There has been an alarming increase in carbon dioxide emissions from human and industrial activities. Scientists have developed a porous liquid that can store and capture carbon dioxide by converting carbon dioxide into calcium carbonate. Porous liquids like this one are easy to make and integrate into industrial processes that use continuous flow. Researchers have developed an enzyme called bicarbonate that catalyzes the conversion of carbon dioxide into calcium carbonate. Carbon dioxide is trapped in a porous liquid by the enzyme’s reaction with hollow silica nanorods containing carbon dioxide.
As carbon dioxide is converted to calcium carbonate, an acidic, porous liquid can be used for industrial purposes. As the acidity in the solution decreases, a dye that changes color can indicate that the conversion has been completed visually.
- Researchers have developed an enzyme called bicarbonate that catalyzes the conversion of carbon dioxide into calcium carbonate.
- Carbon dioxide is trapped in a porous liquid by the enzyme’s reaction with hollow silica nanorods containing carbon dioxide.
- Porous liquids like this one are easy to make and integrate into industrial processes that use continuous flow.
- The innovation lies in the combination of porosity and catalytic activity within a liquid to convert carbon dioxide and then convert it into a useful chemical.
- The carbon dioxide can be removed from the porous liquid and used again.
- The study was published in chemSusChem, a journal published by the European Chemical Societies.
- The Indian Institute of Technology Bombay, Government of India, and the Industrial Research Consultancy Centre (IRC), IITB, funded the research.
Emissions of carbon dioxide from human and industrial activities have risen alarmingly around the world. Carbon dioxide from industrial emissions is captured using physical and chemical absorption methods. Although these methods can capture and store carbon dioxide, they must be transported to a permanent storage location, which requires additional energy expenditure.
Professor Kamendra P. Sharma and his colleagues at the Indian Institute of Technology Bombay have developed a porous liquid that can capture and store carbon dioxide and then convert it into calcium carbonate, a highly sought-after industrial chemical. The innovation lies in the combination of porosity and catalytic activity within a liquid to convert carbon dioxide into calcium carbonate, which can be removed from the porous liquid and used again.. With a honey-like viscosity, this honey-like liquid is easy to produce and integrate into continuous flow industrial processes. Stability is maintained at working temperatures in the industrial sector. SERB, Department of Science and Technology (DST), Government of India, and the Industrial Research Consultancy Centre (IRC), IITB, funded the research. chemSusChem is a journal published by the European Chemical Societies.
Industrial effluent gases have traditionally been trapped in porous solid materials. Such filters can’t be easily retrofitted or integrated into continuous-flow industrial processes because solids don’t flow Although liquids can absorb gases, their storage capacity is significantly lower than that of porous solids. In addition, empty spaces in liquids are not permanent, unlike those in solids.
Liquids with permanent empty spaces were first proposed by scientists in 2007. In 2015, the first porous liquids were created. Several different methods for creating porous liquids that can efficiently absorb gases have been developed since then. Molecule cages were used to keep the large organic molecules from dissolving. However, making porous liquids in the past required lengthy organic chemistry reactions and many tedious steps to perform.
At room temperature, Prof Sharma’s team demonstrated that a simple mixture of hollow silica nanorods and the wetting agent could produce a porous liquid that was capable of capturing carbon dioxide. However, converting the captured carbon dioxide into a useful chemical without wasting additional energy is more valuable..
In the current study, an enzyme is known as bioconjugated carbonic anhydrase (bCA) and calcium chloride was used to create a liquid composite. Using carbon dioxide as a substrate, the enzyme converts the gas into bicarbonate ions. Most enzymes require water to function properly. bCA, on the other hand, thrives in the polymer environment provided by the porous liquid.
Carbon dioxide is trapped in the hollow cavities of silica nanorods when the porous liquid is exposed to carbon dioxide. The nanorods slowly release carbon dioxide after the capture. At room temperature, it reacts with bCA to produce bicarbonate ions. They combine with calcium ions from calcium chloride to form calcium carbonate crystals of micrometer size. This can be done by heating the system and allowing the crystals to settle out. After removing the calcium carbonate, the porous liquid can be reused. Builders use calcium carbonate to make ceramic tiles, chalk and health supplements.
At low temperatures, the trapped carbon dioxide can be stored in the porous liquid. After freezing the porous liquid to -60°C, the polymer shell coating the silica nanorods becomes glassy and the carbon dioxide remains trapped in the nanorods. In order to restart the conversion to calcium carbonate, the carbon dioxide must first be heated up again.
Experiments have shown that adding the enzyme has no effect on the nanorods’ shape or their ability to capture CO2. Each component in the composite was subjected to a series of controlled experiments in the laboratory. According to the experiments, an enzyme and nanorods were found to be responsible for converting carbon dioxide into calcium carbonate. A lack of the enzyme prevented calcium carbonate from forming.
Polymer surfactant liquidity allowed ions to diffuse and react, a process that cannot occur in solids, in another set of experiments by Prof. Sharma’s team. Carbon dioxide is converted to calcium carbonate, which neutralizes the acidic liquid. Chemical tests and microscopic observations are unnecessary if a dye that changes color as acidity decreases can visually indicate completion. The industry needs a simple mechanism to check if a reaction is complete, and that’s what the dye method gives them.
Before the porous liquid can be used commercially in an industrial setting, there is still much work to be done. The commercial viability of the porous liquid is currently compromised by its high cost. Enzyme production is an expensive component, so scientists have looked into finding a lower-cost alternative. Engineers will have to take into account the slow release of carbon dioxide and its conversion into calcium carbonate when designing flow rates and other relevant parameters.
An end-to-end solution to capture, store and convert industrial emissions of carbon dioxide to calcium carbonate has been demonstrated. All the materials used ensure high-temperature stability, including the porous liquid, which can operate at industrial temperatures. This does not affect the rate of carbon dioxide capture conversion until temperatures reach 50 °C. In order to better understand the efficiency of carbon dioxide capture at higher temperatures, Prof Sharma concludes.