关于纯净水的英文文章纯净水的好坏 及你的态度

关于纯净水的英文文章纯净水的好坏 及你的态度
关于纯净水的英文文章
纯净水的好坏 及你的态度

关于纯净水的英文文章纯净水的好坏 及你的态度
瀹氫箟
Purified water is water from any source that is physically processed to remove impurities.Distilled water and deionized water have been the most common forms of purified water,but water can also be purified by other processes including reverse osmosis,carbon filtration,microporous filtration,ultrafiltration,ultraviolet oxidation,or electrodialysis.In recent decades,a combination of the above processes have come into use to produce water of such high purity that its trace contaminants are measured in parts per billion (ppb) or parts per trillion (ppt).Purified water has many uses,largely in science and engineering laboratories and industries,and is produced in a range of purities.
鍑犵?噣姘寸殑鏂规硶褰㈠紡Methods of water purifing
Distilled water has virtually all of its impurities removed through distillation.Distillation involves boiling the water and then condensing the steam into a clean container,leaving nearly all of the solid contaminants behind.Distillation produces very pure water but also leaves behind a leftover white or yellowish mineral scale on the distillation apparatus,which requires that the apparatus be frequently cleaned.
For many applications,cheaper alternatives such as deionized water are used in place of distilled water.
Double-distilled water (abbreviated "ddH2O","Bidest.water" or "DDW") is prepared by double distillation of water.Historically,it was the de facto standard for highly purified laboratory water for biochemistry and trace analysis until combination methods of purification became widespread.
Deionized water which is also known as demineralized water (DI water or de-ionized water; can also be spelled deionised water,see spelling differences) is water that has had its mineral ions removed,such as cations from sodium,calcium,iron,copper and anions such as chloride and bromide.Deionization is a physical process which uses specially-manufactured ion exchange resins which bind to and filter out the mineral salts from water.Because the majority of water impurities are dissolved salts,deionization produces a high purity water that is generally similar to distilled water,and this process is quick and without scale buildup.However,deionization does not significantly remove uncharged organic molecules,viruses or bacteria,except by incidental trapping in the resin.Specially made strong base anion resins can remove Gram-negative bacteria.Deionization can be done continuously and inexpensively using electrodeionization.
It should be noted that deionization does not remove the hydroxide or hydronium ions from water; as water self-ionizes to equilibrium,this would lead to the removal of the water itself.
Other processes are also used to purify water,including reverse osmosis,carbon filtration,microporous filtration,ultrafiltration,ultraviolet oxidation,or electrodialysis.These are used in place of,or in addition to the processes listed above.
敤绾?噣姘碊rinking purified water
Many beverage manufacturers use distilled water to ensure a drink's purity and taste.Bottled distilled water is sold as well,and can usually be found in supermarkets.Water purification,such as distillation,is especially important in regions where water resources or tap water is not suitable for ingesting without boiling or chemical treatment.
Water filtration devices are becoming increasingly common in households.Most of these devices do not distill water,though there continues to be an increase in consumer-oriented water distillers and reverse osmosis machines being sold and used.Municipal water supplies often add or have trace impurities at levels which are regulated to be safe for consumption.Much of these additional impurities,such as volatile organic compounds,fluoride,and an estimated 75,000+ other chemical compounds[citation needed] are not removed through conventional filtration; however,distillation and reverse osmosis eliminate nearly all of these impurities.
The drinking of purified water has been both advocated and discouraged for health reasons.Purified water lacks minerals and ions,such as calcium,which are normally found in potable (drinking) water,and which have important biological functions such as in nervous system homeostasis.Some percentage of our daily consumption of these minerals and ions come from our drinking water,but most of them come from the food we eat,making DI water perfectly fine to drink if one has food in his or her system.The lack of naturally-occurring minerals in distilled water has raised some concerns.The Journal of General Internal Medicine[3] published a study on the mineral contents of different waters available in the US.The study concluded,"drinking water sources available to North Americans may contain high levels of Calcium,Magnesium,and Sodium and may provide clinically important portions of the recommended dietary intake of these minerals," and further encouraged individuals to "check the mineral content of their drinking water,whether tap or bottled,and choose water most appropriate for their needs." Since distilled water is devoid of minerals,supplemental mineral intake through diet is needed to maintain proper health.
It is often observed that consumption of "hard" water,or water that has some minerals,is associated with beneficial cardiovascular effects.As noted in the American Journal of Epidemiology,consumption of hard drinking water is negatively correlated with atherosclerotic heart disease.[4] Since distilled water is free of minerals,it will not have these potential benefits.
It has been suggested that because distilled water lacks fluoride ions that are added by a minority of governments (e.g.,municipalities in the United States) at water treatment plants using sodium hexafluorosilicate or hexafluorosilicic acid for their effect on the inhibition of cavity formation:the drinking of distilled water may increase the risk of tooth decay.[citation needed] However,many medical authorities argue that the effects of fluoridation on teeth are topical (brushed on) rather than systemic (swallowed).Also the benefit of fluoride supplementation,for any purpose,should be cautioned due to potential negative effects to IQ and motor functions.
The costs associated with water distillation have generally been prohibitive.However,distilling water with solar water distillers is becoming increasingly popular around the world; they can be relatively simple to design and build.