Some basic knowledge about formaldehyde

After several years of hard work in the industry, I have learned a lot about the problem of formaldehyde. I will briefly introduce some basic knowledge to my friends.

1. Indoor formaldehyde pollution mainly comes from various wood-based panels. Urea-formaldehyde resin is widely used as an adhesive in wood-based panels, but it is easy to age and decompose under certain temperature and humidity conditions, producing formaldehyde and releasing it into the air. Therefore, formaldehyde is a slow and lasting release process. If the problem of formaldehyde is fundamentally solved, it is necessary to stop using urea-formaldehyde resin as an adhesive. Due to technical and cost reasons, it is difficult to realize it in China in the short term. However, formaldehyde has caused a large number of malignant diseases, so controlling formaldehyde pollution has become the focus of many people's attention.

2. Formaldehyde gas generally exists in the air. The problem is that the concentration should be within the safe range. The national and international standards "WHO Air Quality Guide" and Chinese national standard 18883 all set the limit value of 0. 1mg/m3, which is widely used to judge whether indoor air quality is qualified. However, it is reported that some developed countries have tried to reduce this value to 0.02mg/m3, because 0.02mg/m3 is a relatively safe complete formaldehyde concentration for pregnant women and infants. However, judging from the actual indoor pollution situation in China, the formaldehyde pollution degree is very serious, and it is difficult to reach below 0.02mg/m3.

3. How to reduce the indoor formaldehyde concentration? First, we need to know how the indoor formaldehyde concentration is generated. Various indoor pollution sources constantly release formaldehyde. Under the closed condition, when the formaldehyde concentration rises to a certain extent, it will in turn inhibit the further release of the release source, and then reach a dynamic balance, and the formaldehyde concentration will not change. The indoor formaldehyde concentration we refer to is the equilibrium concentration in this state. Therefore, in order to reduce the indoor formaldehyde concentration, it is necessary to treat or discharge the released formaldehyde outdoors, and the speed of treating or discharging formaldehyde is faster than that of pollution sources; Or reduce the release rate of formaldehyde, the indoor formaldehyde concentration will also be reduced, reaching another equilibrium state, which is the basic principle of reducing formaldehyde concentration.

All methods are based on this principle to reduce the harm of formaldehyde. Therefore, there are three solutions as follows:

A, formaldehyde out of the room there are two ways:

(1) Ventilation and direct exhaust.

⑵ Formaldehyde is transported outdoors through substances with adsorption properties such as activated carbon.

B, remove formaldehyde, mainly through chemical reactions to decompose or convert formaldehyde into safe and secure substances.

C, reduce the formaldehyde release rate, the main method is sealing, sealing the release source with sealant, which can delay the release of formaldehyde.

4. There are two ways to discharge formaldehyde outdoors. The first is ventilation. The better the ventilation, the lower the formaldehyde concentration. The limit state is that the indoor formaldehyde concentration is the same as the outdoor formaldehyde concentration. If the environment where you live or work can be well ventilated for 24 hours, congratulations, the place where you live and work will be envied by many people.

However, due to the influence of temperature, noise and air pollution, it is difficult to do this in practice. Here are two points that must be paid attention to in life: never send your child to a learning institution with poor ventilation; To stay in a hotel, you must first open the window to get some air.

Secondly, use activated carbon to take formaldehyde out of the room. Attention, the key here is to take it out of the room! Generally, activated carbon with good performance can be completely adsorbed in 3 ~ 5 days. At this time, it is necessary to take the activated carbon outdoors for exposure or heating, discharge the adsorbed polluted gas, and then put it back indoors for reuse. Activated carbon with good performance can be reused many times.

Therefore, it is very important to use activated carbon correctly. However, most consumers cannot send activated carbon outdoors for 3-5 days. At the same time, the amount of activated carbon should be sufficient, and a small amount will not play much role. As for the well-known diatom mud, it has a good adsorption capacity, but the ability of diatom mud to adsorb polluted gas is far less than that of activated carbon. Using diatom mud on the wall is equivalent to fixing polluted gas indoors. I believe everyone can easily understand the consequences.

5. Oxidative decomposition or chemical reaction to convert formaldehyde into safe substances is the main way to remove formaldehyde. Formaldehyde is composed of carbon, hydrogen and oxygen, and the products of complete oxidation reaction are water and carbon dioxide. Combustion can oxidize and decompose formaldehyde, and various strong oxidants can also react formaldehyde.

