Carbonation and Graphene Oxide: A Solution for Reducing CO₂ Emissions In previous articles, we discussed the cement industry's impact on CO₂ emissions and the commitments made to reduce them by 2050. Today, we explore how carbonation—a process generally seen as a concrete pathology—could help offset some CO₂ emissions from cement production. What is Carbonation? In concrete, carbonation is a natural process where CO₂ from the environment reacts with moisture in the concrete, converting the alkaline calcium hydroxide in cement paste to calcium carbonate with a more neutral pH. This reaction lowers the concrete's pH from around 12–13 to approximately 9, exposing steel reinforcements to corrosion. What Affects Carbonation? Carbonation rate depends on the diffusion of CO₂ and its reactivity with the cement matrix, which is in turn influenced by the matrix's microstructure, hydration products (calcium hydroxide, calcium silicate hydrate, alkaline oxides, etc.), and pore structure (distribution, size, and saturation). Therefore, carbonation proceeds more slowly in low-permeability or dry concretes than...

Graphene The Most Versatile Carbon Allotrope with Extraordinary Properties  Carbon is one of Earth’s most abundant elements and vital for living organisms. Known as the “king” of the periodic table, its chemical properties are exceptional due to an electronic structure capable of forming single, double, and triple bonds, allowing it to create up to ten million compounds.  Carbon allotropes are carbon-based materials with different molecular configurations and, consequently, unique properties. For instance, in graphite, a soft, thermally resistant, and electrically conductive material, carbon atoms form three covalent bonds in a hexagonal pattern, arranged in stacked layers loosely bonded together.  Graphite's common uses include pencils, batteries, and lubricants. Meanwhile, in diamond, an insulating material highly valued in jewelry, carbon atoms are bonded covalently in a tetrahedral structure, giving it extreme hardness used mainly for cutting tools.  Other lesser-known carbon allotropes are nanometric in size (smaller than 0.1 microns). These include fullerenes, which resemble a soccer ball and can act as semiconductors...