We all use washing and cleaning detergents every day (or maybe, to be more strict, at least every week). But do we know what is their chemical composition and why these substances are so effective?
Washing powder is a type of cleaning detergent usually used for both hand wash and machine laundry. To put it more scientifically it is a mixture of chemical compounds including alkylbenzenesulfonates, which are similar to soap but less affected by hard water. Molecules and ions included in the powder can serve as high-efficiency surfactants. They may be classified according to the charge of the molecule or ion, the three main classes being anionic, neutral, and cationic detergents. Anionic detergents are most commonly used in domestic machines. They may contain both polar and nonpolar components. Polar component allows the detergent to dissolve in the water while the nonpolar ones solubilizes greasy substances usually present at dirty clothes.
Modern laundry detergent contain several components. Three main ingredients are builders, enzymes and bleaches. Builders are chemical compounds that remove calcium ions by complexation or precipitation. In practice they soften the water. Typical builders may be sodium carbonate, soap or zeolites. They function by sequestering or precipitating the problematic ions. Enzymes are required to degrade recalcitrant stains composed of proteins, fats, or carbohydrates.
Each type of stain demands a different type of enzyme. Finally, there are additions to bleach the fabric. The main targets of bleaches have vegetable origin and include, among others, chlorophyll, tannins, humic acids and carotenoid pigments. Most bleaches in the washing powders are oxidizers like sodium perborate or hypochlorite. Sometimes also other agents are added as "bleach activators" to enhance their effectiveness.