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{{Short description|Chemicals used to whiten or disinfect}}
{{other uses}}
{{About|the chemical|other uses}}
]
{{Use dmy dates|date=December 2021}}
] brand bleach]]


'''Bleach''' is the generic name for any chemical product that is used ] or ] to remove color from (i.e. to whiten) fabric or fiber (in a process called bleaching) or to disinfect after cleaning. It often refers specifically to a dilute solution of ], also called "liquid bleach".
A '''bleach''' is a ] that removes color or whitens, often via ]. Common chemical bleaches include household "chlorine bleach", a solution of approximately 3-6% ] (NaOCl), and "oxygen bleach", which contains ] or a peroxide-releasing compound such as ] or ]. To '''bleach''' something is to apply bleach, sometimes as a preliminary ] in the ] of ]. '''Bleaching powder''' is ].


Many bleaches have broad-spectrum ] properties, making them useful for disinfecting and sterilizing. They are used in ] to control bacteria, viruses, and algae and in many places where sterile conditions are required. They are also used in many industrial processes, notably in the ]. Bleaches also have other minor uses, like removing ], killing ]s, and increasing the longevity of ].<ref>{{cite web|url=http://www.rd.com/home/cleaning-organizing/12-smart-ways-to-use-bleach/|title=12 Smart Ways to Use Bleach - Reader's Digest|date=9 March 2010}}</ref>
== Other types of bleaches ==
] is used for the bleaching of ], ]s and ]s, ], ], ]s, ], skin and in a number of other industries.


Bleaches work by reacting with many colored organic compounds, such as natural pigments, and turning them into colorless ones. While most bleaches are ]s (chemicals that can remove electrons from other molecules), some are ] (that donate electrons).
In the ], some ]s (], etc.) and other agents (e.g. ]s) are used as ] and ]s.


], a powerful oxidizer, is the active agent in many household bleaches. Since pure chlorine is a toxic corrosive gas, these products usually contain ], which releases chlorine. "Bleaching powder" usually refers to a formulation containing ].{{citation needed|date=September 2023}}
], ] and ] and ] are used in ] in the pulp industry to produce totally chlorine free (TCF) paper.


Oxidizing bleaching agents that do not contain chlorine are usually based on ]s, such as ], ], and ]. These bleaches are called "non-chlorine bleach", "]", or "color-safe bleach".<ref>{{Cite web|url=https://sciencing.com/oxygen-bleach-vs-chlorine-bleach-6571838.html|title=Oxygen Bleach Vs. Chlorine Bleach|website=Sciencing|language=en|access-date=16 April 2018}}</ref>
Not all bleaches have to be of an oxidizing nature. ] is used as a powerful ] in some bleaching formulas. It is commonly used to ] ] used to make ].


Reducing bleaches have niche uses, such as ], which is used to bleach wool, either as gas or from solutions of ],<ref name=phil>{{cite journal |doi=10.1111/j.1478-4408.1938.tb01992.x |title=The Bleaching of Wool with Sulphur Dioxide and with Solutions of Sulphites |journal=Journal of the Society of Dyers and Colorists |volume=54 |issue=11 |pages=503–512 |year=2008 |last1=Phillips |first1=H. }}</ref> and ].
== Hazards and concerns ==
Since bleaches are strong ] agents, they can be quite hazardous, especially when reacted with other common household chemicals.


Bleaches generally react with many other organic substances besides the intended colored pigments, so they can weaken or damage natural materials like fibers, cloth, and leather, and intentionally applied dyes, such as the ] of ]. For the same reason, ingestion of the products, breathing of the fumes, or contact with skin or eyes can cause bodily harm and damage health.
Mixing sodium hypochlorite with acids like ] or drain cleaners containing ] (sodium hydrogen sulfate), or even lemon juice can release ]. Hypochlorite and chlorine are in equilibrium in water, the position of the equilibrium is pH dependant and low pH (acidic) favors chlorine,<ref name="c&w">{{cite book |last=Cotton |first=F.A |authorlink= |coauthors=G. Wilkinson |title=Advanced Inorganic Chemistry |year=1972 |publisher=John Wiley and Sons Inc |location= |isbn=0-471-17560-9 }}</ref>


== History ==
Cl<sub>2</sub> + H<sub>2</sub>O <math>\rightleftharpoons</math> H<sup>+</sup> + Cl<sup>-</sup> + HClO
]
The earliest form of bleaching involved spreading fabrics and cloth out in a ] to be whitened by the action of the ] and ].<ref name=encyc>{{Cite EB1911 |wstitle=Bleaching}}</ref><ref name="Cotton">{{Cite book |title=The Cotton Industry |last=Aspin |first=Chris |publisher=Shire Publications |year=1981 |isbn=978-0-85263-545-2 |page= |url=https://archive.org/details/cottonindustry0000aspi/page/24 }}</ref> In the 17th century, there was a significant cloth bleaching industry in Western Europe, using alternating alkaline baths (generally ]) and acid baths (such as ] from sour milk, and later diluted ]). The whole process lasted up to six months.<ref name=encyc/>


Chlorine-based bleaches, which shortened that process from months to hours, were invented in ] in the late 18th century. Swedish chemist ] discovered chlorine in 1774,<ref name=encyc/> and in 1785 Savoyard scientist ] recognized that it could be used to bleach fabrics.<ref name=encyc/> Berthollet also discovered ], which became the first commercial bleach, named ''Eau de Javel'' ("Javel water") after the borough of ], near Paris, where it was produced.
] is a respiratory irritant that attacks ]s and ] the skin. As little as 3.5 ] can be detected as an odour, and 1000 ] is likely to be fatal after a few deep breaths. Exposure to chlorine has been limited to 0.5 ] (8-hour time-weighted average—40 hour week) by ] in the U.S.<ref>{{ cite web|url=http://www.osha.gov/SLTC/healthguidelines/chlorine and peroxide/recognition.html| title=OSHA -- Chlorine| work=OSHA| year=2007| accessdate=2007-08-26|author=Occupational Safety & Health Administration}}</ref>


Scottish chemist and industrialist ] proposed in 1798 a solution of ] as an alternative for Javel water, and patented bleaching powder (solid ]) in 1799.<ref name=encyc/>{{sfn|Chisholm|1911}} Around 1820, French chemist ] discovered the disinfecting and deodorizing ability of hypochlorites and was instrumental in popularizing their use for such purpose.<ref name=scott>Scott, James, transl. (1828). '''' Published by S. Highley.</ref> His work greatly improved medical practice, public health, and the sanitary conditions in hospitals, ]s, and all industries dealing with animal products.<ref name="nbu">, '']'', volume 28 (1859), columns 323-324.</ref>
Sodium hypochlorite and ] react to form a number of products, depending on the temperature, concentration, and how they are mixed. <ref>{{Citation | last =Rizk-Ouaini | first =Rosette | author-link = | last2 =Ferriol, Michel; Gazet, Josette; Saugier-Cohen Adad, Marie Therese | first2 = | author2-link = | title =Oxidation reaction of ammonia with sodium hypochlorite. Production and degradation reactions of chloramines. | journal =Bulletin de la Societe Chimique de France
| volume =4 | issue = | pages =512–21 | date =1986
| year = | url = | doi = | id = }}</ref>. The main reaction is chlorination of ammonia, first giving ] (NH<sub>2</sub>Cl), then NHCl<sub>2</sub> and finally ] (NCl<sub>3</sub>). These materials are very irritating to eyes and lungs and are toxic above certain concentrations.


