Powder or home remedies? Chemists from PNIPU share tips on how to remove stubborn stains effectively.

Three components are responsible for stain removal in laundry detergents: surfactants, bleaching agents, and enzymes.

“In the molecule of a surfactant, there is a hydrophobic part that can interact, for instance, with grease, and a hydrophilic part that reacts with the aqueous environment. The surfactant concentrates at the phase boundary and converts the poorly soluble component of the dirt into the aqueous phase. The dirt collected in this form is easily rinsed away with soapy water. Thus, the fabric gets cleaned,” explains Evgenia Gladkikh, an assistant at the Department of Chemistry and Biotechnology at PNIPU.

Interestingly, in this process, the cleaning agents are assisted by anti-resorbents — substances that prevent dirt from settling back onto the fabric. Alkaline compounds enhance the dissolution of greasy stains.

Surfactants can be cationic, anionic, amphoteric, or nonionic, depending on which part of the molecule exhibits surface activity in relation to contaminants. In cationic surfactants, this is a positively charged ion — a cation. Their cleaning ability is low, but they have promising applications as bactericidal components in cleaning agents.

Anionic surfactants have a higher cleaning capacity and are the most commonly used in cleaning products and powders. Soap, for instance, is also an anionic substance.

Nonionic surfactants also exhibit excellent properties in combating contaminants, including greasy ones. Their molecules contain both hydrophobic and hydrophilic parts, but these surfactants do not dissociate into ions when dissolved. As a result, an aggressive alkaline environment does not arise, which is beneficial. However, this may reduce their cleaning capacity against stubborn stains.

“Nonionic surfactants are often used in conjunction with anionic or amphoteric surfactants. They help further remove stains and also soften the action of more aggressive surfactants,” adds Irina Solokha, an expert from Perm Polytechnic, a manufacturer of household cleaning products.

Amphoteric (zwitterionic) surfactants can behave like both cationic and anionic surfactants and possess high effectiveness, but due to their high cost, they are rarely used in household textile cleaning products.

Which surfactants are least harmful to the environment and humans?

Ionic surfactants, particularly anionic ones, create an alkaline environment in solutions and are especially aggressive towards lipid components, not only in contaminants but also, for example, in human skin, whose protective layer is rich in fats. Hand washing with anionic surfactants can lead to skin irritation and dryness; in some cases, these components can be allergens.

The compositions of cheap powders for children's clothing and regular clothing are identical. This is a marketing ploy; the content of major aggressive components, surfactants (especially ionic ones), and bleaching agents is usually the same.

“A good children's detergent will contain a minimum of ingredients. Mainly, it should be unscented soap: soda, citric acid, and a bleaching booster with percarbonate. There should be no fragrances or cationic surfactants,” notes Irina Solokha.

It is essential to rinse clothes thoroughly to ensure that no detergent remains on them. When using a washing machine, opt for an extra rinse cycle. Otherwise, this may cause skin irritation, especially in individuals with atopic dermatitis, and inhalation can lead to runny nose, sneezing, tearing, and allergic reactions to detergent particles released from the fabric into the air.

“Surfactants pose a threat to the environment as they reduce the solubility of carbon dioxide and oxygen in water. This negatively affects ecosystems. Additionally, solid particles of soil, sand, and clay can absorb surfactants. This can lead to the release of harmful substances, such as heavy metal ions,” explains Evgenia Gladkikh.

To avoid negative effects, it is necessary to switch to biodegradable surfactants: they quickly convert into safe substances without surface activity, not accumulating in the environment. An example of such compounds is nonionic alkyl polyglucosides. These components are also safer for humans — they do not act as aggressively on the skin.

What is best for hand washing?

For hand washing, you can use both soap and special powders designed for hand washing. Such products primarily contain fatty acid salts, sometimes with soda and sodium chloride, which aid in dissolving dirt.

