Adsorptive Efficiency of Activated Carbon from Corncob Compared with Commercial Activated Carbon in the Adsorption of Light Alkanes Contaminant in Hydrogen Gas Product

The adsorptive efficiency of activated carbon produced from corncob was compared to commercial activated carbon in the adsorption of light alkanes contaminant in hydrogen gas product. The adsorption was measured over a constant temperature of 27°C and at pressures up to 125 kilo pascal (kPa) using a gravimetric gas adsorption technique. The light alkanes were adsorbed on activated carbon produced from corncob using chemical method with phosphoric acid as the activating agent. The mass of adsorbent used for the adsorption was from 20 – 60 g. Pore size distribution and characteristic functional groups present on the surface of activated carbon were determined using N2 adsorption, Brunauer-Emmett-Teller (BET) method and Fourier Transform Infrared spectroscopy (FTIR spectra) respectively. BET analyses were used to characterise the activated carbons. The BET results of the produced activated carbon compared to the commercial activated carbon has a specific surface area of 1237 m2/g and 2048 m2/g and a pore volume of 0.1162 cm3/g and 0.1959 cm3/g, respectively. FTIR spectra results of the produced activated carbon compared to the commercial activated carbon showed similar band gap at 2337.80 cm-1 with an alkynl C≡C stretch functional group and a vibration type of carbonyl group (carboxylic OH) at 1550.82 cm-1. Experimental data verified using Langmuir isotherm and Freundlich isotherm adsorption models showed best fit for Langmuir adsorption isotherm model indicating the formation of a monolayer adsorbate on the outer surface of the adsorbent with an adsorptive and uptake capacity of 0.016 Pa-1. The adsorptive efficiency of the produced activated carbon compared to the commercial activated carbon was 1.05wt% and 3.55wt%, respectively. Therefore, based on the results obtained, the produced activated carbon may not completely substitute the commercial activated carbon rather it can be used as a potential blend thereby reducing quantity and cost.