Rational surface modification of zirconium-based metal-organic framework nanomaterials for the adsorption and recovery of coloured drugs and proteins from aqueous solutions

Coloured drugs and proteins in pharmaceutical wastewater cause environmental pollution. Metal-organic frameworks (MOFs) can be used for the adsorption and recovery of pollutants from wastewater, however se-lective adsorption and desorption on MOFs are challenging. Herein, UiO-66 and various polyethylene glycol (PEG)-modified MOFs (UiO-66 @mPEG-PO3 and UiO-66 @DSPE) were synthesised to selectively adsorb and separate model drugs [curcumin (CUR) and myricetin (MYR)] and proteins [Bovine serum albumin (BSA) and ovalbumin (OVA)]. Results show that UiO-66 adsorption efficiency for CUR and MYR in aqueous solution reached 93% and 98%, respectively. Additionally, CUR and MYR adsorbed on the UiO-66 surface exhibit good antioxidant activity during the recycling process. X-ray photoelectron spectroscopy and Hirshfeld surface anal-ysis indicate that the adsorption mechanisms of both CUR and MYR by UiO-66 are belonging to the intermolecular interactions. The UiO-66 @mPEG-PO3 significantly reduces the surface area of UiO-66 (216 m2/ g) but does not alter the adsorption behaviour of drugs. In the process of desorption and separation of CUR and MYR, the UiO-66 @PEG-PO3 exhibits a higher desorption rate than UiO-66. By contrast, the UiO-66 @DSPE MOFs exhibits optimal protein adsorption and selectively enhances the desorption of OVA rather than BSA in a 40% acetonitrile solution. This method can be used to capture and detect OVA proteins in cell lysates. Rational surface modification is an effective way to improve the adsorption selectivity and recovery efficiency of zirconium-based MOFs, providing an effective way to use MOFs in treating novel water pollutants.