] first produced ] in 1818 by reacting ] with ].<ref>{{Cite journal| title = Observations sur des nouvelles combinaisons entre l'oxigène et divers acides| author = L. J. Thénard| journal = ] |series=2nd Series| volume = 8| year =1818| pages = 306–312| url = https://books.google.com/books?id=-N43AAAAMAAJ&pg=PA306}}</ref> Hydrogen peroxide was first used for bleaching in 1882, but did not become commercially important until after 1930.<ref>{{cite book|url=https://www.scribd.com/doc/90597292/9/History-of-bleaching-with-hydrogen-peroxide|title=Catalytic Bleaching of Cotton: Molecular and Macroscopic Aspects p 16|author=Tatjana Topalović|publisher=Thesis, University of Twente, the Netherlands |isbn=978-90-365-2454-4|access-date=8 May 2012|year=2007}}</ref> ] as a laundry bleach has been used in Europe since the early twentieth century, and became popular in North America in the 1980s.<ref>{{cite journal |last1=Milne |first1=Neil |year=1998 |title=Oxygen bleaching systems in domestic laundry |journal=Journal of Surfactants and Detergents |volume=1 |issue=2 |pages=253–261 |doi=10.1007/s11743-998-0029-z |s2cid=59456079 }}</ref>
NH<sub>3</sub> + NaOCl --> NaOH + NH<sub>2</sub>Cl


== Mechanism of action ==
NH<sub>2</sub>Cl + NaOCl --> NaOH + NHCl<sub>2</sub>


=== Whitening ===
NHCl<sub>2</sub> + NaOCl --> NaOH + NCl<sub>3</sub>
Colors of natural organic materials typically arise from organic ]s, such as ]. Chemical bleaches work in one of two ways:
*An oxidizing bleach works by breaking the ]s that make up the ]. This changes the molecule into a different substance that either does not contain a chromophore or contains a chromophore that does not absorb ]. This is the mechanism of bleaches based on ] but also of oxygen-anions which react through the initial ] attack.<ref>{{Cite journal|last1=Mayer|first1=Robert J.|last2=Ofial|first2=Armin R.|date=22 February 2018|title=Nucleophilic Reactivities of Bleach Reagents|journal=Organic Letters|volume=20|issue=10|pages=2816–2820|doi=10.1021/acs.orglett.8b00645|pmid=29741385}}</ref>
*A reducing bleach works by converting ]s in the chromophore into ]s. This eliminates the ability of the chromophore to absorb visible light. This is the mechanism of bleaches based on ].<ref>{{cite web|url=http://sci-toys.com/ingredients/bleach.html| title=Ingredients – Bleach| work=Science Toys| year=2006| access-date=2 March 2006|author=Field, Simon Q}}</ref>


Sunlight acts as a bleach through a process leading to similar results: high-energy ]s of light, often in the ] or ] range, can disrupt the bonds in the chromophore, rendering the resulting substance colorless. Extended exposure often leads to massive discoloration usually reducing the colors to a white and typically very faded blue.<ref>{{cite web| url=http://www.howeverythingworks.org/pages_fm.php?topic=all&page=150| title=Sunlight| work=How Things Work Home Page| year=2006| access-date=23 February 2012| author=Bloomfield, Louis A| archive-url=https://web.archive.org/web/20130511065317/http://www.howeverythingworks.org/pages_fm.php?topic=all&page=150| archive-date=11 May 2013| url-status=dead}}</ref>
Additional reactions produce ], in a variation of the ].


=== Antimicrobial efficacy ===
NH<sub>3</sub> + NH<sub>2</sub>Cl + NaOH --> N<sub>2</sub>H<sub>4</sub> + NaCl + H<sub>2</sub>O
The broad-spectrum effectiveness of most bleaches is due to their general chemical reactivity against organic compounds, rather than the selective inhibitory or toxic actions of ]s. They irreversibly ] or destroy many ]s, including all ]s, making them extremely versatile disinfectants.


Hypochlorite bleaches in low concentration were also found to attack bacteria by interfering with ]s on their walls.<ref name=Winter>{{cite journal
The hydrazine generated can further react with the ] in an ] reaction:<ref name="c&w"/>
| last = Jakob
| first = U.
|author2=J. Winter |author3=M. Ilbert |author4=P.C.F. Graf |author5=D. Özcelik
| title = Bleach Activates A Redox-Regulated Chaperone by Oxidative Protein Unfolding
| journal = ]
| volume = 135
| issue = 4
| pages = 691–701
| date = 14 November 2008
| url= | doi =10.1016/j.cell.2008.09.024
| pmid = 19013278
| pmc = 2606091 }}</ref> According to 2013 Home Hygiene and Health report,<ref>{{Cite web|title={{!}} Home Hygiene & Health|url=https://www.ifh-homehygiene.org/review/effectiveness-laundering-processes-used-domestic-home-settings-2013|access-date=12 December 2020|website=www.ifh-homehygiene.org|date=21 October 2013 }}</ref> using bleach, whether chlorine- or peroxide-based, significantly increases germicidal efficiency of laundry even at low temperatures (30-40 degrees Celsius), which makes it possible to eliminate viruses, bacteria, and fungi from a variety of clothing in a home setting.<ref>{{Cite web|last=Ploumanac'h|title=Sanitize Laundry for Delicate Clothes|url=https://www.theploumanach.com/blogs/clothing-care/sanitize-laundry-for-delicate-clothes|access-date=12 December 2020|website=Ploumanac'h|language=en}}</ref>


==Types of bleaches==
2 NH<sub>2</sub>Cl + N<sub>2</sub>H<sub>4</sub> --> 2 NH<sub>4</sub>Cl + N<sub>2</sub>


Most industrial and household bleaches belong to three broad classes:
Industrial bleaching agents can also be sources of concern. For example, the use of elemental chlorine in the ] produces ]s, ]s, including ]s. According to an industry group, the use of ] in these processes has reduced the dioxin generation to under detectable levels.<ref>{{cite web |url=http://www.aet.org/epp/ecf_brochure.pdf |title=ECF: The Sustainable Technology |accessdate=2007-09-19 |last= |first= |coauthors= |date= |work= |publisher=Alliance for Environmental Technology}}</ref> However, respiratory risk from chlorine and highly toxic chlorinated byproducts still remain.
* ]es, whose active agent is ], usually from the decomposition of some chlorine compound like ] or ].
* ]es, whose active agent is ], almost always from the decomposition of a ] compound like ].
* Sulfur dioxide-based bleaches, whose active agent is ], possibly from the decomposition of some oxosulfur anion.


