SYNTHESIS, CHARACTERIZATION AND APPLICATION OF BIMETALLIC OXIDE FOR ADSORPTIVE REMOVAL OF FLUORIDE FROM WATER

Abstract

A new bimetallic oxide (calcium aluminate) was synthesized using the combustion method, which offers the formation of smaller particles with open pores. The material thus synthesized and studied for its fluoride uptake properties in spiked and actual drinking waters, containing fluoride ion. The prepared adsorbent material was characterized by Fourier transform infrared (FTIR) Spectroscopy and X-ray diffraction (XRD) Spectroscopy to know the functional group analysis and surface mean crystalline size. A series of batch adsorption experiments were carried out to assess adsorption parameters that influence the adsorption process. The CA shows high adsorption capacity for fluoride ion and it is possible to effectively remove fluoride up to 98% from the initial concentration of 20 mg L^-1, using adsorbent dose of 2 g L^-1 and 60 min. The experimental data fitted well into Langmuir adsorption isotherm and follows pseudo-second-order kinetics. The thermodynamic parameters suggest the complex nature of fluoride uptake reaction, dominated by physisorption, spontaneous and endothermic process. The effective regeneration achieved up to 82.5% by treating the fluoride-loaded material by NaOH solution. Thus, the most desirable properties of the adsorbent are strong affinity for defluoridation and high adsorption capacity.