The principle and method of sodium alginate gel are shared for free.

　　Sodium alginate is a kind of polysaccharide biopolymer extracted, separated and refined from brown algae such as kelp and kelp, which is white or light yellow powder. Sodium alginate has been a good food additive for more than 70 years because of its good thickening property, and it has been used in medicine for more than 30 years because of its biocompatibility and biodegradability.

　　1. Sodium alginate has good film-forming property and high gel strength. It is not only used in medicine, but also gradually used in water treatment. Traditional active adsorbents include activated carbon and activated diatomite, which have good adsorption performance, but they are expensive to use, difficult to popularize and inconvenient to use in powder form, while sodium alginate gel does not have these problems.

　　2. Sodium alginate can react rapidly with divalent metal ions except magnesium and mercury to form sodium alginate gel, and the gel film formed with calcium chloride has the greatest strength. Sodium alginate gel is not only widely available and cheap, but also convenient to store and use in small spheres.

　　3. The gel properties formed by sodium alginate are significantly different due to the ratio of two monomers, the concentration of sodium alginate, the amount of calcium bound and the gelation conditions. Usually, 3% sodium alginate solution and 5% calcium chloride are gelled at 60℃, and the gel formed has the best properties.