CN101235267A - A kind of preparation method of heterogeneous water evaporation inhibitor - Google Patents

Abstract

The invention prepares a heterogeneous water evaporation inhibitor through adopting the emulsification technology. The technical characteristics are that using petroleum ether as oil phase solvent, using fatty alcohol polyoxyethylene ether series as emulsifying agent, remixing long-chain fatty alcohol and short-chain alcohol as molecular film base material, preparing stable W/O elusion through adopting supersonic dispersion, thereby obtaining water evaporation inhibitor. The water evaporation inhibitor which is obtained through the process can automatically spread out on the water level to form an insoluble molecular film, which has favorable temperature interference resistance ability, matter interference resistance and self-restoring ability, and the efficiency of inhibiting water evaporation is reduced as time prolongs, thereby having excellent stability. The preparation process of the invention is simple, and has small requirement for devices. And the product which is prepared has extensive application prospect in water resource protection field, has great significance for solving the problem of water scarcity in arid area and reducing water resource loss, and can bring out enormous economic benefits and social benefits.

Description

A kind of preparation method of heterogeneous water evaporation inhibitor

technical field

The invention relates to the field of water resource protection, and more specifically relates to a method for preparing a heterogeneous liquid film that inhibits water evaporation in a large area of water by using an emulsification method.

Background technique

Water is one of the important resources that human beings rely on for survival and development. In the current global resource crisis, drought and water shortage are at stake. my country is one of the few countries in the world that is seriously short of water. The per capita water volume is only 1/4 of the world's average level, and it is one of the countries with the poorest water resources in the world. At the same time, there is a huge difference in the possession rate of water resources between the north and the south in my country, and the arid and semi-arid areas account for more than half of the total land area of the country. In arid and water-scarce areas, the evaporation of water in water bodies is several times or even dozens of times the local precipitation, and even hundreds of times in a few areas. Taking Tianjin as an example, the annual evaporation is twice as much as the rainfall, which has a serious impact on agriculture and the national economy.

The evaporation loss of water mainly comes from the surface of large water bodies such as rivers, lakes, reservoirs, and storage tanks. According to statistics, there are about 50,000 hectares of surface water in Tianjin. According to the natural evaporation rate, the annual evaporation loss of each hectare of water surface is nearly 50,000 tons. For this alone, the annual water loss is nearly 2.5 billion tons. In the western region of my country, the annual evaporation loss per hectare of water surface is as high as 300,000 tons, and the economic loss caused is even more alarming. my country's current total water shortage is estimated to be 40 billion cubic meters, with an annual drought-affected area of 2 million to 2.6 million square kilometers, affecting grain output of 15 billion to 20 billion kilograms and industrial output value of more than 200 billion yuan. At present, there are 70 million people in the country who have difficulty drinking water. Water shortage has a serious impact on the environment and people's physical and mental health. For this reason, suppressing water evaporation is an extremely important strategic policy, and it is particularly important to maximize the use of limited water resources. The most feasible way to suppress the evaporation loss of a large area of water is to spread the water evaporation inhibitor on the surface of the water body.

Moisture evaporation inhibitor is a surfactant with high biological safety, which can spontaneously spread on the surface of water to form an insoluble molecular film, change the state of the water surface directly exposed to the air, and effectively inhibit water evaporation. The water surface where the insoluble molecular film is spread does not hinder the penetration of carbon dioxide, oxygen and sunlight, so it does not affect the growth and reproduction of aquatic animals and plants. Evaporation inhibitors can significantly reduce the evaporation loss of a large area of water, which can bring huge economic and social benefits. At present, fatty alcohols, fatty acids, and fatty amine compounds have been studied more as surfactants for water evaporation inhibitors. However, research at home and abroad is only at the laboratory stage. In the actual environment, factors such as wind speed, temperature, and impurities interfere significantly with water evaporation inhibitors, which will lead to unstable performance and even lose the effect of inhibiting water evaporation. Since these problems have not been reasonably resolved, the popularization and application of water evaporation inhibitors has been hindered.

Contents of the invention

At present, the water evaporation inhibitors studied at home and abroad are all single homogeneous systems, which have poor ability to resist environmental interference, which hinders the popularization and application of water evaporation inhibitors. In order to improve the anti-environmental interference ability and self-repairing ability of the water evaporation inhibitor system, the invention discloses a method for preparing a heterogeneous water evaporation inhibitor, that is, compounding a long-chain fatty alcohol with a short-chain alcohol, and combining the Formulated into W/O emulsion system. The heterogeneous water evaporation inhibitor prepared by the invention has certain anti-environmental interference and self-repairing capabilities on the basis of effectively inhibiting water surface water evaporation loss, and its inhibition rate decays little with time, and its stability is good. The preparation process of the present invention is simple, the requirements for equipment are not high, and the prepared product has broad application prospects in the field of water resource protection. benefits and social benefits.

experimental method

Weigh 0-1.25 grams of long-chain fatty alcohol and 0-0.625 grams of short-chain alcohol, fully dissolve in 25 grams of petroleum ether, add an emulsifier, mix well, and use it as the oil phase. Weigh 25 grams of distilled water, and slowly drop the distilled water into the oil phase while stirring rapidly. After the dropwise addition, put the system into a numerically controlled ultrasonic cleaner for intermittent oscillations, each oscillation is 30 seconds, the interval between two oscillations is 10 seconds, and lasts for 5-20 minutes to obtain a stable W/O emulsion. Instant product.

