Green, Simple, and Effective Process for the Comprehensive Utilization of Shrimp Shell Waste

Abstract

An environmentally friendly approach for the comprehensive utilization of shrimp shell waste was reported. Instant catapult steam explosion (ICSE) was employed for shrimp shell waste pretreatment. After ICSE, lower crystallinity and greater surface areas of shrimp shells were achieved, which significantly enhanced the extraction of chitin. Compared to the traditional method, weaker organic acid (HCOOH) and much lower dosages of KOH (90% molar less) were used, and chitin with a high demineralization rate (98.2%) and deproteinization rate (97.7%) was obtained. The wastewater was neutralized by simply intermixing, and it was recycled as a potential plant fertilizer because it contained more oligopeptides, calcium, and potassium, but it was less salty and therefore non-toxic to plants. The whole process produced less solid waste and no waste water. The obtained chitin also showed a low degree of acetylation (50.5%), which demonstrates the potential for environmentally friendly preparation of chitosan in dilute alkali through ICSE.

Nanochitin: Chemistry, Structure, Assembly, and Applications

“…DM and DP are used to remove calcium minerals and proteins complexed with chitin, respectively, which frees tightly bound chitin and might require multiple cycles, depending on the chitin source and intended uses . The discoloration, e.g., using sodium hypochlorite, acetone, or hydrogen peroxide, removes pigments adhered on the shells, e.g., astaxanthin and β-carotene, so that colorless chitin is generated prior to nanofibrillation. , Apart from these procedures, pretreatments involving size reduction, drying, grinding, sieving, and wet processing of crustacean shells are applied before DM and DP, which facilitate the extraction and increase the efficiency of the process. , For instance, a pretreatment using hot glycerol, a plasticizing agent, improved the efficiency of chitin extraction from prawn shells, and utilization of 3% NaClO before DM and DP reduced the processing time and energy consumption . There are reports on the use of atmospheric pressure dielectric barrier discharge plasma or gamma irradiation to increase the removal of minerals and proteins. , Although other treatments might facilitate chitin extraction, impurities or uncontrolled degradation may occur, which would affect the properties of chitin and the obtained nanochitin.…”

“…16,210 Apart from these procedures, pretreatments involving size reduction, drying, grinding, sieving, and wet processing of crustacean shells are applied before DM and DP, which facilitate the extraction and increase the efficiency of the process. 211,212 For instance, a pretreatment using hot glycerol, a plasticizing agent, improved the efficiency of chitin extraction from prawn shells, 213 and utilization of 3% NaClO before DM and DP reduced the processing time and energy consumption. 214 There are reports on the use of atmospheric pressure dielectric barrier discharge plasma or gamma irradiation to increase the removal of minerals and proteins.…”

A Top-Down Procedure for Synthesizing Calcium Carbonate-Enriched Chitosan from Shrimp Shell Wastes

“…Although about 2000 t of chitosan is produced each year from residues of shrimp or crab shells, its proper exploitation and recycling remain challenging due to the high costs [ 7 , 17 , 18 ]. In order to extend the recycling and valorization degree of such wastes, the research for other applications has now intensified [ 19 ].…”

Biopolymer-Based Electrolytes for Dye-Sensitized Solar Cells: A Critical Review

“…Among them, alginate and carrageenan can be extracted in large scale from brown − and red − seaweeds, respectively. On the contrary, chitosan is extracted from the waste shells of sea creatures like crabs, − shrimps, − and lobsters. , This easy, cheap, and huge abundance of base host material for electrolyte preparations opens the possibilities for producing large scale economical solar energy utilization cells. Besides, energy utilization by extracting these polymers from wastages can also reduce the environmental problems like overabundance of seaweeds in the oceans.…”