Green Chemistry and Computational Energy Analysis for Sustainable Chitosan Production: A Case Study of Green Solvent and Water Management

The environmental performance of chitosan production is evaluated through a rigorous computational comparison between traditional thermochemical deacetylation and innovative green synthesis pathways utilizing Deep Eutectic Solvents (DES). Implementation of the Waste Reduction (WAR) algorithm facilitates the quantification of the Potential Environmental Impact (PEI) across eight toxicological and ecotoxicological categories, providing a systematic benchmark for process sustainability. While the conventional route, characterized by the intensive consumption of HCl and NaOH, generates a substantial environmental burden of 1.37 × 10 7 PEI/ton, the optimized green architecture leveraging a choline chloride:ethylene glycol (ChCl:EG) system achieves a radical reduction to 2.25 × 10 4 PEI/ton. This 99.8% decrease in PEI is primarily driven by the mitigation of Human Toxicity Potential (HTP) and Acidification Potential (AP) through the substitution of corrosive mineral acids and volatile organics with biodegradable, low-vapor-pressure alternatives. These findings substantiate the integration of DES-mediated biorefineries as a high-efficiency strategy for the valorization of marine waste into high-purity biopolymers, aligning with the requirements for industrial process intensification and circular bioeconomy standards.