Washing machine

Mar 2020
I am currently writing an assignement about laundry :-D . I am trying to understand the working of surfactants in washing powder, but do not know how it works exactly. I do understand how they work chemically. But apparently not all of the dirt is removed. That is why some clothes remain smelly (e.g. sport clothes or smoking odor) or dirty (build up of dirt in between the fibres) despite the use of washing powder. Can someone explain this to me? What kind of things we do want to see removed are not removed by these surfactants (and washing powder in general)? Are there health hazards to the not-removal of this dirt? There should be some, e.g. the many complaints about formaldehyde, third hand smoke lingering in your clothes,..., but I do not get why these components are not easily removed by these surfactants.

To add to this, I need to come up with a practical sollution for this problem: So what if you want all the dirt removed from your clothing fibres. I was delving deeper into the web and saw a product called odorklenz laundry additive that uses MgO, Mg02, TiO2 and ZnO to get your laundry clean. They say the product removes stuff on the nanolevel, but the ingredients they use (MgO, Mg02, TiO2 and ZnO) are not nanosized particles, so therefore safe to use. These ingredients bind with all kind of chemical components that cause bad odors, but also with toxins. They are however very vague on what kind of components they bind with they only list Esters, Terpenes, Aromatics, Amines, Alcohols, Aldehydes, Ketones and Thiols as the chemical components they bind to. I do know that MgO, Mg02, TiO2 and ZnO are used in water purification, so would you say that by adding these ingredients you would get your laundry pristine clean again? Would there still be things that are not easily removed by a combination of this product with a standard laundry detergent (containing surfactants)? Would proposing this be a good sollution?

Note: I am not a native English speaker, so sorry for any mistake!
Apr 2015
Since you are writing an essay, I will point out where you can do some of your own research.

Reflecting the basic properties of ZnO, fine particles of the oxide have deodorizing and antibacterial[64] properties and for that reason are added into materials including cotton fabric, rubber, oral care products,[65][66] and food packaging.[67][68] Enhanced antibacterial action of fine particles compared to bulk material is not exclusive to ZnO and is observed for other materials, such as silver.[69] This property results from the increased surface area of the fine particles.
Also look up the other compounds you asked about.

Traditional washing powders for clothes are made from a mixture of washing soda (sodium carbonate) with a small amount of surfactant and perhaps some oxidising agent (bleach) or some enzymes.
The washing soda provides an alkaline washing solution where the surfactant works best.

The idea of a surfactant is to provide a molecule with two ends. A polar end (with an electric charge) that will enable it to dissolve in water ( a polar solvent) and a non polar (neutral) end which will attach to lipids (fatty biological substances) and other neutral particles which are normally insoluble in water with its neutral end. This gives these particles a polar part to enable solution in the washing water.

Some proteins and cells stick to fibres and are not so easily washed out, as the stength of the adhesion is greater than the tendency to go into solution, even with the help of surfactants.

This is the purpose of the enzymes or bleach added to the washing powder..

Most of the washing powder is actually inert fillre (cellulose).

This is why there has been a trend towards liquid or concentrated products without all that filler.
This is just advertising.

Years ago the soap companies tried to say they gave more product (powder) for your money by adding the inert filler.
Now they are promoting stronger (more concentrated) products with no filler.
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