Prevention of photocatalytic deterioration of resins using TiO2 pillared fluoromica

The TiO₂ pillared fluoromica powder was kneaded with polylactic acid resin. The composite showed high photocatalytic activity for degradation of acetaldehyde and toluene gas, especially at the range of 1–3 wt.% pillared mica powder, and this photocatalytic activity was higher than that of resins containing even higher amounts of commercial TiO₂ (P-25, Degussa). The composite test pieces of pillared mica showed smaller photocatalytic deterioration than the samples with P-25 powder in out-door weathering tests. Thus, the TiO₂ pillared clay resin composite shows excellent prevention of photocatalytic deterioration and high photocatalytic activity in comparison with P-25.     

Catalytic oxidation of aromatic VOCs with Cr or Pd-impregnated Al-pillared bentonite: Byproduct formation and deactivation studies

The catalytic behavior of chromium and palladium-impregnated Al-pillared bentonite for the oxidation of aromatic VOCs, i.e. chlorobenzene or xylene, was investigated. The Cr-impregnated bentonite showed high activity for the total oxidation of cholorobenzene and xylene but the materials were completely deactivated during the reaction at 600 °C. Atomic absorption, XPS, XRD and TG analyses suggested three main causes for the deactivation, i.e. the loss of Cr due to the formation of volatile CrO₂Cl₂, a strong decrease on the surface area due to the collapse of the pillars and the formation of coke. For the Pd supported pillared bentonite, the impregnation procedure completely destroyed the Al-pillars but produced a very active and stable catalyst to oxidize aromatic contaminants. However, in the case of chlorobenzene almost 20% yield of the hazardous hexachlorobenzene was obtained likely by an oxychlorination process.     

苯甲酸阿格列汀有关物质的合成

苯甲酸阿格列汀为二肽基肽酶抑制剂。为了对苯甲酸阿格列汀产品进行质量控制,以合成路线为基础,制备了4种有关物质,并且通过核磁共振和质谱确定了其化学结构。同时,根据有关物质的结构分析了其可能产生的原因。以此为基础,通过改善实验条件,成功合成出了符合质量标准的苯甲酸阿格列汀。     

Synthesis, Characterization and Lithography Performance of Photoacid Generator with Short Perfluoroalkyl Anion

Summary A new environmentally friendly photoacid generator (PAG) consisting of diphenyliodonium salt as photoactive cation and fluoroalkyl sulfonium anion as counter ion was synthesized. From FT-IR measurement, it was found that non perfluorooctyl sulfonates (PFOS) PAG from UV irradiation could produce strong acid that subsequently catalyzes the deblocking of a protecting group in copolymer. A positive resist formulation at 248 nm based on the chemically amplified resist mechanism indicated that fluoroalkyl sulfonium anion was capable of providing good image profiles.     

Recent Advances in the Synthesis and Catalytic Applications of Pillared Clays

New methods have been developed in recent years that are now being successfully applied in the preparation of pillared interlayered clays (PILCs). Variations in the procedures concern different parameters involved in the synthesis, such as the starting clay, the intercalating solution, the intercalation process, and the drying and calcination steps of the pillared solids, among others. In the present article, the latest results obtained when introducing modifications in the chemical aspects of PILC synthesis are reviewed. These include (1) pillaring with mixed solutions containing two or more cations, (2) using coordination or organometallic compounds, (3) using polymers and surfactants, (4) pillaring of acid-activated clays, and (5) enhancement of PILC acidity. A separate section is devoted to the specific features of preparing these solids in amounts large enough to make their manufacture on an industrial scale economically feasible. Recent developments in the catalytic applications of PILCs are also reviewed, with emphasis on the progressively more extended use of these materials as catalytic supports.     

Terpolymer Chelates: Synthesis,Characterization, and Biological Applications

Terpolymer ligand was synthesized from 8-hydroxyquinoline and anthranilic acid with formaldehyde (QAF) by solution condensation in an acid medium. Polychelates of Cu(II), Ni(II), Zn(II), and Pb(II) were prepared using the terpolymer as ligand. The ligand and chelates were characterized by elemental analysis, TGA, DSC, FTIR, electronic absorption, and NMR spectroscopy. The activation energy was calculated for the ligand and its polychelates formation by the Freeman-Carroll method. The ligand and its polychelates possess antimicrobial activity for certain bacteria such as Staphylococcus aureus, Escherichia coli, and fungi Aspergillus niger and Candida albicans. The surface morphology of the ligand and its polychelates was established by SEM.     

Recent Advances in the Synthesis and Catalytic Applications of Pillared Clays

New methods have been developed in recent years that are now being successfully applied in the preparation of pillared interlayered clays (PILCs). Variations in the procedures concern different parameters involved in the synthesis, such as the starting clay, the intercalating solution, the intercalation process, and the drying and calcination steps of the pillared solids, among others. In the present article, the latest results obtained when introducing modifications in the chemical aspects of PILC synthesis are reviewed. These include (1) pillaring with mixed solutions containing two or more cations, (2) using coordination or organometallic compounds, (3) using polymers and surfactants, (4) pillaring of acid-activated clays, and (5) enhancement of PILC acidity. A separate section is devoted to the specific features of preparing these solids in amounts large enough to make their manufacture on an industrial scale economically feasible. Recent developments in the catalytic applications of PILCs are also reviewed, with emphasis on the progressively more extended use of these materials as catalytic supports.     

