Calcium Oxide Matrices and Carbon Dioxide Sensors

Abstract

Homogeneous matrices of calcium oxide (CaO) were prepared by mixing this material with polyethylene glycol (PEG) acting as malleable inert support in order to obtain processable composites. Preliminary tests were carried out to assess the best concentration of CaO in the composite, individuated in the CaO/PEG weight ratio of 1/4. Experimental data highlighted that the composite was able to selectively detect carbon dioxide (CO2) via a nanogravimetric method by performing the experiments inside an atmosphere-controlled chamber filled with CO2. Furthermore, the composite material showed a linear absorption of CO2 as a function of the gas concentration inside the atmosphere-controlled chamber, thus paving the way for the possible use of these matrices for applications in the field of sensor devices for long-term evaluation of accumulated environmental CO2.

Prototypes of Newly Conceived Inorganic and Biological Sensors for Health and Environmental Applications

“…Taking into account all the considerations so far discussed and the three sensors recently introduced in the literature [2,3,5], in this section we summarize the techniques and procedures utilized in the construction of the three distinct prototypes.…”

“…We used inorganic nanocomposites, such as matrices of calcium oxide [2], and biological ones such as Nucleic Acid Programmable Protein Arrays (NAPPA) [3,4] along with Langmuir-Blodgett (LB) multi-layers of proteins of primary interest such as laccase [5,6]. Special attention was paid to the detection of substances significant for both the environment (such as carbon dioxide) and medicine (drugs and cancer) by means of a wide variety of detection methods (amperometric, conductometric, and nanogravimetric).…”

“…Sensors for detection of CO 2 [2] can be useful to reveal the increased emissions of gases from fossil fuel combustion, industrial processes, and agriculture associated to deforestation and habitat destruction. This can result in consequent changes in the chemical composition of the atmosphere with direct biological effects and negative influence on the Earth’s climate [2] considering that fossil fuel CO 2 emissions can remain in the atmosphere for periods of up to tens of thousands of years.…”

“…This can result in consequent changes in the chemical composition of the atmosphere with direct biological effects and negative influence on the Earth’s climate [2] considering that fossil fuel CO 2 emissions can remain in the atmosphere for periods of up to tens of thousands of years. The instruments generally employed in these determinations basically consist of infrared (IR) detectors performing a continuous plotting in the site with a good degree of accuracy, but they cannot be used for extensive mapping work because of the large number of expensive devices and specialized people that would have to be involved.…”

“…An alternative long-term sampling method for the determination of environmental CO 2 accumulation takes advantages of the properties of CaO to be carbonated by this gas as shown in reference [2], according to the following equation: $\mathbf{CaO}+{\mathbf{CO}}_2\rightleftarrows {\mathbf{CaCO}}_3$…”