Performance characteristics of Changsha 4A molecular sieve
The performance characteristics of Changsha 4A molecular sieve are as follows:
1. Ion exchange performance----softening water quality function: Each oxygen atom in the framework of Changsha 4A molecular sieve is shared by two adjacent tetrahedra. This structure forms large crystals that can be occupied by cations and water molecules. At the acupoints, these cations and water molecules have greater mobility, allowing for cation exchange and reversible dehydration.
2. The ion exchange of 4A is carried out on the framework with aluminum ions. Each aluminum ion is negatively charged and can bind not only sodium ions but other cations as well. Calcium and magnesium ions can enter the large crystal pores occupied by the original sodium ions, replacing the sodium ions in 4A - that is, the sodium ions in the molecular sieve can be ion-exchanged and can be carried in hard water with Ca2+ and Mg2+ ions. Exchange to achieve the purpose of softening water quality.
3. The binding rate of calcium and magnesium ions is slower than that of sodium tripolyphosphate, and the binding ability to magnesium ions is weak. However, 4A molecular sieve can easily remove a small amount of harmful heavy metal ions (such as Pb2+, Cd2+, Hg2+) in aqueous solution, which is of great significance for purifying water quality. Adsorption to Surfactant - Carrier Fluid Features:
4. Due to the pore structure of the 4A crystal and the large specific surface area of u200bu200bthe particles, the adsorption performance is very strong. The adsorption capacity of the nonionic surfactant is three times that of NTA (secondary aminotriacetate) and sodium carbonate, and five times that of sodium tripolyphosphate (STPP) and sodium sulfate. This characteristic is high in agglomeration molding. It makes sense to add more surfactant to concentrated detergents to give products with good wash and flow.
5. Through experiments, the liquid carrying capacity of 4A molecular sieve is ≥30%. Adding 4A in the production process of washing powder can increase the fluidity of the material, adjust the viscosity, and make the product have a good appearance. , fluidity and resistance to caking. Detergency: Through experiments, adding different additives to the same formula, changing the detergency of the additives, it is found that 20% STPP, 20% molecular sieve, 4% polymer decontamination effect is equivalent to 40% STPP, 10% Sodium Carbonate Addition of 4.5% polymer to 20% molecular sieve in a phosphorus-free formulation yields a product with heterogeneous detergency.
6. Anti-redeposition: has good oil adhesion. When zeolite was added to additives such as sodium carbonate, CMC, sodium silicate and sodium sulfate, the adsorption of oil on nylon cloth was significantly reduced. When the particle size of the zeolite is 0.4 to 1.0 μm, the dispersibility is relatively good, and the adhesion to the fabric can be prevented. Although the dispersing ability is not as good as STPP, it can solve the problem of soil dispersion by compounding with sodium polyacrylate. Compatibility with other additives: 4A molecular sieve and other additives can complement its performance.
7. The dispersibility of dirt and the chelation of hardness ions are not as good as STPP, but when 4A is mixed with STPP, the detergency can reach the effect of STPP alone. This is because STPP can rapidly complex calcium and magnesium ions from the solid surface and transfer them to 4A through the aqueous medium. The poor magnesium ion binding ability of 4A sieves can be compensated by the complexation of silicates and carbonates in molecular sieves.
8. PH buffering effect: It is alkaline, the pH value of 1% aqueous solution is 11.0, so it has a certain buffer alkalinity. Safety: 4A is non-toxic to human body and has high safety. It is non-irritating to eyes and skin, does not cause allergies, and is safe and reliable to use. It is washed and deposited in the soil without causing pollution, and it can also improve the adverse effects of soil on ecology.
9. The system based on 4A design is generally smaller than 3A molecular sieve. According to the analysis of actual production data, if it is the adsorption of molecular sieve H 2 S, the total S content of the feed gas entering the dehydration unit needs to be studied in detail, so as to make the molecular sieve dehydration unit more efficient. Normal operation is maximized.
As shown in Figure 10, 4A requires less regeneration gas, but absorbs H2S and other S-generation temperatures higher than 3A molecular sieves while absorbing water. It can also catalyze the formation of COS, and its catalytic ability is relatively strong. 3A molecular sieve does not absorb H 2 S contained in the raw gas, and another group of S has little effect on the generation of COS.
11,4A, 3A molecular sieve, 5A molecular sieve are mainly used for adsorption, and a small part is used for catalysis. It is widely used in the oil and gas industry, and there are some special molecular sieves, such as 3A insulating glass, 5A oxygen enrichment, etc. The working principle is mainly related to the pore size of molecular sieves, which are 0.3 nm, 0.4 nm and 0.5 nm, respectively. They can adsorb gas molecules whose molecular diameter is smaller than the pore size, and the larger the pore size, the greater the adsorption capacity. Molecular sieves are polar, and they have good adsorption properties for molecules with the same polarity, and special molecular sieves such as hydrogen production and hydrogen production have appeared. The properties of molecular sieves are adsorption and catalysis. The evaluation standard has basic national standards, but different industries have different requirements for molecular sieves, which can be customized.