Composite separating membrane of Si-doped TiO2 nanotube and its preparing method and application

Abstract

The present invention relates to membrane technology, and is especially composition separating membrane of Si-doped TiO2 nanotube and its preparation and application. The process of preparing composition separating membrane of Si-doped TiO2 nanotube includes the following steps: cleaning and stoving porous inorganic ceramic membrane carrier with pores of 10-200 nm diameter, preparing TiO2 sol containing Si in 5-50 mol%, soaking the carrier in the sol, drying, roasting at 400-700 deg.c, and cooling to obtain the composition separating membrane with TiO2 nanotube of inside diameter 1-200 nm. The composition separating membrane of Si-doped TiO2 nanotube is used in water treatment.

Description

technical field [0001] The invention relates to a separation membrane product and its preparation method and application, more specifically, to a silicon-doped titanium dioxide nanotube composite separation membrane using porous inorganic ceramic membranes as a carrier and template, and its preparation method and application, belonging to the field of membrane technology . Background technique [0002] Membrane separation technology is a gas-phase or liquid-phase separation process under the driving force of pressure difference. It has attracted widespread attention because of its obvious advantages such as no phase change, low energy consumption, simple equipment, and less land occupation. Membrane separation technology has been initially industrialized, and ultrafiltration and microfiltration technology first appeared. In 1918, Zsigmondy proposed the preparation method of commercial microfiltration membrane, which was patented in 1921. With the development of membrane se...

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Problems solved by technology

[0003] Inorganic ceramic membrane has more practical application value and prospect. It has the advantages of high temperature resistance, good chemical stability, high mechanical strength, strong anti-microbial ability and narrow pore size distribution range; however, its disadvantages are: small filling area, The operating cost is high, the membrane is easy to pollute, and the separated pollutants need secondary treatment. In the separation process, the membrane only plays a simple filtering function, and the membrane separation cannot completely decompose and remove the pollutants.

[0005] Although photocatalytic technology has many advantages, this method is difficult to industrialize. The main problems are: (1) powder catalyst particles are easy to lose with the treatment liquid or treatment gas, and are difficult to recycle; TiO 2 Photocatalysts usually have a narrow spectral utilization range, weak surface hydrophilicity, and low mechanical strength, resulting in low photocatalytic activity and application stability of the catalyst.

[0006] Based on the advantages and disadvantages of membrane separation technology and photocatalytic technology, on July 30, 2005, Dalian University of Technology proposed a patent application for titanium dioxide nanotube composite separation membrane, its preparation method and application with the publication number CN1745886A, which has become a typical example of the existing technology. , this technology uses an inorganic photocatalytic composite membrane to combine two mutually independent unit operations of photocatalysis and membrane separation into one unit operation, which has the integrated function of photocatalytic decomposition and membrane separation, but there are also shortcomings: since there is no element The doping of titanium dioxide cannot effectively inhibit the growth of titanium dioxide grains, resulting in the minimum pore size that can be prepared by the composite film is only 20nm, the photocatalytic treatment rate reaches 80-95% in 4-6h, the surface hydrophilic wetting angle is greater than 10° and the film fragile surface

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