Designing of the green γ-AlOOH@Naringin thin film composite PVDF based nanofiltration membrane and application for pharmaceutical wastewater treatment

Abstract

Herein, the green naringin functionalized boehmite (γ-AlOOH@Nar) bionanocomposite was used to fabricate the high-performance thin film composite (TFC) polyvinylidene fluoride (PVDF) based nanofiltration (NF) membrane with enhanced antifouling properties and pharmaceutical rejection. For this aim, the PVDF NF membrane was first activated by triazinyl groups. Then the membrane surface was subsequently functionalized by the γ-AlOOH@Nar nanocomposite at different concentrations (0.2, 0.4, and 0.6 wt%). The γ-AlOOH@Nar TFC NF membranes were characterized by means of Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscope (AFM), zeta potential, and thermogravimetric analysis (TGA). Moreover, the mean pore radius, porosity, surface hydrophilicity, salt rejection, pure water flux, and antifouling properties of the membranes were investigated. The 0.4 wt% γ-AlOOH@Nar TFC (TFC-0.4) membrane showed a pure water flux of 53.6 L/m2h and FRR of 95.4%, which were about 2.3 and 2.4 times that of the blank membrane. The TFC-0.4 membrane not only provided the highest permeability and surface hydrophilicity but also lowered the irreversible fouling ratio while keeping high pharmaceuticals rejection (99.8% for both Ceftriaxone (CTX) and cephalexin (CEX)). The pharmaceutical wastewater filtration showed that the γ-AlOOH@Nar TFC membranes achieved high normalized flux and also provided 89.8% COD removal, 100% turbidity removal, and moderate TDS removal (53.0%). Overall, the γ-AlOOH@Nar TFC membranes exhibited high separation performance and excellent antifouling properties showing their great potential for use in pharmacutical wastewater treatment facilities.