Wiki: Bleach

More info welcome....

NT

Bleaches:

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Bleaches sterilise and remove dirt's colour, but don't remove the dirt itself. The remaining bleached dirt acts as a lodging place for more dirt, hence items cleaned with bleach get dirty quicker. Bleaches are useful when all other attempts to remove the dirt have failed. Bleaches are also to some extent toxic and antibacterial.

===Chlorine bleach=== The most common household bleach. Irritant to lungs, exacerbates asthma.

Contact with acids releases toxic chlorine gas (chlorine was used for chemical warfare in WW1). Toilet cleaners are usually acidic, and must not be mixed with bleach.

Discolours and damages many fabrics, particularly natural fabrics and natural dyes. A mild environmental toxin. Kills bacteria and moulds.

Thick bleach is not a stronger bleach mix, it is bleach with detergent, thickener and pH buffer.

Minimum cost bleaches lack the pH buffer usually addded to other bleaches. The buffer minimises release of chlorine gas when mild acid is added.

If you ever encounter unpleasant or choking fumes from bleach, leave immediately. Don't wait to work out what happened or sort it out, as little as a few breaths can kill.

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Material Safety Data Sheet]

===Milton=== Milton solution is 1% chlorine bleach, 16.5% salt. Tablets are Sodium Dichloroisocyanurate. Kills bacteria, fungi, viri and spores. Tablets can be used to disinfect drinking water, 1 tablet in 32 litres. Milton is a higher purity grade than basic cleaning bleach, intended for food handling equipment.

===Hydrogen Peroxide=== Hydrogen peroxide avoids most of the downsides of chlorine bleaches, and does not discolour fabrics. Oxygen bleach can be used in laundry & hair bleaching. Not as powerful as chlorine bleach, and not such an effective antibacterial.

Forms toxic compounds when combined with many common materials: avoid contact with wood, asbestos, soil, rust, copper, iron, steel, alcohol, and other cleaning agents. Rinse away well after use. Can cause serious eye injury.

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===Sun & soap=== Soaping clothes and hanging them in sunlight while wet can bleach discolouration not removed by chlorine or oxygen bleaches. Its slow, taking many hours. The clothes should be kept wet or [[damp]]. The uv in sunlight also has some sterilising effect. This was a standard way to bleach clothes before the introduction of household chlorine bleach.

Traditionally the clothes were placed on grass rather than on a clothes line. This slows drying so they need spraying with water less often to keep them wet.

===Electrolysed salt=== Electrolysed salt water makes a dilute chlorine bleach solution. Can be used for sterilisation, as with food grade salt the result is of good purity.

===Chloride of Lime===

  • aka bleaching powder.
  • The forerunner of today's liquid bleaches.
  • Dissolves to make a bleach.
  • Dessicant, store in a tightly closed container
  • Can be used as a deicer, can prevent freezing down to -52C
  • Cacl is used as tyre liquid in tractors
  • CaCl accelerates concrete setting, but corrodes rebar
  • Powder containing calcium chloride & calcium hypochlorite or chlorinated calcium hydroxide.

===Borax=== Borax produces hydrogen peroxide in solution.

  • It also has cleaning and antibacterial effects.
  • warm solution removes stains of blood, chocolate, coffee, mildew and urine
  • mix with citric acid to remove rust stains

==See also==

  • [[Acid]]

[[Category:Cleaning]] [[Category:Chemicals]] [[Category:Laundry]]

Reply to
NT
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Add in Sodium perborate an oxidising bleach used in products like Nappisan (as was) and Vanish

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> Bleaches:

A good example is the use of bleach to clean toilet bowls. The smooth porcelain surface means that bacteria has no foothold & should be flushed away. In hard water areas limescale will build up, leaving a rough surface which bacteria can colonise.

Bleach will remove the discolouration & kill the germs, but is ineffective against the limescale, so the bacteria & discolouration will quickly return.

Reply to
The Medway Handyman

Does it? I think sodium perborate does

Reply to
stuart noble

Sounds a bit over dramatic to me... Brian

Reply to
Brian Gaff

Isn't "stain" better than "dirt"? Dirt to me suggests mud and grease too. Also, the oxidised stain is likely to be a smaller, more polar molecule and therefore more easily removed by subsquent washing.

You could add:

"If swallowed, household bleach causes immediate vomiting but no serious consequences except those associated with vomiting in general."

Source: Chemistry in the Marketplace, 5th ed. p 62

Reply to
Reentrant

The OP has the entry for sodium perborate confused with borax.

Borax is a relatively benign moderate base rather like washing soda. Though the boron content makes it a slightly harmful. Perborate is the result of reacting diborate with peroxide and when dissolved in water will provide active oxygen.

Also most of the dire warnings about hydrogen peroxide are because if provoked by the right catalysts it will decompose very fast with considerable heating. Strong solutions of it will burn skin. A very dilute solution is sometimes used as a dental hygiene mouthwash.

