First, color.
The role of photocatalyst is determined by the particle size of the main raw material titanium dioxide. The smaller the particles, the better the photocatalytic effect. The titanium dioxide in high-quality photocatalyst stock solution is nano-scale, and the appearance of photocatalyst is colorless liquid, translucent liquid or milky white liquid. Because the core technology of photocatalyst, namely dispersion technology, is better, high-quality photocatalyst generally has no precipitation or only a little precipitation, while inferior products will have a lot of white precipitation due to poor material selection and poor dispersion technology. This kind of precipitation is not caused by the so-called high content of nano-titanium dioxide, but is entirely caused by materials and technology. Some products are high-viscosity slurry, which is generally not caused by the high content of nano-TiO _ 2, but by the selected adhesives (most of these products are organic adhesives, which will lead to poor product stability due to the gradual decomposition of organic adhesives by photocatalyst) and backward dispersion technology.
Second, the smell
A high-quality photocatalyst is an odorless aqueous solution. If the bottle cap containing photocatalyst liquid is opened, there will be peculiar smell, such as alcohol smell, resin smell and other organic smells, all of which are inferior photocatalyst, and the secondary pollution is serious.
Third, the color change of the product under illumination.
Fake photocatalyst is made by adding organic binder, dispersant and other organic substances into titanium dioxide, which will turn black in a few hours under direct sunlight. Because titanium dioxide can also have a weak photocatalytic reaction under illumination to oxidize the organic components in its solution. A good photocatalyst solution is an inorganic binder, and the product has no color change under illumination.
Fourth, measure the PH value.
Buy a pack of PH test paper in the chemical reagent shop, and the price is around 2 yuan; Insert test paper into photocatalyst to measure PH value. High-quality photocatalyst products are neutral, with a PH close to 7, and will not corrode objects. Strong acid or alkali is used in the production of inferior photocatalyst, and the PH value is below 6 or above 8, which has obvious corrosion effect. After a period of time, the surfaces of walls, furniture and fabrics will change color. If the dealer buys such goods, wait for the user to claim compensation.
Verb (abbreviation of verb) Test of oxidation ability under indoor natural light.
Good photocatalyst can only show its effect under indoor visible light, while inferior products can only be excited by ultraviolet light and can only be used outdoors, and the indoor use effect is extremely poor. Buy a bottle of methyl blue (an organic dye) in a chemical store and make it into a solution with a concentration of 100ppm (one in ten thousand). Dropping methyl blue solution into a glass test tube filled with photocatalyst and placing it indoors. The quality of photocatalyst which can make methyl blue fade is good, but the fading is not obvious. You can also use the method of red ink, dip a little red ink in the photocatalyst solution and stir until it is reddish (too heavy color may lead to too long decomposition time, which is difficult to judge in a short time), and expose it to the sun. The decomposition effect of high-quality photocatalyst is obvious for a few hours, while the fake photocatalyst will not change even after a few days. The determination of this method should first be based on the PH value of photocatalyst.
Six, objectively and scientifically judge the product description
Photocatalyst acts as a catalyst by absorbing light energy. In the dark state, photocatalyst has no energy and naturally has no effect. It is extremely irresponsible for consumers to add formaldehyde scavenger to cope with the detection after treatment just because the quality of their products is not up to standard. Formaldehyde scavengers and decoration deodorants have a quick deodorizing effect, but the effect is only a few days. Because formaldehyde is constantly released from boards and adhesives, the treated room will soon exceed the standard, causing secondary pollution. The makers of these fake and shoddy products have also invented many new terms such as cold catalyst and natural catalyst to deceive dealers and consumers. Of course, we can't use such products. Imagine the real technological development of photocatalyst in just a few years. Japan, South Korea and other developed countries have not developed so-called photocatalyst (cold catalyst, natural catalyst) that can work without light, but how can this product appear everywhere in China? Therefore, consumers should learn to make scientific and objective judgments.
From /view/23839.htm