performed by the Gram and ES staining, SEM analysis, and 16S rRNA sequencing. Reusability test showed that the material could be used multiple times by washing and re-immobilizing it with ES. The spent liquid, subjected to 0.22 mu m-syringe filtration, was declared free from bacterial cells. The integrated approach using ES_g-C3N4 is scalable, and can be used for the efficient desulfurization of liquid fuels.