Tham khảo tài liệu 'thermodynamics interaction studies solids, liquids and gases part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 530 Thermodynamics - Interaction Studies - Solids Liquids and Gases between S-MnO2 and manganite as well as the linkage modes of adsorbed Zn II on S-MnO2 and Fig. 9. Adsorption closed symbols and desorption open symbols isotherms of Zn II on manganite. EXAFS samples were indicated by arrows. Fig. 10. Adsorption and desorption isotherms of Zn II on S-MnO2. EXAFS samples were symboled with blank triangles A . Manganite had a structure with rows of edge-sharing Mn II O6 octahedra linked to adjacent rows through corners. Due to the Jahn-Teller effect of Mn II ions and to the presence of both O and OH groups the MnO6 octahedra were highly distorted each Mn is bound to four equatorial oxygen and two axial oxygen 22 This distortion gave rise to a mild layered structure. Hydrolyzable Zn could be bonded on MnO6 octahedra of manganite surface via edge and corner-sharing coordination 22 The basic structure of S-MnO2 consisted of layers of edge-sharing MnO6 octahedra alternating with a layer of water molecules. One-sixth of Mn4 positions were empty which gave a layer charge that was compensated by two Zn atoms located above and below the 24 Hydrolyzable Zn could be taken up in the interlayer to form tridentate corner-sharing 26 These differences in crystallographic structure resulted in different linkage modes for the adsorption of Zn on manganite and S-MnO2. 531 Advances in Interfacial Adsorption Thermodynamics Metastable-Equilibrium Adsorption MEA Theory Fig. 11. Corner-sharing linkage a and interlayer structures of Zn II adsorbed on 0-MnC 2 b . a RZn-C Ẵ RMn-C Ẵ RZn-Mn Ẳ. b Squares were vacant sites illustration diagram adapted from Wadsley 27 Post and Appleman 28 and Manceau et Fig. 12. Two types of linkage between adsorbed Zn II octahedron and tetrahedron and MnC6 octahedra on the y-MnCCH surfaces. a Double-corner linkage mode b edgelinkage mode. Extended X-ray absorption fine structure EXAFS .
