Preparation and Characterization of Chitosan by a Novel Deacetylation Approach Using Glycerol as Green Reaction Solvent

Abstract

Traditional methods for chitin deacetylation require aqueous solution with high alkali content as reaction solvent, which generate huge environmental pressure for the treatment of vast alkaline wastewater. In this work, glycerol, a nontoxic, biodegradable, and sustainable liquid from biodiesel production, is employed as a novel reaction solvent for chitin deacetylation at elevated temperature. The results showed that the chitosan deacetylation degree (DD) was up to 85.36 ± 1.04% and the corresponding viscosity-average molecular weight (M V) was 30 874 ± 1123 g mol–1 under the optimized conditions of this process. The subsequent Fourier transform infrared (FTIR) characterization structurally demonstrated the occurrence of deacetylation and the fracture of glucosidic bond. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) analysis further revealed that the DD presented a negative effect on the thermal stability and crystallinity of chitosan. Consequently, the study successfully indicated that using glycerol as a reaction solvent could realize the deacetylation of chitin with lower NaOH concentration and provide an efficient and green process for chitosan preparation from chitin.

Production of 5-Hydroxymethylfurfural from Chitin Biomass: A Review

“…Using citric acid is also more environmentally friendly than using HCl. Using glycerol as the reaction solvent for deacetylation of chitin could realize deacetylation of chitin with low NaOH concentration and provide an efficient and green process for chitosan extraction from chitin [34]. Recently, Yang et al [35] developed a new economical and feasible shrimp shell fractionation method using hot water deproteinization and carbonic acid demineralization to extract high-value chitin from crustacean shells such as shrimp shells.…”

Removal and Recovery of Hazardous Metal Ions from the Industrial Effluent using Waste Fish Scale Impregnated Polyurethane Foam: Voltametric Method

“…The residue was kept in oven at 60 o C temperature for 8 hrs. The dried prawn scales powdered chitosan was stored in air tight polythene bottle for further analysis [11] .…”

“…Among the many other low cost absorbents identified, chitosan has the highest absorption capacity for several metals. Chitosan chelates five to six times [8][9][10][11][12] greater amounts of metals than chitin. This is attributed to the free amino groups exposed in chitosan because of deacetylation of chitin [13][14][15] .…”

Comprehensive utilization of Aspergillus niger mycelium waste from citric acid fermentation on the basis of steam explosion and ionic liquid pretreatment

“…Table 3 shows disappeared. The main reason may be that SE could break the crystal structure of chitin and promote the cracking and dissolution of chitin chain, which enhanced the deacetylation reaction due to more reactive sites exposed [28,37]. Noticeably, when combined pretreatments were employed, the acetic acid concentration was 1.3-fold higher than that produced by single SE pretreatment.…”