efficacy of blending g-c3n4 positioning in the polysulfone support layer on the performance of fo membrane for removal of dexamethasone

Due to their potential or established negative effects on human health and the aquatic environment, pharmaceutical chemicals such as antibiotics, nonsteroidal anti-inflammatory medications (nsaids), anticonvulsants, blockers, etc. have become new categories of water pollutants. similar to other active pharmaceutical ingredients (apis), dexa has contributed to the treatment of millions of people globally for various medical conditions. however, dexamethasone has been identified among the apis of emerging concern (ec) in aquatic systems, thanks to advances in analytical techniques with very low detection limits (parts per trillion (ppt) levels). this is because, firstly, dexa is a known endocrine disruptor because it is in the family of glucocorticoids. secondly, bu and colleagues have raised the possibility of dexa as an ec since it is a high-production volume (hpv) drug with consequently large emissions into ecosystems (musee et al., 2021). the expansion of nanomaterials with their unique features makes it possible to modify membrane systems using nanomaterials. nanomaterials can be incorporated into membranes differently (rezaei‐dashtarzhandi., 2020). in a study, functionalized carbon nanotubes (fcnt) were blended with the support layer, and then the polyamide layer on the substrate was obtained from the interfacial polymerization reaction. by using this membrane in the forward osmosis system, they were able to increase the water flux by 72% and improve the reverse salt flux selectivity (rsfs) by 15% (choi et al., 2017). the performance of thin-film composite (tfc) reverse osmosis (ro) membranes is discussed in relation to the effectiveness of placing functionalized carbon nanotubes (fcnt) in a polyethersulfone (pes) support layer. observations of membrane hydrophilicity, under the seawater reverse osmosis (swro) operating pressure, the tfc membrane with fcnt in the support layer of the ftfc membrane displays a 44% improved water permeability, which can be further broken down into a 10–20% enhanced water flow and a 90% improvement. (son et al., 2015). in this work, we decide to synthesize a thin-film composite mixed matrix membrane (tfc mmm) with g-c3n4 by the same method and to see the effect of g-c3n4 in improving the performance of forward osmosis system in pharmaceutical pollutant rejection and water flux. for the preparation of thin film nanocomposite (tfc) membrane, first, 17.5% wt of polysulfone, and 0.5% wt of pvp were mixed in nmp solvent, then it was cast on glass and immersed in the water bath for phase inversion. the polyamide layer was obtained by the interfacial polymerization reaction of tmc and mpd. in this regard, 15 ml of mpd (0.2% wt) and tmc solution in hexane (0.1% wt) were respectively poured on the substrate and then removed from the substrate. to prepare the tfc mmm membrane, all the same steps are performed as for the tfc membrane, with the difference that in this case, 0.2 wt% g-c3n4 was added to the mixture of polysulfone, pvp and, nmp. as the result, in comparison to blank thin film composite, water flux improved by 46%.