Comparative Study of Adsorption Dynamics of Fe(II) Using Bentonite Clay and Activated Carbon

Abstract

Demands for a better quality of treated effluent have led to an intensive use of adsorption process as a polishing technology. The present study was aimed at removing iron using a non-conventional adsorbent, bentonite clay and a comparison of the same with activated carbon which happens to be a conventional adsorbent. The effect of contact time. adsorbent dosage. pH
and initial concentration on the kinetics of adsorption was studied. It was
shown that iron removal increases with increasing contact time and becomes
constant after 1 h. In case of both bentonite clay and activated
carbon percentage of adsorption was found to increase with increasing
adsorbent dosage. The effect of pH on removal of Fe(II) showed that %
adsorption increases with inceasing pH up to a certain level; thereafter it
decreases. The rate constants for removal of Fe(II) with bentonite clay and
activated carbon for varying initial metal concentration showed it to be a
first order kinetics. The adsorption data fitted well into Freundlich adsorption
isotherm. The comparison of K, the adsorption capacity, and 1/n, the
adsorption intensity, values showed that bentonite clay, a non-conventional
adsorbent, is on par with activated carbon in effectively removing Fe(II)
from an aqueous solution.