Conversion of eggshells into calcium titanate cuboid and its adsorption properties

Abstract

This article presents an economical approach for the production of calcium titanate using a simple hydrothermal reaction of calcined eggshells and TiO2. The characterization of the product is carried out by using X-ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and nitrogen adsorption/desorption. The result shows that as-prepared calcium titanate has a cuboid-like structure with a size of 0.2 μm, as determined by SEM. The formation mechanism of the cuboid-like morphology of calcium titanate is suggested. The BET surface area was calculated to be 20.9 m2/g. The prepared calcium titanate was investigated for the adsorption of Congo Red and its adsorption capacity was found to be 30 mg/g. The optimum adsorption conditions were found to be initial Congo Red concentration = 50 mg/L−1, pH = 7, adsorbent dose = 0.1 g and contact time = 120 min. The adsorption process was found to be spontaneous and endothermic in nature and follows a pseudo-second-order kinetic model. This research furthers understanding of the ability of calcium titanate to adsorb Congo Red and opens up a new method for recycling eggshells.