Distilled water is
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
that has been boiled into
vapor
In physics, a vapor (American English) or vapour (British English and Canadian English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Her ...
and condensed back into
liquid in a separate container. Impurities in the original water that do not boil below or near the boiling point of water remain in the original container. Thus, distilled water is a type of
purified water
Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently puri ...
.
History
Drinking water
Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
has been distilled from
seawater
Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has appr ...
since at least about AD 200, when the process was clearly described by
Alexander of Aphrodisias
Alexander of Aphrodisias ( grc-gre, Ἀλέξανδρος ὁ Ἀφροδισιεύς, translit=Alexandros ho Aphrodisieus; AD) was a Peripatetic philosopher and the most celebrated of the Ancient Greek commentators on the writings of Aristotle ...
.
Its history predates this, as a passage in
Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of ph ...
's ''
Meteorologica
''Meteorology'' (Greek: ; Latin: ''Meteorologica'' or ''Meteora'') is a treatise by Aristotle. The text discusses what Aristotle believed to have been all the affections common to air and water, and the kinds and parts of the earth and the affect ...
'' refers to the distillation of water.
Captain Israel Williams of the
''Friendship'' (1797) improvised a way to distill water, which he described in his journal.
Applications
In chemical and biological laboratories, as well as in industry, in some appliances
deionised water can be used instead of distilled water as a cheaper alternative.
If exceptionally high-purity water is required,
double distilled water
Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently puri ...
is used.
In general, non-purified water could cause or interfere with chemical reactions as well as leave mineral deposits after boiling away. One method of removing impurities from water and other fluids is
distillation
Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the heat ...
.
For example,
ions
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...
commonly found in tap water would drastically reduce lifespans of
lead–acid batteries used in cars and trucks. These ions are not acceptable in automotive cooling systems because they corrode internal engine components and deplete typical
antifreeze
An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments. Common antifreezes also increase the boiling point of the liquid, all ...
anti-corrosion additives.
Any non-volatile or mineral components in water are left behind when the water evaporates or boils away. Water escaping as steam, for example from a boiler of heating system or steam engine, leaves behind any dissolved materials leading to mineral deposits known as
boiler scale
Boilers for generating steam or hot water have been designed in countless shapes, sizes and configurations. An extensive terminology has evolved to describe their common features. This glossary provides definitions for these terms.
Terms which re ...
.
Low-volume humidifiers such as
cigar humidor
A humidor is a humidity-controlled box or room used primarily for storing cigars, cigarettes, cannabis, or pipe tobacco. Either too much or too little humidity can be harmful to tobacco products; a humidor's primary function is to maintain a ste ...
s can use distilled water to avoid mineral deposits.
Certain biological applications require controlled impurities, especially in experiments. For example, distilling water to be added to an
aquarium would remove known and unknown non-volatile contaminants. Living things require specific minerals; adding distilled water to an ecosystem, such as an aquarium, would reduce the concentration of these minerals. Fish and other living things that have evolved to survive in lakes and oceans should be expected to thrive at mineral ranges found in their original habitat.
Controlled impurities as well as equipment reliability are critically important in medical applications where, for example, distilled water is used in
continuous positive airway pressure
Continuous positive airway pressure (CPAP) is a form of positive airway pressure (PAP) ventilation in which a constant level of pressure greater than atmospheric pressure is continuously applied to the upper respiratory tract of a person. The ...
(CPAP) machines to humidify air for breathing. Distilled water will not leave contaminants behind when the humidifier in the CPAP machine evaporates the water.
It is also possible for brewers to blend distilled water with hard water to mimic the soft waters of
Pilsen.
Another application was to increase the density of the air to assist early airplane jet engines during takeoff in 'hot and high' atmospheric conditions, as was used on the early
Boeing 707.
Use in steam irons
Distilled water can be used in
steam irons for pressing clothes to minimizes the build-up of limescale in hard water areas shortening the lifespan of steam irons, some steam irons have built in filters to remove minerals from the water meaning standard tap water can be used.
Equipment to distill water
Until World War II, distilling seawater to produce
fresh water was time-consuming and expensive in fuel. The saying was: "It takes one gallon of fuel to make one gallon of fresh water." Shortly before the war, Dr. R. V. Kleinschmidt developed a compression still, which became known as the Kleinschmidt still, for extracting fresh water from seawater or contaminated water. By compressing the steam produced by boiling water, of fresh water could be extracted from seawater for every gallon () of fuel used. During World War II this equipment became standard on Allied ships and on trailer mounts for armies. This method was in widespread use in ships and portable water distilling units during the latter half of the century. Modern vessels now use
flash-type evaporators to boil seawater, heating the water to between and evaporating the water in a vacuum; this is then collected as condensation before being stored.
