Removal, Adsorption, and Cleaning of Pharmaceutical on Polyamide RO and NF Membranes

Pharmaceuticals are present in various waters and can be almost completely rejected by membrane separation processes, i.e., nanofiltration (NF) and reverse osmosis (RO). Nevertheless, the adsorption of pharmaceuticals can decrease their rejection, so adsorption can be considered a very important removal mechanism. In order to increase the lifetime of the membranes, the adsorbed pharmaceuticals must be cleaned from the membrane. The used pharmaceutical (albendazole), the most common anthelmintic for threatening worms, has been shown to adsorb to the membrane (solute-membrane adsorption). In this paper, which is a novelty, commercially available cleaning reagents, NaOH/EDTA solution, and methanol (20%, 50%, and & GE;99.6%) were used for pharmaceutical cleaning (desorption) of the NF/RO membranes used. The effectiveness of the cleaning was verified by Fourier-transform infrared spectra of the membranes. Of all the chemical cleaning reagents used, pure methanol was the only cleaning reagent that removed albendazole from the membranes.

Automated summary

Pharmaceuticals present in water can be removed almost completely by membrane separation processes like nanofiltration and reverse osmosis. However, their adsorption onto the membranes can reduce their removal efficiency, making adsorption an important removal mechanism. Commercially available cleaning reagents including NaOH/EDTA solution and methanol were used to clean the membranes, and pure methanol was found to be the most effective in removing albendazole from the membranes, as confirmed by Fourier-transform infrared spectra.