A complex system of two fatty alcohol polyoxyethylene ethers (AEO) with different chain lengths is used as an emulsifier, and the amount of the emulsifier is 5-20% of petroleum ether, and the optimum amount is 10-15%.

Long-chain fatty alcohols can be selected from myristyl alcohol, cetyl alcohol, stearyl alcohol, eicosanol and behenyl alcohol, and short-chain alcohols can be selected from n-propanol, n-butanol and n-pentanol. The mass ratio of long-chain alcohol and short-chain alcohol can be 5:1, 4:1, 3:1, 2:1 and 1:1. The best ratio is cetyl alcohol and n-butanol, and the best mass ratio is 3:1.

Test method for water evaporation inhibition rate

The weighing method was adopted, and the water evaporation inhibition rate was used as an index to evaluate the inhibition efficiency of the studied system. Calculated as follows:

In the formula: W _f = W _{f original} - W _{f after} ; W _d = W _{d original} - W _{d after}

W _d : water evaporation with film, g; W _f : water evaporation without film, g

Example 1

Weigh 25 grams of petroleum ether (30-60° C.), add 3.6 grams of AEO-7 and 0.15 grams of AEO-2 compound emulsifiers, mix well, and use it as the oil phase. Weigh 25 grams of distilled water, and slowly drop the distilled water into the oil phase while stirring rapidly. After the dropwise addition, put the system into a numerically controlled ultrasonic cleaner to vibrate intermittently, each time for 30 seconds, and the interval between two vibrations is 10 seconds, and last for 10 minutes to obtain a stable W/O emulsion.

Take two identical porcelain plates, the surface area of which is about 100cm ² , inject 1000 grams of water respectively, add 30 microliters of emulsion to one plate, and not add to the other plate, and place them at 30°C for 72 hours. Weigh and calculate the water evaporation loss of the two porcelain plates, and use the formula to calculate the water evaporation inhibition rate of the system spread with the emulsion. The results show that the emulsion has no effect of inhibiting water evaporation, which means that the emulsion system without adding film substrate-fatty alcohol has no inhibitory effect.

Example 2

Weigh 0.625 g of n-butanol and fully dissolve it in 25 g of petroleum ether (30-60° C.), add 3.6 g of AEO-8 and 0.15 g of AEO-2 compound emulsifier, mix well, and use it as the oil phase. Weigh 25 grams of distilled water, and slowly drop the distilled water into the oil phase while stirring rapidly. After the dropwise addition, put the system into a numerically controlled ultrasonic cleaner to vibrate intermittently, each time for 30 seconds, and the interval between two vibrations is 10 seconds, and last for 10 minutes to obtain a stable W/O emulsion.

Take two identical porcelain plates, the surface area of which is about 100cm ² , inject 1000 grams of water respectively, add 30 microliters of emulsion to one plate, and not add to the other plate, and place them at 30°C for 72 hours. Weigh and calculate the water evaporation loss of the two porcelain plates, and use the formula to calculate the water evaporation inhibition rate of the system spread with the emulsion. The results show that the emulsion has almost no effect of inhibiting water evaporation, which shows that the emulsion system with only short-chain alcohols and no long-chain fatty alcohols has no obvious inhibitory effect.

Example 3

Weigh 1.25 g of cetyl alcohol and fully dissolve it in 25 g of petroleum ether (30-60° C.), add 3.6 g of AEO-9 and 0.15 g of AEO-2 compound emulsifier, mix well, and use it as the oil phase. Weigh 25 grams of distilled water, and slowly drop the distilled water into the oil phase while stirring rapidly. After the dropwise addition, put the system into a numerically controlled ultrasonic cleaner to vibrate intermittently, each time for 30 seconds, and the interval between two vibrations is 10 seconds, and last for 10 minutes to obtain a stable W/O emulsion.

Take two identical porcelain plates, the surface area of which is about 100cm ² , inject 1000 grams of water respectively, add 30 microliters of emulsion to one plate, and not add to the other plate, and place them at 30°C for 72 hours. Weigh and calculate the water evaporation loss of the two porcelain plates, and use the formula to calculate the water evaporation inhibition rate of the system spread with the emulsion. The results showed that the water evaporation of the porcelain plate on which the emulsion was spread decreased significantly, and the water evaporation inhibition rate of the emulsion system reached 48.7%.

