Phosphates in detergents account for a significant share of outlets to the Baltic Sea. According to the latest estimates from the Environmental Protection Agency (2006) the total phosphorus loading to waters from approximately 750 000 private sewers is about 300 tons. About one-fifth is considered to come from phosphate detergents. Phosphates in laundry, dishwashing and cleaning can be reduced. There are alternative complexes commercially available that can replace phosphates. In Sweden, As of March 1st, 2008, phosphates are no longer permitted in detergents. The rest of the EU will follow suit in the coming years.
Alternatives to phosphates
The role and value of phosphate detergency builders in laundry detergent compositions are well-known. However, excess use of phosphates in detergents has lead eutrophication, with algal bloom and dead sea bottoms as a result. There is now a need for alternatives to phosphates as not only phosphates have been banned, but also compounds containing phosphorous such as phosphites and acrylic phosphinate polymers.
The phosphates have several roles that have to be replaced. They can bind ions such as calcium, magnesium and iron ions present in detergents, which otherwise would precipitate and adhere to the surface to be cleaned and cause undesirable effects. Furthermore, the phosphates can provide alkalinity and thereby the increase the ability to buffer the wash liquor, above pH 9. Another function is to disperse calcium carbonate, which causes spotting on glasses in a dishwasher.
Following phosphate alternatives can be mentioned:
Zeolites, water-insoluble aluminosilicates that are used as alternative builders to phosphates. These dominate as replacements for phosphates.
Zeolite A is considered be non toxic to aquatic fauna and is also most cost-efficient among the alternatives.
Citric acid can be used as bleaching agent as pH-regulating agent.
The citric acid or and alkali metal citrate can be combined with a peroxybenzoid acid bleach precursor and inorganic peroxide compounds.
Citrates have many advantages, such as:
• “generally recognized as safe” (GRAS) status, with an unlimited ADI value (“acceptable
daily intake”);
• fast and complete biodegradation in sewage treatment plants;
• good binding capacity for water hardness (calcium ions) between 20° and 60°;
• assists the functioning of surfactants;
• citrate and zeolites can complement each other;
• compatible with enzymes and other auxiliary agents.
The safe characteristics of citrate towards humans and the environment are clearly documented and can be considered as an important advantage over STPP and NTA.
Moreover, citric acid and its salts are produced by fermentation based on renewable raw materials like sugar beets, wheat and corn.
NTA (nitrilotriacetic acid) and EDTA (ethylenediaminetetraacetic acid) are used as alternatives and their function is to sequester metal ions such as calcium, magnesium and iron.
Polycarboxylates and polyacrylates are also used in detergents to replace phosphates.
Alternatives in bleaching products
Alternatives in dishwashing detergents
Alternatives in laundry detergents