Removal and recovery of amantadine from water by liquid–liquid extraction

Liquid–liquid extraction (LLE) was firstly introduced for the removal and recovery of amantadine from its aqueous solution. The effects of process conditions, including different types of extractants and diluents, oil to water phase ratio (O/A ratio), initial concentration of amantadine and pH, on the extraction efficiency were investigated. The results showed that when the initial concentration is 1000 mg/L, more than 99.5 % of amantadine can be removed using the mixture of P 204 and n -octanol (volumetric ratio of 3:2) as mixed extractant, with the initial pH in the range of 8.0–10.0 and O/A ratio of 1:1. The removal efficiency can still be as high as 97.0 % even concentrated amantadine solution (10 g/L) was treated. A mechanism of cation-exchange reaction between amantadine and P 204 was proposed. Back extraction of amantadine using 2.0 M HCl solution as stripping agent demonstrated that about 51.1 % of amantadine was stripped from the loaded extractant. Present findings suggest that LLE could be a promising technology for the removal and recovery of amantadine from water.