===Chlorine-based bleaches===
== Chemistry ==
Chlorine-based bleaches are found in many household "bleach" products, as well as in specialized products for hospitals, public health, ], and industrial processes.
The process of bleaching can be summarised in the following set of chemical reaction:


The grade of chlorine-based bleaches is often expressed as ]. One gram of 100% active chlorine bleach has the same bleaching power as one gram of elemental ].
Cl<sub>2</sub>(aq) + H<sub>2</sub>O(l) <math>\rightleftharpoons</math> H<sup>+</sup>(aq) + Cl<sup>-</sup>(aq) + HClO(aq)


The most common chlorine-based bleaches are:
The H<sup>+</sup> ion of the hypochlorous acid then dissolves into solution, and so the final result is effectively:
* ] ({{chem|NaClO}}), usually as a 3–6% solution in water, usually called "liquid bleach" or just "bleach". Historically called "] water" ({{langx|fr|eau de Javel}}). It is used in many households to whiten laundry, disinfect hard surfaces in kitchens and bathrooms, treat water for drinking, and ].
* Bleaching powder (formerly known as "chlorinated lime"), usually a mixture of ] ({{chem|Ca|(|ClO|)|2}}), ] (slaked lime, {{chem|Ca|(|OH|)|2}}), and ] ({{chem|CaCl|2}}) in variable amounts.<ref name=Ullmann>{{cite book |doi=10.1002/14356007.a06_483.pub2|chapter=Chlorine Oxides and Chlorine Oxygen Acids|title=Ullmann's Encyclopedia of Industrial Chemistry|year=2010|last1=Vogt|first1=Helmut|last2=Balej|first2=Jan|last3=Bennett|first3=John E.|last4=Wintzer|first4=Peter|last5=Sheikh|first5=Saeed Akbar|last6=Gallone|first6=Patrizio|last7=Vasudevan|first7=Subramanyan|last8=Pelin|first8=Kalle|isbn=978-3527306732|s2cid=96905077 }}</ref> Sold as a white powder or in tablets, it is used in many of the same applications as sodium hypochlorite but is more stable and contains more available chlorine.
* ] gas ({{chem|Cl|2}}). It is used as a disinfectant in ], especially to make ] and in large public ]. It was used extensively to ], but this use has decreased significantly due to environmental concerns.
* ] ({{chem|ClO|2}}). This unstable gas is generated in situ or stored as dilute aqueous solutions. It finds large-scale applications for the ], ]s and ]s, ], ], ]s, ], ], and in a number of other industries.


Other examples of chlorine-based bleaches, used mostly as disinfectants, are ], ], and ].<ref name=WHO19th>{{cite web|title=WHO Model List of Essential Medicines (19th List)|url=https://www.who.int/medicines/publications/essentialmedicines/EML_2015_FINAL_amended_NOV2015.pdf?ua=1|work=World Health Organization|access-date=8 December 2016|date=April 2015|url-status=live|archive-url=https://web.archive.org/web/20161213052708/http://www.who.int/medicines/publications/essentialmedicines/EML_2015_FINAL_amended_NOV2015.pdf?ua=1|archive-date=13 December 2016}}</ref>{{failed verification|date=February 2020}}
Cl<sub>2</sub>(aq) + H<sub>2</sub>O(l) <math>\rightleftharpoons</math> 2H<sup>+</sup>(aq) + Cl<sup>-</sup>(aq) + ClO<sup>-</sup>(aq)


===Peroxide-based bleaches===
== Mechanism of bleach action ==
]es are characterized by the ] chemical ], namely two oxygen atoms connected by a ], (–O–O–). This bond is easily broken, giving rise to very reactive oxygen species, which are the active agents of this type of bleach.
Color in most ]s and ]s is produced by ], such as ], which contain ]s. Chemical bleaches work in one of two ways:


The main products in this class are:
*An oxidizing bleach works by breaking the ]s that make up the chromophore. This changes the molecule into a different substance that either does not contain a chromophore, or contains a chromophore that does not absorb ].
* ] ({{chem|H|2|O|2}}). It is used, for example, to bleach wood pulp and hair or to prepare other bleaching agents like perborates, percarbonates, peracids, etc.
* ] ({{chem|Na|2|H|3|CO|6}}), an ] of hydrogen peroxide and ] ("soda ash" or "washing soda", {{chem|Na|2|CO|3}}). Dissolved in water, it yields a solution of the two products, that combines the ] action of the carbonate with the bleaching action of the peroxide.
* ] ({{chem|Na|2|H|4|B|2|O|8}}). Dissolved in water it forms some hydrogen peroxide, but also the perborate anion ({{chem|B(OOH)(OH)|3|-}}) which can perform ] oxidation.<ref>{{cite web|url=https://www.organic-chemistry.org/chemicals/oxidations/sodiumperborate.shtm|author=Douglass F. Taber|title=Oxidizing agents: Sodium perborate|access-date=7 June 2012}}</ref>
* ] ({{chem|H|3|C|C(O)OOH}}). Generated in situ by some laundry detergents, and also marketed for use as industrial and agricultural disinfection and water treatment.<ref name=peracepa>V. Namboodiri and A. Garg (2017): "". document EPA/600/R-17/172, National Risk Management Research Laboratory, U.S. Environmental Protection Agency,</ref>
* ] ({{chem|(C|6|H|5|COO)|2}}). It is used in topical medications for ]<ref name=WHO19th/> and to bleach ].<ref name=fao1>(2004) "" FAO Publication FNP 52 Addendum 12.</ref>
* ] ({{chem|O|3}}). While not properly a peroxide, its mechanism of action is similar. It is used in the manufacture of paper products, especially ] and white ].<ref>{{cite web | url = http://www.ozonesolutions.com/Ozone_Color_Removal.html | work = Ozone Information | title = Ozo formulas | access-date = 9 January 2009 | archive-url = https://web.archive.org/web/20110715031645/http://www.ozonesolutions.com/Ozone_Color_Removal.html | archive-date = 15 July 2011 | url-status = dead }}</ref>
*] (] ]) and other persulfate salts. It, alongside ammonium and sodium persulfate, is common in hair-lightening products.<ref>{{Cite journal|title=Final Report on the Safety Assessment of Ammonium, Potassium, and Sodium Persulfate|journal = International Journal of Toxicology|volume = 20|issue = 3_suppl|pages = 7–21|language=en|doi=10.1080/10915810152630710|pmid = 11766134|year = 2001|last1 = Pang|first1 = S.|last2 = Fiume|first2 = M. Z.|s2cid = 25763799}}</ref>
*] salts such as ] (KMnO<sub>4</sub>).


In the ], other oxidizing products like ]s are used as ] and ]s.
*A reducing bleach works by converting ]s in the chromophore into ]s. This eliminates the ability of the chromophore to absorb visible light.<ref>{{ cite web|url=http://sci-toys.com/ingredients/bleach.html| title=Ingredients -- Bleach| work=Science Toys| year=2006| accessdate=2006-03-02|author=Field, Simon Q}}</ref>


===Reducing bleaches===
Sunlight acts as a bleach through a process leading to similar results: high energy ]s of light, often in the ] or ] range, can disrupt the bonds in the chromophore, rendering the resulting substance colorless. Extended exposure often leads to massive discoloration usually reducing the colors to white and typically very faded blue spectrums.<ref>{{ cite web|url=http://howthingswork.virginia.edu/sunlight.html| title=Sunlight| work=How Things Work Home Page| year=2006| accessdate=2006-03-02|author=Bloomfield, Louis A}}</ref>
] (also known as sodium hydrosulfite) is one of the most important reductive bleaching agents. It is a white crystalline powder with a weak ]ous odor. It can be obtained by reacting ] with ].

