| Popis: |
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%. |