“Regular soap is unlikely to be more effective than powder, but it is definitely more effective than products for washing machines: during hand washing, they do not lather well, failing to create an effective environment for rinsing away dirt. Moreover, the components of washing machine powders can be harmful to the skin with prolonged exposure,” explains a chemist from PNIPU.

“If the stains are superficial and minor, a laundry powder will generally suffice. However, serious stains need to be pre-treated, and here soap will be more effective since we apply it locally,” adds Irina Solokha.

Enzymes — for stubborn stains and pilling

Enzymes (ferments) are specific proteins that act as catalysts for chemical reactions in living systems. The most significant for the production of detergents are hydrolases, which enhance the breakdown of complex high-molecular components into simpler ones that can be easily removed with the washing solution.

Each type of hydrolase is effective against a corresponding type of stain. Proteases target protein stains (for example, residues of food and blood), lipases help with greasy stains. Amylases remove stains that contain polysaccharides, such as starch stains. Pectinases eliminate traces from fruits, vegetables, and berries.

“The enzyme cellulase is a relatively new and unusual component in fabric care products. The thing is, natural plant-based fabrics, such as cotton and linen, are made up of cellulose fibers. Introducing cellulase into the detergent allows for the cleavage of certain bonds in cellulose molecules, thus ensuring the softening of the fabric, removal of pilling, and improving its appearance,” notes Evgenia Gladkikh.

What does “fake” bleach mean?

Optical brighteners are not actually bleaches: these products consist of fluorescent dyes that enhance the brightness of the fabric. They do not combat stains but merely mask them.

“Among ‘real’ bleaches, there are chlorine, oxygen-containing, and organic types. Chlorine bleaches are effective but aggressively affect fabrics, thinning them. They are unsuitable for wool, silk, or lace. Organic components are milder but less effective for stubborn stains. The most optimal are oxygen-containing bleaches, which, when interacting with water, release oxygen that fights stains, but they are not as aggressive as chlorine bleaches,” explains Evgenia Gladkikh.

Which components do not like high temperatures?

“Hot water positively influences the solubility of both powder components and the stains themselves. Bleaches are especially effective at 60-70 degrees Celsius and higher. However, if the fabric shrinks, it is better to try organic bleaches and powders with enzymes in their composition. For the latter, low temperatures are optimal,” explains Evgenia Gladkikh.

Irina Solokha adds that heating is necessary if the powder contains sodium percarbonate. High temperatures (above 60°C) are needed for its activation. Under this effect, the component decomposes, releasing oxygen that will bleach the fabric.

“If you need to remove a stain from a delicate item, use special bleaches that contain, in addition to sodium percarbonate, a bleaching activator tetraacetylethylenediamine (TAED). In this case, the chemistry of the process changes. However, the effect will be achieved at just 40°,” adds the entrepreneur.

“For delicate fabrics, liquid products are recommended instead of powders — they rinse out more easily, leaving no residue in the fabric and not damaging its structure. For wool and silk items, the presence of proteases in the product is unacceptable — this class of enzymes breaks down the protein that is the basis of the fabric fibers,” explains Evgenia Gladkikh.

“When choosing a detergent for delicate items, ensure that it uses mild surfactants, not sulfate ones — the most aggressive. Enzymes in the composition are also undesirable. Of course, silk and wool items won’t ‘fall apart’ after the first wash, but their quality will deteriorate after each washing,” advises Irina Solokha.

What to do if a garment has shrunk after washing?

“In some cases, soaking the item in water or steaming it followed by stretching the shrunk fabric may help. Wet or steamed clothing can be hung on hangers and left to dry in that position to restore the lost appearance of the fabric fibers,” advises a chemist from Perm Polytechnic.

What type of water is best for washing?

Hard water contains calcium and magnesium ions. Anionic components can form insoluble compounds with them, complicating the removal of stains as the surfactants simply won't ‘work’. Furthermore, such compounds may precipitate on the fabric