For completeness you might also want to mention the amusing tale of the undies destroying manganese catalysed bleach that Unilever used in its Persil Power formultion with notorious clothes wrecking properties.

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other warning obviously missing is never mix bleach with any other cleaning agent. Ammonia is potentially dangerous in combination with bleach as well as the more obvious acids that release free chlorine.

Regards, Martin Brown

Reply to
Martin Brown

Your usual mix of truth and bollocks with your own unique folksy interpretation that makes the whole slightly risible. For a start you need to discover the difference between perborate and borax. Flipping between peroxide and "oxygen" in the same paragraph is poor and will lead to confusion. It seems as if your major input was advertising.

No mention of oxalates.

Reply to
Steve Firth

Great post, v informative.

I'll see your Persil Power and raise you a Formula Shell (OT for bleach, OnT for head burying scandals):

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favourite product related corporate denial scandal.

Reply to
fred

Mention might be made of the Retr0 bright process

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Reply to
Owain

There seems to be plenty of authoritative bleach stuff on Wiki already.

Reply to
stuart noble

Bleaches should always be treated as poisons and should never be kept in unlabeled bottles. Most bleaches are effective biocides and will kill most bacteria and fungi.

Nt in any realistic domestic scenario. You should add a mention of the use of chlorine products in disinfecting swimming pool water. The larger quantities involve mean a higher risk.

Kills most bacteria and fungi. There is no domestic product which can guarantee to kill spores of either bacteria or fungi.

Tablets

in one of three strengths; 10, 20 and 30 volume. This is a measure of how much oxygen will be released if all of the peroxide decomposes. !0 vol peroxide is 3% w/vol and 30 vol, the strongest easily available, is

9%. The 30% solution that data-sheet refers to would be 100 vol.

Hydrogen peroxide is unstable and if exposed to light it can form explosive byproducts. Peroxide should always be stored in a dark place and never in clear glass bottles.

Are you sure? I would expect that "chloride of lime" would refer to calcium chloride.

Reacts with water to release chlorine. The same precautions as for liquid bleach should be taken when using it.

You are confusing bleaching powder with calcium chloride. Bleaching powder is a mixture of calcium hypochlorite and calcium chloride. Calcium chloride is also available separately.

Borax and perborates are not the same.

Perborate salts...

Various perborate salts are used as "oxygen bleach" in cleaning products. In general they work by reacting with water to release hydrogen peroxide. They are used because they are safer and easier to handle than hydrogen peroxide itself. In concentrated form they should be stored away from heat.

Reply to
Bernard Peek

harry wrote: [snip]

Wrong. Even a moment's thought from someone who isn't a thicko like you would have seen a little light dawning. Do you imagine that body parts preserved in formalin are anything other than sterile? How do you think delicate equipment is sterilised before use in an operating theatre? Never heard of activated glutaraldehyde? How about peroxide sterilisation, has that passed you by?

Reply to
Steve Firth

When I was working in microbiolgy we used 10% peracetic acid. It's not

100% effective but it's better than most and evaporates completely. There are lots of ways of killing most bacteria and some spores. In a relatively undemanding environment like an operating theatre that's sufficient.

Harry's not quite correct but he's better informed than you.

Reply to
Bernard Peek

Thanks, when I get a little time I'll incorporate the info in.

A couple of the comments seem a bit childish, but then I'm familiar with the person concerned. Wiki is a collaborative process, where we pool knowledge, and pick up on others mistakes & omissions.

NT

Reply to
NT

I think nitric acid would do the trick.

Reply to
Tim Streater

It bleaches hair, but doesn't discolour fabrics? You sure?

"Always test on an inconspicuous area"

Andy

Reply to
Andy Champ

Fuming red nitric acid is pretty good too, and it also evaporates completely.

Sterility is like security. You understand it if you don't look too closely but when you do it's not really there.

You can establish a probability that there are less than N viable cells of species X in a given place. Whether you consider that to be "sterile" depends on N, X and the reason why you asked the question in the first place.

Reply to
Bernard Peek

Drivel and proof that you don't have a bloody clue either.

Cold sterilisation destroys spores as well as microbial cells. The last thing needed in a surgical wound are C. Botulinum spores and activated glutaraldehyde ( trade name Cidex) was thoroughly tested and shown to inactivate the spores of Clostridium sp. and the tubercle bacillus after 10 minutes.

"Preliminary Evaluation of an Activated Glutaraldehyde Solution for Cold Sterilization" Max S. Rittenbury and Miles E. Hench Ann Surg. 1965 January; 161(1): 127?130.

Perhaps you could indicate how many of the specimens in the Wellcome museum have suffered from gas gangrene?

Peroxide sterilisation also destroys bacterial spores.

Reply to
Steve Firth

Yes. I read that before I posted.

Reply to
Bernard Peek

Which question did I ask in the first place?

Reply to
Tim Streater

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