Removal of toxic metal ions from simulated wastewater using hydrophilic interpenetrating polymer networks

The synthesis and characterization of interpenetrating polymer networks (IPN) comprised of chitosan and polyacrylamide, which could be used as a biosorbent was successfully achieved. The uptake of metal ions such as Cr(VI), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)was investigated and the conditions were optimized.Various spectroanalytical tools such as FT-IR, EPR, SEM, SEM EDAX and PXRD were used for the characterization of the synthesized IPN and the derived metal complexes. Parameters such as pH of the solution, concentration of the metal ion solution, and temperature were found to control adsorption process and the order of adsorption capacities for the studied metal ions was Cr(VI) > Fe(II) > Cu(II) > Zn(II) > Ni(II) > Co(II). Of the various adsorption isotherms Freundlich isotherm explains the experimental data satisfactorily. Thermodynamic study revealed the exothermic nature as well as the spontaneity of Cr(VI) adsorption by IPN. The possibility of IPN to be used as an effective adsorbent was evident from the selectivity towards Cu(II) from simulated waste water. This study showed that IPN could be used as an efficient adsorbent material for the removal of metal ions from aqueous solutions.