Enhanced Solar Water Desalination by CuCo₂S₄-decorated Carbon Foam Derived from Waste Plastics

Interfacial solar desalination is an emerging technology for freshwater production, but the finding of novel solar evaporators is still challenging. In the present research, graphitic carbon foam (CF) was synthesized from the upcycling of waste plastic polyethylene terephthalate (PET) waste bottles functionalized with carrollite CuCo₂S₄ as a photothermal layer. Analytical characterization [X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS)] confirms the functionalization of carrollite CuCo₂S₄ on graphitic carbon foam. The UV-Vis spectroscopy analysis showed an enhanced optical absorption in the UV-Vis-near IR region (>96%) for functionalized CuCo₂S₄-CF foam compared to carbon foam (67%). The interfacial solar desalination experiment presented a significantly enhanced evaporation rate of 2.4 kg·m⁻²·h⁻¹ for CuCo₂S₄-CF compared to that of CF (1.60 kg·m⁻²·h⁻¹) and that of CuCo₂S₄ (1.60 kg·m⁻²·h⁻¹). The obtained results proved that the newly synthesized CuCo₂S₄-CF from the upcycled plastic into new material for the photothermal desalination process can enhance the practice of a circular economy to produce fresh water.