Impact of humic acid fouling on membrane performance and transport of pharmaceutically active compounds in forward osmosis

Abstract

The impact of humic acid fouling on the membrane transport of two pharmaceutically active compounds (PhACs) -namely carbamazepine and sulfamethoxazole -in forward osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was promoted by the complexation with calcium ions in the feed solution and the increase in ionic strength at the membrane surface due to the reverse transport of NaCl draw solute. The increase in the humic acid deposition on the membrane surface led to a substantial decrease in the membrane salt (NaCl) permeability coefficient but did not result in a significant decrease in the membrane pure water permeability coefficient. As the deposition of humic acid increased, the permeation of carbamazepine and sulfamethoxazole decreased, which correlated well with the decrease in the membrane salt (NaCl) permeability coefficient. It is hypothesized that the hydrated humic acid fouling layer hindered solute diffusion through the membrane pore and enhanced solute rejection by steric hindrance, but not the permeation of water molecules. The membrane water and salt (NaCl) permeability coefficients were fully restored by physical cleaning of the membrane, suggesting that humic acid did not penetrate into the membrane pores. Abstract 16The impact of humic acid fouling on the membrane transport of two pharmaceutically 17 active compounds (PhACs) -namely carbamazepine and sulfamethoxazole -in forward 18 osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was 19 promoted by the complexation with calcium ions in the feed solution and the increase in ionic 20 strength at the membrane surface due to the reverse transport of NaCl draw solute. The 21 increase in the humic acid deposition on the membrane surface led to a substantial decrease 22 in the membrane salt (NaCl) permeability coefficient but did not result in a significant 23 decrease in the membrane pure water permeability coefficient. As the deposition of humic 24 acid increased, the permeation of carbamazepine and sulfamethoxazole decreased, which 25 correlated well with the decrease in the membrane salt (NaCl) permeability coefficient. It is 26 hypothesized that the hydrated humic acid fouling layer hindered solute diffusion through the 27 membrane pore and enhanced solute rejection by steric hindrance, but not the permeation of 28 water molecules. The membrane water and salt (NaCl) permeability coefficients were fully 29 restored by physical cleaning of the membrane, suggesting that humic acid did not penetrate 30 into the membrane pores. 31

Osmotic dilution for sustainable greenwall irrigation by liquid fertilizer: Performance and implications

“…We surmise that foulant deposition facilitated the formation of a thin fouling layer which reduced reverse solute diffusion. Similar reduction in reverse solute transport was reported in our previous study where humic acid fouling was examined using NaCl draw solution [43].…”

The performance of forward osmosis process in treating the surfactant wastewater: The rejection of surfactant, water flux and physical cleaning effectiveness

“…For instance, X. Jin et al [18] investigated the rejection of pharmaceuticals by FO membranes and found that thin film composite (TFC) polyamide based FO membranes exhibited excellent performance with high water flux and great rejection of pharmaceutical (>94%). Xie and his co-workers [19,20] applied FO to treat the wastewater containing pharmaceutically active compounds and found that humic acid fouling decreased water flux, but enhanced solute rejection. R.V.…”

Isotope osmosis—Osmotic transfer of water isotopologues through the polymer membrane in the course of direct osmosis

“…Since the active layer of the membrane is characterized by selective ionic penetrability along the flow the transfer of dissolved components J c will take place counter to this flow. As is known, the process of forward osmosis always takes place against the background of internal and external concentration polarization (CP) [17][18][19][20]. External CP appears at the membrane-solution interface.…”