Síntese, caracterização e avaliação do adsorvente HDL-Mg/Al magnético na remoção de arsênio(V) de água

Abstract

Magnetic magnesium/aluminum layered double hydroxide (Magnetic Mg/Al LDH) was prepared and characterized, aiming to evaluate its adsorptive capacity for the removal of arsenic ions present in aqueous solution. Two types of experiments were carried out: batch and continuous fixed-bed column. For the batch experiments adsorbent mass, contact time, pH of the contaminant solution and temperature of the contaminant solution. In the fixed-bed column, a certain adsorbent mass was packed in a column, through which the standard solution of the contaminant was eluted. The data obtained in the batch and continuous flow experiments were adjusted by the isotherms and kinetics models using adsorption reaction equations. Indeed, adsorbent solid was characterized by infrared vibrational spectroscopy (FTIR), thermogravimetric analysis (TGA), X ray diffractometry (XRD), N2-BET physiosorption analysis and point of zero charge of the material to evaluate the surface dependence of charge and pH of the contaminant solution, as an important factor for the adsorption process of the arsenic ions. The obtained results in the batch experiments indicated a 98% removal of the arsenic ions from the aqueous medium and the data was fitted using Langmuir isotherm model, with magnetic Mg/Al LDH maximum adsorption capacity of approximately 17 mg of arsenic per gram of adsorbent. The adsorption reaction follows pseudo-second order kinetics, with a rate constant of 1.13 mg.g-1.min-1. The experiments peformed with continuous flow showed a maximum capacity of 2.79 mg.g-1.min-1.