Green synthesis of copper oxide/nanographene nanocomposite as a novel adsorbent for enhanced CO2 capture.

The present study examined the carbon dioxide (CO2) capture capabilities of copper oxide/nanographene (CuO/NG) nanocomposites, representing a novel generation of eco-friendly adsorbents. In addition to CuO/NG nanocomposites prepared using conventional methods, CuO/NG-green nanocomposites were developed using a "green synthesis" method involving hemp (Cannabis sativa L.) stalk bio-extract. The nanomaterials were characterized using a range of techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and Brunauer-Emmett-Teller (BET) method. Greater homogeneity in morphology and particle size distribution was revealed in the nanocomposites obtained by green synthesis. It has been indicated by BET analysis that a surface area of 644 m2 g-1 and an average pore diameter of 4.28 nm are possessed by the CuO/NG-green nanocomposite. Experiments involving CO2 adsorption were carried out at temperatures of 273 K and 298 K within a pressure range of 0-1 bar. The results showed that the CuO/NG-green nanocomposite had the best performance, with CO2 uptake capacities of 4.21 mmol g-1 at 273 K and 3.62 mmol g-1 at 298 K under 1 bar. The values obtained for this material are higher than those of the CuO/NG nanocomposite that was synthesized using the conventional method. Additionally, it was indicated by the isosteric heat of adsorption (Qst) values that stronger interactions with CO2 were exhibited by the CuO/NG-green nanocomposite. Additionally, after 10 cycles of reuse testing, the CuO/NG-green nanocomposite exhibited excellent reusability, maintaining 93% of its CO2 uptake capacity. The findings indicate that synthesized CuO/NG-green nanocomposites have the potential to be utilized as sustainable, high-performance CO2 adsorbents, positioning them as promising candidates for environmentally friendly carbon management technologies.