Photosynthesis of Chromium Oxide/Reduced Graphene Oxide Nanocomposites and its Application in Water Desalination and Purification

Introduction: Clean, safe and potable water with high specifications has been acquired from the red seawater (Suez, Egypt) by utilizing graphene-based chromium oxide (Cr2O3/r-GO) nanocomposites. Experimental: Cr2O3 nanoparticles and Cr2O3/ r-GO nanocomposites have been synthesized from a toxic source (K2CrO7) using the photochemical reduction method where trimethyl ammonium chloride and trisodium citrate working as capping and reducing agents under visible light irradiation. The size, morphology and optical properties have been characterized by Transition Electron Microscopy (TEM), X-ray Diffraction (XRD) and UV-Vis spectrophotometry. Water without salts, lethal metals and no recording micro-organisms were secured in less than 3 hours by utilizing simple distillation in the presence of Cr2O3 nanoparticles with average size 5.0 ± 1.36 nm and Cr2O3/r-GO nanocomposites with average size 3.0 ± 1.69 nm. The evaporation of water was improved due to the productive photothermal change of the Cr2O3 nanoparticles that have two plasmonic bands (423 nm and 576 nm) and the presence of exceptionally highly efficient thermal capacitor, graphene. These Cr2O3/r-GO nanocomposites demonstrated a high gain of temperature and high stability after multiple times of recycling processes. Results: The antimicrobial action of Cr2O3 and Cr2O3/r-GO nanocomposites was examined against Bacillus subtilis (gram positive, G+), Escherichia coli (gram negative, G-), Pseudomonas aeruginosa (gram negative, G-) and Staphylococcus aureus (gram positive, G+). From the results, Cr2O3 nanoparticles showed higher inhibition zone diameters against these microbes than Cr2O3/r-GO nanocomposites. Conclusion: The unique properties, environmental safe, low cost and ease of these composites became them highly efficient alternative in water desalination technology.