How to make the water in the aquarium sour and soft? Because carbon dioxide will be added to the aquarium, it will increase the photosynthesis of aquatic plants and make the water hard and sour. After the CO2 tank was added to our aquarium, the pH was once reduced to pH5.0, so the fish raised in the aquarium should be suitable for living in a hard and sour environment. However, guppies have been kept in aquariums without burning their tails. The method is to add coral bones to the aquarium water filter. The main component of coral bone is calcium carbonate, so coral bone will neutralize acid.
The method is to add coral bones to the water filter of straw vat. The main component of coral bone is calcium carbonate, so coral bone will neutralize acid and raise pH value. If it reaches GH value, it is not only calcium carbonate but also calcium sulfate.
Other methods of softening water
Firstly, the hardness of water is measured, and then quantitative calcium hydroxide and sodium carbonate are added to precipitate calcium and magnesium ions in hard water.
For boiler water, sodium hypophosphite (NaPO3) can be added as a water softener, which forms a complex with calcium and magnesium ions. When water is boiled, calcium and magnesium will not precipitate, so scale will not form. This method is not suitable for softening drinking water.
Although zeolite and ion exchanger are insoluble in water, sodium ions and hydrogen ions in them can be exchanged with calcium and magnesium ions in hard water, so that calcium and magnesium ions are adsorbed and removed by zeolite, artificial zeolite and ion exchanger. Zeolite and ion exchanger that have failed for a long time can be reused through regeneration, so this method is an economical and advanced soft water method.
Adding special scale inhibitor to water can change the characteristics of combining calcium and magnesium ions with carbonate ions, so that scale can not be deposited.
Adding a certain electric or magnetic field to water changes the characteristics of ions, thus changing the deposition speed and physical characteristics of calcium carbonate (magnesium carbonate) and preventing the formation of hard scales.
Both nanofiltration membrane (NF) and reverse osmosis membrane (RO) can intercept calcium and magnesium ions in water, thus fundamentally reducing the hardness of water. The method is characterized by obvious and stable effect and wide application range of treated water;
You can use the method of "heating and boiling" at home.
How to soften hard water? Soft water refers to water that contains no or less soluble calcium and magnesium compounds, and is called soft water. In natural water, rainwater and snow water belong to soft water. Springs, streams and rivers are temporarily hard water, and some groundwater is hard water. Distilled water is artificially processed soft water.
Hard water refers to water containing more soluble calcium and magnesium compounds. Hard water will not cause direct harm to health, but it will bring a lot of troubles to life, such as scaling on water appliances and reducing the washing efficiency of soap and detergent.
The easiest way to soften hard water is to boil it.
Cooking is the most commonly used in the family. In the laboratory, ion exchange method is used.
1. precipitation method: treat with lime and soda ash to precipitate calcium and magnesium in water, and filter to obtain soft water, in which manganese and iron plasma can also be removed.
2. Water softener
( 1)na3po 4:3 caso 4+2 na3po 4→Ca3(PO)4↓+3 na 2 so 4
(2) Sodium hexametaphosphate: na4 [Na2 (P03) 6]+Ca→ na4 [Ca (P03) 6]+2na.
(3) Acetic acid derivative of amine (EDTA): forms chelates with calcium, iron and copper plasma.
3. Ion exchange method:
Principle (1): use inorganic or organic substances to form a mixed gel, and form an exchange core surrounded by two different layers.
Water can exchange ions through the electric double layer.
Cation exchanger: solid containing hydrogen and sodium is exchanged with calcium and magnesium ions.
Anion exchanger: contains basic genes and can exchange anions with water.
(2) Ordinary exchanger:
A. zeolite: hydrated sodium aluminum silicate
Na2O Z+Ca(HCO3)2=CaO Z+2NaHCO3
Na2O Z+ calcium sulfate =CaO Z+Na2SO4
B. sulfonated coal:
2Na(K)+CaSO4=Ca(K)2+Na2SO4
2H potassium+calcium sulfate = calcium nitrate+sodium sulfate
C. ion exchange resin
4. Electrodialysis method:
Powered by DC power supply, ions in water selectively permeate through resin exchange membrane to obtain soft water.
5. Magnetization method:
When water flows through the magnetic field, the intermolecular attraction of calcium and magnesium salts decreases, and it is not easy to produce hard scale.
How to make hard water soft The hardness (also called salinity) of water refers to the content of calcium salt and magnesium salt dissolved in water. The hardness is high when the content is high, and low when the content is low. 1 liter of water contains 10mmgCaO (or equivalent to 10mmgCaO), which is called 1 degree. Soft water is water with hardness less than 8, such as rainwater, snow water, purified water, etc. Water with hardness greater than 8 is hard water, such as mineral water, tap water, surface water and groundwater in nature.
