Chitosan-based materials for emerging contaminants removal: Bibliometric analysis, research progress, and directions

Chitosan and its derivatives, as natural biopolymers, play a crucial role in various industries such as food, agriculture, paper, medicine, textiles, and biotechnology, as well as in environmental applications, including wastewater treatment. However, a comprehensive bibliometric analysis is lacking to evaluate the current status and research trends in removing contaminants from wastewater through chitosan. This study analyzed 9711 relevant papers published from 1993 to 2024 in the Web of Science database using CiteSpace and VOSviewer software. The findings reveal that Chitosan-based materials—initially investigated for removing metals, dyes, and pesticides—are increasingly explored for tackling emerging pollutants such as pharmaceuticals, personal care products (PPCPs), and per- and polyfluoroalkyl substances (PFAS), while research has also expanded to innovative domains including solar-driven water purification scaffolds and advanced composites (e.g., chitosan@graphene oxide, chitosan-based molecularly imprinted polymers, photocatalytic chitosan hybrids, chitosan/clay, and chitosan/metal sulfides). Machine learning methods have been introduced to improve chitosan-based water treatment processes, although progress lags behind that of commercial adsorbents like activated carbon and biochar. Large-scale adoption of chitosan-based technologies requires validation in complex real-world settings, enhancement of cost-effectiveness and regeneration efficiency and mitigation of environmental impacts during chitosan extraction and processing. Future efforts should focus on pilot-scale and field trials, refining chitosan-based materials for niche applications, and developing “smart materials” that respond dynamically to environmental stimuli, ultimately advancing chitosan-based solutions from laboratory-scale demonstrations to impactful, scalable innovations in global water treatment.