Studying On The Preparation Of Nanoscale Aluminum Magnesium Hydroxide Powders And Its Sol Adsorption Of Heavy Metal Cation

AlC13·6H2O, MgCI2·6H2O and NH3-H2O were used as the main raw materials to prepare precursory sol in this study, and then we prepared AMH by Vacuum freezy-desiccation technology and characterized it by using transmission electron microscope (TEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer(FT-IR) and physical adsorption analyer. The effects of various factors, such as different Mg-Al molar ratio, time, temperature and pH value on the absorption behavior of AMH have been investigated by chemical analysis method. The results showed that:1. Precursory sol was the prerequisite for the preparation of Nanoparticles..The pH value was the key factor in the preparation parameters of aluminum magnesium hydroxides sol. Only when the pH value was between 8.5 and 10.0, could the gelatin be changed into the sol normally, the best pH value Of sol existence was between 9.0 and 9.2. The composition of the products related to the proportion of the raw materials. when the raw materials' magnalium ratio was smaller than 3:1,the product was the mixture of Mg2Al(OH)7 and Al(OH)3. The ralative content of Al(OH)3 in the product could be decrease with the raw material's magnalium ratio increasing. When the raw materials' magnalium ratio was 3:1, the only product was the Mg2Al(OH)7.2.The product of Mg2Al (0H)7 Powder which was produced by using Vacuum freezy-desiccation technology with table-shaped feature, its particle diameter distributed uniformity and average particle diameter was below 30nm. The Nanoparticles specific surface area increased when through the heat treatment at 400℃,but its specific surface area dropped quite sharply when temperature was above 900℃.3. Along with the extension of time,the adsorbability of product was enhanced gradually,the adsorption process could finish in 40min. The product got better adsorption effect to heavy metal such as Cr3+, Fe3+,but the product got worse adsorption effect to the heavy metal such as Mn2+.4. The product got the best adsorption of when the molar ratio of Mg(Ⅱ)/Al(Ⅲ) was 3:1 in the raw materials, the most appropriate reaction temperature was 45℃and pH value was 9.2.