:2 NaHSO<sub>3</sub> + Zn → Na<sub>2</sub>S<sub>2</sub>O<sub>4</sub> + Zn(OH)<sub>2</sub>

It is used as such in some industrial dyeing processes to eliminate excess dye, residual oxide, and unintended pigments and for ].

Reaction of sodium dithionite with ] produces ].

:Na<sub>2</sub>S<sub>2</sub>O<sub>4</sub> + 2 CH<sub>2</sub>O + H<sub>2</sub>O → NaHOCH<sub>2</sub>SO<sub>3</sub> + NaHOCH<sub>2</sub>SO<sub>2</sub>

Thus is used in bleaching ], ], ], ] and ].<ref>{{cite book
| title = Organic building blocks of the chemical industry
| author = Herman Harry Szmant
| publisher = John Wiley and Sons
| year = 1989
| isbn = 978-0-471-85545-3
| page = 113 | url=https://books.google.com/books?id=a2XNyj1WtkMC&q=Rongalite+reducing+agent | oclc=19122597
}}</ref>

===Photographic bleach===
In ], silver halide grains are associated with couplers which, on development, produce metallic silver and a colored image. The silver is 'bleached' to a soluble form in a solution of ferric EDTA, which is then dissolved in 'fix', a solution of sodium or ammonium thiosulfate. The procedure is the same for paper processing except that the EDTA and thiosulfate are mixed in 'bleachfix'.

In ], residual ] in the emulsion after the first development is reduced to a soluble silver salt using a chemical bleach, most commonly ]. A conventional fixer then dissolves the reduced silver but leaves the unexposed silver halide intact. This unexposed halide is then exposed to light or chemically treated so that a second development produces a positive image. In color and ] film, this also generates a dye image in proportion to the silver.

Photographic bleaches are also used in black-and-white photography to selectively reduce silver to reduce silver density in negatives or prints. In such cases, the bleach composition is typically an acid solution of ].

== Environmental impact ==
A Risk Assessment Report (RAR) conducted by the European Union on sodium hypochlorite conducted under Regulation EEC 793/93 concluded that this substance is safe for the environment in all its current, normal uses.<ref>European Union Risk Assessment Report. 2007. Sodium Hypochlorite (CAS No: 7681-52-9; EINECS No: 231-668-3): Final report, November 2007 (Final Approved Version); see , Scientific Committee on Health and Environmental Risks, 12 March 2008.</ref> This is due to its high reactivity and instability. The disappearance of hypochlorite is practically immediate in the natural aquatic environment, reaching in a short time concentration as low as 10<sup>−22</sup> μg/L or less in all emission scenarios. In addition, it was found that while volatile chlorine species may be relevant in some indoor scenarios, they have a negligible impact in open environmental conditions. Further, the role of hypochlorite pollution is assumed as negligible in soils.

Industrial bleaching agents can be sources of concern. For example, the use of elemental chlorine in the ] produces ]s and ]s, including ]s. According to an industry group, the use of chlorine dioxide in these processes has reduced the dioxin generation to under-detectable levels.<ref>{{cite web|url=http://www.aet.org/epp/ecf_brochure.pdf|title=ECF: The Sustainable Technology|access-date=19 September 2007|publisher=Alliance for Environmental Technology|archive-url=https://web.archive.org/web/20080414143537/http://www.aet.org/epp/ecf_brochure.pdf|archive-date=14 April 2008|url-status=dead}}</ref> However, the respiratory risk from chlorine and highly toxic chlorinated byproducts still exists.

A European study conducted in 2008 indicated that sodium hypochlorite and organic chemicals (e.g., ]s, ]s) contained in several household cleaning products can react to generate chlorinated ]s (VOCs).<ref name="odabasi-2008est">{{cite journal|last1=Odabasi|first1=Mustafa|title=Halogenated Volatile Organic Compounds from the Use of Chlorine-Bleach-Containing Household Products|journal=]|date=March 2008|volume=42|issue=5 |pages=1445–1451|doi=10.1021/es702355u|pmid=18441786|bibcode=2008EnST...42.1445O}}</ref> These chlorinated compounds are emitted during cleaning applications, some of which are toxic and probable human ]s. The study showed that indoor air concentrations significantly increase (8–52 times for ] and 1–1170 times for ], respectively, above baseline quantities in the household) during the use of bleach-containing products. The increase in chlorinated volatile organic compound concentrations was the lowest for plain bleach and the highest for the products in the form of "thick liquid and ]".

The significant increases observed in indoor air concentrations of several chlorinated VOCs (especially carbon tetrachloride and chloroform) indicate that bleach use may be a source that could be important in terms of inhalation exposure to these compounds. While the authors suggested that using these cleaning products may significantly increase the cancer risk,<ref name="odabasi-2008est" /><ref>{{cite web|last=Odabasi|first=Mustafa|url=http://www.slideworld.org/ViewSlides.aspx?URL=5092|url-status=|title=Halogenated Volatile Organic Compounds from the Use of Chlorine-Bleach- Containing Household Products, Flash Slide presentation|date=2008}}{{dead link|date=September 2023}}</ref> this conclusion appears to be hypothetical:

:* The highest level cited for a concentration of carbon tetrachloride (seemingly of highest concern) is 459 micrograms per cubic meter, translating to 0.073 ppm (part per million), or 73 ppb (part per billion). The ]-allowable time-weighted average concentration over eight hours is 10 ppm,<ref name="OSHA_CCl4">{{cite web|url=http://www.osha.gov/dts/chemicalsampling/data/CH_225800.html |title=Chemical Sampling Information: Carbon Tetrachloride |publisher=OSHA |date=16 June 2004 |access-date=4 December 2009 |archive-date=14 November 2009 |url-status=dead |archive-url=https://web.archive.org/web/20091114235827/http://www.osha.gov/dts/chemicalsampling/data/CH_225800.html }}</ref> almost 140 times higher;
:* The ] highest allowable peak concentration (5-minute exposure for five minutes in 4 hours) is 200 ppm,<ref name="OSHA_CCl4"/> twice as high as the reported highest peak level (from the ] of a bottle of a sample of bleach plus detergent).

