Synthesis, Characterization And Adsorption Properties For Cu²⁺ Of MgAl Hydrotalcite-like Compounds

This thesis is mainly composed of the following four sections. Synthesis, characterization and the adsorption properties for Cu²⁺ of MgAl-NO₃-LDHs, MgAl-EDTA-LDHs, MgAl-EDTA-LDHs/PVA composite membrane and MgAl-EDTA-LDHs@PAN nanofibrous membrane.Firstly, a series of good crystal structure of layered double hydroxides （MgAl-N03-LDHs） were synthesized by coprecipitation method, and then did orthogonal experiments to study the influences factors in every step of the synthesis process,. The samples are characterized by XRD, FT-IR, element analysis and SEM, and their chemical composition and structure are determined. The adsorption properties for Cu²⁺ in MgAl-NO₃-LDHs were explored, the results show that MgAl-NO₃-LDHs has good adsorption effect for Cu²⁺, and it may become promising adsorbent of heavy metals.Secondly, a certain amount of EDTA4" were dispersed into the interlayer region of MgAl hydrotalcite by double drops of coprecipitation method, and the EDTA intercalated hydrotalcite （MgAl-EDTA-LDHs） were synthesized. The XRD, FT-IR and elemental analysis show that the EDTA4" were arranged in tilt angle between the layers. The Cu²⁺ adsorption experiments of MgAl-EDTA-LDHs were examined, which were used by chelation of EDTA. The results show that MgAl-EDTA-LDHs has a good adsorption ability for Cu²⁺, and it’s expected to become an adsorbent of heavy metals.In order to overcome the shortcoming of powder materials in practical application, we combined MgAl-EDTA-LDHs with polyvinyl alcohol （PVA）, and the MgAl-EDTA-LDHs/PVA composite membrane was obtained. The FT-IR, XRD and SEM analysis results indicated that MgAl-EDTA-LDHs were chemically bonded with PVA, moreover, the structure of MgAl-EDTA-LDHs has been preserved. Hence, MgAl-EDTA-LDHs/PVA composite membrane can easily overcome the difficulties of sorbent loss and agglomeration, in practical process.Finally, via electrospinning technique, the MgAl-EDTA-LDHs@PAN nanofibers membrane was manufactured with excellent appearance. The results of XRD, FT-IR, TG and SEM analysis show that the structure of MgAl-EDTA-LDHs was not destroyed. The adsorption experiments show that MgAl-EDTA-LDHs@PAN nanofibers membrane has a high capacity for Cu²⁺, and it could be a good candidate for the development of new environmental remediation nanomaterials.As heavy metal absorbents, hydrotalcite materials have the advantage of larger adsorption capacity, low cost, easily synthesized and so on. The composite membrane which combining hydrotalcite material and PVA or PAN, can greatly extended the using range of hydrotalcite materials.