Zeolite A And Al-MCM-41 Mesoporous Molecular Sieve From Hangjin 2~# Clay: Synthesis And Characterization

Molecular sieves have attracted considerable attention in the region of chemical engineering, industrial catalysis, biomedicine,environmental protection, and fabrication of novel Nano-object materials due to their adsorption, separation, ion exchange and shape-selectivity properties Molecular sieves are prepared using water glass, sodium silicate tetraethoxysilne as silica sources, the resource consumption is expensive.Recently, attention has been paid to a new process to prepare molecular sieves from natural clays. The Zeolite A and the mesoporous molecular sieves Al-MCM-41 were first synthesized from hangjin 2# clay The samples were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), N2 adsorption-desorption measurements, Scanning Electron Microscope (SEM), and X-ray Flourescent (XRF). At last, a layered-porous silicate mineral was prepare by organic-modification method from acided-hangjin 2# clay. The main contents are as follows(1) The hangjin 2# clay was obtained from inner Mongolia China and its chemical composition was analyzed by XRF. The hangjin 2# clay was actived by acid-activated and alkali fusion methods.(2) Zeolite A was synthesized from hangjin 2# clay by hydrothermal treatment. The samples were characterized by X-ray diffraction (XRD) Scanning Electron Microscope (SEM) techniques. The optimum conditions of crystallization on the formation of Zeolite A were:n(SiO2)/n(Al2O3)=2 n(Na2O)/n(SiO2)=1, n(H2O)/n(Na2O)=65, crystallization temperature T=95℃, crystallization time t≥6h. The quality of products reached the standard of the industry.(3) The ordered mesoporous materials Al-MCM-41 were synthesized from hangjin 2# clay. The Al-MCM-41 materials were investigated by powder X-ray diffraction (XRD), N2 adsorption-desorption measurements and transmission electron microscopy (SEM). A lot of experiments were adopted to optimize the processing parameters. The optimum conditions of crystallization on the formation of Al-MCM-41 were:pH=10-11 crystallization temperature T=100℃, crystallization time t=48h,mCTAB=1g (4) Layered-porous silicate mineral materials were prepared from acidification hangjin 2# clay as raw material, CTAB as a directing agent. The materials had uniform size of mesoporous (2.6nm), high surface area (389m2/g).