Starting from environmental protection, this paper introduces the present situation and prevention methods of environmental pollution, and summarizes the definition, characteristics and research contents of green chemistry. It is pointed out that green chemistry is a research topic generally advocated and carried out internationally in recent years. Developing green chemistry can save resources and reduce environmental pollution, which will become the core content of sustainable development strategy.
Keywords: environmental pollution, environmental governance, green chemistry
1 preface
In the process of transforming nature and creating material wealth, especially in the 20th century, with the development of organic chemical industry and the rapid growth of oil and gas production, chemical pollution has become increasingly prominent and environmental problems have become increasingly serious. It is undeniable that the research results of chemical science and the application of chemical knowledge have made great contributions to promoting human progress, and chemistry and its products have penetrated into all fields of human life, production and national economy. On the other hand, with the mass production and wide application of chemicals, it has brought black sewage, yellow smoke and dust, colorful waste residue and invisible colorless poisons to the original green and peaceful ecological environment of mankind. In the atmosphere, there are smog incidents in Mas Valley, Donora and London. In particular, the smog incident in London, which killed the most people, killed more than 4oo people in five days. The reason is that the sulfur dioxide produced by coal combustion is converted into sulfuric acid mist, which makes people feel chest tightness, cough and vomiting, and the elderly and infirm die. 1956, 13 Minamata Bay in Kumamoto Prefecture was polluted by mercury-containing wastewater discharged from chemical plants, causing Minamata disease, making some people numb and insane, sleeping soundly for a while and dying of extreme excitement for a while. Environmental pollution is threatening people's health and the sustainable development of the natural environment on which human beings depend. How to protect the natural environment on which we live has become a concern and consideration of all countries in the world.
2 Environmental pollution and control
2. 1 Water pollution and its control
Water is an important part of all cells and living tissues and an important material basis of all life in nature. Due to large-scale human production activities, while using water, some harmful substances often enter human water bodies, causing physical and chemical changes in natural water bodies and causing water pollution. Water pollution can be divided into pathogen pollution, aerobic pollution, plant nutrition pollution, oil pollution, thermal pollution, toxic chemical pollution, inorganic pollution and radioactive pollution.
In water pollution prevention and control technology, China scientific and technological personnel have made some achievements through unremitting efforts. The five-year "comprehensive prevention and control of methyl mercury pollution and countermeasures research" has achieved gratifying results; "Study on Ecological Fisheries in Shallow Lakes in the Middle and Lower Reaches of the Yangtze River" passed the expert appraisal; The development and production of phosphorus-free washing powder have made positive contributions to the protection and sustainable utilization of water resources.
2.2 Air Pollution and Control
The main pollutants discharged into the atmosphere are sulfur dioxide, floating dust, nitrogen oxides, hydrocarbons, carbon monoxide and carbon dioxide. There are three main sources of air pollution: first, domestic pollution sources, including harmful gases and smoke discharged into the atmosphere during the consumption or heating of fuel; Second, industrial pollution sources, including thermal power generation, steel and non-ferrous metal smelting, and air pollution caused by various chemical industries; The third is traffic pollution sources, including smoke and tail gas emitted by vehicles such as cars, planes, trains and ships. The global atmospheric changes and environmental problems caused by human activities can be mainly attributed to three aspects: first, the increase of greenhouse gases in the atmosphere leads to climate change; Second, the destruction of the atmospheric ozone layer; The third is the cross-border transportation of acid rain and pollutants. In order to protect the global atmospheric environment and improve their own environmental quality, some countries have made new plans to control air pollution. For example, the British government announced the implementation of the 10 "National Air Quality Strategy" plan to make the air in Britain fresh; China has acceded to the United Nations Framework Convention on Climate Change and the revised Montreal Protocol on Substances that Deplete the Ozone Layer, and promulgated the People's Republic of China (PRC) Air Pollution Prevention Act, aiming at adjusting energy policy, improving energy production structure and increasing the proportion of hydropower, nuclear power and solar energy in primary energy.
3 to prevent environmental pollution
Although great achievements have been made in the prevention and control of chemical pollution today, new sensitive analytical monitoring methods have been developed to determine pollutants in the environment. Identify the types of toxic compounds in chemicals; Invented a chemical method to treat waste; It reduces the discharge of waste and so on. And some progress has been made in the research, control and treatment of some global chemical pollution such as oil spill, soot, acid rain, automobile exhaust, greenhouse effect, organochlorine pesticides and environmental carcinogens. However, for many years, the solution to the problem of a large number of wastes and toxic and harmful substances produced in the chemical production process is basically based on treatment. The effects of these methods are limited, and the cost is expensive and increasing. Therefore, we need to vigorously develop green chemistry, reduce terminal treatment, and fundamentally solve the problem of environmental pollution.
3. 1 Definition and importance of green chemistry
"Green chemistry" was put forward in 1990s. Also known as harmless chemistry, environmentally friendly chemistry and clean chemistry. Green chemistry refers to the research and design of chemicals and chemical processes that have no or less negative environmental impact as far as possible and are technically and economically feasible under the guidance of green consciousness. Its core is to use chemical knowledge and technology to prevent pollution, eliminate pollution from the source, and avoid or reduce the generation of waste. The goal of green chemistry is to study and find a process that can make full use of non-toxic and harmless raw materials, save energy to the maximum extent, and realize purification and pollution-free reaction paths in all links. The biggest feature of green chemistry is that it uses scientific means to prevent pollution from the beginning, so the process and terminal are zero emissions or zero pollution. Because it makes full use of the atoms of each raw material in the process of obtaining new substances through chemical transformation, it has "atomic economy", so it not only makes full use of resources, but also prevents pollution. Although traditional chemistry plays an irreplaceable role, it can't effectively use resources in many occasions, and it also causes serious pollution by discharging a lot of waste. Taking 1993 as an example, the United States only estimated the emissions of 365 harmful substances, and the emissions of chemical industry were1360,000 tons. 1992, the American chemical industry spent1150 billion dollars on the environment and 700 billion dollars on cleaning up the polluted areas. Therefore, from the perspective of environmental protection, economy and society, the chemical industry can no longer. Green chemistry includes saving materials and energy and eliminating toxic raw materials; Reduce the quantity and toxicity of waste before discharging waste in the production process; For products, green chemistry aims to reduce the adverse effects of the whole process from raw material refining to final disposal of products. Green chemistry will not only bring revolutionary changes to the traditional chemical industry, but also promote the establishment and development of green energy industry and green agriculture.