The source and prevention of chemical pollution

With the development of society, the problem of environmental pollution has become more and more serious, and industrial pollution has occupied a large proportion of environmental pollution. The more developed countries, the more rapid the development of chemical industry, chemical pollution is more serious.

Chemical pollution refers to the waste gas and pollutants produced in the production process of the chemical industry. Most of these wastes are harmful above a certain concentration, and some are highly toxic substances, which will cause pollution when entering the environment. Some chemical products in the process of use will cause some pollution, even more serious than the pollution caused by the production itself, more extensive.

Chemical industry development process

From the perspective of the development process of chemical industry, foreign chemical pollution can be generally divided into three stages.

The occurrence period of chemical industry pollution

The early chemical industry (about the end of the 19th century) was based on the production of inorganic chemical raw materials such as acids and alkalis, so the pollutants in the chemical industry at that time were mainly inorganic pollutants such as acids, alkalis and salts. In addition, the scale of inorganic chemical production in this period can not be compared with the current chemical industry, and the variety is relatively small, so the pollutants generated are relatively single, which is not enough to constitute a large area of regional pollution, and the environmental pollution problem is not obvious.

The development period of chemical industry pollution

From the beginning of the 20th century to the 1940s, due to the rapid development of metallurgy and coking industry, the chemical industry also developed, and entered the period of coal chemical industry that uses coal as raw materials to produce chemical products. Coal can not only be burned as fuel, but also become the main raw material of the chemical industry. A series of organic chemical industrial products with coal, coke and coal tar as raw materials began to mass production, a large number of new chemical enterprises continue to build, the world chemical industry has a rapid development. At the same time, the scale and quantity of the inorganic chemical industry are also expanding during this period, so the inorganic pollution caused by the quantity and the degree of harm have been intensified, and the organic chemical industry has also begun to develop, resulting in the increased impact of organic pollution on environmental pollution, and sometimes there is a synergistic effect with inorganic pollutants. Therefore, the phenomenon of chemical industry pollution is more important.

A period of widespread pollution from the chemical industry

Since the 1950s, countries in the world have discovered rich reserves of oil and gas fields, since the rapid development of the petroleum industry, the petroleum industry has become an important part of modern energy and national economy, the rise of the petroleum industry, caused the fuel structure of countries in the world gradually from coal to oil and gas. Thus, the chemical industry has also entered the "petrochemical era" with oil and natural gas as the main raw materials, and the petrochemical industry has begun to develop rapidly, and environmental pollution has been flooded, reaching an unprecedented point. The pollution type has also undergone a qualitative change, from the original coal smoke type to oil type pollution.

Chemical pollution is an important problem to be solved urgently in the process of chemical industry development. If it cannot be solved properly, it will inevitably restrict the sustainable development of chemical industry. Now has entered the era of control and prevention of chemical pollution, environmental protection requirements are constantly harsh, pollution-free biochemical and green chemical industry has been advocated, and has been rapidly developed.

The source of chemical pollution

The types of chemical pollutants can be divided into inorganic chemical industry and organic chemical industry pollution according to the nature of pollutants. According to the form of pollutants, there are waste gas, waste water and waste residue. The main sources of chemical pollutants can be roughly divided into two aspects, namely raw materials, semi-finished products and products of chemical production; Waste released during chemical production.

Raw materials, semi-finished products and products for chemical production

(1) The chemical reaction is incomplete

In all chemical production, there is a conversion rate problem, that is, it is impossible to convert all raw materials into semi-finished or finished products. Although unreacted raw materials can be recycled, a part of them is always discharged due to incomplete or impossible recycling. If the chemical raw materials are harmful substances, they will cause environmental pollution after discharge.

(2) Raw materials are not pure

Sometimes the chemical raw materials themselves are not pure enough, which contain impurities. In general, these impurities do not need to participate in chemical reactions and are finally discharged. However, most of the impurities are harmful chemicals that can cause environmental pollution. Some chemical impurities even participate in the reaction, and the resulting reaction product is also an impurity of the desired product. It is also a harmful pollutant to the environment.