Photo-oxidation of phenol over titania pillared zirconium phosphate and titanium phosphate

The photodegradation of phenol was studied in the aqueous solutions over titania pillared zirconium phosphate and titanium phosphate under solar radiation and compared with that of the UV-radiation (6 W low pressure Hg vapor lamp). This reaction was studied by varying different parameters such as catalyst dose, initial phenol concentration, pH of solution and irradiation time. The degradation rate of phenol was favourable under neutral pH condition. The degradation process approximately obeyed first-order kinetics with apparent rate of degradation constant increasing with decreasing the initial phenol concentration.     

Photodegradation of dye pollutants on TiO<Subscript>2</Subscript> pillared bentonites under UV light irradiation

TiO₂ pillared bentonite samples dried under different conditions are used to degrade 2,4-dichlorophenol and orange II under UV light irradiation. The supercritical dried sample exhibits a high activity for the photodegradation of 2,4-dichlorophenol and orange II due to its structural features. TOC and COD are measured during the degradation of 2,4-dichlorophenol under UV light irradiation using P25 and TiO₂ pillared bentonite samples dried under different conditions. The clay-based catalysts can be readily separated by filtration or sedimentation.     

含过渡金属离子的交联蒙托土交联柱中Keggin结构的作用

利用Keggin结构可以发生同晶取代的性质,合成了含过渡金属离子铬、镍的羟基铝交联蒙托土,并运用XRD、~(27)Al-NMR、UV-DRS、XPS、TPR等方法研究了Keggin结构的作用。结果表明,铬、镍都可以和铝生成具有Keggin骨架结构的羟基共聚体,并以此作柱子支撑着蒙托土的层间。铬的取代反应比镍容易发生。共聚法合成出的羟基镍铝交联蒙托土中镍存在两种状态;过量的金属离子对Keggin结构有较大地破坏;Keggin结构的存在增加了交联蒙托土的热稳定性。     

Accommodation of an aliphatic guest molecule in hofmann-diaminooctane-type host. A model structure of a pillared intercalation compound

catena-[catena--(1,8-Diaminooctane)cadmium(II) tetra--cyanonickelate(II)]-(1-hexanol)(1/1) has been prepared as the first example of an aliphatic guest clathrate of the Hofmann-type and analogous metal complex hosts. The clathrate crystallizes in the monoclinic space groupP2/m,a=11.470(2),b=7.782(1), andc=6.945(1) Å, =105.29(1)°,Z=1;R=0.043 for 1865 reflections. The structure presents a model of pillared intercalation compounds formed between layers of metal complex sheets pillared by ,-ambidentaten-alkaneskeletal ligands andn-alkyl derivative guests. Supplementary Data relating to this article are deposited with the British Library as supplementary publication SUP 82069 (16 pages).     

柱撑杂多阴离子粘土的合成及表征

采用水热合成及离子交换法将Keggin结构三铁九钨镓酸盐杂多阴离子GaW9Fe3（H2O）3嵌入Zn2Al型阴离子粘土层间，得到了新型层柱状微孔材料Zn2Al－GaW9Fe3．用元素分析、XRD、IR、XPS等手段对产物的组成和结构进行了表征．结果表明，杂多阴离子嵌入Zn2Al型阴离子粘土层间，使柱撑杂多阴离子粘土具有1．0nm的通道高度．     

Solar photooxidation of azo dye over mixed (Al-Fe) pillared bentonite using hydrogen peroxide

Summary The mixed Al-Fe pillared bentonite (Al/Fe-B) was tested as a heterogeneous catalyst for the photo-Fenton discoloration of azo dye X-3B under solar light irradiation. The structural characteristics of the catalyst were examined by XRD, BET, and TEM. The results indicate that the heterogeneous photo-Fenton process employing the Al/Fe-B as catalyst exhibits higher photo-catalytic activity compared to its corresponding homogeneous photo-Fenton process. The amount of Fe ions in solution leaching from the Al/Fe-B is less than 0.26% of the total iron content in the catalyst.     

Mixed Al/Ce oxide pillaring of montmorillonite: XRD and UV-VIS diffuse reflectance study

Ce and Al pillared clays were prepared by (i) pillaring Ce³⁺-exchanged montmorillonite with Al₁₃ polycation (Ce-Al-PILC) and (ii) by pillaring Na-montmorillonite with an oligomer obtained from cohydrolysis of Ce³⁺ and Al³⁺ salts (Al-Ce-PILC). Cohydrolyzed oligomer gives larger intercalating species with Ce³⁺ incorporated in it. The UV-DRS spectrum of clay sample intercalated with this species shows four distinct absorption bands at 224, 263, 294 and 342 nm, which are attributed to the 4f-5d interconfigurational transitions of Ce³⁺ ions associated with alumina pillars.     

Depollution of uranyl polluted waters using pillared clays

This paper reports on the use of clays pillared with copper polyhydroxycations in the depollution of waters polluted with radioactive elements. The pillared clays have very good surface properties which recommend them for use in cationic depollution. The article includes a kinetic study on the depollution of radioactive polluted waters, studying the influence of temperature on the process. The pillared clays are prepared from Romanian clay originally from Valea Chioarului deposits; the experiments have used an autochthonous material in an unconventional performant depollution technology.     

Comparative Studies of the Micropore Size Distributions of an Alumina Pillared Montmorillonite and a Molecular Sieve Carbon

The aim of this work is to applicate and to compare various analysis methods for the characterization of the microporous structure from nitrogen adsorption at 77 K of an alumina pillared montmorillonite and a molecular sieve carbon. The adsorption potential distribution (X(A)), the Horvath-Kawazoe (HK) method, the Jaroniec-Gadkare-Choma (JGC) one and a numerical algorithm for the reconstruction of the micropore size distribution (MPSD) from the adsorption equilibrium isotherm have been applied. Comparison of all distributions revealed that the molecular sieve carbon shows smaller micropores and smaller structural hetereogeneity than the alumina pillared montmorillonite.     

Synthesis of ϵ‐Caprolactam from Cyclohexanone Oxime Using Zeolites Hβ, HZSM‐5, and Alumina Pillared Montmorillonite

The Beckmann rearrangement of cyclohexanone oxime (CHO) to ?‐caprolactam (?‐C) was studied in a plug flow reactor at 300–400°C under atmospheric pressure by using Hβ, ZSM‐5, and alumina pillared montmorillonite. With Hβ(X) Y zeolites, raising the SiO₂/Al₂O₃ molar ratio (X) results in the enhancement of catalyst acid strength with concomitant decrease of the total acid amount. In creasing the calcination temperature (Y) causes remarkable diminution of catalyst surface area, acid strength, and acid amount. A similar trend was found for AlPMY catalysts. In there action of CHO, the initial catalytic activity correlates well with the total acid amount of various catalysts except for Hβ(10) Y (Y > 600°C). The reaction proceeds on both Brönsted and Lewis acid sites and the catalyst deactivation most likely occurs at the strong Brönsted acid sites. The effect of solvents in the feed on the catalytic results was also investigated; it was found that polar solvents such as ethanol or n‐butanol give high ?‐C yield and longer catalyst life time. In the reaction of CHO/C₂H₅OH over Hβ(10)800 at 400°C and W/F 74.6 gh/mol, the CHO conversion and ?‐C yield remain 100% and 92%, respectively, for at least 20 h time‐on‐stream. The reaction paths and the mechanism for ?‐C formation are proposed.