Preparation and Application of TiO2 Nanowires-loaded Porous Ti-Ni Alloy

Porous Ti-Ni alloy was prepared by dipping method and vacuum sintering. Glue and Ti-Ni powders (95 wt% Ti+ 5 wt% Ni) were mixed together to get a slurry. Then a piece of open cell polymer foam (20 mm X 20 mm X 2 mm) was dipped into the shiny. After being stirred in the slurry for 1 h, the polymer foam was pulled out and squeezed to remove extra slurry. The polymer foam loaded with Ti-Ni slurry was sintered at 1473 K in vacuum for 2 h. With the decomposition of polymer foam at high temperature, an open cell porous Ti-Ni alloy with pore diameter about 0.2 mm was obtained. Because of the addition of Ni powders, porous Ti-Ni alloy has obvious metal luster. A hydrothermal process was applied for TiO2 nanowires preparation. 5 g of porous Ti-Ni alloy was placed in 20 mL H2O2 (30%) aqueous solution at 373 K for 16 h. Then the porous Ti-Ni alloy was filtered out and washed with deionized water. After being dried at 373 K for 6 h, TiO2 nanowires-loaded porous Ti-Ni alloy (TWP-alloy) was obtained. Then the TWP-alloy was characterized by X-ray diffraction and scanning electron microscope. The length of TiO2 nanowires on the surface of Ti-Ni porous alloy was about 2 mu m and the diameter of the nanowires was about 20 nm. In the XRD pattern of TWP-alloy, the major phase was Ti and minor phase was TiNi. After being heat-treated at 723 K for 4 h, the phase of the TiO2 nanowires coated on porous Ti-Ni alloy was changed into rutile. During the heat-treatment from 298 K to 723 K, no anatase phase was observed. This means the formation of anatase phase was blocked by the dimension effect of TiO2 nanowires. Then a kind of streaming wastewater treatment instrument was assembled by using TWP-alloy as anode and porous Ni as cathode. Methyl orange solution was taken as a sample to investigate the wastewater processing efficiency of TWP-alloy. Under the anode voltage of 30 V, the discoloration of methyl orange can get 93% under the flow velocity of 200 mL/min.