Recent advances in chitosan and its derivatives as adsorbents for removal of pollutants from water and wastewater

• Mechanical strength and adsorption capacity were improved.
• Adsorption selectivity was enhanced and expanded.
• Effective recovery of nano adsorbents was achieved.
• Multi-functions were realized.
• Column mode test made a step closer for practical applications.

This article reviews the recent advances in chitosan and its derivatives as adsorbents for their environmental applications, particularly in pollutant removal from water and wastewater. The adsorbents are discussed in terms of a few distinctive groups, including semi-interpenetrating network (semi-IPN), molecular-imprinting polymer, magnetic nanoparticles, polymer-grafted-chitosan, and cost-effective chitosan composites. The applications of these adsorbents, potentially of great significance, are outlined in several aspects, such as multi-functional adsorption, targeted adsorption for real pollutants and the column adsorption process studies. The primary objective of the paper is to provide a brief summary of the progress in the past five years or so and put forward some possible future perspectives of the related studies.