Open AccessAdsorption, Kinetic, Equilibrium, Thermodynamic and Photocatalytic Investigations of the Removal of Nigrosin, Alizarin, Indigo and Acid Fuchsin Dyes on Modified CaO Surface
Author(s) -
Mouayed A. Hussein,
Ibtighaa K. Radhi,
Zaki N. Kadhim
Publication year - 2020
Publication title -
asian journal of applied chemistry research
Language(s) - English
Resource type - Journals
ISSN - 2582-0273
DOI - 10.9734/ajacr/2020/v6i430167
Subject(s) - adsorption , alizarin red , indigo carmine , chemistry , freundlich equation , langmuir , endothermic process , nuclear chemistry , langmuir adsorption model , aqueous solution , alizarin , gibbs free energy , inorganic chemistry , organic chemistry , medicine , staining , physics , pathology , quantum mechanics
Calcium oxide was obtained from eggshell and modified with Sulfur, Nitrogen and, Oxygen. The adsorbents were characterized using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and, scanning electron microscopy (SEM). The adsorbents were used for the removing of the dyes of Nigrosin, Alizarin red S, Indigo carmine, and Acid fuchsin from their aqueous solutions. The adsorption isotherm experiments were studied, and the equilibrium adsorption found either obeyed the Langmuir or Freundlich isotherm depending on the Sips isotherm results. Thermodynamic studies showed that the adsorption processes of the studied dyes were spontaneous, endothermic and randomness increases according to their ΔG, ΔH and ΔS values, respectively. The kinetic studies revealed that the pseudo second-order model best represented adsorption kinetics. Moreover, the photocatalytic ability of adsorbents was investigated under the sunlight, the results revealed the adsorbents have a strong photo-catalytic ability to absorb the dyes, particularly that observed for Acid fuchsin.