Investigation of Adsorptive Desulphurisation of Diesel Fuel Using Activated Carbon from Corn Cobs in Kwara State

High sulphur content in locally refined diesel fuel distributed across Kwara State, North Central Nigeria, contributes to vehicle emissions of sulphur dioxide and particulate matter, accelerating respiratory disease burden in urban populations. This study investigates adsorptive desulphurisation of diesel fuel using activated carbon prepared from corn cob agricultural waste sourced from farms in Ilorin East Local Government Area. Corn cobs were carbonised at 500 degrees Celsius and chemically activated with zinc chloride at an impregnation ratio of 1:1. The activated carbon was characterised by BET surface area analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy. Adsorptive desulphurisation experiments were conducted in batch mode at sorbent doses of 5 to 30 g/L diesel, contact times of 15 to 120 minutes, and temperatures of 25, 40, and 55 degrees Celsius. Total sulphur concentration in diesel was measured before and after treatment by wavelength-dispersive X-ray fluorescence. Activated corn cob carbon achieved a maximum sulphur removal of 68.4% from diesel containing 1,820 ppm sulphur under optimised conditions of 25 g/L sorbent, 90 minutes contact time, and 40 degrees Celsius. Adsorption equilibrium data conformed to the Langmuir isotherm model with a maximum adsorption capacity of 3.24 mg sulphur per gram of adsorbent. The study supports corn cob-derived activated carbon as a cost-effective material for partial desulphurisation of high-sulphur diesel in the Nigerian market context. Keywords: desulphurisation, activated carbon, corn cob, diesel fuel, Kwara State