There are many kinds of chemicals that can react with formaldehyde, but we are dealing with formaldehyde in the air in our living and working environment. Therefore, the chemicals used need to be harmless to people first, so safety and security are the first.

Secondly, effectively reducing the concentration of formaldehyde requires sufficient efficiency, including the speed and capacity of treating formaldehyde (capacity refers to treating a large amount of formaldehyde with few substances).

Then it needs to be sustained. Because formaldehyde is released for many years, it is meaningless to treat the existing formaldehyde in the air, which needs to be consumed and treated for several years. With these three conditions, it is a good product to treat formaldehyde sincerely.

Although there are many substances that can react with formaldehyde, few products can meet the above three conditions. At present, most governance companies in the market adopt photocatalyst technology, claiming that formaldehyde can be oxidized and decomposed into water and carbon dioxide.

Photocatalyst has certain redox ability under ultraviolet irradiation, and can oxidize and decompose formaldehyde to some extent. However, the ultraviolet intensity in real life and working environment is far from strong enough to decompose formaldehyde by oxidation and reduction. Please pay attention to the experimental conditions in the report of photocatalytic decomposition of formaldehyde provided by the manufacturer. As for some new terms, such as plain photocatalyst and air catalyst, they are just new concepts used to fool people.

There are also various new concepts and terms such as plant extracts and biological enzymes, which are essentially substances secreted by organisms that can react chemically with formaldehyde under certain conditions. However, due to the small amount of active ingredients or the low reaction efficiency with formaldehyde, its effect is very small.

Developed countries have gone through our present stage. After years of exploration, it is a very effective method to convert formaldehyde into safe and complete substances by decomposing safe and complete polymer compounds. The amino polymer formaldehyde scavenger of GRAFTON Co., Ltd. is an excellent product with safety, full efficiency and long-term decomposition and conversion of formaldehyde, and has applied for patent protection in many countries, including China.

The product has been used in Japan for more than ten years, and a large number of experiments have been carried out to verify its safety, safety, effectiveness and long-term, with formal experimental reports as proof. At the same time, with the rigor of the Japanese and the spirit of being responsible for their own people, I feel I can trust them, so while solving the problems facing our country, I introduced grafton's products and studied their cutting-edge technology, hoping to improve our level.

6. The sealing method to reduce the release rate of formaldehyde is mainly to coat some substances with infiltration filling function on the surface of furniture to isolate the board from the air, make it difficult for water to enter the board, block the humidity condition of urea-formaldehyde resin decomposition, and delay the release of formaldehyde from the board to the air to some extent. Generally speaking, this method can delay the release of formaldehyde in a short time and reduce the indoor formaldehyde concentration. However, after half a month to one month, its blocking effect gradually disappears, and the purpose of reducing formaldehyde concentration cannot be achieved for a long time, and after the blocking effect disappears, it is easy to cause more serious formaldehyde release. At the same time, as the sealant needs to contact with human body, please pay attention to the safety and safety of the sealant used.

7. Another widely used high-temperature fumigation method is to use high-temperature steam to heat and humidify indoor articles, which accelerates the release of various organic volatile substances and the decomposition of urea-formaldehyde resin, and has an obvious effect on reducing decoration odor and formaldehyde in a short time. However, the damage of heating and humidification to articles is inevitable. Accelerating the decomposition of urea-formaldehyde resin will reduce the role of its adhesive, and its advantages and disadvantages need to be judged by consumers. Heating and humidifying for a long time will cause great damage to articles, which is not desirable. Short-term heating and humidification can only accelerate the release of formaldehyde in the shallow layer of the plate, and the effect lasts for a short time.

8. In short, the two key indicators to reduce indoor formaldehyde concentration are that the speed of eliminating formaldehyde is faster than the release speed of formaldehyde, and it must have the effect of eliminating formaldehyde for a long time. Therefore, a common misunderstanding is that you can live in a new house after a period of cooling, which can make the decoration smell smaller. If you let the new house and furniture live for a summer, the smell will be greatly reduced, but the amount of formaldehyde released will not change greatly.

There are too many tragedies caused by formaldehyde pollution in society. I hope this article can help consumers to know more about formaldehyde and cause the society to explore ways and methods to solve the harm of formaldehyde.

Yantai Yin Guang Environmental Technology Co., Ltd. is a scientific and technological service-oriented environmental protection enterprise dedicated to indoor environment detection, treatment and air purification, focusing on indoor maternal and infant in addition to formaldehyde, formaldehyde detection, sterilization and deodorization and other home services.

Company website: www.ytyinguang.com.