Cross-linking organic frameworks (MOF, COF, POF) with graphene oxide for the fabrication of composite membranes for the rejection of antibiotics (amoxicillin and metronidazole) and bisphenol A from wastewater.

The increasing levels of micro pollutants in water bodies possess a huge threat to the environment and human health. In this study, composite membranes for the rejection of micro pollutants were prepared by cross-linking graphene oxide (GO) with metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and porous organic frameworks (POFs) nanomaterials using glutaraldehyde as the cross-linking agent to improve the stability and effectiveness of the membranes. Four composite membranes were fabricated: MOF-GO, COF-GO, POF-GO (1:1), and POF-GO (1:5). The micro pollutants attempted to be removed were amoxicillin, bisphenol A, and metronidazole at 1 M concentration. From the experimental data, out of the membranes produced, the POF-GO (1:5) membrane showed the maximum rejection rates of 93%, 90%, and 92% for amoxicillin, bisphenol A, and metronidazole, respectively. This high performance is achieved to its optimal porosity and increased hydrophilicity (pore size, 28.21; contact angle = 74.7° ± 3.2°), leading to better water flow. And the MOF-GO membrane obtained a high pure water flux of 152 L·m⁻2·h⁻1 and a rejection of 92%, 94%, and 90% for amoxicillin, bisphenol A, and metronidazole, respectively. The results show that POF-GO (1:5) and MOF-GO membranes can efficiently remove micro pollutants from wastewater.