I.W. Mwangi, R. Nthumbi, K. Macharia, J.C. Ngila
Kenyatta University,
Kenya
Keywords: pollution, desulphurization, diesel, in-situ, quaternized adsorbent
Summary:
Sulphur containing fuels are of concern as pollute the environment upon combustion. The demand for clean air is fundamental hence a need to remove thio-compounds in fuels. Sulphur containing organic compounds cannot be completely removed by the distillation process due to the formation of azeotropic mixtures. The removal of such organic pollutants from fuels can only best be done by sorption. This paper reports on the use an adsorbent prepared using powdered maize tassels quaternized with polydiallyldimethylammonium chloride for the removal of sulphanillic compounds in diesel. The study revealed that modification improved the thermal stability of the adsorbent material. Adsorption parameters such as time, pH and sorbent dose were optimized and the material then applied for removal of sulphur in diesel. The pH for maximum adsorption was found to pH 6. In a separate investigation, kinetic studies showed that the adsorbent was able to take up to 95% of the analyte in synthetic samples in less than 10 min. The adsorption capacities for carbon disulphide, phenol-thio and ethan-thio doped diesel samples were found to be 3.23, 1.88 and 1.36 mg g-1 respectively. The adsorbed pollutants were then stripped using a solution of 0.1M HCl dissolved in tetrahydrofuran (THF) confirming its regeneration. It was observed that 95% of the phenol thio and 85% of aliphatic thiol in commercially diesel samples were removed using > 0.03 g of the material. This confirmed that the material has potential application for the removal of sulphanillic compounds for diesel engines thus improving its quality.