Multifunctional Nb-Cu Nanostructured Materials as Potential Adsorbents and Oxidation Catalysts for Real Wastewater Decontamination
This work describes the preparation of two niobium(V)-copper(II) based materials using a bifunctional dicopper(II) complex as a template. Material 1 was prepared by coprecipitation method in the presence of an aqueous solution of the dicopper(II) complex (n-Bu4N)4[Cu2L2] (n-Bu4N+ = tetra-n-butylammonium cation and L= N,N’-2,2’-ethylenediphenylenebis(oxamate)), ammonium niobium(V) oxalate (NH4[NbO(C2O4)2(H2O)2]), and ammonia. Material 2 was obtained by calcination of 1 at 600 oC. Both hybrid materials were characterized by micro-ATR FT-IR, RAMAN, XRPD, TEM and SEM microscopy, Brunauer, Emmett and Teller (BET) surface measurements. A microporous nanostructured niobium(V)-copper(II) complex material 1 exhibited high surface area (200 m2 g‒1) whereas material 2 consisted of a crystalline mixture of Nb2O5 and CuO phases with low surface area (40 m2 g‒1). The ability of both materials as adsorbents as well as heterogeneous catalysts to remove methylene blue dye from real wastewater was evaluated. Material 1 exhibited a remarkable maximum adsorption capacity according to the Langmuir model to niobium-based nanostructured materials (qmax = 199.20 mg g‒1). Both 1 and 2 were used as heterogeneous catalysts for removal of methylene blue dye from real wastewater by Fenton-like reaction. In the presence of hydrogen peroxide, 2 removed approximately 89% of the dye from water while 1 took 85% out of the contaminant.