Extraction of penicillin-G from pharmaceutical wastewaters via a developed hydrophobic PVDF-HFP hollow fiber membrane contactor and process optimization

Abstract

Discharge of pharmaceutical wastewaters can cause substantial environmental impacts. Since the conventional wastewater treatment processes are not efficient for comprehensive separation of pharmaceutical substances, a non-dispersive solvent extraction via a hollow fiber membrane contactor can be a promising alternative. In the present study, a structurally developed poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hollow fiber membrane was fabricated via a non-solvent induced phase separation (NIPS) process to enhance extraction of penicillin-G (Pen-G) from the wastewater. Response surface methodology (RSM) was used for optimization of the main operating variables in the liquid–liquid membrane contactor process. From FESEM examination, the prepared membrane showed an open structure with large finger-likes, ultra-thin outer skin, and inner skinless layer. The membrane presented a narrow pore size distribution with mean pore size of 0.038μm, water contact angle of about 94°, critical water entry pressure of 350 kPa, and overall porosity of about 84 %. Extraction of Pen-G from the aqueous phase by 5 wt% organic solution of Aliquat 336 was performed. The feed concentration of 218 ppm, temperature of 41 °C, flowrate of 51 ml/min, and the organic phase flowrate of 144 ml/min were the optimum values predicted by the model. A maximum Pen-G extraction flux of 1.55×10−3 kg/m2 s was predicted at the optimum operating conditions. The value of error between the experimental and predicted fluxes was about 3.23% which confirmed accuracy of the model. Due to the developed membrane structure, the prepared PVDF-HFP hollow fiber membrane showed a considerably higher Pen-G extraction flux compared to the PP commercial membranes.