Sodium citrate is a salt of citric acid. Citric acid is an organic acid that occurs naturally in plants and animals. It occurs as colorless crystals or white powder, and is commonly found in citrus fruits, corn, and other foods. Two ounces of orange juice has about 500 mg, according to yhe FDA. Citric acid is an alpha-hydroxy acid and a beta-hydroxy acid. Sodium citrate in detergents.
Sodium citrate is often used as a pH adjuster and water softener. It is common in liquid laundry detergent, though it is also often used in food and medical products. In food, it helps control the acidity of ice cream, candy, jelly, and gelatin desserts. Sodium citrate is also in dozens of personal care products, such as shampoo, conditioner, sunscreen, facial moisturizer, makeup, baby wipes, soap, and other products. We use sodium citrate as a water softener and to adjust the acidity of products. The FDA has deemed the ingredient Generally Recognized as Safe, and Whole Foods has deemed the ingredient acceptable in its body care and cleaning product quality standards. The Cosmetics Ingredient Review has also deemed the ingredient safe for use in cosmetic products. Studies show the ingredient is not a skin irritant or sensitizer.
Sodium citrate production occurs by neutralizing citric acid with sodium hydroxide. Citric acid may be produced from fruits or other foods, through yeast fermentation, and by solvent extraction. Most large-scale production occurs by fermenting molasses or other sugar stocks with Aspergillus niger. The liquid is separated by filtration, and the citric acid is separated by precipitation. Sodium citrate is usually offered commercially as the white, crystalline trisodium citrate dihydrate this is a Applications of trisodium citrate.
Sodium citrate in detergents , With the advent of liquid heavy duty detergents, sodium citrate, the trisodium salt of citric acid, has become the builder of choice. Sodium citrate is suitable for use as a builder in heavy duty laundry detergents because of its ability to sequester positively charged calcium and magnesium ions found in tap water and, unlike phosphate builders, it is environmentally safe. It is especially suitable for inclusion in liquid detergent formulations because, unlike other environmentally safe detergent builders, trisodium citrate is soluble therein. sodium citrate can be used as the sole builder in anionic detergent formulations intended for use in high temperature cleaning. A major component of liquid laundry detergent is based on surfactants that remove soil from the fabric and clean it. A combination of anionic and nonionic surfactants is commonly used for optimum performance. In general, anionics are good for particulate soil removal and nonionics are good for greasy soil removal. Other components of a liquid laundry detergent formula are detailed in this article. Thus, a liquid laundry detergent formula can be as simple and economical as say 5% active surfactant solution in water with preservatives. The formula will foam and do some cleaning of the clothes. From here one can improve this basic formula to any desired level in order to enhance the performance and position it for various categories such as economical, mid tier, premium, ultra, and 2X, 3X, 4X etc. Some common additives include:
Builders: Remove the hardness ions so the surfactant can be fully functional. Sodium citrate, tetrasodium EDTA and acrylic polymers are commonly used in liquid laundry detergents.
Antiredeposition agents: Keeps the soil particles suspended in the wash liquor so they do not get deposited back on the fabric. A variety of polymers can be used.
Enzymes: For tough stain removal, color and fabric care. Enzymes help remove stains and soils like blood, grass and gravy by breaking them down to smaller, easily removable components. Lipase (0.2%) removes grease and oil; cellulase (0.1%) whitens and brightens; amylase (0.5%) removes starch-based soils; and protease (0.6%) removes protein stains. To stabilize the enzymes, pH should be 7-9; water content (less than 60%), calcium chloride (0.2%), sodium tetraborate (1-2%), propylene glycol (5-10%), sodium formate (1-2%), sodium citrate (3-5%) and monoethanolamine (1%).
PH control: Add citric acid or monoethanolamine to reach the desired pH.
Preservatives: Microbial control.
Other applications of trisodium citrate, in Buffering agent. Manufacture of household cleaners, degreasers and detergents. In industry trisodium citrate finds many uses including alkaline degreaser baths, electroplating chemicals for copper and nickel etc, photo chemicals. It is also used in the paper and pulp indstries and the textiles industry. sodium citrate is effective to retard plaster mixes. It must be used carefully as adding too much will prevent the plaster curing properly. Premix the citrate in water first and add to the plaster mix.
Trisodium citrate has many uses in our daily lives. It is used as a flavoring and additive in many food products. Sodium citrate is present in detergent products as a buffering agent.