Solar still
A solar still distills water with substances dissolved in it by using the heat of the Sun to evaporate water so that it may be cooled and collected, thereby purifying it. They are used in areas where drinking water is unavailable, so that cle ...
s can be relatively simple to design and build, with very cheap materials.
Drinking distilled water
Bottled distilled water can usually be found in supermarkets or pharmacies, and home water distillers are available as well. 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.
Municipal water supplies almost always contain trace components at levels which are regulated to be safe for consumption. Some other components such as trace levels of
aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
may result from the treatment process.
Fluoride and other ions are not removed through conventional water filter treatments. However, distillation eliminates most impurities.
Distilled water is also used for drinking water in arid seaside areas lacking sufficient freshwater, via
desalination of seawater.
[ (Chapter 12 of the ]World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...
report
Nutrients in drinking-water
')
Health effects
Distillation removes all minerals from water. This results in demineralised water, which has not been proven to be healthier than drinking water. The
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...
investigated the health effects of demineralised water in 1982, and its experiments in humans found that demineralised water increased
diuresis
Diuresis () is increased urination (polyuria) or, in the related word senses more often intended, the physiological process that produces such an increase or the administration of medications to encourage that process. It involves extra urine pr ...
and the elimination of
electrolytes, with decreased serum potassium concentration.
Magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
,
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
, and other nutrients in water can help to protect against nutritional deficiency. Recommendations for magnesium have been put at a minimum of 10 mg/L with 20–30 mg/L optimum; for calcium a 20 mg/L minimum and a 40–80 mg/L optimum, and a total water hardness (adding magnesium and calcium) of 2–4
mmol/L
Molar concentration (also called molarity, amount concentration or substance concentration) is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solut ...
. At water hardness above 5 mmol/L, higher incidence of
gallstone
A gallstone is a stone formed within the gallbladder from precipitated bile components. The term cholelithiasis may refer to the presence of gallstones or to any disease caused by gallstones, and choledocholithiasis refers to the presence of mi ...
s,
kidney stone
Kidney stone disease, also known as nephrolithiasis or urolithiasis, is a crystallopathy where a solid piece of material (kidney stone) develops in the urinary tract. Kidney stones typically form in the kidney and leave the body in the urine s ...
s,
urinary stone
A bladder stone is a stone found in the urinary bladder.
Signs and symptoms
Bladder stones are small mineral deposits that can form in the bladder. In most cases bladder stones develop when the urine becomes very concentrated or when one is d ...
s,
arthrosis
Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the w ...
, and
arthropathies
An arthropathy is a disease of a joint. Types
Arthritis is a form of arthropathy that involves inflammation of one or more joints, while the term arthropathy may be used regardless of whether there is inflammation or not.
Joint diseases can be cl ...
have been observed. For fluoride the concentration recommended for dental health is 0.5–1.0 mg/L, with a maximum guideline value of 1.5 mg/L to avoid
dental fluorosis
Dental fluorosis is a common disorder, characterized by hypomineralization of tooth enamel caused by ingestion of excessive fluoride during enamel formation.
It appears as a range of visual changes in enamel causing degrees of intrinsic tooth d ...
.
Water filtration and distillation devices are becoming increasingly common in households. Municipal water supplies often have minerals added or have trace impurities at levels which are regulated to be safe for consumption. Much of these additional impurities, such as
volatile organic compounds
Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a t ...
,
fluoride, and an estimated >75,000 other chemical compounds are not removed through conventional filtration; however, distillation and reverse osmosis eliminate nearly all of these impurities.
The drinking of distilled water as a replacement for drinking water has been both advocated and discouraged for health reasons. Distilled water lacks minerals and ions such as calcium that play key roles in biological functions such as in nervous system
homeostasis
In biology, homeostasis (British also homoeostasis) (/hɒmɪə(ʊ)ˈsteɪsɪs/) is the state of steady internal, physical, and chemical conditions maintained by living systems. This is the condition of optimal functioning for the organism and ...
, and are normally found in potable water. The lack of naturally occurring minerals in distilled water has raised some concerns. The ''Journal of General Internal Medicine'' published a study on the mineral contents of different waters available in the US. The study found that "drinking water sources available to North Americans may contain high levels of
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
,
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
, and
sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
and may provide clinically important portions of the recommended dietary intake of these minerals". It encouraged people 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, mineral intake through diet is needed to maintain good health.
The consumption of
"hard" water (water with 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.
See also
*
Atmospheric water generator
*
Deionized water
Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently puri ...
*
Heavy water
*
Ultrapure water
Ultrapure water (UPW), high-purity water or highly purified water (HPW) is water that has been purified to uncommonly stringent specifications. Ultrapure water is a term commonly used in manufacturing to emphasize the fact that the water is treated ...
References
{{DEFAULTSORT:Distilled Water
Distillation
Drinking water
Water chemistry