Open AccessINVESTIGATION OF Cr (VI) IONS ADSORPTIVE REMOVAL FROM AQUEOUS SOLUTION ONTO TiO2-AC COMPOSITE: NON-LINEAR EQUILIBRIUM MODELING AND KINETICS.
Author(s) -
Sali Mouhamadou,
Constant Tcheka,
Raphaël Djakba,
Narcisse Dobe,
Gilbert Mando,
Harouna Massaï
Publication year - 2021
Publication title -
international journal of engineering, sciences and research technology
Language(s) - English
Resource type - Journals
ISSN - 2277-9655
DOI - 10.29121/ijesrt.v10.i1.2021.3
Subject(s) - freundlich equation , adsorption , langmuir , ionic strength , endothermic process , point of zero charge , chemistry , aqueous solution , chemisorption , langmuir adsorption model , thermodynamics , analytical chemistry (journal) , inorganic chemistry , chromatography , physics
The present work dedicated to the removal of Cr(VI) ions in aqueous solution onto a synthetized TiO2-AC composite. Composite characterization was carried out by determining of the point of zero charge pHpzc, iodine number, methylene blue index and FT-IR spectra. Adsorption experiments were conducted in batch mode and the influences of composite quantity, contact time, Cr(VI) ions concentration, ionic strength, and pH were studied. The highest adsorption were obtained in acid medium, with lowest adsorbent quantity (0.01 g) and initial solution concentration of 10 ppm. The results of kinetic studies revealed that Cr(VI) adsorption process on TiO2-AC composite followed pseudo second-order kinetic model. Non-linear regression was applied to equilibrium data and Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models were used for evaluation of adsorption parameters. The best-tting was estimated based on correlation coefficient R2 value and the calculation of error deviations between experimental and predicted equilibrium adsorption data, using non-linear analysis. The results showed that Freundlich model describing adsorption process the best. The isotherm parameters from Langmuir and Freundlich models revealed that Cr(VI) adsorption mechanism on the composite is linear, spontaneous, and endothermic follows chemisorption process.