•A novel amine-grafted mesoporous coppersilicate named CSNS-TA was synthesized for CO2 capture.•The CO2 adsorption was at relatively mild conditions, e.g., ambient temperature and pressure.•CSNS-TA presents high CO2 capture capacity, recyclability and long-term stability.•The high efficiency was proposed from the unique microstructure, stable amines grafted on CSNS.Amine-functionalized nanomaterials have significant potential in CO2 capture technology because of their low energy consumption, stable performance, and high regeneration capacity. Novel amine-functionalized adsorbents composed of copper silicate nanospheres (CSNSs) grafted with mono-, di- and tri-aminosilanes were synthesized for CO2 capture. The synthetic process and formation mechanism were systematically investigated using transmission electron microscopy, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, and N2 physisorption analysis, etc. The copper silicates with rich surface hydroxyl groups, significant surface areas and mesoporous structures facilitated chemical modification of amines, leading to a high CO2 adsorption capacity (a maximum CO2 uptake of 47.88 mg/g) and excellent cyclic regenerability (maximum deviation of 3.51% after 20-times test) for CSNS-TA. In addition, the CO2 capture process was carried out under relatively mild conditions, e.g., adsorption at 298 K, desorption at 373 K and ambient pressure, suggesting that these amine-modified CSNSs have potential as solid sorbents for CO2 capture.Download high-res image (145KB)Download full-size image

This article describes a novel CO2 mineralization approach using natural insoluble K-feldspar and phosphogypsum for the emission of CO2, reduction of phosphogypsum waste, and production of soluble potash. K-feldspar was activated with CaSO4 at high temperature and then mineralized with CO2 to extract potassium under hydrothermal conditions. Activation and mineralization conditions (e.g., ore/CaSO4 mass ratio, calcination and mineralization temperatures, initial pressure of CO2) were systematically investigated with an optical potassium extraction ratio of ∼87% and a CO2 mineralization ratio of ∼7.7%. A reaction mechanism was proposed based on the experimental results and the characterizations, such as polarized light microscopy, X-ray diffraction, and thermogravimetric and differential thermal analyses. This new methodology is a promising process and has the potential to reduce emissions of CO2 and phosphogypsum from a practical point of view.