TITLE:
Adsorptive Removal of Ni(II) from Water Using Alginate-Fixed Water Hyacinth: Effect of Organic Substances
AUTHORS:
Courtie Mahamadi, Bridget Madocha
KEYWORDS:
Eicchornia crassipes; Adsorption; Langmuir Model; Freundlich Model; Nickel
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.4 No.8,
August
2,
2013
ABSTRACT: The potential of water hyacinth—Eichhornia
crassipes biomass immobilized in calcium alginate for
the adsorption of Ni(II) from water was studied using the Langmuir and Freundlich
adsorption models. The equilibrium adsorption data were obtained at different
initial Ni(II) concentrations = 0.05-2 mg/L, temperature
= 30℃± 0.2℃, agitation rate = 150 rpm, equilibration time = 3 hr, biosorbent dose
=4 g/L, and pH range = 4-7.4. Langmuir isotherms gave monolayer sorption capacities (qm) of 26.5, 44.3 and 53.0
mg/g for the removal of Ni(II) in the presence of methanol, without added
organic substance, and in the presence of acetonitrile, respectively. These
findings were also confirmed by the trend in the Freundlich isotherm parameter
(1/n 1). Interpretation of the sorption data in terms of the
separation factor, SF, suggested that the
removal of Ni(II) from water mainly occurred through a chemisorption mechanism.
Desorption experiments to recover Ni(II) from the adsorbent showed that highest
amounts of the metal could be removed from the adsorbent when previously
adsorbed in the presence of 1-(2-Thiazolylazo)-2-naphtol (TAN) (>90%). The results
from these studies indicated that E. crassipes fixed on calcium alginate
beads is a viable metal enrichment media that can be used freely immersed in
solution to achieve very high adsorption capacities and possible
preconcentration of Ni(II) in aquatic environments.