== Disinfection ==
Sodium hypochlorite solution, 3–6%, (common household bleach) is typically diluted for safe use when disinfecting surfaces and when used to treat drinking water.<ref>{{cite web |url=http://www.cfsph.iastate.edu/BRM/resources/Disinfectants/Disinfection101Feb2005.pdf |title=Disinfection |last=Dvorak |first=Glenda |date=February 2005 |work=Center for Food Security and Public Health |publisher=Center for Food Security and Public Health, Iowa State University|page=12|access-date=7 February 2011 |location=Ames, IA |url-status=dead |archive-url=https://web.archive.org/web/20100619114657/http://www.cfsph.iastate.edu/BRM/resources/Disinfectants/Disinfection101Feb2005.pdf|archive-date=19 June 2010}}</ref><ref>{{cite web |url=http://www.vahealth.org/childadolescenthealth/EarlyChildhoodHealth/HealthyChildCareVA/documents/2009/doc/Disinfectionguidelines-childcare_8_14_09_FINAL.doc |title=Guidelines for the Use of Sanitizers and Disinfectants in Child Care Facilities |publisher=Virginia Department of Health |access-date=16 March 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100614021743/http://www.vahealth.org/childadolescenthealth/EarlyChildhoodHealth/HealthyChildCareVA/documents/2009/doc/Disinfectionguidelines-childcare_8_14_09_FINAL.doc |archive-date=14 June 2010}}</ref>

A weak solution of 2% household bleach in warm water is typical for sanitizing smooth surfaces before the brewing of beer or wine.{{citation needed|date=February 2023}}

US government regulations (21 CFR 178 Subpart C) allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach, provided that the solution is allowed to drain adequately before contact with food and that the solutions do not exceed 200 parts per million (ppm) available chlorine (for example, one tablespoon of typical household bleach containing 5.25% sodium hypochlorite, per gallon of water).

A 1-in-47 dilution of household bleach with water (1 part bleach to 47 parts water: e.g. one teaspoon of bleach in a cup of water, or 21 ml per litre, or {{sfrac|1|3}} cup of bleach in a gallon of water) is effective against many ] and some ]es in homes.<ref>{{Cite web|url=https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/disinfecting-your-home.html |title=Everyday Steps and Extra Steps When Someone Is Sick|website=Center for Disease Control|date=11 February 2020}}</ref> Even "scientific-grade", commercially produced disinfection solutions such as Virocidin-X usually have sodium hypochlorite as their sole '''active''' ingredient, though they also contain ] (to prevent beading) and fragrances (to conceal the bleach smell).<ref>{{Cite web|url=https://www.kamscientific.com/|title=Kam Scientific Inc.|website=Kam Scientific Inc.|access-date=2 May 2020|archive-date=9 May 2020|archive-url=https://web.archive.org/web/20200509002002/https://www.kamscientific.com/|url-status=dead}}</ref>

See ] for a discussion of the mechanism for disinfectant action.

An oral rinse with a 0.05% dilute solution of household bleach is shown to treat ].<ref>{{Cite journal | last1 = De Nardo | first1 = R. | last2 = Chiappe | first2 = V. N. | last3 = Gómez | first3 = M. | last4 = Romanelli | first4 = H. | last5 = Slots | first5 = J. R. | title = Effects of 0.05% sodium hypochlorite oral rinse on supragingival biofilm and gingival inflammation | doi = 10.1111/j.1875-595X.2011.00111.x | journal = International Dental Journal | volume = 62 | issue = 4 | pages = 208–212 | year = 2012 | pmid = 23017003| pmc = 9374941 | doi-access = free }}</ref>

==Color-safe bleach==
Color-safe bleach is a solution with hydrogen peroxide as the active ingredient (for stain removal) rather than sodium hypochlorite or chlorine.<ref>{{cite web|url=https://www.clorox.com/how-to/laundry-basics/general-laundry-advice/your-questions-disinfecting-laundry/ |title=Dr Laundry - Clorox |date=28 October 2015 |url-status=dead |archive-url=https://web.archive.org/web/20110609033024/http://www.clorox.com/blogs/dr-laundry/2008/06/10/your-questions-disinfecting-laundry/ |archive-date=9 June 2011}}</ref> It also has chemicals{{which|date=July 2024}} in it that help brighten colors.<ref name="clorox.com">{{Cite web|url=https://www.clorox.com/products/clorox2-pretreat-stain-remover-spray/|title=Clothes Stain Remover - Pretreat Spray &#124; Clorox®|date=27 June 2015}}</ref> Though hydrogen peroxide is used for sterilization purposes and water treatment, its ability to disinfect laundry is limited because the concentration of hydrogen peroxide in laundry products is lower than what is used in other applications.<ref name="clorox.com"/>

==Health hazards==
The safety of bleaches depends on the compounds present, and their concentration.<ref name="slaughter">{{Citation |vauthors= Slaughter RJ, Watts M, Vale JA, Grieve JR, Schep LJ |title=The clinical toxicology of sodium hypochlorite |journal=Clinical Toxicology |year=2019 |volume=57 |issue=5 |pages=303–311 |doi=10.1080/15563650.2018.1543889 |pmid=30689457 |s2cid=59339240 }}</ref> Generally speaking, the ingestion of bleaches will cause damage to the ] and ], possibly leading to death. On contact with the skin or eyes, it causes irritation, drying, and potentially burns. Inhalation of bleach fumes can cause mild irritation of the upper airways.<ref name="slaughter"/> ] should always be used when using bleach.

Bleach should never be mixed with ] or other acids, as this will create highly toxic ], which can cause severe burns internally and externally.<ref name="Washington">{{cite web |url=https://www.doh.wa.gov/YouandYourFamily/HealthyHome/Contaminants/BleachMixingDangers |title=Dangers of Mixing Bleach with Cleaners |author=<!--Not stated--> |publisher=Washington State Department of Health |access-date= 12 February 2020}}</ref><ref name="Missouri">{{cite web |url=https://missouripoisoncenter.org/some-things-just-dont-mix/ |title=Some Things Just Don't Mix: Poison Control Tips for Chemicals |author=<!--Not stated--> |date=2 March 2018 |publisher=Missouri Poison Center |access-date=12 February 2020}}</ref><ref name= "Berkley">{{cite web |url=https://ehs.berkeley.edu/lessons-learned/lesson-learned-accidental-mixing-bleach-and-acid |title=Lesson Learned - Accidental Mixing of Bleach and Acid |author=<!--Not stated--> |publisher=Regents of the University of California |access-date=12 February 2020}}</ref><ref name="GH">{{cite magazine |url= https://www.goodhousekeeping.com/home/cleaning/tips/a32773/cleaning-products-never-mix/ |title=6 Cleaning Products You Should Never, Ever Mix |last1=Freedman |first1=Lisa |last2=Mcdonough |first2=Lauren Smith |date=22 March 2019 |magazine= ] |access-date=12 February 2019}}</ref> Mixing bleach with ] similarly produces ] gas, which can burn the lungs.<ref name= "Washington"/><ref name="Missouri"/><ref name="GH"/> Mixing bleach with ] or ] makes ],<ref>{{cite web |title=Dangerous Household Cleaning Combinations: WHAT NOT TO MIX |url=https://dph.georgia.gov/document/document/envhealthchemhazwhatnottomixeng1020pdf/download |publisher=Georgia Department of Public Health |access-date=22 January 2024}}</ref> while mixing with ] results in an ] and potentially explosive chemical reaction that releases ].<ref>{{cite news |title=Accidental mix of bleach and acid kills Buffalo Wild Wings employee |url=https://cen.acs.org/safety/consumer-safety/Accidental-mix-bleach-acid-kills/97/i45 |work=Chemical & Engineering News |date=13 November 2019 |language=en}}</ref>

