| Layered Double Hydroxides (LDHs)was a sort of magnesium material with double-layer structure. Because of their special structure, they had received a lot of attention, for example adsorption, anionic exchange and catalysis, et al. Recently, the research work about LDHs was proceeding. Layered double hydroxides were prepared hydrothermal by perfect mixed spraying reactor using industrialization equipment and the stuff was industrial magnesium sulfate, aluminum sulfate, sodium hydroxide, sodium carbonate. Different instruments such as XRD and IR were used to characterize the chemical component, crystal structure, thermal decomposition. Results indicated that the sample's crystal structure and character accord with Mg/Al layered double hydroxides, there was carbonate in the middle of layered double hydroxides. TG-DTA characterized that there were two stages in the process of thermal decomposition and the lost weight was consistent with the theoretic value.This article explored the adsorption of fluoride and sulfate behavior of LDHs and their calcined products at 500℃(CLDH-5) as the adsorbent. The affecting factors, including adsorbent amount, adsorption time, pH value, temperature and the initial concentration etc, were investigated in the treatment of the fluoride and sulfate, so that we can find the perfect condition of adsorption. This article studied on adsorption mechanism by contrasting analysis of X-ray diffract grams of synthesized LDHs and their products before and after sorption experiment, and also compared LDHs and their calcined products with other adsorbents.The fluoride and sulfate were adsorbed on LDHs and their calcined products by the"anionic exchange mechanism"and"structure memory effect". At the same experiment condition, LDHs had poor adsorption of fluoride and sulfate comparing with their calcined products at 500℃. Other anionic were hard to displace CO32- because of its high affinity.The adsorption of fluoride in water by calcined layered double hydroxides was... |
PDF Full Text Request