Updates on the materials for desulphurization of thiophene, benzothiophene and dibenzothiophene

The presence of sulphur in fuels is undesirable as their combustion products contain oxides of sulphur which has been linked to causes like asthma, heart disease and other respiratory illnesses. Asides, these oxides are the main cause of atmospheric contamination, acid rain and global warming. The predominant source of sulphur in fuels is due to the presence of thiophene, benzothiophene and dibenzothiophene. Different desulphurization methods, including hydrodesulphurization, biodesulphurization, adsorptive desulphurization, extractive desulphurization and oxidative desulphurization. Some of these technologies requires harsh conditions for the sulphur to be removed. Hence, there is a need for modification of the existing technologies. One of the modifications involve the use of innovative materials (such as pristine, doped materials, heterojunctions and composites) for sulphur removal. These materials were particularly used for the adsorptive and photocatalytic desulphurization. Photocatalytic desulphurization will only be effective in the presence of a good photocatalyst and light. In this work, the photocatalysts (oxides, sulphides, phosphides, phosphate, nitrides and composites) that have been employed for the removal of these sulphur compounds, their performance as well as existing photocatalytic desulphurization reactors are reported. Furthermore, the mechanism of photocatalytic desulphurization is explained. In addition, recent updates on the utilization of nanomaterials for adsorptive desulphurization were also addressed. Impacts of aromatic, olefinic and additive compounds on the desulphurization of fuel were examined. Finally, the future perspectives on how to improve on the adsorptive and photocatalytic desulphurization processes were suggested.