Heavy metal removal adsorption capacity, chitosan

The process does not stabilize the removed heavy metals, additional treatment is required for recycling or disposal of the removed ions. The crosslinking process renders the chitosan beads insoluble in dilute acid but reduces compression strength and adsorption capacity relative to the uncrosslinked chitosan adsorbent bead. Adsorption capacity of chitosan is reduced as pH decreases. 

Guan et al. (2009) removed trivalent chromium ions from waste water using synthetic zeolites. It was observed that zeolite can selectively adsorb chromium even in the presence of other alkali and alkaline earth metal cations including sodium and potassium. Xie et al. (2012) stated that if zeolites are modified with chitosan by forming a monolayer of chitosan on zeolite surface their adsorption capacities increases and they can preferentially adsorb phosphorous along with many other heavy metals from waste water. It was attributed to the increased porous structure of zeolites and non-zeolite fraction of different oxides. Monolayer of chitosan acted as binding material for adsorption of different heavy metal ions. 

---