Evaluación de la adsorción de fosfatos a partir de soluciones acuosas utilizando esponjas cerámicas de esmectita natural

Abstract

Abstract: The present research study was carried out with the purpose of evaluating the adsorption of phosphates from aqueous solutions using ceramic sponges of natural smectite. For this, the modification of the natural smectite to the Al+3 form was made, the synthetic sponge molds were impregnated with a 45% by weight suspension of the modified clay and the sponges were subsequently calcined at 1000 °C. The maximum adsorption capacity of this material was 0.210 mg P/g. The experimental results were adjusted to the isothermal model of Langmuir, which indicates that the adsorption of phosphate ions occurs in specific active centers. The model that satisfactorily describes the kinetics is the pseudo first order, the intraparticular diffusion model allowed to determine that the particle diffusion, is the limiting stage that regulates the speed of adsorption. The saturation of the ceramic sponges in the continuous tests was reached at five hours. Finally, for initial solutions with concentrations lower than 25 ppm the 51% of the phosphorus adsorbed in the ceramic sponge was recovered.