Phosphate removal from aqueous solutions using natural and thermic treated dolomites: equilibrium, kinetic, and thermodynamic

This study aims to evaluate the effect of natural and calcined dolomites on phosphate removal in aqueous solution. The solids were characterized and the effects of pH, contact time, and solid concentration on the removal process were analyzed. Dolomite showed an enhanced surface property induced by the thermal treatment at 800 degrees C, which increased the surface area from 2.350 to 6.229 m(2) g(-1), calcium and magnesium carbonates were converted to their respective oxides, and the material showed better sorption proprieties for phosphate removal. The adsorption process showed 70-90% of phosphate removal using natural and calcined dolomites, respectively, under the experimental conditions of pH 11, 60 min contact time, and 10 mg L-1 initial phosphate concentration. Pseudo-second-order and Langmuir/Redlich-Peterson were the mathematical models that best described the kinetic and equilibrium mechanisms for phosphate removal. The thermodynamic parameters suggest a spontaneous, endothermic, and random process at the solid/solution interface, confirming a favorable adsorption system. The removal process was controlled by chemisorption phenomena. In that context, natural dolomite can be modified to enhance the surface property induced by the thermal treatment making it a more promising material for use in immobilization of anion pollutants such as phosphate.

Automated summary

The study evaluates the effectiveness of natural and calcined dolomites for phosphate removal in aqueous solution. Calcined dolomite exhibited enhanced surface properties and improved sorption capabilities compared to natural dolomite. The adsorption process showed high phosphate removal rates using both types of dolomites, indicating their potential for efficient removal of phosphate pollutants.