It is stipulated in China that the chemical oxygen demand of waste water (sewage) is determined by potassium dichromate method. Other methods include coulometric titration, fast closed catalytic digestion, chlorine gas correction and so on.
Biochemical oxygen demand refers to the amount of dissolved oxygen consumed by aerobic microorganisms in the biochemical oxidation process of decomposing organic matter in water under the condition of dissolved oxygen. BOD was determined by microbial electrode method, coulometry, manometry and activated sludge aeration degradation method.
Total organic carbon (TOC) is a comprehensive index to express the total amount of organic matter in water by carbon content. Because TOC is determined by combustion method, organic matter can be completely oxidized, which can better reflect the total amount of organic matter than BOD5 or COD. At present, the widely used method to determine TOC is combustion oxidation-non-dispersive infrared absorption method.
Volatile phenol:
The main analytical methods of phenol include volumetric method, spectrophotometry and chromatography. At present, 4- aminoantipyrine spectrophotometry is widely used in various countries; Bromination volumetric method can be used for high concentration phenol-containing wastewater. Regardless of bromination volumetric method or spectrophotometry, when oxidants, reductants, oils and some metal ions exist in water samples, they should be eliminated and pre-distilled. For example, adding ferrous sulfate to free chlorine for reduction; Adding copper sulfate to sulfide to precipitate it, or making it escape in the form of hydrogen sulfide under acidic conditions; Extract and remove oil with organic solvent. Distillation has two functions, one is to separate volatile phenol, and the other is to eliminate the interference of color, turbidity and metal ions.
Nitrobenzene: The common nitrobenzene compounds are nitrobenzene, dinitrobenzene, dinitrotoluene, trinitrotoluene and dinitrochlorobenzene. They are insoluble in water. Reduced azo spectrophotometry is often used to determine mononitro and dinitrobenzene compounds in wastewater. Trinitrobenzene compounds were determined by cetylpyridinium chloride spectrophotometry.
Oil:
Gravimetric method: Acidify the water sample with sulfuric acid, extract mineral oil with petroleum ether, then evaporate the petroleum ether, weigh the residue and calculate the mineral oil content.
Infrared Spectrophotometry: The key points of the method are as follows: firstly, the total extract in water sample (water sample with low content of petroleum substances) is directly extracted with carbon tetrachloride or enriched by flocculation, and the extract is divided into two parts after constant volume, one part is used to determine the total extract, and the other part is used to determine petroleum substances after being adsorbed by magnesium silicate.
Non-dispersive infrared absorption method: methyl (-CH3) and methylene (-CH2-) of petroleum substances have characteristic absorption of light in the near infrared region of 2930 cm- 1 (or 3.4μm), and are determined by non-dispersive infrared absorption oil meter. During the determination, the water sample was acidified with sulfuric acid, emulsified with sodium chloride, then extracted with carbon tetrachloride, and the extract was filtered with anhydrous sodium sulfate layer.
Benzene series: According to the content of benzene series in water samples, gas chromatography (GC) or gas chromatography-mass spectrometry (GC-MS) can be selected for determination.
Volatile halogenated hydrocarbons: The methods for determining halogenated hydrocarbons in water samples include headspace gas chromatography (HS-GC), purge gas chromatography (P & T-GC) and headspace gas chromatography-mass spectrometry (HSGC-MS).
Chlorobenzene compounds: Various chlorobenzene compounds in water samples can be qualitatively and quantitatively analyzed by gas chromatography.
Volatile organic pollutants: The main determination methods are gas chromatography and gas chromatography-mass spectrometry.
What are the analysis methods of common pollutants? Conventional analytical methods: visible spectrophotometry, volumetric method and gravimetric method.
Analysis and detection methods and principles of major pollutants in the environment: nutrients, heavy metals, radioactive substances and toxic substances.
The main components in the atmosphere are: carbon monoxide, nitrogen oxides and sulfur oxides.
Pollution is also divided into solid waste pollution and noise pollution.
What are the main analysis methods of stock index futures? The analysis of stock index futures mainly includes fundamental analysis methods and technical analysis methods of stock index futures, among which the fundamental analysis methods of stock index futures are widely designed.
In addition to grasping and analyzing the international situation and national policies, we also need relevant fundamental statistical data, while the technical analysis method of stock index futures is relatively simple, as long as we use the market transaction data for statistical analysis. Therefore, most investors in stock index futures choose technical analysis to trade stock index futures.
The fundamental analysis of stock index futures mainly includes three aspects: economy, policy and supply and demand. Economy is the foundation of the stock market, and economic growth will cause the stock index to rise; Economic depression will lead to a decline in the stock index; There is an inflection point in the economy, and there will also be an inflection point in the stock index trend. On the basis of economy, policy plays an important role. If the stock market rises too much, * * * will introduce a negative policy to curb the stock market's rise, and the stock market will generally enter the down cycle; If the stock market falls too much, * * * will introduce favorable policies and the stock market will generally rebound. The supply of funds or stocks is also an important factor affecting the trend of stock indexes. With the increase of capital supply, the purchasing power of the market has increased, resulting in a situation of short supply, which has caused the stock index to rise; The decrease of capital supply and the decrease of market purchasing power will lead to the decline of stock index. Similarly, the increase of stock supply will lead to oversupply, which will lead to the decline of stock index; The decrease of stock supply will cause the situation that the supply exceeds the demand, which will cause the stock index to rise. The change of fundamentals has become an important basis for the change of stock index trend.
