Title : Adsorptive desulfurization of diesel fuel using activated carbon from waste biomass (Carica papaya-PVA)
Abstract:
The use of fossil fuels in transportation and industrial sectors contributes significantly to the world's economy. However, the combustion of these fossil fuels also results in the emission of various air pollutants such as sulfur oxides, which results in acid-rain by reacting with the air moisture, photochemical smog, which is detrimental to human health and the environment, corrosion problems in pumping, pipeline, and refinery equipment due to the oxyacid formation and catalytic poisoning of converters in automotive engines [1]. Deep desulfurization of these fuels is of paramount importance. Adsorptive desulfurization has shown to be the most environmentally friendly, cost effective, simple and efficient method for deep desulphurization as compared to other conventional methods such as Hydrodesulfurization (HDS), Oxidative Desulfurization (ODS), Bio-desulfurization (BDS) which are not effective to remove organosulfur compounds such as dibenzo-thiophene (DBT) due to steric hinderance, expensive oxidants and biocatalysts respectively [2]. ADS utilises different types of adsorbents which include zeolites, activated carbons (AC), metal-organic-frameworks (MOFs). The application of AC for adsorptive desulfurization offers a solution to one of the pressing global issues regarding environmental pollution. Activated carbon (AC) has gotten lots of research attention due to its steady adsorption performance, superior mass transfer, cost effectiveness, different pore sizes (microporous, mesoporous and macropores) for adsorption of various sulphur compound sizes, large surface area for ample reactions to occur. Activated carbon (AC) from renewable and low-cost waste biomass is economical and prevents environmental degradation. Activated carbon (AC) from waste biomass (rice husk, saw dust, coconut shell, banana stem) is ideal over coal and coke because of its environmental friendliness, cost effectiveness, easiness to modify (oxidation, metal and nitrogen doping etc), surface area, porosity, cost effectiveness, fewer inorganic matter, high volatility and relatively high density [3]. This research focuses on the synthesis of a low-cost adsorbent and the feasibility of activated carbon from Carica Papaya biomass for adsorptive desulfurization with polyvinyl alcohol (PVA) as a support/oxidise the activated carbon to increase its surface acidity towards organo-sulfur compounds. Characterization techniques such as FTIR (For functional groups), SEM (pore size distribution), BET (surface area) will be used with comparison to other activated carbon sources. Batch adsorption for desulphurisation will be utilised to study the efficiency of DBT removal with varying adsorbent ratios, contact time also the isotherms and kinetics of the adsorption capacity will also be studied as compared to that of rice husks AC, Ni-MOF and hybrid of Carica Papaya AC-PVA-Ni-MOF. Chemical regeneration of the spent adsorbent will be performed and the number of adsorption cycles will be determined.
