Application of solvent extraction for the removal of amoxicillin drug residues in environmental waters

In this study, extraction of amoxicillin (AMOX) ions from aqueous solution by liquid-liquid extraction (LLE) was investigated. The LLE process by response surface methodology (RSM) was carried out based on central composite design (CCD). The organic phase consisted of extractant and toluene as diluent. In this process, triethylamine (TEA), di-2-ethylhexyl phosphoric acid and mono-2-ethylhexyl phosphoric acid mixture (MDEHPA) were used as extractant. The process parameters such as extractant concentration, feed acidity, extraction time and effect of diluents were optimized. The contours and 3D response surfaces of AMOX extraction efficiency were obtained. The optimum conditions for the AMOX extraction using RSM for TEA were: feed pH 2.7, extractant concentration 12.9 %( V/V) and extraction time 19 min and for MDEHPA: feed pH 11, extractant concentration 12.3 %( V/V) and extraction time 21 min. At these condition the maximum AMOX extraction was found to be 93.5 % and 96 % using TEA and MDEHPA, respectively.