Training and Research Institute of Hubei Institute of Education Green Chemistry and Environmental Protection Wang Yang Luo Houben Yi Siqiu (Department of Chemistry and Metabolism, Lake 4 North Education Institute, Wuhan 430060, China) Luo Hou Ben (1968-), male, Department of Metaphysics, Hubei Institute of Education.
Easy Reality (1943-), male, Department of Biology, Hubei Institute of Education, Professor.
0 Foreword y The meaning of green chemical industry is: to achieve ecological greenization in chemical production, and to use chemical products to serve related industries, we must also pursue the pursuit of making the production of related industries ecologically green, and simulate animal and plant ecology and microbial ecology. The function of the system is to establish a chemical ecological chain similar to that of an ecological person, a consumer, and a reducer, with low consumption (material consumption and energy consumption such as water, electricity, gas, and cooling, and labor consumption), and no pollution (at least low pollution). , Recycling of resources, comprehensive utilization of waste, separation, degradation, etc., to achieve the 1 ecological "cycle" of chemical production of non-toxic chemical products, to achieve clean production and 1 green production safety, the result.
In the war, it was developed on the basis of a new discipline of green chemistry, preventing environmental pollution and the entire process of governance from the source, and comprehensively utilizing the chemical technology, with a view to achieving zero emissions of waste in the process of chemical production and use, and producing Environmentally friendly, safe and non-toxic chemical products.
The cause of environmental pollution and damage is the unreasonable layout of industry and urban construction, and the unreasonable use of natural resources. In the cause of environmental pollution and ecological crisis, the chemical industry is the largest waste emitter. Most of the materials handled by the chemical industry are large quantities of chemicals, and chemical reactions are generally included in the treatment process. For example, raw materials, semi-finished products, products or waste gas, waste residues, waste liquids, or discharged into the environment cause environmental pollution. The problem is shocking.
For example, in 1993, the US chemical industry emitted 350 million tons of toxic waste, equivalent to 4.5 Kg of poisons per person per day, which cost US$20 billion to manage. At present, one-fifth of the US’s new investment costs are For waste management and control of pollution. It can be said that environmental protection is the main basis for the sustainable development of chemical industry in the 21st century.
1 Controlling toxic materials, renovating and eliminating varieties of contaminated products is a prerequisite for the implementation of green chemicals. 1.1 To achieve green chemicals, the first step is to control benzene as a raw material for the processing of toxic raw materials, and green chemicals are replaced with C6H126 as a raw material, completely eliminated. Benzene contamination of the atmosphere. It was also reported that recently Nagoya University in Japan developed a new method for preparing adipic acid. They originally used traditional methods to use phenol line, hydrogenation of phenol to cyclohexanol, and then concentrated HNO3 concentration of 60% to cyclohexanone, and finally made adipic acid. Concentrated hydrogen peroxide has been used instead of concentrated HN3 as the oxidant, and the yield can reach over 90%. At the same time, the pollution of the atmosphere by concentrated HN3 is eliminated.
1.2 Implementing green chemicals to protect the surrounding ecological environment. It is necessary to constantly reform and eliminate the variety of pollution products. The variety of chemical products involves various aspects of industrial and agricultural production and daily life. Some chemical products are highly toxic and pollute the environment during production and use. Need to take measures to reform product varieties, such as pesticide production in view of the residual nature of mercury preparations, some countries have banned or restricted the use of mercury preparations. China has banned the production and suspension of imports of organic mercury pesticides and actively developed non-mercury sterilized alternatives. If carbendazim is produced using non-mercury synthesizing circuits: o-benzene = amine + hydrochloric acid OZSPmcooci carbendazim is a high-efficiency low-toxic broad-spectrum systemic fungicide that can effectively control crops such as rice, wheat and cotton. The disease has replaced mercury-based fungicide with residual toxicity.
The reform of product varieties for dye production is also a prominent issue. Some products of benzidine and azo dyes are carcinogenic and need to change their structure and develop nontoxic products. Now add water-soluble or easily decomposable groups to the study, transform the benzidine into non-planar stereoisomerism, reduce the depth of chlorination, etc., so that the structure of the chemical composition of Taiwan becomes non-carcinogenic to avoid poisoning.
