Relevant chemical reaction of
water and carbon dioxide
The hydrogen gas produced from protons derived from a carbon dioxide/water mixture can be used for the storage of renewable energy during periods of high availability of renewable energy (strong sunlight, high wind, etc.). The hydrogen gas produced from protons derived from a carbon dioxide/water mixture can be used also to produce methane. Methane is produced when hydrogen gas is reacted with carbon dioxide emissions derived from combustion of fossil fuels, particularly methane and coal combustion. That is, methane production can be the result of recycling carbon dioxide emissions.
One area of research conducted by Unique Global Possibilities explores the chemical properties of water and carbon dioxide. The chemical properties of water and carbon dioxide provide the foundation for eliminating carbon dioxide (greenhouse gas) emissions from fossil fuel combustion, particularly methane (natural gas) and coal combustion. In addition, the chemical properties of water and carbon dioxide provide the foundation for the storage of renewable energy during periods of high availability of renewable energy (strong sunlight, high wind, etc.).
The water molecule consists of one oxygen atom and two hydrogen atoms and has chemical formula H₂O. Water has bonds angled at about 104 degrees. The molecule is a polar molecule with a dipole moment (1.85 Debyes). The oxygen atom is partially negatively charged and the hydrogen atoms are partially positively charged.
The bond angles and the partial charges of water molecules give water its physical properties. At ambient temperature the partial positive and negative charges on water molecules attract other water molecules and water is a liquid.
The carbon dioxide molecule consists of one carbon atom and two oxygen atoms and has chemical formula CO₂. The molecule does not possess a dipole moment but has polarizability (2.63 x 10‾²⁴ cm³). Carbon dioxide can be described as a linear resonance hybrid where the oxygen atoms can be partially negatively charged and the carbon atom can be partially positively charged. At ambient temperature carbon dioxide is a gas.
When carbon dioxide is mixed/dissolved in water, the slight negative charge on the oxygen atom of a water molecule can interact with the slight positive charge on the carbon atom of a carbon dioxide molecule.
The products of this interaction can be a proton (H⁺) and a bicarbonate ion (HCO₃‾). Under standard conditions, the equilibrium constant of this interaction is given generally as Ka = 4.3 x 10‾⁷ (giving a mild acidic pH value of pH = 6.4).
The production of protons and bicarbonate ions by the reaction of water and carbon dioxide can be represented schematically by the following chemical equation:
H₂O + CO₂H+ + HCO₃-
The solubility of carbon dioxide gas in water increases as the temperature of water decreases. That is, carbon dioxide is more soluble in cold water than it is in warm water. For example, the solubility of carbon dioxide at various temperatures is:
0°C 1.6 liters of CO₂ per liter water
10°C 1.0 liters of CO₂ per liter water
20°C 0.8 liters of CO₂ per liter water
40°C 0.5 liters of CO₂ per liter water
In addition, the solubility of carbon dioxide in water increases as the pressure of the carbon dioxide gas increases. That is, carbon dioxide is more soluble in water under higher pressures.
Carbon dioxide in cold water under pressure is the method used to produce common soda drinks (carbonated soft drinks). Soda drinks can often have an acidic pH value of about pH = 3.0.
When carbon dioxide is mixed/dissolved in water, under appropriate conditions of temperature and pressure, the concentrations of protons and bicarbonate ions in water can be quite substantial. It is possible to achieve proton and bicarbonate ion concentrations of more than 10‾¹ moles per liter. That is, it is possible to reach an acidic pH value less than pH = 1.0.
In a carbon dioxide/water mixture, an acidic pH value less than pH = 1.0 has potential for the production of hydrogen gas economically. Hydrogen gas may be derived from the protons in solution by using a small electric current passed between two electrodes that are immersed in the carbon dioxide/water mixture.