Adsorption of phenol on mono, bis and tris (2, 2'-bipyridine) nickel (II)-and tris (ethylenediamine)-nickel (II)-saponite intercalation compounds from aqueous solution was examined. Mono, bis and tris (2, 2'-bipyridine) nickel (II)-saponites were prepared by the reactions of Ni (II)-form of a synthetic saponite (Sumecton SA) with 2, 2'-bipyridine at the molar 2, 2'-bipyridine to Ni (II) ratios of 1: 1, 2: 1 and 3: 1. Tris (ethylenediamine) nickel (II)-saponite was prepared by the reactions of the Ni (II)-saponite with ethylenediamine at the molar ratio of 3: 1 (ethylenediamine: Ni (II)). X-Ray diffraction and thermal analysis indicated that 2, 2'-bipyridine and ethylenediamine were intercalated into Ni (II)-saponite to form mono, bis and tris (2, 2'-bipyridine) nickel (II) and tris (ethylenediamine) nickel (II) complexes. The adsorption isotherms of phenol for the mono, bis and tris (2, 2'-bipyridine) nickel (II)-saponites followed Langmuir type, indicating strong adsorbate-adsorbent interactions. The basal spacings of the mono, bis and tris (2, 2'-bipyridine) nickel (II)-saponites did not change by the adsorption of phenol, indicating that the adsorbed phenol existed in the interlayer micropore formed by the pillaring with the complexes. The adsorption of phenol on the tris (ethylenediamine) nickel (II)-saponite was less effective than those on the (2, 2'-bipyridine) nickel (II)-saponites, suggesting that the interactions between pyridine rings and phenol played an important role in the adsorption of phenol.

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Both refluxing reaction under atmospheric pressure and hydrothermal reaction underautogenous water vapor pressure of two kinds of starting slurry with the initial molar ratio Na: Zn: Li: Si =0.7: 5.4: 0.6: 8.0 and 1.4: 5.4: 1.2: 8.0 made from Zn-Si homogeneous precipitates, lithium fluoride and sodium hydroxide successfully have yielded Zn-hectorites containing Zn²⁺ instead of Mg²⁺ in the trioctahedral sheets. Zn-hectorites have expansion of the basal spacing (door) by the treatment with ethylene glycol on powder X-ray diffraction (XRD) patterns, and characterized by Zn-O vibration in the around 660-670cm^-1 on fourier transform infrared spectrometer (FT-IR) spectra, peaks assigned to Zn2p on X-ray photoelectron spectrometer (XPS) spectra and thermal dehydroxylationat lower temperature on thermogravimetry and differential thermal analysis (TG-DTA). It hasalso clarified that Zn-hectorite synthesized by hydrothermal reaction under autogenous water vapor pressure is relatively large massive particles and has a larger CEC, although it has lower MB adsorptive ability compared to a commercial Mg-hectorite as reference.

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The weathering mechanism of pyroclastic rocks distributed at the landslides in Lembo area, Bana-Bangou district, was investigated from a mineralogical viewpoint. Specimens collected from the landslide profile were composed mainly of kaolinite, illite, chlorite, illite-smectite interstratified mineral, gibbsite, goethite, anatase, maghematite, hematite, quartz and feldspar.
The landslide area (pyroclastic rock) was characterized by slow creep movement every raining season. The slip zone was recognized on the landslide profile. Chemical composition of the landslide materials showed the complete leaching of CaO and Na₂0, whereas a small amount of K₂0 and MgO remained in the whole profile. Detail examinations of the microtexture indicated that the material showed aggregate skeletal matrix with high porosity. This process further caused the decrease of soil strengths and development of micro-texture characteristics that tended to increase the creeping landslide. This displacement rate of the creeping landslide mechanically depended mostly on the pore water pressure in the landslide profile. High pore water pressure always corresponded to the large displacement rate. The mechanism of the creeping landslide was considered from mineralogical characteristics.

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In order to grasp the adsorptive selectivities of heavy metal ions on the phyllosilicates, the GainsThomas ion exchange selectivity coefficients, KGT of Cd²⁺, Cu²⁺, Pb²⁺ and Zn²⁺ on Ca-saturated kaolinite and bentonite were determined in comparison with Ca²⁺. Adsorption mechanism was also estimated by the determination in desorption of the ions adsorbed on the phyllosilicates. The average Kars (min.-max.) on the Ca-kaolinite were 1.0 (0.7-1.3) for Cd²⁺, 1.3 (0.5-2.1) for Cu²⁺, 4.5 (3.3-5.6) for Pb²⁺ and 1.3 (0.6-2.1) for Zn²⁺. On the Ca-bentonite, the average Kars (min.-max.) were 1.0 (0.7-1.9) for Cd²⁺, 1.4 (0.8-2.7) for Cu²⁺, 1.9 (1.5-2.5) for Pb²⁺ and 1.7 (1.1-2.7) for Zn²⁺. These results indicated that Cd²⁺ has the same adsorptive selectivity onto the surfaces of the phyllosilicates as Ca²⁺. The selectivity of Pb²⁺ to kaolinite was found to be specifically higher than those of the other heavy metal ions. It was confirmed that Cu²⁺ and Zn²⁺ can be adsorbed on the surface of the phyllosilicates with the slightly higher selectivities than the alkaline-earth metal ion.
Except for Pb²⁺ on kaolinite, most Cd²⁺, Cu²⁺ and Zn²⁺ (>70%) adsorbed on the phyllosilicates can be desorbed with the 1 mol dm^-3 (mol L^-1) ammonium acetate extraction regardless of clay species and adsorptive equilibrium pH, indicating that many Cd²⁺, Cu²⁺ and Zn²⁺ are adsorbed on the phyllosilicates in fashion of ion exchange reaction. Half of Pb adsorbed on kaolinite was desorbed with the 1mol L^-1 ammonium acetate extraction and 25% was extracted by 1mol L^-1 HCl, implying the possibility of specific sorption of some Pb²⁺ on the phyllosilicate.

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To elucidate the adsorption sites and behavior of Sr atoms on smectite, EXAFS spectroscopy was performed at the Spring-8 using air-dried and wet-paste samples of Sr-adsorbed bentonite adjusted to pH 4.7 and 9.6. EXAFS analyses were conducted for the two-oxygen shell fit using a crystalline SrSO₄ as a reference compound. The first-neighbor shells consisted of 5.5 0 atoms of water molecules at a distance of 2.58 Å in the air-dried sample and 7.0 0 at 2.60 Å in the wet sample. The second shells consisted of 2.6 0 atoms at a distance of 2.77 Å and 2.5 0 at 2.81 Å for the air-dried and wet samples, respectively. Only the Debye-Waller factors of the second shells were affected by the pH, resulting to be smaller at pH 4.7 than those observed at pH 9.6. It is concluded from the EXAFS results that Sr atoms are attracted stronger to the 2: 1 sheets of smectite in the air-dried compacted samples than in the wet-paste samples because of the smaller Debye-Waller factors in the air-dried compacted samples. The Sr atoms hovered on a triangle of the oxygen hexagonal cavity on the flat surface of 2: 1 sheets and resided on the broken face of the octahedral sheets at the edge surface. In addition, they behaved as hydrated ions and formed incomplete outer-sphere complexes at high water content; however, they formed incomplete inner-sphere-like complexes together with oxygen atoms of the 2: 1 sheets in the air-dried samples. The Sr atoms also played a role combining two sheets of the 2: 1 layer of smectite in forming the edge-toedge and edge-to-face associations.

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