Rejection rate and mechanisms of drugs in drinking water by nanofiltration technology

Abstract

Nanofiltration (NF) technology is a membrane-based separation process, which has been pervasively used as the high-effective technology for drinking water treatment. In this study, a kind of composite polyamide NF thin film is selected to investigate the removal efficiencies and mechanisms of 14 trace drugs, which are commonly and frequently detected in the drinking water. The results show that the removal efficiencies of most drugs are quite high, indicating the NF is an effective technology to improve the quality of drinking water. The removal efficiencies of carbamazepine, acetaminophen, estradiol, antipyrine and isopropyl-antipyrine in ultrapure water are 78.8 ± 0.8%, 16.4 ± 0.5%, 65.4 ± 1.8%, 71.1 ± 1.5% and 89.8 ± 0.38%, respectively. Their rejection rates increase with the increasing of their three-dimensional sizes, which indicates that the steric exclusion plays a significant role in removal of these five drugs. The adsorption of estradiol with the strongest hydrophobicity has been studied, which indicates that adsorption is not negligible in terms of removing this kind of hydrophobic neutral drugs by NF technology. The removal efficiencies of indomethacin, diclofenac, naproxen, ketoprofen, ibuprofen, clofibric acid, sulfamethoxazole, amoxicillin and bezafibrate in ultrapure water are 81 ± 0.3%, 86.3 ± 0.5%, 85.7 ± 0.4%, 93.3 ± 0.3%, 86.6 ± 2.5%, 90.6 ± 0.4%, 59.7 ± 1.7%, 80.3 ± 1.4% and 80 ± 0.5%, respectively. For these nine drugs, their rejection rates are better than the above five drugs because they are negatively charged in ultrapure water. Meanwhile, the membrane surface presents the negative charge. Therefore, both electrostatic repulsion and steric exclusion are indispensable in removing these negatively charged drugs. This study provides helpful and scientific support of a highly effective water treatment method for removing drugs pollutants from drinking water.

110th Anniversary: Polyamide/Metal–Organic Framework Bilayered Thin Film Composite Membranes for the Removal of Pharmaceutical Compounds from Water

“…5 Several research studies have examined the use of membrane technologies as effective processes to remove micropollutants from water. 6,7 Nanofiltration has become an interesting membrane separation process in a wide range of fields (pharmaceuticals, 8 food, 9 textile, 10 drinking water, 11 etc.) due to its low consumption of energy and low-cost maintenance in comparison with other separation processes such as distillation 12 or reverse osmosis 13 for both aqueous and organic streams.…”

Reclamation of aqueous solution synthetically polluted with endocrine disturbing chemicals by commercial NF membrane

“…At pH  5 the rejection of DBP decreases with the increase of the pH and at pH  7, the rejection is increased with increasing the pH value while, lower rejection has been recognized between pH 5-7 with insignificant effect of pH at this range [20]. Meanwhile, at pH  7 the rejections of APAP and BPA decrease with the increase of the pH and at pH  9, their rejections are increased with increasing the pH value while, lower rejection has been recognized between pH 7-9 with insignificant effect of pH at this range [21]. This may be linked to the dissociation equilibrium pKa values the understudied EDCs which 5 for DBP and 9 for APAP and BPA.…”

Removal of Enantiomeric Ibuprofen in a Nanofiltration Membrane Process

“…Mechanisms of adsorption could include both hydrophobic interactions and the formation of hydrogen bonds between IBU and the membrane surface [36]. Previous studies have attributed IBU adsorption only to the membrane surface, neglecting to fully understand the behavior of IBU, hence, conceivably reporting inaccurate rejection values in flat-sheet studies [37][38][39][40]. At an initial racemic concentration of 1.08 mg/L, 83.7 µg/L IBU adsorbed onto the equipment and NF270 membrane.…”