The technical analysis of stock index futures is mainly: mainly using market price statistics to analyze, such as:
1. Trend indicator MACD:
MACD (Convergence and Divergence of Moving Average) is Gerald Appel.
It was put forward by 1979. A technical index for judging the trading time by using the aggregation and separation between the short-term (usually 12) moving average and the long-term (usually 26) moving average. MACD also has an auxiliary indicator bar. MACD is developed from the double moving average, but it is more convenient and effective than the moving average.
2. Average system
Professor glanville, an American, created the Eight Rules of Average, which has always been regarded as a treasure by ordinary users. It is precisely because of this that the EMA can give full play to the essence of Dow theory. Four of the eight rules are used to judge the timing of buying and four are used to judge the timing of selling. In the process of application, we should use it flexibly, not by rote.
What are the main ways to degrade organic pollutants entering the environment? The migration and transformation of organic pollutants in water is mainly determined by their own physical and chemical properties and water environment properties, in which the interaction with dissolved organic matter plays an important role. Organic pollutants generally migrate and transform through adsorption, volatilization, hydrolysis, photolysis, biological enrichment and biodegradation.
The analytical methods of trace elements in seawater mainly include direct determination of trace elements in seawater with high sensitivity. In addition, there are a lot of matrix salts in seawater, so it is difficult to obtain reliable results. Before determination, separation and enrichment are often used to eliminate interference and improve the concentration of trace elements to be determined. The common methods of enrichment and separation are solvent extraction, ion exchange, precipitation and freeze drying. ① Solvent extraction method. For example, ammonium pyrrolidone-methyl isobutyl ketone can be used to extract cadmium, copper, nickel, lead, zinc, silver, cobalt, iron and other elements in seawater for atomic absorption spectrophotometry. ② ion exchange method. Cellulose exchange method can enrich cobalt, chromium, copper, iron, molybdenum, nickel, lead, zinc, uranium and other elements in seawater, and is used in X-ray fluorescence method and neutron activation method. Chelating resin exchange method can enrich cadmium, chromium, copper, iron, manganese, nickel, lead, zinc and other elements for atomic absorption spectrophotometry. ③ * * * precipitation method. Before the determination of trace elements in seawater by spectrophotometry, atomic absorption spectrometry or neutron activation method, precipitation method can be used for enrichment and separation. If ferric hydroxide is used as precipitant, arsenic, europium, lanthanum, ruthenium, tin and tantalum are separated from seawater, and then their contents are determined by neutron activation method. ④ Freeze-drying method. Before the determination of various elements in seawater by neutron activation method, it can be used for enrichment, but it cannot separate interfering elements.
What are the main methods and devices to control particulate pollutants? Particulate pollutants refer to particles suspended in the air. In the production process of metallurgy, machinery, building materials, light industry, electric power and many other industries, a lot of smoke and dust will be produced. If effective control measures are not taken, it will pollute the workshop and atmospheric environment and cause great harm to human health and industrial and agricultural production.
1. Improve the energy structure.
2. Improve energy utilization rate and utilization level, improve process equipment and production operation methods, and fundamentally prevent and reduce the generation of harmful substances.
3. Control the concentration of harmful substances by ventilation and dilution.
4. Use smoke control devices and measures to control smoke emission.
5. Establish a strict inspection management system.
According to the particle size properties of particulate pollutants, the most commonly used are bag filter (filtration), cyclone filter (dry method), foam filter (wet method) and electrostatic precipitator.
What are the main pollutants in automobile exhaust? Automobile exhaust contains carbon monoxide and oxygen.
Nitrogen and other solid particles that have adverse effects on human body, especially leaded gasoline, are more harmful to human body.
It's huge. Lead is in a particulate state in the exhaust gas and diffuses with the wind. Rural residents usually inhale lead from the air.
The sky is about one microgram; Urban residents, especially those on both sides of the street, will greatly exceed rural residents. After tin enters the human body, it mainly
It should be distributed in liver, kidney, spleen, gallbladder and brain, with the highest concentration in liver and kidney. After a few weeks, lead was transferred from the above tissues to the bones.
Skeleton, deposited as insoluble lead phosphate. About 90% ~ 95% of lead in human body is accumulated in bones, and only a small amount of lead exists.
In the liver, spleen and other organs. Lead in bone is generally stable, when food is calcium deficient or infected, injured, drinking alcohol or taking acid.
When alkaline drugs destroy the acid-base balance, lead will be transferred from bones to blood, causing lead poisoning symptoms. Symptoms of lead poisoning
It has a wide range of manifestations, such as dizziness, headache, insomnia, dreaminess, hypomnesis, fatigue, loss of appetite, fullness and warmth in the upper abdomen.
Gas, nausea, diarrhea, constipation, anemia, peripheral neuritis, etc. Severe poisoning patients have obvious liver damage and yellow color will appear.
Symptoms such as jaundice, hepatomegaly and abnormal liver function. 1943, in Los Angeles, California, there are 2.5 million cars.
Cars burn 1 100 tons of gasoline every day. Hydrocarbons produced by gasoline combustion are chemically irradiated by ultraviolet rays from the sun.
Reaction, the formation of light blue smoke, so that most people in this city envy, headache. Later, people called this pollution photochemistry.
It's smoking There were two photochemical smog incidents in Los Angeles at 1955 and 1970. The former has more than 400 people! ! ! 1. The inflation coefficient of the engine decreases.
Introduction to East China Environmental Science of China University of Petroleum What are the main pollutants in sewage?
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