Environmental Application of Two- and Three-Dimensional Nanomaterials for Wastewater Treatment
MXenes and metal-organic frameworks have become well-known materials among chemists, physicists, material scientists, and other field researchers, and they have attracted significant attention because of their novel chemical, magnetic, electronic, mechanical, and optical properties. Water pollution is one of the most significant challenges worldwide, and the application of novel two- and three-dimensional materials for wastewater treatment is of high importance.The first chapter of this work introduces the history, chemistry, properties, and applications of metal-organic frameworks and MXenes, two different groups of two- and three-dimensional materials. Chapter 2 of this work proposes two classes of novel silver-based metal azolate frameworks (MAF) to decorate polyamide (PA) forward osmosis membranes to improve numerous fouling and water transport aspects. Membranes functionalized with two concentrations of each MAF are compared with a pristine control material, with results that highlight their tunability and bio-inhibitory effects. These features improve the long-term water flux performance of the membranes, tested during 24 hours of accelerated biofouling and organic fouling conditions, and show lower than 10% and 20% decline in water flux. In the third chapter of this work, the surface functionalization of an ultrafiltration membrane obtained via UV-initiated grafting polymerization of acrylic acid (AA) and silver-containing metal-organic frameworks (Ag-MOFs) to achieve combined bactericidal and hydrophilic properties has been studied. The effectiveness of different modification pathways is evaluated, including Ag-MOFs blending into the AA solution followed by grafting and in-situ synthesis of Ag-MOFs over the surface of AA-grafted membranes, with the in-depth characterization of the resulting materials. In the final chapter, nanocomposites of graphene oxide (GO)-AgMOF and MXene-AgMOF were fabricated for the first time using a silver-based metal-organic framework (AgMOF) functionalized by the intercalation of graphene-oxide (GO) and MXene and investigated for the adsorption of cationic methylene blue (MB) and anionic orange G (OG) dyes. Very high adsorption efficiencies were observed for MB, with GO-AgMOF, MXene-AgMOF, and AgMOF able to remove 99.9%, 99%, and 98% of this dye from water at an initial concentration of 200 mg/L and an adsorbent mass of 0.01 g.