Carbon Capture Utilization (CCU) is promising technology, which has been developed under the umbrella of ideas to mitigate the adverse effects of carbon dioxide emissions by capturing CO₂ directly from the atmosphere or point sources, such as from industrial plants, for conversion into useful productss There are three basic principles behind the operation of this technology: post-combustion, pre-combustion, and oxy-fuel combustion. In post-combustion, CO₂ is separated after combustion of the fossil fuel. This technology has been applied in most of the existing power plants and industrial facilities around the world. Pre-combustion gasifies fossil fuels into a mixture of hydrogen and CO₂, separating the latter before combustion. A combustion of oxy-fuel burns fossil fuels in pure oxygen to a flue gas that is virtually just water vapor and CO₂-easy to separate. In recent years, huge strides have been made concerning the enhancement of carbon capture technology efficiency, cost reduction, and extension of applicability. These include the advanced development of solvent-based systems for capturing CO₂. New amine-based solvents have been proposed with higher CO₂ absorption capacity and/or higher reaction rates compared to traditional ones. Particularly, the use of amine-functionalized ionic liquids showed real perspectives for further reduction of energy consumption and minimization of the solvent degradation, enhancing the process cost-effectiveness and sustainability.

Other breakthroughs include the appearance of solid adsorbents, especially in the form of MOFs and zeolites, that showed immense capacity for CO₂ capture. MOFs, with tunable pore sizes combined with high surface area, have captured special attention due to selective adsorption of CO₂ against other gases. Recently, the researchers at the Massachusetts Institute of Technology have introduced a new class of MOFs that can capture CO₂ from ambient air with unparalleled efficiency, thus enabling new possibilities for technologies associated with direct air capture. Once captured, utilization of CO₂ is very important in making the CCU process viable-economically, apart from environmentally. The various products in which economic value is derived from CO₂ include chemicals, fuels, and even building materials. A case in point is the production of synthetic fuels-from captured CO₂, for example, methanol and dimethyl ether-which recently increasingly has become a promising sustainable alternative to conventionally used fossil fuels. Firms like Carbon Clean and Climeworks are among the frontrunners in developing scaled solutions for producing sustainable fuels and chemicals from captured CO₂.
It could even find its way into the construction industry by creating more sustainable building materials like carbonated concrete. A technology from a company called CarbonCure Technologies of Canada injects captured CO₂ into concrete during mixing and the material is coming out stronger, with increased durability because of the permanent sequestration of CO₂.

Notwithstanding these developments, a number of issues remain to be addressed if CCU technologies are to be scaled up. In addition, full care has to be taken vis-à-vis the risks associated with CCU technology deployment, which include indirect environmental impacts or carbon lock-in.

Adhish Mishra

University/College name : Amity University, Noida, Uttar Pradesh