INVESTIGATION AND SIMULATION OF PH VARIATION IN THE SYSTEM OF ETHANOL-WATER EXTRACTION OF REED

摘要

The organic acid produced in the system of ethanol-water extraction of reed is investigated and its influences on the pH are explored and simulated.The investigation based on the selective auto-catalytic depolymerization of the lignocellulose biomass in its primary ingredients(cellulose,hemicellulose and lignin)is carried out in a biphasic solvent system with different extracting duration.The organic acid of the spent liquor were subsequently evaluated by Ion Exchange Chromatography(IEC).The results showed that AA(acetic acid),LA(levulinic acid),FA(formic acid)are the primary Organic acid in the spent liquor(in the sequence of concentration).The acidity result,from low to high,is FA,LA and AA.To confirm the investigation,the effect of organic acid on acid environment of the system is simulated with the formic acid and acetic acid.Results demonstrates that the ionization of hydrogen ions is inhibited due to the interaction of formic acid and acetic acid in the system,which causes the increase of pH rather than decline.The acidity primarily depends on the formic acid in the co-existence system of formic acid and acetic acid.Overall,this investigation analyses the mechanism of pH variation caused by organic acid in bio-refinery process,and promotes a solution for obtaining by-products under environmentally-friendly conditions.