Synthesis of nano-sized calcium carbonates employing molecular effect on CO2 conversion via biodegradable chelating-system

[Display omitted] •Investigated the effects of MGDA-Na3 and GLDA-Na4 as additives on morphological changes of CaCO3.•Synthetized nano-sized CaCO3 with a distinct morphology and diameter less than 50 nm.•Adsorption of chelating agents onto the edges of CaCO3 layers.•Prospect of absorbent regeneration is evaluated. With current energy demand and increased carbon dioxide emissions, the development of CO2 reduction technologies is imperative. One promising approach is to capture and utilize CO2 as a feedstock in various industrial processes. One such process is through the production of nano-sized calcium carbonate which have a wide variety of industrial applications including building materials and bio-medicine. Crystallization reaction is one of the essential factors to determine the particle size and other properties of CaCO3. Based on this background, this study proposed a novel approach to the crystallization reaction using the chelating agent’s actions under various conditions in producing high-value added CaCO3 while capturing CO2, simultaneously. Due to the limited biodegradability and environmental persistence of certain chelators, biodegradable chelating agents, such as L-Glutamic acid-N,N-diacetic acid tetrasodium salt (GLDA-Na4), and DL-Alanine-N,N-diacetic acid trisodium salt (MGDA-Na3) were used as alternatives. These are well known as a complexing agent of Ca2+ and were selected because their presence would reduce free ions, hence weakening the nucleation driving force. The proposed process involves two phases. Surrounding Ca2+ control based on chelating-systems, followed by CO2 mineralization. This study revealed that incorporating chelating agents promoted the synthesis of nano-sized CaCO3 with a diameter less than 50 nm. Furthermore, the system is technically feasible since the regenerated NaOH leachate may be reused for CaCO3 synthesis and carbonation. The suggested approach shows promise as an indispensable green technology for reducing carbon emissions and synthesizing nano-sized CaCO3 which has high demand on industries on a global basis.