Abstract:
In the present work, hexavalent chromium and COD removal from electroplating wastewater
was investigated using a low cost activated carbon, which was carbonized and activated from
corncobs. Corncob based activated carbon (CAC) was characterized to understand the
adsorption characteristics of chromium (VI) ions on adsorption and its physiochemical
properties. The particle size of CAC was in the range of 450-850 jim. Proximate and ultimate
analysis of CAC showed the presence of high carbon content. BET surface area and pore
volume were found 399.006 m2g' and 0.23 cm3g 1 respectively. The effect of parameters
such as temperature (T), adsorbent dose (w), pH and contact time (t) on adsorption of
chromium ions by CAC was investigated. The pH z3.0 is found to be optimum for the
removal of Cr(VI) and COD from wastewater by CAC at an optimum dose of 15 Kg/m3.
Optimum value of contact time is found as 6 hr. Various isotherm models were fitted for
Cr(VI) and COD removal. Freundlich model well fitted to Cr(VI) adsorption while Redlich-
Peterson is found to be fit for COD removal. Pseudo-second order kinetic model was well
fitted for both Cr(VI) and COD removal. Thermodynamic parameters represent the
exothermic and spontaneous nature of adsorption.
