Cobalt nanoparticles embedded into polydimethylsiloxane-grafted cocoa shell: functional agrowaste for CO₂ capture

This paper presents for the first time surface functionalization of cocoa shells (CS) through the covalent grafting of 3-aminopropyltriethoxysilane (APTES) followed by the substitution of poly(dimethylsiloxane) (PDMS) and in situ generation/insertion of cobalt nanoparticles (Co-NP). The immobilization and stability of APTES–PDMS on cocoa shell were confirmed by Fourier transform infrared spectroscopy and differential scanning calorimetry. Morphological analyses by scanning electron microscopy demonstrated that Co-NPs successfully grew on the surface of CS–APTES–PDMS. The CO₂-adsorption capacity of these new materials was examined at ambient conditions. Both CS–APTES–PDMS and CS–APTES–PDMS–Co showed increased CO₂ adsorption capacities as compared to unmodified cocoa shell. This enhancement was explained by the synergetic behavior of the silane derivate, PDMS grafting, and Co-NP incorporation for CO₂ adsorption. This work represents a new step toward using cocoa shell as an excellent low-cost candidate for a variety of environmental applications such as CO₂ storage at ambient temperature.