EQUILIBRIUM AND KINETICS STUDY OF REACTIVE RED 123 DYE REMOVAL FROM AQUEOUS SOLUTION BY ADSORPTION ON EGGSHELL
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 (R-2>0.90) and based on the Langmuir isotherm the maximum amount of adsorption (q(max)) was 1.26 mg/g. Increase of the eggshell dose and the solution temperature beyond 45 degrees 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 the improvement of dye adsorption. The kinetic studies revealed that the adsorption of reactive red 123 was rapid and complied with pseudo-second order kinetic (R-2= 0.99), with the kinetic constant of 0.02 g/mg.min.