Removal of water hardness from aqueous solution by BaCO3 nanoparticles

Abstract

The present study reports the water softening by removal of hardness producing ions using barium carbonate nanoparticles (BaCO₃ Nps). BaCO₃ Nps were synthesized by the PVP-assisted precipitation method. The synthesized nanoparticles were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), Scanning electron microscope (SEM), and Dynamic light scattering (DLS) analysis. The aptitude of the BaCO₃ Nps for removal of hardness from aqueous solution has been investigated by ion exchange chromatography. Effect of various parameters viz. contact time, pH effect (pH 2–10), dose of nanoparticles (0.01–0.1 g/100 ml), initial calcium and magnesium concentration (0.01–10 mg L-1) and effect of competitive ions has been investigated to determine the hardness removal capacity of BaCO₃ nanoparticles. Results of kinetic data correlated well with the pseudo-second-order kinetic model, indicate that the chemical adsorption is the rate limiting step. Thermodynamic parameters show that the removal process is spontaneous and endothermic in nature. Isotherm data suggested that not only adsorption but precipitation transformation mechanisms playing a key role in the removal of hardness respectively.