===False claims as a cure===
{{Recentism|date=June 2024}}
{{main|Miracle Mineral Supplement}}
] (MMS), also promoted as "Master Mineral Solution" or "Chlorine Dioxide Solution" or CDS,<ref>{{Cite journal |last1=Loh |first1=John Ming Ren |last2=Shafi |first2=Humaira |date=24 November 2014 |title=Kikuchi-Fujimoto disease presenting after consumption of 'Miracle Mineral Solution' (sodium chlorite) |journal=BMJ Case Reports |volume=2014 |pages=bcr2014205832 |doi=10.1136/bcr-2014-205832 |issn=1757-790X |pmc=4244351 |pmid=25422331}}</ref> to evade restrictions by online retail platforms, is a bleach solution that has been fraudulently promoted as a cure-all since 2006.<ref>{{Cite news |last=Robbins |first=Martin |date=15 September 2010 |title=The man who encourages the sick and dying to drink industrial bleach |work=The Guardian |location= London |url= https://www.theguardian.com/science/2010/sep/15/miracle-mineral-solutions-mms-bleach |access-date=20 July 2020}}</ref> Its main active ingredient is ], which is "activated" with citric acid to form chlorine dioxide. In an attempt to evade health regulations, its inventor, Jim Humble, a former ], founded the ''Genesis II Church of Health and Healing'', which considers MMS as its sacrament.<ref>{{cite press release |publisher=] |title=FDA warns consumers about the dangerous and potentially life threatening side effects of Miracle Mineral Solution |url= https://www.fda.gov/news-events/press-announcements/fda-warns-consumers-about-dangerous-and-potentially-life-threatening-side-effects-miracle-mineral |access-date=16 January 2024 |archive-url= https://web.archive.org/web/20231013155515/https://www.fda.gov/news-events/press-announcements/fda-warns-consumers-about-dangerous-and-potentially-life-threatening-side-effects-miracle-mineral |archive-date=13 October 2023 |date=12 August 2019}}</ref><ref>{{Cite news |url= https://www.huffpost.com/entry/robert-baldwin-mms_n_5ce54e53e4b0d513447dab77 |title=New Jersey Pastor Has Been Passing Off Bleach As A 'Miracle Cure' In Uganda: Report |last=Kuruvilla |first=Carol |date=22 May 2019 |website=HuffPost |access-date=25 April 2020}}</ref>


== See also == == See also ==
* ] * ]
* ] * ]
* ] * ]
* ] * ]
* ]


== References == == References ==
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== Further reading == == Further reading ==
* Bodkins, Dr. Bailey. ''Bleach''. Philadelphia: Virginia Printing Press, 1995. <!-- Can not find in the Library of Congress, British Library, or WorldCat catalogs, nor via Amazon.com, BookFinder.com, or Google. --> * Bodkins, Bailey. ''Bleach''. Philadelphia: Virginia Printing Press, 1995.<!-- Can not find in the Library of Congress, British Library, or WorldCat catalogs, nor via Amazon.com, BookFinder.com, or Google. -->{{Full citation needed|date=May 2022}}
* Trotman, E.R. ''Textile Scouring and Bleaching''. London: Charles Griffin & Co., 1968. ISBN 0852640676. * Trotman, E. R. ''Textile Scouring and Bleaching''. London: Charles Griffin & Co., 1968. {{ISBN|0-85264-067-6}}.
*


== External links == == External links ==
{{Commons category}}
{{wiktionary|bleach}}
* in the '']''
*
*

{{Laundry navbox}}
{{Authority control}}


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Latest revision as of 17:15, 2 January 2025

Chemicals used to whiten or disinfect This article is about the chemical. For other uses, see Bleach (disambiguation).

Clorox brand bleach

Bleach is the generic name for any chemical product that is used industrially or domestically to remove color from (i.e. to whiten) fabric or fiber (in a process called bleaching) or to disinfect after cleaning. It often refers specifically to a dilute solution of sodium hypochlorite, also called "liquid bleach".

Many bleaches have broad-spectrum bactericidal properties, making them useful for disinfecting and sterilizing. They are used in swimming pool sanitation to control bacteria, viruses, and algae and in many places where sterile conditions are required. They are also used in many industrial processes, notably in the bleaching of wood pulp. Bleaches also have other minor uses, like removing mildew, killing weeds, and increasing the longevity of cut flowers.

Bleaches work by reacting with many colored organic compounds, such as natural pigments, and turning them into colorless ones. While most bleaches are oxidizing agents (chemicals that can remove electrons from other molecules), some are reducing agents (that donate electrons).

Chlorine, a powerful oxidizer, is the active agent in many household bleaches. Since pure chlorine is a toxic corrosive gas, these products usually contain hypochlorite, which releases chlorine. "Bleaching powder" usually refers to a formulation containing calcium hypochlorite.

Oxidizing bleaching agents that do not contain chlorine are usually based on peroxides, such as hydrogen peroxide, sodium percarbonate, and sodium perborate. These bleaches are called "non-chlorine bleach", "oxygen bleach", or "color-safe bleach".

Reducing bleaches have niche uses, such as sulfur dioxide, which is used to bleach wool, either as gas or from solutions of sodium dithionite, and sodium borohydride.

Bleaches generally react with many other organic substances besides the intended colored pigments, so they can weaken or damage natural materials like fibers, cloth, and leather, and intentionally applied dyes, such as the indigo of denim. For the same reason, ingestion of the products, breathing of the fumes, or contact with skin or eyes can cause bodily harm and damage health.

History

Early method of bleaching cotton and linen goods on lawns, using a combination of exposure to direct sunlight and the application of water

The earliest form of bleaching involved spreading fabrics and cloth out in a bleachfield to be whitened by the action of the Sun and water. In the 17th century, there was a significant cloth bleaching industry in Western Europe, using alternating alkaline baths (generally lye) and acid baths (such as lactic acid from sour milk, and later diluted sulfuric acid). The whole process lasted up to six months.

Chlorine-based bleaches, which shortened that process from months to hours, were invented in Europe in the late 18th century. Swedish chemist Carl Wilhelm Scheele discovered chlorine in 1774, and in 1785 Savoyard scientist Claude Berthollet recognized that it could be used to bleach fabrics. Berthollet also discovered sodium hypochlorite, which became the first commercial bleach, named Eau de Javel ("Javel water") after the borough of Javel, near Paris, where it was produced.

Scottish chemist and industrialist Charles Tennant proposed in 1798 a solution of calcium hypochlorite as an alternative for Javel water, and patented bleaching powder (solid calcium hypochlorite) in 1799. Around 1820, French chemist Antoine Germain Labarraque discovered the disinfecting and deodorizing ability of hypochlorites and was instrumental in popularizing their use for such purpose. His work greatly improved medical practice, public health, and the sanitary conditions in hospitals, slaughterhouses, and all industries dealing with animal products.

Louis Jacques Thénard first produced hydrogen peroxide in 1818 by reacting barium peroxide with nitric acid. Hydrogen peroxide was first used for bleaching in 1882, but did not become commercially important until after 1930. Sodium perborate as a laundry bleach has been used in Europe since the early twentieth century, and became popular in North America in the 1980s.

Mechanism of action

Whitening

Colors of natural organic materials typically arise from organic pigments, such as beta carotene. Chemical bleaches work in one of two ways:

  • An oxidizing bleach works by breaking the chemical bonds that make up the chromophore. This changes the molecule into a different substance that either does not contain a chromophore or contains a chromophore that does not absorb visible light. This is the mechanism of bleaches based on chlorine but also of oxygen-anions which react through the initial nucleophilic attack.
  • A reducing bleach works by converting double bonds in the chromophore into single bonds. This eliminates the ability of the chromophore to absorb visible light. This is the mechanism of bleaches based on sulfur dioxide.

