Synthesis and surface modification of CuO nanoparticles: Evaluation of dispersion and lipophilic properties

The CuO nanoparticles (NPs) were synthesized by chemical precipitation from the reaction of CuCl2⋅2H2O with ammonia solution, and then the calcination of precipitate at 450 °C for 5 h. The surfaces of CuO NPs were modified using palmetic acid and stearic acid. The optimum of surface modification NPs were obtained 5% of modifier, room temperature and an hour for reaction time. The CuO NPs and its modified were characterized by FT-IR, XRD, SEM, EDX, and TGA analysis. The average sizes of CuO particles were calculated 22 nm from XRD diffraction. TGA analysis of modified CuO NPs indicates that the grafting amount of palmitic acid and stearic acid are 3.4 and 5.0% respectively. The change of behavior of hydrophobic surfaces of modified CuO NPs was confirmed through lipophilic degree (LD) experiments. The results revealed that LD increased with the rising amount of modifier up to 5% for both modifiers. The dispersion of modified CuO NPs was determined in ethanol, acetone, tetrahydrofuran (THF), dioxane, n-hexane, CH2Cl2 and CCl4. The experimental results showed that the highest dispersion of modified CuO NPs happened in CCl4. The photocatalytic activity of NPs was also studied in the degradation of methyl orange solution. The results show that the photocatalytic degradation of CuO NPs decreases when modified by both fatty acids.