Structural, AC conductivity, dielectric and catalytic behavior of calcium oxide nanoparticles derived from waste eggshells

Abstract

Calcium Oxide (CaO) nanoparticles have been synthesized from waste eggshells (ES) as a source of calcium by solution combustion technique using muffle furnace and microwave oven. CaO nanoparticles obtained using muffle furnace (CaO-F) and via microwave oven (CaO-M) were characterized using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, AC conductivity and dielectric studies to correlate the physico-chemical behavior. The frequency dependence of AC conductivity, the permittivity (ε′) and dielectric loss tangent (D) studies have been undertaken in the frequency range 50 Hz–5 MHz at room temperature. AC conductivity was found to enhance with an increase in the frequency. The ε′ was found to decrease initially with the frequency and finally reaching a constant value at higher frequencies. The frequency dependence of D was found to exhibit a resonance peak in the studied frequency region. Catalytic activity of CaO-M was correlated with its dielectric behavior.

Adsorption of CO2 on Activated Carbon, Fe‐Based Metal Organic Framework, ZnO, and CaO for Carbon Capture and Storage Application

“…at 37.56°, respectively. The XRD characteristic peaks for CaO at 18.23° (001), 28.86° (100), 32.48° (111), 34.29° (101), 37.56° (200), 43° (202), 47.43° (102), 50.97° (110), and 54° (220) were observed and in agreement with the literature report for CaO 32.…”

“…In the case of Fe-MOF (orange line), the initial stage of thermal degradation relates to the elimination of entrapped water molecules followed by the decomposition of O-containing functional groups. The mass decrease continuously occured until 700 °C, which is ascribed to the decomposition of the organic moiety (trimesic acid) of the MOF [32][33][34].…”

Production of Bio-Calcium Oxide Derived from Hatchery Eggshell Waste Using an Industrial-Scale Car Bottom Furnace

“…In comparison, the crystallite size of these black and white calcined eggshell samples is different from the crystallite size of natural eggshell (93 nm) [43]. In addition, chemically treated nano-calcium oxide derived from eggshell has a crystallite size of 46 nm and 82 nm [44]. Finally, pure chemical grade calcium oxide (66.3 nm) [45] and calcium oxide obtained from limestone calcined at 900°C for 30 min in a N 2 atmosphere (~57 nm) also has different crystallite sizes [46].…”

Sustainable PET Waste Recycling: Labels from PET Water Bottles Used as a Catalyst for the Chemical Recycling of the Same Bottles

“…The FTIR of the three catalysts (Figure a) shows peaks at 710, 875, and 1390 cm –1 for the calcium carbonate (CaCO 3 ), which shifted to around 1440 cm –1 for samples with higher-temperature thermolysis, indicating the change of the calcite polymorph to aragonite and the partial conversion of CaCO 3 to calcium oxide (CaO) , and a broad peak at 440–820 cm –1 for titanium dioxide (TiO 2 ) . The sharp peak at 3640 cm –1 that was observed for 800 and 1000 °C samples is attributed to Ca­(OH) 2 , which is a result of the adsorption of water by CaO and/or surface OH groups. , XRD patterns of the catalyst prepared at 600 °C (Figure b) clearly show CaCO 3 peaks as well as some of the CaO and heat-treated titanium dioxide (TiO 2 ). ,, As the temperature of the thermolysis in the furnace increased to 800 and 1000 °C, the peaks associated with CaCO 3 are diminished and the sample shows more characteristic peaks of CaO, its hydrated product Ca­(OH) 2 , as well as the peaks for heat-treated TiO 2 . , The increasing CaO content with the temperature increase is not unexpected because it is well-known that CaCO 3 starts losing carbon dioxide (CO 2 ) at higher temperatures and converts to CaO. , This is further confirmed by increasing weight loss with temperature during the preparation of the catalyst by thermolysis, as we recovered 13.5, 12.0, and 10.4 wt % of the solid content from labels at 600, 800, and 1000 °C, respectively. TGA thermograms of the label show the thermal behavior of PET/polypropylene multilayer films with the highest weight loss at 412 °C (Figure c).…”

“…34,35 XRD patterns of the catalyst prepared at 600 °C (Figure 3b) clearly show CaCO 3 peaks as well as some of the CaO and heat-treated titanium dioxide (TiO 2 ). 33,36,37 As the temperature of the thermolysis in the furnace increased to 800 and 1000 °C, the peaks associated with CaCO 3 are diminished and the sample shows more characteristic peaks of CaO, its hydrated product Ca(OH) 2 , 38 as well as the peaks for heat-treated TiO 2 . 33,37 The increasing CaO content with the temperature increase is not unexpected because it is well-known that CaCO 3 starts losing carbon dioxide (CO 2 ) at higher temperatures and converts to CaO.…”