Chemical compositions, surface chemistry and residual biomass surface morphology of Nigerian Jatropha curcas L. slow-pyrolytic oil produced from de-oiled Jatropha curcas L. seed kernel

Abstract

In today's energy-demanding lifestyle, the need for exploring and exploiting new sources of energy that are renewable as well as environmentally benign is a must. Nigeria has a lot of non-edible oil tree-born seeds. The country is endowed with a lot of species of tree-born non-edible oils seeds which can be exploited for the production of biofuels to meet her energy needs. Jatropha curcas is a versatile plant with several actual and potential uses. The effect of chemical pretreatment on De-oiled Jatropha curcas L. kernel (DJSK) on the chemical compositions, surface chemistry, and residual biomass surface morphology was studied. The dried resulting cake from the Jatropha curcas L. kernels was pretreated with 4 % sulphuric acid solution and 4 % alkaline solution using NaOH respectively. Both
the raw and pretreated samples were subjected to slow pyrolysis in a fixed bed reactor. The temperature of the furnace was set at 450 ℃ and as the biomass sample (≤ 2 mm particle size, 1000 g) gets pyrolysed at about 245 ℃, volatiles released, exits from the volatile delivery tube and are passed through the Liebig condenser. The sample was pyrolysed to the set pyrolysis temperature of 450 ℃
and held for about 45-50 min. until no release gas was observed from the reactor. The pyrolysis liquid products - viscous phase (Bio-oil) and aqueous phase (polar liquid) were collected via flat bottom flask by condensing in a condenser and cold traps maintained at about 0-5 ℃. The viscous phase was separated from the aqueous phase using a colloquially sep funnel, weighed, and stored in a plastic
container for further use and analysis. The chemical composition of both the raw and pretreated samples was identified by Gas Chromatography-Mass Spectrometry (GC-MS) which shows different peaks and data of different compounds. The surface chemical properties of the raw and pretreated (acid and alkali) Bio-oil revealed the functional groups present through Fourier Transform Infrared Spectroscopy (FTIR). Surface morphological characteristics of the residual biomass used for the pyrolysis process for both raw and pretreated samples were examined by Scanning Electron Microscope (SEM). The results showed that the bio-oil obtained from the De-oiled Jatropha curcas L. seed kernel might be an important fuel source and chemical feedstock.