Phosphonium-Crosslinked Chitosan (PCC)


Researchers at the University of Calgary have developed a non-toxic adsorbent material, phosphonium-crosslinked chitosan (PCC), for the removal of heavy metal ions from water. This invention uses a one-step chemical reaction to incorporate a low-cost phosphonium salt to the polymer.

Heavy metal-ions, such as hexavalent chromium (Cr(VI)), are extremely hazardous to humans, animals, and the environment and as such, the World Health Organization mandated a maximum allowable concentration of these heavy metal-ions in water. Heavy metal-ions are produced by a variety of processes used in industry.

Adsorption is a commonly used method for treating water and wastewater streams containing heavy metal-ions, and most adsorbents for heavy metal-ions, including Cr(VI), and other anions, rely on nitrogen-based functional groups. Industrially, synthetic polymers are often used rather than naturally occurring materials for adsorbing heavy metal-ions due to their greater adsorption capacities. Production of synthetic polymer-based adsorbents itself produces undesirable wastes and increases the carbon footprint.



  • Removal of heavy metal-ions, such as hexavalent chromium (Cr(VI)), from a solution.
  • Water and wastewater treatment.



  • PCC is an environmentally friendly biomass-based adsorbent.
  • Chitosan is non-toxic and readily available.
  • A one-step chemical reaction for production.
  • Cost-effective method of production.