Efficient adsorption of erionyl red from polluted water using activated calcium clay as a novel natural-based adsorbent

Nowadays, water is regarded as a rare resource that must be protected. However, the increase in industrial activities is generating increasing pressure on the planet's freshwater reserves. These activities generate a wide variety of chemicals that flow into the water cycle, endangering the fragile natural equilibrium that has allowed life to develop on earth. Often, chemicals in wastewater are difficult to biodegrade and the lack or insufficiency of treatment systems leads to their accumulation in the water. As part of this work, the adsorption properties of Erionyl Red dye on acidified calcic clay were studied using experimental methods. After activation with sulphuric acid, X-ray diffraction analysis was carried out indicating an increase in the basal distance, X-ray fluorescence analysis showed the chemical composition of the clay in the form of oxides. The results showed that the material produced had very significant adsorption properties, with the Freundlich model describing the isotherm well and the pseudo-second-order model giving a better account of the adsorption kinetics, the thermodynamic study shows that adsorption is spontaneous, favorable and endothermic. From the results obtained, we can conclude that clay chemically activated by sulfuric acid can be used successfully for the treatment of textile effluents.