Abstract
Froth flotation is one of surfactant based separation processes which is suitable for dilute wastewater treatment. There are several advantages such as low space requirement, high removal efficiency, flexibility for various pollutants at different scales, and low cost. To achieve high performance for froth flotation, the combination of ultra-low interfacial tensions between oil and water and stable foam production must be achieved. To get the ultra-low interfacial tensions, Winsor type's III microemulsion or middle phase has to be formed. In this study, branched alcohol propoxylate sulfate sodium salt with 14 - 15 carbon and 4 PO groups (Alfoterra 145 - 4PO) was used to form microemulsion formation with diesel. The effects of surfactant concentration and NaCl concentration on phase study, foam characteristics, and performance of froth flotation operation were investigated in this work. An increase in surfactant concentration decreases interfacial tension (IFT), but increases foam stability. For the effect of NaCl concentration, the minimum IFT was achieved at 5 wt% NaCl. However, this optimum salinity cannot be operated in froth flotation experiment due to poor foam characteristics. Therefore, both IFT and foam characteristics should be optimized to achieve high efficiency of froth flotation.
