Zeolitic imidazolate framework-67/carboxylated graphene oxide nanosheets incorporated polyethersulfone hollow fiber membranes for removal of toxic heavy metals from contaminated water

The removal of toxic heavy metals (e.g., copper and lead), owing to their hazardous effects on the human body, from water sources using membrane technology has been an attractive research area in recent years. In the present study, a novel nanohybrid comprising of zeolitic imidazolate framework-67 nanoparticles-decorated carboxylated graphene oxide nanosheets (ZIF-67/cGO) was synthesized and incorporated in polyethersulfone (P) hollow fiber membranes (HFMs) to enhance their separation performance. It was found that the presence of ZIF-67/cGO nanohybrid in HFMs positively altered the physicochemical properties of the resulting nanocomposite (ZcGP) HFMs, which helped them in achieving remarkably high pure water flux (346.4 ± 11.2 L/m²/h) and excellent flux recovery (95.7%). The adsorption capacity of these HFMs was 66.4 ± 3.2 mg/g for Cu²⁺ and 86.4 ± 4.3 mg/g for Pb²⁺. Moreover, significantly high removal of heavy metal ions (94.5 ± 1.2% for Cu²⁺ and 97.8 ± 1.1% for Pb²⁺) from the contaminated water was measured. The nanocomposite HFMs were easily regenerated to reuse them for 5 filtration cycles. Therefore, with these results, this study presented a novel membrane material for the efficient separation of heavy metals from the contaminated water sources.