Nickel(II) Removal by Phosphorylated Tamarind Nut Carbon.

Abstract

Activated carbon prepared from phosphorylated tamarind nut
(PTNC) has been used for the removal of Ni(II) from aqueous system
by batch and column experiments. The efficiency of PTNC was compared
with commercial granular activated carbon (CAC). The equilibrium
adsorption capacity was determined as a function of the solution pH,
adsorbent dosage and contact time for both carbons and found to follow
Freundlich and Langmuir isotherms. Kinetic studies indicated that the
removal process followed reversible first order equation and adsorption
of Ni(II) governed by film diffusion process. Desorption of Ni(II) from
carbons were also done by 0.3 N HCl. Column studies were conducted
in 2.5 cm diameter columns. Under optimum conditions of flow rate
and bed height, breakthrough capacities were found out. PTNC was
found to be 6 times superior to CAC in the removal of Ni(II). The mechanism
of adsorption for Ni(II) on to PTNC was found to follow ion exchange
process predominantly and supported by FT-IR. Nickel(II) removal was
also confirmed by XRD and SEM studies.