Chitosan and chitosan derivatives: Recent advancements in production and applications in environmental remediation

Abstract

This review, which presents recent advancements in production and applications in environmental remediation of chitosan and chitosan derivatives, covers relevant literature in the last 7-8 years, which is nearly half-term of the 15-year period where the global agenda focuses on achieving the United Nations Sustainable Development Goals (SDGs) by 2030. Chitosan is a natural, non-toxic, polycationic polymer synthesized by deacetylating chitin, using several methods for producing its derivatives. The polycationic nature of chitosan and its derivatives offers them huge prospects as adsorbents due to their extraordinary and diverse properties of biocompatibility, biodegradability, non-hazardous and chemical versatility. As such, they are very useful in environmental remediation. Chitosan and its derivatives have stood the test of time. They effectively remove fine suspended particles and heavy metals from polluted water and wastewater. Also, the marine environment is usually heavily polluted by hydrocarbons through oil spills with an effectual removal by these adsorbents. Soil, water, and air remediation techniques using chemical methods have the propensity to generate secondary pollution by modifying their chemical structures, which significantly impact the environment, ecosystem integrity, and health. Hence, the need for less costly, efficacious, and environmentally benign methods, such as using chitosan and its derivatives, is warranted. The current review first identifies relevant literature sources and knowledge gaps, such as a rare exposition of issues in the order of the first two stages of the traditional and industrial chitosan production process. It presents an overview of its sources and then examines recent advancements in chitosan chemistry. Chitosan transformation and applications in environmental remediation are also highlighted. Finally, the review identifies research gaps and future dimensions to clear issues about the chitosan production process and promote sustainable production and utilization as the world has embraced a paradigm shift toward circular and green economies, particularly during the SDGs.