Hard water is divided into temporary hard water and permanent hard water. The hardness of temporary hard water is caused by calcium bicarbonate and magnesium bicarbonate, which can be removed after boiling. This hardness is also called carbonate hardness. The hardness of permanent hard water is caused by salts such as calcium sulfate and magnesium sulfate, which cannot be removed after boiling. The above two kinds of hardness are collectively called total hardness.
When water droplets condense in the atmosphere, they will dissolve carbon dioxide in the air and form carbonic acid. Carbonic acid eventually falls to the ground with rain, and then penetrates into the soil to reach the rock layer, dissolving lime (calcium carbonate and magnesium carbonate) to produce temporary hard water. In some areas, karst caves and nearby hard water are formed in this way.
Hard water has many disadvantages: 1. It reacts with soap to produce insoluble precipitate, which reduces the washing effect. (Hard water and soft water can also be distinguished by this. 2. In industry, the precipitation of calcium and magnesium salts will cause boiler scaling, hinder heat conduction, and even lead to boiler explosion in serious cases. Due to the problem of hard water, the maintenance and replacement of equipment and pipelines in industry costs tens of millions of yuan every year. Drinking hard water will also have a certain impact on human health and daily life. People who don't often drink hard water occasionally drink hard water, which will cause gastrointestinal dysfunction, the so-called "acclimatization"; Cooking fish and vegetables with hard water will destroy or reduce the nutritional value of food, because it is not easy to cook; Making tea with hard water will change the color and flavor of tea and reduce its drinking value; Using hard water to make tofu will not only reduce the yield, but also affect the nutritional composition of tofu.
So hard water is useless? No, otherwise how could so many people buy mineral water to drink? It turns out that calcium and magnesium are both macro metal elements in essential elements of life. Scientists and medical scientists have found that the mortality of some cardiovascular diseases, such as hypertension and atherosclerotic heart disease, is inversely proportional to the hardness of drinking water. The hardness of water is low, but the mortality rate is high. In fact, drinking water that is too hard or too soft for a long time is not good for human health. China stipulates that the hardness of drinking water should not exceed 25 degrees.
Hard water can be converted into soft water after treatment. Here are three main ways to soften hard water:
1. Boiling method (only applicable to temporary hard water)
Reaction when boiling hard water temporarily:
Ca(HCO3)2 =CaCO3 ↓+H2O+CO2
Mg(HCO3)2 =MgCO3↓ +H2O+CO2
Because CaCO3 is insoluble and MgCO3 is slightly soluble, magnesium carbonate can react with water to generate more insoluble magnesium hydroxide under further heating;
Magnesium carbonate +H2O = magnesium hydroxide ↓+carbon dioxide
It can be seen that the main components of scale are CaCO3 and Mg(OH)2.
2. Lime-Soviet style of play (for industrial use)
In this method, the temporary hardness can be completely eliminated by adding lime, and HCO3- is converted into CO32-. The permanent hardness of magnesium will be converted into the hardness of calcium with the same amount of substance under the action of lime, and finally it will be removed. During the reaction, magnesium precipitates in the form of magnesium hydroxide, while calcium precipitates in the form of calcium carbonate.
Ca2+(AQ)- lime-Soviet style->; calcium carbonate
Mg2+(AQ)- lime-Soviet style->; magnesium hydrate
3. Ion exchange method
The ion exchangers used in this method are inorganic and organic. Inorganic ion exchangers, such as zeolites; Organic ion exchangers include: carbon-containing ion exchangers-sulfonatase, anion exchange resin, etc. The general ion exchanger can be reused after failure.
Pants are too hard, how can they become soft? Pants are too hard because they have pulp on them. Soaking hot water with vinegar or salt for two or three times will soften them. It can also prevent fading in the future, killing two birds with one stone.
Generally speaking, if the fabric is too hard, the quality of pants is not very good! Jeans with good fabrics are very comfortable to wear. Of course, different fabrics contain different materials. Generally speaking, jeans with more cotton will be more comfortable to wear.
At the same time, it should be noted that the new jeans are a little stiff. Wear it a few times before you see it. If it is still stiff, it means that the fabric quality is not good.
How can hair become soft if it is too hard? Use conditioner.
The body is too hard, how to soften it? You can try yoga.
At first, many actions may not be done in place.
But as long as you keep doing it, try your best every time.
After a period of time, your body will be much more flexible.
I used to play a lot, and my bones were hard.
Later, I practiced yoga for more than a month, and slowly I could do many things that I couldn't do before.
Sleep has also become better, and menstruation has become regular, which is very good ~ you can try it.
How to soften the sesame seed cake if it is put too hard? Add some water, and then steam it in the pot until soft.
Or add more water and heat it in the microwave oven.