Use of silver impregnated activated carbon (SAC) for Cr(VI) removal

In the present study silver impregnated activated carbon (SAC) after use in domestic water filter has been used for the removal of Cr(VI) from the synthetic solution. The Cr(VI) uptake with used SAC is very less (21 %). However, it is improved a lot (94.1 %) after treating it with H2SO4. The surface of sulphuric acid treated used SAC is characterized by XRD, FTIR, pzc, surface area, bulk density, % moisture content and % mass loss on ignition etc. Effect of different adsorption parameters such as contact time, pH, adsorbent/adsorbate doses, temperature are also studied for Cr(VI) adsorption on SAC. Lower pH favors the adsorption process with optimum contact time of 150 min. This adsorption is greatly interfered in presence of anions and the interference increases with increasing anionic charge and ionic strength. This adsorption follows Langmuir isotherm and Ho & Mc-Kay equation well. The same adsorbent can be reused in 2 more cycles. Suitability of linear form of Freundlich, Langmuir and Dubinin-Radushkevich (D.R.) isotherms are compared with the nonlinear forms of the same.