The traditional process method for the a6 adipic acid intermediate has always been the acceptance of the yig period: 2003-06- Wangchen Luo Hou Benyi is realistic: green chemicals and environmental protection 2 implementation of green chemical industry should continue to technical innovation, we must vigorously promote Clean technology 2.1 To achieve ecological "green" in chemical production, it is necessary to innovate in technology, to promote the development of the enterprise we must vigorously promote the development of chemical industry." "Chemical development refers to the development of new chemical products, new processes, research and development . “Chemical development is a technical field that requires obedience to the principle of being viable in production, economically reasonable, and in line with market needs. The results should enable developers to obtain economic benefits or profits. Research and development is the source of activity for chemical companies.
2.2 Clean technology is a system that does not have a negative impact on ecosystems. It is within the allowable content of ecosystems, and production technologies that have made significant progress in reducing the negative impact on ecosystems. Cleaner production meets people's needs. It uses natural resources rationally. Energy, and the actual production methods and measures to protect the environment, reduce waste, recycle, harmless, or exterminate wastes in the production process. At the same time, the production of green products that are harmless to the human body and the environment will also develop with sustainable development. The in-depth process has increasingly become the dominant direction of product production in the future.
3 Biochemistry is a powerful measure for the development of green chemistry Biochemistry is an edge science where biochemistry, microbiology, and chemical engineering intersect. It is an essential part of biotechnology that translates biological achievements into productivity. component. Nowadays, all countries in the world are aware that biotechnology has great economic and social benefits. People attach great importance to their development and research. At the end of the 20th century, sales of bio-tech products in the world have exceeded 10 billion. The sales of bio-chemical products in the United States now account for about 70% of all chemical products. How to use bio-chemical high-tech to synthesize non-pollution 1 green "high-tech chemical industry, the following combination of examples to express.
3.1 Production of Chitosan by Bio-fermentation Technology: Chitosan is a kind of bio-polysaccharide with many uses. It is widely used in medicine, food, cosmetics, adhesives and other industries. In the field of environmental protection, it can be used as a flocculant for the treatment of industrial waste water and domestic sewage, as well as a removal agent for heavy metal ions. It has excellent application prospects and has become a hot spot in China's current development, but its preparation method is based on shrimp shells. The crab shell is obtained after treatment with a strong alkali, and the preparation process itself is likely to cause pollution to the environment. The process is complicated and the price is high. Also affected by the region and time.
Starting from the requirements of a green “high-tech chemical industry, bio-fermentation method is used to produce chitosan, which is used to prepare high-efficiency biological environment-friendly water treatment. Its production is completely free of the time and season and the influence and restrictions of the region. The operation is simple and the cost is low. It is inexpensive, and it is important that it has no pollution to the environment. It has been used for the adsorption and separation of heavy metal ions in industrial wastewater, and has achieved good results.
3.2 Production of PHB using genetically recombinant cyanobacteria PHB: Poly-3-hydroxybutyrate 3*Hydroxybutyrate (abbreviated as PHB) is the earliest biodegradable polymer material discovered so far. The production of PHB to date has been mainly using organic carbon sources. And nitrogen sources are produced through heterotrophic microbial fermentation, and the production cost is too high. Considering the cost of raw materials, CO2 is the cheapest carbon source on the earth, and the use of plants for the production of PHB has a long growth cycle, requires occupation of cultivated land, and PHB expression is low. Separation and extraction is a kind of microalgae, which can use CO2 to synthesize all other molecules required for cell growth and division by photosynthesis. After some particles similar to bacterial PHB are found in some cyanobacteria, cyanobacteria are the expression vectors for PHB. become possible. In addition, gratifying results have also been achieved in the development of biodegradable plastic products.
4 Continuously control the pollution of the production process, and actively create and implement non-waste technology, which is an important way to implement green chemicals 4.1 In the production of green chemicals, to control the pollution of the production process, attention should be paid to the following aspects: 4.1.1 Produce serious pollution Raw material route, production method reform Some chemical materials used in chemical production, catalysts and intermediate products of the production process are harmful and toxic, and directly pollute the production environment, and endanger the health of operators for a long time. Therefore, it is important to implement process reforms, use harmless or less harmful source routes, streamline process flows, and change process production methods accordingly.
For the use of highly toxic production processes, this reform is even more urgent.
For malathion production, maleic acid and acetic acid are used as synthetic source materials to obtain the intermediate product maleic acid diethyl carbonate. If it is refined, it will cause waste water pollution during the washing process, and it will be replaced by In the new process, crude malozonate was synthesized directly from the crude product, and the leather was washed in the water and alkali-washed. This reduced the loss of hydrolysis and resulted in almost no need to discharge the wastewater.
