Removal of Zn(II) from Wastewater by Ion Flotation: Determination of Optimum Conditions

Ion flotation includes removing of ions from solution by adding chemical reagents such as collectors in the presence of air bubbles. In this study, removal of Zn(II) cations was studied from low concentration synthetic wastewater by ion flotation. Sodium dodecyl sulfate (SDS) and ethylhexadecyldimethylammonium bromide (EHDABr) were used as collectors and methyl isobutyl carbonyl (MIBC) and Dowfroth250 as frothers. To investigate the effective parameters, the experimental design was performed supporting by DX7 software. Two-level factorial method was used. Sixteen experiments including 6-level variables were designed. The tests were conducted in Hallimond tube. The results showed that the optimal conditions for the removal of Zn(II) ions were: pH=3, SDS= 300 ppm, Dowfroth250= 90 ppm and air flow rate= 1.8 ml/min. Optimal results were evaluated in a mechanical flotation cell. In optimal condition, recovery of Zn(II) ions and water were more than 92% and 8.65% after 10 min, respectively. This study showed that the use of ion flotation is a very effective method for Zn(II) ions removal from industrial wastewaters.