Example 4

Weigh 0.938 grams of cetyl alcohol and 0.312 grams of n-butanol and fully dissolve them in 25 grams of petroleum ether (30-60 ° C), add 3.6 grams of AEO-8 and 0.15 grams of AEO-2 compound emulsifier, mix well, and It serves as the oil phase. Weigh 25 grams of distilled water, and slowly drop the distilled water into the oil phase while stirring rapidly. After the dropwise addition, put the system into a numerically controlled ultrasonic cleaner to vibrate intermittently, each time for 30 seconds, and the interval between two vibrations is 10 seconds, and last for 10 minutes to obtain a stable W/O emulsion.

Take two identical porcelain plates, the surface area of which is about 100cm ² , inject 1000 grams of water respectively, add 30 microliters of emulsion to one plate, and not add to the other plate, and place them at 30°C for 72 hours. Weigh and calculate the water evaporation loss of the two porcelain plates, and use the formula to calculate the water evaporation inhibition rate of the system spread with the emulsion. The results showed that the water evaporation of the porcelain plate on which the emulsion was spread decreased significantly, and the water evaporation inhibition rate of the emulsion system reached 61.9%.

Application performance comparison

The following table is a comparison of the performance of cetyl alcohol ether solution system, cetyl alcohol/n-butanol compound ether solution system and cetyl alcohol/n-butanol compound emulsion system under the same conditions. The test time is 96 hours, the film surface concentration is 8.0×10 ^-2 g/m ² , and the influence of temperature change on the water evaporation inhibition rate is discussed.

It can be seen from the above table that the change of temperature has a significant impact on the performance of the cetyl alcohol solution system, and the inhibition rate fluctuates greatly with the change of temperature. When the temperature reaches 40°C, the system almost completely loses the inhibition effect. When the temperature is between 20 and 30°C, the cetyl alcohol/n-butanol compound solution system shows better stability, but when the temperature exceeds 30°C, the inhibition rate drops significantly. As the temperature changes, the inhibition rate of the cetyl alcohol/n-butanol emulsion system fluctuates very little. When the temperature reaches 40°C, the inhibition rate remains at 52%, showing a more significant ability to resist temperature interference than the former two. .

Time is an important factor affecting the effect of the system on inhibiting water evaporation. As time goes on, many impurities in the air (such as dust) will invade the surface film formed by the inhibitor on the gas-liquid interface, and form some water molecules in the film molecular layer The pores of the evaporation cause the film structure to be loose, which directly affects the performance of the surface film.

The following table is a comparison of the performance of cetyl alcohol ether solution system, cetyl alcohol/n-butanol compound ether solution system and cetyl alcohol/n-butanol compound emulsion system under the same conditions. The test temperature was 25°C, and the surface concentration of the film was 8.0×10 ^-2 g/m ² , to investigate the influence of the change of time on the water evaporation inhibition rate.

It can be seen from the above table that the inhibition rate of the emulsion system is higher than that of the solution system. Moreover, within the test time range, the inhibition rate of the solution system showed a downward trend, while the inhibition rate of the emulsion system showed a gradual upward trend, indicating that the ability of the emulsion system to resist interference from impurities is higher than that of the solution system, showing better resistance to impurities. intrusive.

The emulsion system prepared by the invention can greatly improve the inhibition rate of water surface evaporation, and the system has small attenuation with time extension, good stability, good resistance to temperature interference, anti-impurity interference and self-repairing ability. The preparation method of the invention is simple, does not require high equipment, has stable product performance, has good promotion prospects, and has great significance for solving the problem of water shortage in arid areas and reducing water resource loss.

Claims (3)

1. the preparation method of a heterogeneous water evaporation inhibitor, concrete operations are as follows: take by weighing the short chain alcohol of the pure and mild 0-0.625 gram of 0-1.25 gram long-chain fat, fully be dissolved in the 25 gram sherwood oils, add emulsifying agent, thorough mixing is even, with it as oil phase.Take by weighing 25 gram distilled water, the limit is stirred the limit fast distilled water is added dropwise in the oil phase lentamente.After dropwising, system is put into the numerical control supersonic cleanser intermittently shake, each concussion is 30 seconds, and twice shakes pitch time is 10 seconds, continues 5-20 minute, can make stable w/o type emulsion, promptly gets product.

2. the preparation method of a kind of heterogeneous water evaporation inhibitor as claimed in claim 1, the feature of its molecular film base material is that long chain aliphatic alcohol can be selected tetradecyl alcohol, hexadecanol, stearyl alcohol, eicosanol and behenyl alcohol for use, and short chain alcohol can be selected n-propyl alcohol, propyl carbinol and Pentyl alcohol for use.The mass ratio of long-chain alcohol and short chain alcohol can be 5: 1,4: 1,3: 1,2: 1 and 1: 1.Best proportioning is that hexadecanol and propyl carbinol are composite, and optimum quality ratio is 3: 1.

3. the preparation method of a kind of heterogeneous water evaporation inhibitor as claimed in claim 1, its emulsifying agent can be the compound system of the fatty alcohol-polyoxyethylene ether (AEO) of two kinds of different chain lengths, the consumption of emulsifying agent is the 5-20% of sherwood oil, and optimum amount is 10-15%.