Adsorption study of an organo-arsenical with chitosan-based sorbents.

In this study, chitosan-based copolymers were prepared at various weight ratios of chitosan (C) to glutaraldehyde (G): 1:1 (CG11), 2:1 (CG21), and 3:1 (CG31). The sorption properties of these copolymers were investigated with roxarsone in simulated aquatic conditions at pH 7 in phosphate buffer, similar to that found in poultry litter leachate. The relative sorption capacity (Q(m); mmol/g) of the sorbents are listed in parentheses in descending order: CG11 (1.80)>CG31 (0.945)>CG21 (0.802)>chitosan (0.416). The sorptive properties of the copolymers are comparable to granular activated carbon (GAC), a standard carbonaceous sorbent material, where Q(m)=2.36 mmol/g. The adsorption properties of phenolic adsorbates such as o-nitrophenol, p-nitrophenol, and roxarsone with the CG copolymers and GAC were investigated at various pH and compared with phosphate and carbonate buffer systems.