Chitosan and its functionalized derivatives for heavy metal ion elimination: A review of synthesis, mechanisms, and characterization studies

Due to its widespread distribution, lower environmental impact, sustainability, and antimicrobial attributes, chitosan is a multifunctional polysaccharide. Composite materials composed of chitosan convey the promotion of a viable and environmentally friendly engagement and eliminate the growing worries associated with the ecological contamination being caused by the metallic ions. Due to its special coordination property, chitosan combines with other beneficial substances. This feature improves its qualities and fosters the realization of a concentric economy through the deployment of numerous relevant methods. For example, for the concentration range of 100-2000 mg L^-1, alginate aerogel with melamine chitosan performed exceptionally well with the assessed Pb adsorption capacity of 1331.6 mg g^-1 and desorption efficacy of 60% up to 8 adsorption-desorption cycles and with the 0.05 M HNO₃ eluent. The article details many methods that promote successful modification of chitosan for the desired application in terms of environmental remediation. After providing a summary of popular chitosan harvesting and transformation procedures, the authors delve further into the influence of the manufacturing processes on the structural characteristics and functionality of chitosan-assisted composite materials. The most comprehensive evaluation being undertaken to date has been detailed in this study, and henceforth, the article engages the readers to uniquely categorize and methodologically understand the most recent research advances in the chosen field of study. Also, the ecological and financial consequences of chitosan-assisted compound utilization have been evaluated in terms of the viability and proximity scenarios. Also, relevant characterization tools have been detailed for the betterment of the understanding related to the real-world application scenarios. Finally, the difficulties and potential pathways for the chitosan-assisted compounds were addressed. Accordingly, the outcomes can be used as pragmatic advice for further advances in the policy and application matters associated with the environmental remediation with the chitosan-based resins.