Sunlight acts as a bleach through a process leading to similar results: high-energy photons of light, often in the violet or ultraviolet range, can disrupt the bonds in the chromophore, rendering the resulting substance colorless. Extended exposure often leads to massive discoloration usually reducing the colors to a white and typically very faded blue.

Antimicrobial efficacy

The broad-spectrum effectiveness of most bleaches is due to their general chemical reactivity against organic compounds, rather than the selective inhibitory or toxic actions of antibiotics. They irreversibly denature or destroy many proteins, including all prions, making them extremely versatile disinfectants.

Hypochlorite bleaches in low concentration were also found to attack bacteria by interfering with heat shock proteins on their walls. According to 2013 Home Hygiene and Health report, using bleach, whether chlorine- or peroxide-based, significantly increases germicidal efficiency of laundry even at low temperatures (30-40 degrees Celsius), which makes it possible to eliminate viruses, bacteria, and fungi from a variety of clothing in a home setting.

Types of bleaches

Most industrial and household bleaches belong to three broad classes:

Chlorine-based bleaches

Chlorine-based bleaches are found in many household "bleach" products, as well as in specialized products for hospitals, public health, water chlorination, and industrial processes.

The grade of chlorine-based bleaches is often expressed as percent active chlorine. One gram of 100% active chlorine bleach has the same bleaching power as one gram of elemental chlorine.

The most common chlorine-based bleaches are:

Other examples of chlorine-based bleaches, used mostly as disinfectants, are monochloramine, halazone, and sodium dichloroisocyanurate.

Peroxide-based bleaches

Peroxide-based bleaches are characterized by the peroxide chemical group, namely two oxygen atoms connected by a single bond, (–O–O–). This bond is easily broken, giving rise to very reactive oxygen species, which are the active agents of this type of bleach.

The main products in this class are:

  • Hydrogen peroxide (H
    2O
    2). It is used, for example, to bleach wood pulp and hair or to prepare other bleaching agents like perborates, percarbonates, peracids, etc.
  • Sodium percarbonate (Na
    2H
    3CO
    6), an adduct of hydrogen peroxide and sodium carbonate ("soda ash" or "washing soda", Na
    2CO
    3). Dissolved in water, it yields a solution of the two products, that combines the degreasing action of the carbonate with the bleaching action of the peroxide.
  • Sodium perborate (Na
    2H
    4B
    2O
    8). Dissolved in water it forms some hydrogen peroxide, but also the perborate anion (B(OOH)(OH)
    3) which can perform nucleophilic oxidation.
  • Peracetic (peroxoacetic) acid (H
    3CC(O)OOH). Generated in situ by some laundry detergents, and also marketed for use as industrial and agricultural disinfection and water treatment.
  • Benzoyl peroxide ((C
    6H
    5COO)
    2). It is used in topical medications for acne and to bleach flour.
  • Ozone (O
    3). While not properly a peroxide, its mechanism of action is similar. It is used in the manufacture of paper products, especially newsprint and white kraft paper.
  • Potassium persulfate (K2 S2O8) and other persulfate salts. It, alongside ammonium and sodium persulfate, is common in hair-lightening products.
  • Permanganate salts such as Potassium permanganate (KMnO4).

In the food industry, other oxidizing products like bromates are used as flour bleaching and maturing agents.

Reducing bleaches

Sodium dithionite (also known as sodium hydrosulfite) is one of the most important reductive bleaching agents. It is a white crystalline powder with a weak sulfurous odor. It can be obtained by reacting sodium bisulfite with zinc.

2 NaHSO3 + Zn → Na2S2O4 + Zn(OH)2

It is used as such in some industrial dyeing processes to eliminate excess dye, residual oxide, and unintended pigments and for bleaching wood pulp.

Reaction of sodium dithionite with formaldehyde produces Rongalite.

Na2S2O4 + 2 CH2O + H2O → NaHOCH2SO3 + NaHOCH2SO2

Thus is used in bleaching wood pulp, cotton, wool, leather and clay.

Photographic bleach

In negative film processing, silver halide grains are associated with couplers which, on development, produce metallic silver and a colored image. The silver is 'bleached' to a soluble form in a solution of ferric EDTA, which is then dissolved in 'fix', a solution of sodium or ammonium thiosulfate. The procedure is the same for paper processing except that the EDTA and thiosulfate are mixed in 'bleachfix'.

In reversal processing, residual silver in the emulsion after the first development is reduced to a soluble silver salt using a chemical bleach, most commonly EDTA. A conventional fixer then dissolves the reduced silver but leaves the unexposed silver halide intact. This unexposed halide is then exposed to light or chemically treated so that a second development produces a positive image. In color and chromogenic film, this also generates a dye image in proportion to the silver.

Photographic bleaches are also used in black-and-white photography to selectively reduce silver to reduce silver density in negatives or prints. In such cases, the bleach composition is typically an acid solution of potassium dichromate.

Environmental impact

A Risk Assessment Report (RAR) conducted by the European Union on sodium hypochlorite conducted under Regulation EEC 793/93 concluded that this substance is safe for the environment in all its current, normal uses. This is due to its high reactivity and instability. The disappearance of hypochlorite is practically immediate in the natural aquatic environment, reaching in a short time concentration as low as 10 μg/L or less in all emission scenarios. In addition, it was found that while volatile chlorine species may be relevant in some indoor scenarios, they have a negligible impact in open environmental conditions. Further, the role of hypochlorite pollution is assumed as negligible in soils.

Industrial bleaching agents can be sources of concern. For example, the use of elemental chlorine in the bleaching of wood pulp produces organochlorines and persistent organic pollutants, including dioxins. According to an industry group, the use of chlorine dioxide in these processes has reduced the dioxin generation to under-detectable levels. However, the respiratory risk from chlorine and highly toxic chlorinated byproducts still exists.

A European study conducted in 2008 indicated that sodium hypochlorite and organic chemicals (e.g., surfactants, fragrances) contained in several household cleaning products can react to generate chlorinated volatile organic compounds (VOCs). These chlorinated compounds are emitted during cleaning applications, some of which are toxic and probable human carcinogens. The study showed that indoor air concentrations significantly increase (8–52 times for chloroform and 1–1170 times for carbon tetrachloride, respectively, above baseline quantities in the household) during the use of bleach-containing products. The increase in chlorinated volatile organic compound concentrations was the lowest for plain bleach and the highest for the products in the form of "thick liquid and gel".

The significant increases observed in indoor air concentrations of several chlorinated VOCs (especially carbon tetrachloride and chloroform) indicate that bleach use may be a source that could be important in terms of inhalation exposure to these compounds. While the authors suggested that using these cleaning products may significantly increase the cancer risk, this conclusion appears to be hypothetical:

  • The highest level cited for a concentration of carbon tetrachloride (seemingly of highest concern) is 459 micrograms per cubic meter, translating to 0.073 ppm (part per million), or 73 ppb (part per billion). The OSHA-allowable time-weighted average concentration over eight hours is 10 ppm, almost 140 times higher;
  • The OSHA highest allowable peak concentration (5-minute exposure for five minutes in 4 hours) is 200 ppm, twice as high as the reported highest peak level (from the headspace of a bottle of a sample of bleach plus detergent).

