Preparation And Water Purification And Photocatalysis Of Niobate Composites

This article was prepared two niobium-based composite materials(Fe3O4@K4Nb6O17and g-C3N4/NbOX), with respect to their adsorption properties and photoelectrochemical performance testing.Firstly,one kind of niobium-based adsorbent Fe3O4@K4Nb6O17 with varies roads to adsorb radioactive cation in waste water was synthesized by hydrothermal method. Then we tested its structures and properties by using SEM, XRD, AAS and other equipments.We explore the radioactive cation exchange capacity in simulated radioactive water with the adsorbent by using the non-radioactive Ba、Sr and Cs instead of radioactive elements131Ba、 226Ra、90Sr and 137 Cs. The theoretical saturated cation exchange capacity(CEC) to Ba2+, Sr2+, Cs+of Fe3O4@K4Nb6O17 is 1.64 mmol/g, 1.64 mmol/g and 3.28 mmol/g by calculating. The results show that Fe3O4@K4Nb6O17 can absorb Ba2+, Sr2+,Cs+and the adsorption balance can reach 1.25 mmol/g, 1.30 mmol/g and 1.12 mmol/g, accounting for76.22 %,79.27 % and 34.15 % with theoretical capacity. In addition to porous channel structure, Fe3O4@K4Nb6O17 also has the magnetic properties than other absorbents which can be recycled by one permanent magnet magnetic.Secondly, we synthesized a hydrated sodium niobate fiber Na2Nb2O6·2/3 H2 O by hydrothermal method, we made a H2Nb2O6·2/3 H2 O fiber by proton exchange method and we got different NbOX fibers by sintering method. We successfuly obtained narrow bandgap semiconductor nanocomposites with g-C3N4/NbOX by loading sheet-shaped g-C3N4 in the surface layer of the oxides.We confirmed that the addation of narrow bandgap(2.7 eV) g-C3N4 overcomes the difficuties with larger band gap of NbOX(> 3.2eV) by characterizing with DRS, PL and FTIR. Its spectral response range can be extended to the visible region by compounding. The experiments of visible degrade SRB showed that the capality of 450 ℃ 20 % g-C3N4/NbO1.64 is up to 35%.We simulated sunlight to test photoelectrocatalytic performance by means of hernia light source(filtered light below 425 nm). The results show that the PEC performance of 450 ℃20 %g-C3N4/NbO1.64 composite catalyst is preferably(0.5 μA·cm-2) and far outweigh pure g-C3N4(0.1 μA·cm-2) and pure NbO1.64(0.2 μA·cm-2).