Effect of precursor chemistry on purity and characterization of CaCO₃ nanoparticles and its application for adsorption of methyl orange from aqueous solutions

Abstract

Pure calcium carbonate (CaCO₃) nanoparticles were synthesized by the sol-gel citrate method using either Ca (NO₃)₂ or CaCl₂ as a precursor. CaCO₃ powder analysis was conducted using X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), BET analysis, and Fourier-transform infrared spectroscopy (FTIR). The XRD patterns show that the pure phase of CaCO₃ nanoparticles was produced at calcination temperatures of 500 °C and 600 °C with surface areas of 97.8 and 195.3 m²/g for CaCl₂ and Ca (NO₃) precursor, respectively. The second phase was obtained when using CaCl₂ precursor compared with Ca (NO₃)₂. Batch experiments were conducted to study the effect of pH, initial dye concentration, adsorbent dose, and contact time on the adsorption of methyl orange (MO) dye. Three isothermal models were investigated by Freundlich, Langmuir, and Temkin, and the resulting data were well fitted into Langmuir isotherm with R²= 0.98 and adsorption capacity 110.9 mg\g. The finding reveals that 98 ± 4.9% of 50 ppm MO dye may be adsorbed at pH 2 and shaking time 2 h. Furthermore, with an increase in the initial dye concentration and dose amount, the efficiency of the removal process increases. The adsorption kinetic behavior is well acceptable with pseudo-second-order. Desorption experiments were conducted to regenerate the adsorbent with an efficiency of 92.9 ± 4.6%.

Graphical Abstract

Keywords:

• CaCO₃ nanoparticle
• sol-gel citrate method
• adsorption
• methyl orange
• desorption

Acknowledgment

Special thanks and gratefully acknowledge to Professor Fatma S. M. Hassan, professor of inorganic chemistry for support and valuable revision of the manuscript.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Funding

None.

Data availability statement

The data that supports the findings of this study are available in this article and in supporting information file.