The invention relates to the field of comprehensive utilization of
biomass resources and preparation of
high polymer materials, in particular to a green preparation method of high-deacetylation-degree
chitin capable of recycling reaction waste liquid. The invention aims to solve the problems of serious environmental
pollution, resource waste, low product purity and incomplete waste liquid recycling in
chitin extraction. The method comprises the following steps: by taking
crustacean biomass as a
raw material, firstly carrying out high-
voltage pulse electric field pretreatment to crush the tissue structure of the
raw material and improve the reaction activity, and then heating and extracting in a
choline chloride-
lactic acid deep eutectic solvent system to realize efficient removal of proteins and
inorganic salts in the
raw material; according to the method, the
chitin and the alkali liquor are subjected to a rapid deacetylation reaction by adopting
microwave assistance and cooperating with the action of the
phase transfer catalyst; according to the method, a waste liquid graded recycling
system is adopted,
hydrochloric acid in waste acid liquid generated by decalcification is recycled through
electrodialysis, alkali liquid is recycled through
ultrafiltration-
nanofiltration double-membrane combination,
deep eutectic solvent components are recycled through reduced pressure
distillation, and recycling of acid, alkali and a
solvent is achieved.