Intensification of the separation of CuO nanoparticles from their highly diluted suspension using a foam flotation column with S type internal

Foam flotation is a promising technique for recovering nanoparticles from their highly diluted suspensions. In this work, a novel S type internal was developed to intensify the foam flotation of CuO nanoparticles (357.6 nm in average particle size) from their suspension of 6.2 × 10 −2  mmol/L. By enhancing foam drainage, the S type internal increased the enrichment ratio of CuO nanoparticles by 139.3 ± 12.5 % without significantly affecting their recovery percentage. Under the optimal conditions of Cetyl trimethyl ammonium bromide (CTAB) concentration 0.45 mmol/L, superficial airflow rate 2.6 mm/s, and volumetric feed rate 1.0 mL/min, the enrichment ratio and recovery percentage of CuO nanoparticles reached 81.6 ± 4.1 and 95.4 ± 4.9 %, respectively, using the foam flotation column with the S type internal. Furthermore, about 95 % CTAB could be recycled by recovering CTAB from the foamate and the residual solution. The recovered CuO nanoparticles were associated with CTAB molecules, so they had better dispersity and dispersion stability than the starting CuO nanoparticles. Therefore, they would have good reusability.