Investigation of efficient hydrolysis and conversion of waste biomass under different conditions

The use of non-renewable resources such as fossil fuels in the industrial field as well as in energy production and also their rapid depletion have caused the studies on the use of renewable resources to increase. In recent studies, it has been observed that as a result of the conversion of biomass, it is possible to produce chemicals that can be used in many different industrial fields such as fuel, solvent and plastic. Compared to fossil fuels, biomass is an environmentally friendly low-cost clean source, can be easily stored and produced in almost any condition and scale, and last but not least it contributes to the CO2 cycle. Therefore, the importance of the use of biomass among renewable resources has significantly increased. In this study, hydrolysis ratios of biomass and amount of valuable chemicals (5-hydroxymethylfurfural, furfural, levulinic acid, succinic acid) were determined by reaction of three different solvent types; organic solvent (methanol, THF, acetone, hexane), ionic liquid ([BMIM]Cl, [BMIM]HSO4) and deep eutectic solvent (choline chloride:ethylene glycol), in aqueous medium. HPLC was used to determine valuable chemicals and monosaccharides and UV-VIS spectroscopy analysis was used to determine total reducing sugar content. The reaction conditions in each solvent medium were optimized to determine the appropriate reaction temperature, reaction time and solvent ratio. The optimum reaction temperature for all solvents was found to be 180°C, the reaction time and solvent ratio varied according to the solvent medium. The experiments were carried out using microcrystalline cellulose as a model compound, corn straw, wheat straw and sorghum as lignocellulosic biomass source and waste fluff and linter as cellulosic biomass source and the effect of starting material on product formation was investigated. The experiments were repeated in the presence of commercial catalyst Amberlyst-15 and BT300S, a solid acid catalyst obtained from wheat straw at low cost in the laboratory and the effect of catalyst type on product formation was investigated. The most effective hydrolysis ratio and the highest sugar content were achieved by reaction with [BMIM]HSO4-water medium. The order of activity in organic solvent-water medium was found to be polar aprotic solvent > polar protic solvent > apolar solvent. Although the hydrolysis of biomass materials differed with the use of different solvent media, it was observed that the hydrolysis efficiency generally followed the sorghum ~ corn straw > wheat straw ~ waste fluff > cellulose > linter.