The effective recovery of CuO nano-particles from organic solvent by using froth flotation

The recovery of nano-catalysts from organic wastewater is still one of the most significant problems in the catalytic industry. In this work, froth flotation was used to solve this problem. CuO nano-particles were considered as the desired materials. First, four surfactants were screened for determining a suitable collector through comparing their foam properties and capture capacity to CuO nano-particles. Subsequently, froth flotation was performed by using cocamidopropyl betaine (CAB) as the collector. Under the suitable operation conditions, the enrichment ratio and recovery percentage of CuO nano-particles reached as high as 20.52 and 91.50%, respectively. Finally, the size distribution and morphology of CuO nano-particles before and after froth flotation were characterized. Experimental results indicated that the dispersibility of the recovered CuO nano-particles after froth flotation was better than that of the commercial CuO nano-particles due to the existence of surfactant molecules around the nano-particle surface. This work is expected to provide a new insight into the effective recovery of nano-catalysts from the downstream industrial effluent and to facilitate the industrialization of froth flotation in the green catalytic industry.