When shopping for laundry detergent, the variety of options can be overwhelming. All products will clean clothes to some extent, but what gives the best results for your clothes and your budget?
Do you want whiter clothes? Do you need enzymes? And what is the difference between a powder and a liquid detergent?
As is often the case, knowing the chemistry behind these products will help you answer these questions.
What is a detergent?
The active ingredients in both types of detergent, powder and liquid, are surfactants, surfactants, also known as detergents (hence the name of the product). These are usually charged or “ionic” molecules that have two distinct parts. One interacts well with water and the other with fats.
This useful property allows surfactants to lift grease and dirt from fabrics and suspend them in water. Surfactants can also form foam.
Metal salts dissolved in water can reduce the performance of surfactants. So-called hard water contains many calcium and magnesium salts, which can easily form soap scum.
Modern laundry detergents therefore contain phosphates, softeners and other substances that “block” metals to prevent the formation of soap scum. Phosphates can cause algae growth in freshwater environments, which is why modern detergent formulas contain lower amounts of phosphates.
Many products also contain optical brighteners. These compounds absorb ultraviolet light and emit blue light, giving the effect of “brighter whites” or “more vivid colors.”
Laundry detergents usually also contain fragrances. They are not essential for cleaning, but they create the impression of freshness.
Finally, some detergents contain enzymes.
What does the powder detergent contain?
Although the components that prevent soap deposits are the most important, they are not the predominant ones in the composition. The main ingredients in powders are salts (such as sodium sulfate) that add volume and prevent powder from clumping.
Another common salt in powder detergents is sodium carbonate, also known as washing soda. Baking soda (a chemical relative of baking soda) helps change grease and grime so they dissolve in water.
Laundry detergents also frequently contain oxidizing agents such as sodium percarbonate. This is a stable combination of baking soda and hydrogen peroxide. An additive called tetraacetylethylenediamine activates the percarbonate to provide a mild whitening effect.
Chemically, powders have an advantage – their components can be formulated and mixed, but kept separate in a solid form. (Different types of granules can usually be seen in washing powder.)
What does the liquid detergent contain?
The main ingredient in liquid detergent is water. The rest of the ingredients must be carefully selected to be stable in the bottle and to act together during washing.
These include ingredients similar to powders, such as alkaline salts, metal blocking agents, water softeners, and surfactants.
Surfactants in liquid products are often listed as “ionic” (charged) and “nonionic” (uncharged). Nonionic surfactants can be liquid in nature, making them unsuitable for powder formulations. These nonionic surfactants are effective in suspending oils in water and do not form soap scum.
Liquid detergents also contain preservatives to prevent the growth of microbes that could compromise the mixture.
There are also microbial implications inside the washing machine. Liquid products cannot contain peroxides (mild bleaching agents) found in powder products. Peroxides kill microbes. The absence of peroxides in liquid detergents increases the risk of mold biofilm formation in the washing machine and the transfer of bacteria between garments.
As an alternative to peroxides, liquid detergents usually only contain optical brighteners.
Liquids have one advantage over powders though – they can be applied directly to stains before putting the item in the wash.
Another version of liquid detergent is the highly concentrated detergent capsules. Colorful and candy-like, these products have been shown to be dangerous to young children and people with cognitive difficulties.
Capsules also eliminate the possibility of using less detergent if you have a smaller load of laundry or simply want to use less detergent in general.
What are enzymes used for?
Enzymes are natural proteins included in laundry products to remove certain stains. Chemically, they are catalysts – substances that speed up chemical reactions.
Enzymes are named after the molecules they act on, followed by the suffix “-ase”. For example, lipase breaks down fats (lipids), protease breaks down proteins, while amylase and mannanase break down starch and sugar.
These enzymes are derived from organisms found in cold climate regions, which allows them to function at low wash water temperatures.
Using an excessively hot wash cycle can damage or distort the structure of the enzymes, preventing them from helping to clean clothes. Think of an egg white that turns opaque white when cooked – this is the denaturation of a protein.
If your detergent contains enzymes, the wash temperature should be neither too high nor too low. As a guide, standard washing tests use temperatures of 15–20°C.
Is powder or liquid detergent better?
We make consumer choices guided by performance, psychology, cost, smell, environmental considerations and convenience.
It’s worth experimenting with different products to find what works best for you and suits your needs, your home budget and environmental considerations such as recyclable packaging.
You can wash, for example, at 20°C with half the recommended dose of a pleasant-smelling powder detergent packed in recyclable cardboard, which contains a wide range of enzymes and a source of activated peroxide.
Knowing a little chemistry can do a lot to keep your clothes clean.
However, detergent manufacturers do not always disclose the full list of ingredients on the product packaging.
If you want more information about what your product contains, you should consult the product website. You can also learn more from documents called safety data sheets (SDS). Every product containing potentially dangerous chemicals must have such a label, it says theconversation.com.
Source: ziare.com