Disinfection

Sodium hypochlorite solution, 3–6%, (common household bleach) is typically diluted for safe use when disinfecting surfaces and when used to treat drinking water.

A weak solution of 2% household bleach in warm water is typical for sanitizing smooth surfaces before the brewing of beer or wine.

US government regulations (21 CFR 178 Subpart C) allow food processing equipment and food contact surfaces to be sanitized with solutions containing bleach, provided that the solution is allowed to drain adequately before contact with food and that the solutions do not exceed 200 parts per million (ppm) available chlorine (for example, one tablespoon of typical household bleach containing 5.25% sodium hypochlorite, per gallon of water).

A 1-in-47 dilution of household bleach with water (1 part bleach to 47 parts water: e.g. one teaspoon of bleach in a cup of water, or 21 ml per litre, or ⁠1/3⁠ cup of bleach in a gallon of water) is effective against many bacteria and some viruses in homes. Even "scientific-grade", commercially produced disinfection solutions such as Virocidin-X usually have sodium hypochlorite as their sole active ingredient, though they also contain surfactants (to prevent beading) and fragrances (to conceal the bleach smell).

See hypochlorous acid for a discussion of the mechanism for disinfectant action.

An oral rinse with a 0.05% dilute solution of household bleach is shown to treat gingivitis.

Color-safe bleach

Color-safe bleach is a solution with hydrogen peroxide as the active ingredient (for stain removal) rather than sodium hypochlorite or chlorine. It also has chemicals in it that help brighten colors. Though hydrogen peroxide is used for sterilization purposes and water treatment, its ability to disinfect laundry is limited because the concentration of hydrogen peroxide in laundry products is lower than what is used in other applications.

Health hazards

The safety of bleaches depends on the compounds present, and their concentration. Generally speaking, the ingestion of bleaches will cause damage to the esophagus and stomach, possibly leading to death. On contact with the skin or eyes, it causes irritation, drying, and potentially burns. Inhalation of bleach fumes can cause mild irritation of the upper airways. Personal protective equipment should always be used when using bleach.

Bleach should never be mixed with vinegar or other acids, as this will create highly toxic chlorine gas, which can cause severe burns internally and externally. Mixing bleach with ammonia similarly produces chloramine gas, which can burn the lungs. Mixing bleach with rubbing alcohol or acetone makes chloroform, while mixing with hydrogen peroxide results in an exothermic and potentially explosive chemical reaction that releases oxygen.

False claims as a cure

This article appears to be slanted towards recent events. Please try to keep recent events in historical perspective and add more content related to non-recent events. (June 2024)
Main article: Miracle Mineral Supplement

Miracle Mineral Supplement (MMS), also promoted as "Master Mineral Solution" or "Chlorine Dioxide Solution" or CDS, to evade restrictions by online retail platforms, is a bleach solution that has been fraudulently promoted as a cure-all since 2006. Its main active ingredient is sodium chlorite, which is "activated" with citric acid to form chlorine dioxide. In an attempt to evade health regulations, its inventor, Jim Humble, a former Scientologist, founded the Genesis II Church of Health and Healing, which considers MMS as its sacrament.

See also

References

  1. "12 Smart Ways to Use Bleach - Reader's Digest". 9 March 2010.
  2. "Oxygen Bleach Vs. Chlorine Bleach". Sciencing. Retrieved 16 April 2018.
  3. Phillips, H. (2008). "The Bleaching of Wool with Sulphur Dioxide and with Solutions of Sulphites". Journal of the Society of Dyers and Colorists. 54 (11): 503–512. doi:10.1111/j.1478-4408.1938.tb01992.x.
  4. ^ Chisholm, Hugh, ed. (1911). "Bleaching" . Encyclopædia Britannica (11th ed.). Cambridge University Press.
  5. Aspin, Chris (1981). The Cotton Industry. Shire Publications. p. 24. ISBN 978-0-85263-545-2.
  6. Chisholm 1911.
  7. Scott, James, transl. (1828). On the disinfecting properties of Labarraque's preparations of chlorine Published by S. Highley.
  8. Labarraque, Antoine-Germain, Nouvelle biographie générale, volume 28 (1859), columns 323-324.
  9. L. J. Thénard (1818). "Observations sur des nouvelles combinaisons entre l'oxigène et divers acides". Annales de chimie et de physique. 2nd Series. 8: 306–312.
  10. Tatjana Topalović (2007). Catalytic Bleaching of Cotton: Molecular and Macroscopic Aspects p 16. Thesis, University of Twente, the Netherlands. ISBN 978-90-365-2454-4. Retrieved 8 May 2012.
  11. Milne, Neil (1998). "Oxygen bleaching systems in domestic laundry". Journal of Surfactants and Detergents. 1 (2): 253–261. doi:10.1007/s11743-998-0029-z. S2CID 59456079.
  12. Mayer, Robert J.; Ofial, Armin R. (22 February 2018). "Nucleophilic Reactivities of Bleach Reagents". Organic Letters. 20 (10): 2816–2820. doi:10.1021/acs.orglett.8b00645. PMID 29741385.
  13. Field, Simon Q (2006). "Ingredients – Bleach". Science Toys. Retrieved 2 March 2006.
  14. Bloomfield, Louis A (2006). "Sunlight". How Things Work Home Page. Archived from the original on 11 May 2013. Retrieved 23 February 2012.
  15. Jakob, U.; J. Winter; M. Ilbert; P.C.F. Graf; D. Özcelik (14 November 2008). "Bleach Activates A Redox-Regulated Chaperone by Oxidative Protein Unfolding". Cell. 135 (4): 691–701. doi:10.1016/j.cell.2008.09.024. PMC 2606091. PMID 19013278.
  16. "| Home Hygiene & Health". www.ifh-homehygiene.org. 21 October 2013. Retrieved 12 December 2020.
  17. Ploumanac'h. "Sanitize Laundry for Delicate Clothes". Ploumanac'h. Retrieved 12 December 2020.
  18. Vogt, Helmut; Balej, Jan; Bennett, John E.; Wintzer, Peter; Sheikh, Saeed Akbar; Gallone, Patrizio; Vasudevan, Subramanyan; Pelin, Kalle (2010). "Chlorine Oxides and Chlorine Oxygen Acids". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a06_483.pub2. ISBN 978-3527306732. S2CID 96905077.
  19. ^ "WHO Model List of Essential Medicines (19th List)" (PDF). World Health Organization. April 2015. Archived (PDF) from the original on 13 December 2016. Retrieved 8 December 2016.
  20. Douglass F. Taber. "Oxidizing agents: Sodium perborate". Retrieved 7 June 2012.
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Further reading

  • Bodkins, Bailey. Bleach. Philadelphia: Virginia Printing Press, 1995.
  • Trotman, E. R. Textile Scouring and Bleaching. London: Charles Griffin & Co., 1968. ISBN 0-85264-067-6.

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