ABSTRACT
This research focused on the production of furfural from microalgae biomass and optimizing the process parameters using Response Surface Methodology (RSM). Furfural production was carried out by hydrolysis of Pentosans to Pentoses where Pentosans in hemicelluloses is hydrolyzed with dilute mineral acids and NaCl as a promoter at relatively low temperature to pentoses and subsequent dehydration of pentoses to furfural in a single stage process. Central Composite Design (CCD) was employed to determine the effect of process parameters: reaction temperature (39.43 oC-165oC), reaction time (30- 90 min), and concentration of 1M H2SO4 (35 mL/g of microalgae biomass used -70 mL/g of microalgae biomass used) on the yield of furfural. The regression analysis showed good fit of the experimental data to the second-order polynomial (Quadratic model) with coefficient of determination (R2) value of 0.9807 and model F-value of 56.54. The model was found to be significant as its Predicted R2 of 0.8771 was in close agreement with the Adjusted R2 of 0.9634. Sodium chloride concentration have significant effect on furfural yield; furfural yield increased with increase in sodium chloride concentration up to about 1.0g/g of biomass, however, it prolongs reaction time and subsequent increase in sodium chloride concentration led to decrease in furfural yield after 1.0 (g / g of biomass used) concentration of the salt and make furfural become very pink instead of been colorless. Furfural yield of 73.10% was obtained at optimum conditions of reaction temperature of 140oC, H2SO4 concentration of 35.02 mL/g of microalgae biomass used and reaction time of 65.3 min.Validation experiments conducted at the optimum conditions gave an experimental value of 73.10% which was in close agreement with the predicted value of 69.36%.The polymerization of by- products were observed to be accelerated as the process variables were varied therefore; optimization of these process conditions was helpful to facilitate furfural production and to obtain high yield of 73.10% which was recorded.FTIR result confirm the presence of carbonyl and aldehyde functional groups at wave length of 1674.27cm-1and 2924.18cm-1 respectively, while GC-MS analysis of the sample confirms the presence of furfural of relative percent with respect to the column area of 50.86% with the GC-MS Spectrum showing a molecular ions peak at mass to charge (m/z) ratio of 96 g/mol which corellate to a molecular formular of furfural of C5H4O2.