The effective process reforms not only increase the utilization of source materials and improve the selectivity of the reaction, but also achieve the purpose of reducing three wastes and reducing pollution.
4.1.2 Reforming Equipment and Improving Operations To reduce and eliminate pollution, it is necessary to reform the production equipment that pollutes the environment, and to use suitable equipment. Many chemical production molding and packaging operations have a very polluting environment; they need to be improved. Some chlor-alkali plants still use artificial packaging in the production of hydrochloric acid, and the area is filled with acid mists that endanger the health of operators and pollute the air. After the adoption of the method of closed packaging, the gas discharged during packaging was treated at the same time, so that the environmental quality was greatly improved. Some powder products formed a large amount of dust that pollutes the atmosphere during production, packaging, and use. Therefore, a new powder-making device was developed. The use of granules instead of powder protects the ecological environment.
For equipment with contaminated materials, it is necessary to avoid manual cleaning operations as much as possible. For example, resin adheres to the wall of the kettle during the PVC production process, which affects the normal operation of the equipment and must be removed. For manual cleaning, the workers must be allowed to enter the kettle to be exposed to high concentrations of vinyl chloride. To this end, measures must be taken to reduce the sticking kettle and reduce the number of clean kettles. High pressure water (200-100 kg/cm2) is used abroad. The pressure), cleaning agent (tetrachlorofuran, N-methylpyrrolidone, etc.) is automatically cleaned, allowing the operator to avoid contact with vinyl chloride.
4.1.3 Draining for closed loops Contaminated material discharged from the chemical production process should be closed as much as possible. Most of the materials are mixed with raw materials and intermediate products. After a certain processing step, they are returned to the system for recycling. This not only reduces the discharge of pollutants, but also reduces the consumption of the source material. The closed loop is the elimination of the three wastes in the process. An important measure in the process.
To achieve a closed circulation of the discharge, the reaction raw material is required to have a high purity.
Otherwise, some of the impurities in the raw materials will accumulate in the system, which will also hinder the operation of the closed cycle.
4.1.4 To reduce system leakage From the viewpoint of controlling pollution, in addition to reducing the discharge of the three wastes in the system, it is also very important to increase the stringency of equipment piping and reduce the leakage of reactive materials. Running, running, dripping and leaking are often the main causes of environmental pollution in factories.
Difficulty and other shortcomings greatly hindered the conversion of this technology to actual production. To prevent leakage, cyanobacteria should be designed to minimize mechanical connections. Corrosion resistant materials or anti-corrosion should be used for material training and research in the journal of the Hubei Institute of Education. coating. The parts that are likely to cause leakage due to corrosion should be designed for ease of monitoring and repair. Depending on the nature of the fluid, an automatic alarm or leak detection device should be installed to prevent leakage accidents.
4.2 The implementation of green chemicals, we must actively create and promote waste-free processes 4.2.1 No concept of waste process: held in Geneva in November 1979, "in the international cooperation in the field of international cooperation in Europe-wide high-level meeting" was made It is defined as follows: “The non-waste process is the practical application of various knowledge, methods, and means in order to achieve the goal of ensuring the most reasonable use of natural resources and energy and protecting the environment within the scope of human needs.”
In 1984, the United Nations Economic Commission for Europe (UNECE) further defined the non-waste process at an international conference hosted by the Soviet Union in Tashkent: “No waste technology is such a method of producing products (processes, enterprises, regional production complexes). In this way, all raw materials and energy are most rationally and comprehensively utilized in the cycle of production of raw material resources for the consumption of a secondary raw material resource, and at the same time, any effect on the environment will not destroy its normal function.” Wang Daquan. China's green chemical industry. Guangzhou Chemical Industry, 2000, (4): 1 - Yuan Lubing, Shi Yuxiang, Li Haihong. In the 21st century, the sustainable development of the chemical industry Wang Yingluo, Liu Xu. Clean manufacturing. 1998: 5 - Wu Guifang, Shen Zhongyao. Green chemical new case utilizes the preliminary results of genetically recombinant cyanobacteria to produce PHB. Journal of Process Engineering, 2002, (3): 4-S. No waste process. New model of industrial development, 1990:85 - Sinopec General Mechanical Engineering Corporation Guangzhou Institute of Environmental Resources. Waste Polystyrene Plastic Cracking Recovery of Styrene Monomer Technology. Urban waste treatment technology push
