Biomass waste dissolution with imidazole ionic liquids for biohydrogen production

Abstract

Cellulosic biomass waste from municipal solid and agricultural biomass residue are Second Generation energy source, mainly contain glucose and xylose monomers, were`extensively studied in present research for fermentable sugar hydrolysate in biohydrogen production. Scrap paper cup (SPC), bamboo stem wall (BSW), sugar cane bagasse (SCB) and oil palm empty fruit bunch (OPEFB) were dissolved in laboratory prepared imidazole ionic liquids; 1-allyl-3-methylimidazolium chloride ([Amim]Cl) and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). A comparative study on biomass composition was presented by Van Soest and thermalgravimetric analysis (TGA) method. TGA was proved as comparative, cheaper and faster method in measuring the lignoellulose composition. Experimental result show that the ionic liquids were completely dissolved the SPC, BSW, SCB and OPEFB with high cellulose recovery; 96.00%, 91.34% 87.16% and 99.51% respectively. The used ionic liquids were highly recovered from the mixture at 94% to 99% recovery rate and FTIR analysis proofed that the recycled ionic liquid is principally consistent with the original. The regenerated cellulose was undergo acid hydrolysis to reducing sugars (glucose/xylose) hydrolysate to be used as feedstock fermentation for biohydrogen production. Acid hydrolysis of the recovered cellulose resulted up to 96% sugar conversion. IL-SPC hydrolysate reported higher total sugar conversion compare to SPC (control) due to higher surface area and disintegration of the cellulosic fibril structure resulted from the dissolution process. IL-SPC, IL-BSW, IL-SCB and IL-OPEFB hydrolysate contained higher total sugar compared to SPC hydrolysate even though their cellulose recovery are lower that the SPC (control). Biohydrogen fermentability test of this hydrolysate was carried out using biohydrogen producing bacterium Clostridia sp. Almost 85% of biomass waste hydrolysate substrate was utilized by the bacteria. Up to 196 ml H 2 / 100 ml cumulative bioydrogen production was collected for fermentation using the biomass hydrolysate while 174.91 ml H 2 / 100 ml was produced from the control.