Preparation and Characterization of a Calcium Carbonate Aerogel

Abstract

We report on a facile method for the preparation of a calcium carbonate aerogel consisting of aggregated secondary vaterite particles with an approximate average diameter of 50 nm. It was synthesized via a sol-gel process by reacting calcium oxide with carbon dioxide in methanol and subsequent supercritical drying of the alcogel with carbon dioxide. The resulting monolith was opaque, brittle and had overall dimensions of 6 × 2 × 1 cm. It was characterized by X-ray powder diffraction, nitrogen adsorption method (BET), and scanning electron microscopy.

Synthesis and properties of magnesium carbonate xerogels and aerogels

“…After completeness of the reaction with CO 2 (30 min), the product was isolated from the solution by removal of methanol in vacuo, yielding a colourless, x-ray amorphous powder. Comparison with literature data [21,22] and earlier work of the authors [18] suggested that methoxymagnesium methyl carbonate was obtained. This was confirmed by infrared spectroscopy which produced the spectrum ( Quantification of the mass of dried product obtained, compared to the amount of magnesium methanolate employed proved that CO 2 was inserted into one methylate group (theoretical mass increase factor 1.51, found 1.58).…”

“…However, plasters consisting of an inorganic and an organic material present a problem for disposal later on when the building is modified or torn down. In 2009, we reported on the facile synthesis of a CaCO 3 aerogel from simple raw materials (CaO, CO 2 and methanol) [18]. Its preparation involves a calcium methanolate solution which is purged with CO 2 gas to yield calcium di(methylcarbonate) as intermediate compound which is then subject to controlled hydrolysis to produce a CaCO 3 sol containing particles in the low nanometer size range.…”

Preparation of CaCO3 and CaO Replicas Retaining the Hierarchical Structure of SpruceWood

“…The concept of wood replication with CaCO 3 is based on the hydrolysis of calcium di(methylcarbonate) as precursor [25]. First, calcium dimethylate is prepared by reacting calcium metal with methanol (Eq.…”

“…Very recently calcium carbonate aerogels have been considered as a potential replacement for polystyrene foam contained in heat insulating renders and panels used by the construction industry [24]. The preparation of CaCO 3 aerogels utilizes calcium di(methylcarbonate) as precursor and subsequent hydrolysis to calcium carbonate particles [25]. However, their poor mechanical strength currently restricts their use as insulating material in cement mixtures.…”

“…In this study, we investigated the fabrication of hierarchically structured CaCO 3 by using calcium di(methylcarbonate) as calcium precursor [25] and subsequent hydrolysis into a CaCO 3 sol. After infiltrating spruce wood templates with the precursor, their cellulose matrix was removed by calcination at temperatures varying between 350 and 900 • C. Calcination temperature and duration was varied in order to study their effect on the type of CaCO 3 polymorph formed, on the CaCO 3 particle size, the quality of replication, and the mechanical stability of the replica.…”