The adsorption capacity of CaO-based adsorbents decreases over several cycles of CaO carbonation/calcination. CaO can also be prepared from CaCO 3 by decomposition above 900 ☌. The calcination temperatures of CaO from Ca(OH) 2 precursor are found in the range of 450–650 ☌. Varying these methods, all physical and chemical properties of nano-CaO can be changed morphology, specific surface area, and capturing efficiency can be carefully controlled under specific synthesis conditions. Various methods such as sol–gel, thermal decomposition, hydrothermal technique, combustion method, co-precipitation technique, biogenic method, precipitation method, two-step thermal decomposition technique, one-step multi-component synthesis, and microwave synthesis can be used for the preparation of CaO nanoparticles.

It is demonstrated even by the fact the CaO is unstable in air and will gradually convert back to CaCO 3 when cooled back to room temperature. Calcium oxide has been regarded as one of the most promising candidates for carbon capture due to its good kinetics and high capture capacity, low running cost, and even under low CO 2 partial pressures. It can be used as a catalyst, pellet for CO 2 capture and kinetic analysis, toxic-waste remediation agent, or as an additive in refractory and paint industries, antimicrobial agent, a drug delivery agent, as well as in various other biomedical applications. However, when the CaO nanoparticles are kept in the air at 100–200 ☌, they mostly capture water vapor from the air instead of carbon dioxide, and the resulting calcium hydroxide blocks the carbon dioxide capture by CaO nanoparticles.Ĭalcium oxide (CaO) is an important inorganic compound.

Therefore, if this material is disposed in open fields (not necessarily in industrial conditions), it is able to capture carbon dioxide from normal air slowly, but surely. It is also shown that when these CaO nanoparticles are kept at room temperature in air, they fully and spontaneously transform into CaCO 3 within 3 weeks. It is shown that calcination of Ca(OH) 2 in vacuum takes place faster/at a lower temperature compared to the calcination in air due to the higher entropy of the gaseous product of calcination. The produced NPs were characterized for chemical composition, phase composition, particle size distribution, morphological features, specific surface area, and crystallite sizes. In this paper, the preparation of calcium oxide (CaO) nanoparticles (NPs) is reported by a precipitation method, using CaCl 2 and NaOH as starting raw materials.

Calcium chloride precipitation