Adsorption Behavior Of Mg-Al Hydrotalcite And Construction Of New Materials

Hydrotalcite is an anionic layered double hydroxide.It is simple and economical to synthesize.It has excellent properties such as large specific surface area,anion exchangeability,adjustable delamination and good thermal stability.Hydrotalcite and its derivatives have a good research and application prospect in the field of environment and adsorption materials.However,there are few studies on the adsorption behavior of hydrotalcite on antibiotics and the preparation of new materials using hydrotalcite.In this dissertation,different anionic hydrotalcites were prepared by co-precipitation method,and carbonate-type hydrotalcite was reconstructed by roasting.In this dissertation,the adsorption behaviors of doxycycline on different anionic hydrotalcite and calcined carbonate hydrotalcite were studied,and the relevant mechanism was studied by molecular dynamics simulation.Three different anionic magnesium aluminum hydrotalcites were prepared by coprecipitation.Hydrotalcite was used to adsorb doxycycline hydrochloride.Three different anionic magnesium-aluminum hydrotalcites have adsorption effects on doxycycline hydrochloride.Among them,nitrate-type Mg-Al hydrotalcite had the best adsorption effect,followed by chloride-type Mg-Al hydrotalcite,and carbonate-type Mg-Al hydrotalcite had the worst effect.The carbonate-type Mg-Al hydrotalcite cannot undergo ion exchange reaction with doxycycline hydrochloride during the adsorption process,so the adsorption effect is the worst.The carbonate-type magnesium-aluminum hydrotalcite was calcined and used for the doxycycline hydrochloride adsorption experiment.After the carbonate-type magnesium-aluminum hydrotalcite was roasted,doxycycline hydrochloride was adsorbed and the original hydrotalcite layered structure was restored.XRD results showed that The interval between layers is changed compared with carbonate-type Mg-Al hydrotalcite.It can be presumed that doxycycline hydrochloride may enter the interlayer of hydrotalcite,so the adsorption behavior may have inter-layer adsorption in addition to surface adsorption.This experiment investigated the adsorption behavior of three different anion type Mg-Al hydrotalcite and calcined carbonate Mg-Al hydrotalcite on doxycycline hydrochloride.Roasting carbonate-type magnesium-aluminum hydrotalcite has the best adsorption effect on doxycycline hydrochloride.There are two adsorption mechanisms: surface adsorption and interlayer adsorption.The use of molecular dynamics simulation provides theoretical support for experimental results.The research results of this experiment are of great significance for the development of the adsorption technology for the removal of antibiotics in water,which is helpful for the development of an efficient and low-cost adsorbent,and provides an important theoretical basis and guidance for the treatment of increasingly severe water pollution.