Hebei Messi Biology Co., Ltd. stated that hydrotalcite (LDH) is also called layered double metal hydroxide. The alkalinity of hydrotalcite itself, the adaptability of cations on the layers, and the exchangeability of anions between layers allow hydrotalcite to be used in many aspects, such as as an environmental pollutant scavenger, catalyst fire extinguishing agent, acid scavenger, acid Absorbents, halogen absorbers, flame retardants, auxiliary combustion accelerants, etc.
Using aluminum oxide as the aluminum source, hydrothermal reaction with magnesium oxide and sodium carbonate was carried out under closed conditions to synthesize magnesium aluminum hydrotalcite. Fourier transform infrared spectrometer, X-ray diffraction and scanning electron microscope were used to analyze the product. The results showed that: molar ratio n (MgO):n(Al(OH)_3):n(Na_2CO_3)=2:1:1, reaction at 160°C for 14 hours can synthesize magnesium aluminum hydrotalcite with good crystallinity, pure phase and complete lamellar structure. In addition , a preliminary investigation was conducted on the feasibility of phosphorus adsorption by magnesium-aluminum hydrotalcite. When the phosphorus solution concentration is 20mg/L and the magnesium-aluminum hydrotalcite dosage is 0.7g, the removal rate can reach 97.4%, and the applicable pH value range is 4~ 10.
This article discloses a method for preparing magnesium aluminum hydrotalcite. Follow the following steps: (1) Prepare an aluminum chloride aqueous solution with a concentration of 0.24~0.03g/mL, and take magnesium oxide according to a Mg:Al molar ratio of 2~3:1 Add aluminum chloride aqueous solution, heat and stir at a constant temperature of 40~80°C for 2~4 hours to obtain a mixed solution; (2) Adjust the pH value of the mixed solution obtained in step (1) to between 9 and 10, and continue at 40 React at ~80°C for 2~4h; (3) Crystallize the slurry after the reaction in step (2) at a constant temperature of 60~80°C for 12~24h; (4) Filter the reaction solution after the crystallization in step (3), Wash, dry and grind to obtain magnesium aluminum hydrotalcite. The raw materials used in the method of the invention are cheap and easy to obtain, and the atomic conversion rate is high, which can reduce industrialization costs.