Difference between revisions of "Hardness (water)"
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== Description == | == Description == | ||
| − | The hardness of water is measured as the amount of total dissolved solids (TDS), such as [http://cameo.mfa.org/materials/fullrecord.asp?name=calcium | + | The hardness of water is measured as the amount of total dissolved solids (TDS), such as [http://cameo.mfa.org/materials/fullrecord.asp?name=calcium%20sulfate calcium sulfate] or [http://cameo.mfa.org/materials/fullrecord.asp?name=magnesium%20carbonate magnesium carbonate]. Hard water will leave a visible residue upon evaporation (limescale). It can also react with soaps to minimize bubble formation and to form an insoluble scum that interfers with cleaning. Hardness may be removed by distillation, by adding [http://cameo.mfa.org/materials/fullrecord.asp?name=sodium%20carbonate sodium carbonate] and [http://cameo.mfa.org/materials/fullrecord.asp?name=lime lime] or by filtering the water. Filtration may be done with [http://cameo.mfa.org/materials/fullrecord.asp?name=zeolite zeolites], an [http://cameo.mfa.org/materials/fullrecord.asp?name=ion%20exchange%20resin ion exchange] column or a [http://cameo.mfa.org/materials/fullrecord.asp?name=reverse%20osmosis reverse osmosis] system. |
== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
| − | + | Wasserhärte (Deut.); dureté (Fr.); hard water; limescale; total dissolved solids (TDS) | |
== Other Properties == | == Other Properties == | ||
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== Authority == | == Authority == | ||
| − | * | + | * Hoechst Celanese Corporation, ''Dictionary of Fiber & Textile Technology'' (older version called Man-made Fiber and Textile Dictionary, 1965), Hoechst Celanese Corporation, Charlotte NC, 1990 |
| − | * | + | * Richard C. Wolbers, Nanette T. Sterman, Chris Stavroudis, ''Notes for Workshop on New Methods in the Cleaning of Paintings'', J.Paul Getty Trust, Los Angeles, 1990 |
* Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Hard_water (accessed Nov. 30, 2004) | * Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Hard_water (accessed Nov. 30, 2004) | ||
| − | * | + | * Random House, ''Webster's Encyclopedic Unabridged Dictionary of the English Language'', Grammercy Book, New York, 1997 |
* ''The American Heritage Dictionary'' or ''Encarta'', via Microsoft Bookshelf 98, Microsoft Corp., 1998 | * ''The American Heritage Dictionary'' or ''Encarta'', via Microsoft Bookshelf 98, Microsoft Corp., 1998 | ||
Revision as of 06:55, 24 July 2013
Description
The hardness of water is measured as the amount of total dissolved solids (TDS), such as calcium sulfate or magnesium carbonate. Hard water will leave a visible residue upon evaporation (limescale). It can also react with soaps to minimize bubble formation and to form an insoluble scum that interfers with cleaning. Hardness may be removed by distillation, by adding sodium carbonate and lime or by filtering the water. Filtration may be done with zeolites, an ion exchange column or a reverse osmosis system.
Synonyms and Related Terms
Wasserhärte (Deut.); dureté (Fr.); hard water; limescale; total dissolved solids (TDS)
Other Properties
TDS scale:
Soft water = 0-20 mg/l (calculated as calcium)
Moderately soft = 20-40 mg/l
Slightly hard= 40-60 mg/l
Moderately hard = 60-80 mg/l
Very hard = greater than 120 mg/l
Authority
- Hoechst Celanese Corporation, Dictionary of Fiber & Textile Technology (older version called Man-made Fiber and Textile Dictionary, 1965), Hoechst Celanese Corporation, Charlotte NC, 1990
- Richard C. Wolbers, Nanette T. Sterman, Chris Stavroudis, Notes for Workshop on New Methods in the Cleaning of Paintings, J.Paul Getty Trust, Los Angeles, 1990
- Wikipedia, the free encyclopedia, at http://www.wikipedia.com Comment: http://en.wikipedia.org/wiki/Hard_water (accessed Nov. 30, 2004)
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998