Everyone may know carbon molecular sieve, but what is molecular sieve? The materials whose molecular diameter is smaller than the pore size of molecular sieve can enter the molecular sieve crystal be adsorbed, otherwise it will be rejected. The properties of molecular sieves are as follows:
1. Ion exchange performance water softening function: each oxygen atom in the framework of 4A molecular sieve is shared by two adjacent tetrahedrons. This structure forms a large crystal cavity, which can be occupied by cations water molecules. Moreover, these cations water molecules have higher mobility, which can be exchanged by cations dehydrated reversibly. The ion exchange of 4A molecular sieve with aluminum ion is carried out on the framework. Each aluminum ion has a negative charge, which can bind only sodium ions, but also other cations. Calcium magnesium ions can enter the large crystal cavity occupied by the original sodium ions replace the sodium ions in 4A molecular sieves. That is to say, sodium ions in 4A molecular sieves can be exchanged with Ca2 Mg2 ions in hard water to soften water quality. The binding rate of molecular sieve 4A to calcium magnesium ions is slower than that of sodium tripolyphosphate, the binding ability of molecular sieve 4A with magnesium ions is weak. However, 4A molecular sieve can easily quickly remove a small amount of harmful heavy metal ions aqueous solution, which is very important for water purification.
2. Surfactant carrier adsorption function: 4A molecular sieve has strong adsorption performance due to its pore structure large specific surface area of particles. For the adsorption of nonionic surfactants, 4A molecular sieve is three times as much as NTA sodium carbonate, five times as much as sodium tripolyphosphate sodium sulfate. It is of great significance to mix more surfactants in the production of high concentration washing powder to make the product have good washing flowing properties. The experimental results show that the liquid carrying capacity of 4A molecular sieve is more than 30%. Adding 4A molecular sieve in the production process of washing powder can increase the fluidity of materials, adjust the viscosity, produce products with good appearance, fluidity anti caking.
3. Detergency: the detergency of 20% STPP, 20% molecular sieve 4% polymer is equivalent to 40% STPP. In the phosphate free formulation, compared with 20% molecular sieve, the product with excellent detergency can be obtained by using% sodium carbonate 4.5% polymer.
4. Anti redeposition performance: 4A molecular sieve has good oil adhesion. When sodium carbonate, CMC, sodium silicate, sodium sulfate other additives are added together with zeolite, the oil absorption of nylon cloth is significantly reduced. When the particle size of zeolite is 0,4-1,0 μ m, its dispersion is relatively good, which can prevent adhesion on the fabric. Although the dispersibility of 4A molecular sieve is as good as that of STPP, mixing 4A molecular sieve with sodium polyacrylate can solve the problem of fouling dispersion.
5. Compatibility with other additives: 4A molecular sieve other additives can appropriately supplement its performance. 4A molecular sieve is as good as STPP in dispersing dirt chelating hardness ions, but mixing 4A molecular sieve with STPP can achieve the effect of using STPP alone. This is because STPP can rapidly complex calcium magnesium ions solid surface transfer them to 4A molecular sieve through aqueous medium. The ability of 4A molecular sieve to bind magnesium ions is very poor, which can be compensated by mixing silicate carbonate in the molecular sieve.