Abstract
Chitosan was cross linked with gluteraldehyde and chemically modified by introducing xanthate group onto its backbone using
carbon disulfide under alkaline conditions. This crosslinked xanthated chitosan flakes (XC) was used as an adsorbent for the
removal of mercury ions from contaminated water streams near the coal mines. XC was found to be far more efficient than the
conventionally used adsorbent activated carbon. FTIR studies indicated the interaction both amine and the xanthate groups. The
maximum uptake of mercury by XC in batch studies was found to be 425.5 ± 2.5 mg/g at an optimum pH of 4.0. Due to the high
formation constant of mercury with xanthate and adsorption was carried out at pH 4, anions like nitrate, chloride and sulfate up to
0.5M did not interfere in the adsorption behavior of mercury. Thermodynamic parameters such as ΔS, ΔH and ΔG indicated the
suitability of XC towards the removal of mercury. Desorption of the bound mercury from XC was accomplished with 0.01 M
NaOH. The data from regeneration efficiencies for five cycles, evidenced the reusability of XC in the treatment of mercury-laden
wastewater.