EQUILIBRIUM AND KINETICS STUDY OF REACTIVE RED 123 DYE REMOVAL FROM AQUEOUS SOLUTION BY ADSORPTION ON EGGSHELL

Abstract

The aim of this study was to determine the equilibrium and kinetics
adsorption of reactive red 123 dye (RR 123) from aqueous solution with
chicken's eggshell as an adsorbent. The initial concentrations of
reactive red 123 dye were selected in the range of 25 and 50 mg/L. The
target adsorbent was prepared in laboratory conditions and pulverized by
ASTM standard sieves. Measurement of the adsorbent surface area was
carried out via Brunauer-Emmett-Teller isotherm. The experimental data
were analyzed with Langmuir, Freundlich and Temkin isotherm models. The
results showed that the calcium components were the main constituents of
eggshell (around 95% Ca). The experimental adsorption isotherm was in
good concordance with Langmuir and Freundlich models (R2>0.90) and
based on the Langmuir isotherm the maximum amount of adsorption (qmax)
was 1.26 mg/g. Increase of the eggshell dose and the solution
temperature beyond 45◦C led to decrease of the adsorbed dye per mass
unit of the adsorbent, but increase of the solution pH up to 9 led to
improvement of dye adsorption. The kinetic studies revealed that the
adsorption of reactive red 123 was rapid and complied with pseudo
second-order kinetic (R2= 0.99), with the kinetic constant of 0.02
g/mg.min.