腐植物质结构鉴定研究方法进展

综合评述了目前国内外研究腐植物质结构的定性和定量分析方法,对腐植物质进行定性和定量分析的方法包括波谱分析方法(紫外/可见、荧光、红外、顺磁共振和核磁共振)、降解法(氧化、水解和高温裂解)结合色谱/质谱联用法、化学/物理法(元素分析、酸/碱滴定和电位滴定法)等.重点介绍了常用的波谱法和化学法,分析比较了化学滴定法与波谱分析方法的部分测定结果,总结了目前通过上述方法研究腐植物质结构得到的一些重要结论.     

分形吸附理论及其对粘土性质的表征方法

粘土被广泛地应用于环境污染物的吸附处理。概述了分形几何的基础及其对粘土吸附和性质表征的方法。归纳了常见的分形吸附模型以及分维数测定方法。     

Synthesis and properties of polybenzoxazole-clay nanocomposites

A novel polybenzoxazole (PBO)/clay nanocomposite has been prepared from a PBO precursor, polyhydroxyamide (PHA) and an organoclay. The PBO precursor was made by the low temperature polycondensation reaction between isophthaloyl chloride (IC) and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with an inherent viscosity of 0.5 dl/g. The organoclay was formed by a cation exchange reaction between a Na⁺-montorillonite (Na⁺-Mont) clay and an ammonium salt of dodecylamine. The PHA/clay was subsequently thermal cured to PBO/clay. Both X-ray diffraction and transmission electron microscope analyzes showed that the organoclay was dispersed in the PBO matrix in a nanometer scale. The in-plane coefficient of thermal expansion (CTE) of PBO/clay film decreased with increasing amounts of organoclay. The CTE of PBO/clay film containing 7 wt% clay was decreased by 21% compared to the pure PBO film. Both of the glass transition temperature (T_g) and the thermal decomposition temperature of PBO/clay increased with increasing amounts of organoclay. The thermal decomposition temperature and the T_g of PBO/clay containing 7 wt% clay increased to 12 and 16 °C, respectively.     

Synthesis of pillared clays with Al13-Fe and Al13-Fe-Ce polymers in solid state assisted by microwave and ultrasound: Characterization and catalytic activity

A new methodology for the synthesis of pillared clays with the Al₁₃-Fe and Al₁₃-Fe-Ce polymers in solid state was developed by using microwaves and ultrasound in the aging of the olygomeric solution, in the precipitation of the corresponding sulphates, and in the intercalation of the polymer with the powdered clay. This methodology reduces significantly the water consumption in the intercalation process, and the time for the synthesis of both the polymer in the solid state, and the pillared clay. The resulting polymers were characterized by XRF, XPS, XRD and SEM. The XRF analysis showed that a high percentage of Fe and Ce associated to Al₁₃-Fe and Al₁₃-Fe-Ce sulphates, was dissociated during the exchange process with nitrate. Using XPS analyses we established the presence of Ce (III) in the polymers. By means of XRD and SEM we determined that Al₁₃ and Al₁₃-Fe sulphates present a monoclinical structure, whereas the Al₁₃-Fe-Ce sulphates present two crystalline phases, monoclinical and cubical, whose cell parameters are slightly different from those of the sulphates reported in literature. The XRD, XRF and sortometry analyses showed that the pillared clays (synthesized with the proposed methodology), show more intense and remarkably homogenous pillaring signals, and also better textural properties than the clays pillared by the conventional method of synthesis. The catalytic activity was assessed in the phenol oxidation in dilute aqueous medium at 25 °C and at atmospheric pressure. The solids synthesized showed similar catalytic properties than those reported for the solids synthesized by the conventional method.     

The Extraction of 137Cs and 89Sr from Waste Simulants Using Pillared Montmorillonite

ABSTRACT

Two samples of a silica-pillared montmorillonite produced using 3-aminopropyltrimethoxy silane and an alumina-pillared montmorillonite were evaluated for the removal of ¹³⁷Cs and ⁸⁹Sr from a simulated nuclear waste solution and a simulated groundwater, and the results were compared to the parent montmorillonite and two zeolites, AW500 (chabazite) and clinoptilolite. The parent and pillared clays were characterized using x-ray powder diffraction and surface area analysis by nitrogen adsorption/desorption studies. The pillared clays exhibited d-spacings of between 173 and 182 A after calcination, and surface areas ranging from 71 to 264 m²g^-1. Both of the silica-pillared clays and the alumina-pillared clay exhibited excellent K_dsfor ¹³⁷Cs from simulated groundwater with values of 23,650, 23,260 and 144,570 mL/g, respectively. These were far better than the K_ds obtained by clinoptilolite and AW500 which had K_ds of only 14,560 and 9650 mL/g, respectively. None of the pillared clays showed a high selectivity for ⁸⁹Sr from groundwater or ^l37Cs from simulated alkaline tank waste. They did, however, show a slight selectivity for ⁸⁹Sr in the simulated Hanford tank wastes, but this is thought to be due to a precipitation mechanism rather than to ion exchange.     

Synthesis and exfoliation of bismaleimide–organoclay nanocomposites

Bismaleimide-clay nanocomposites were synthesized by swelling two kinds of organophilic clays (OCLs) in allyl-compound modified bismaleimide (BMI) resins and subsequent thermal curing and characterized by DSC, Wide-angle X-ray diffraction (WAXD), Field emission SEM, TEM and Rheometer. The results indicated that the synthesis of modified BMI-clay nanocomposites was determined by the factors including the preparation methodology, curing conditions, and nature of OCLs. Exfoliation of clay can be promoted by homogeniser and ultrasonication. Allyl-compound played a key role for the exfoliation of OCLs in modified BMI matrix as the pre-intercalation agent. It seems that the exfoliation should be carried out before gelation in order to obtain fully exfoliated structure in modified BMI matrix. The good combination of compatibility and acceleration effect on the intragallery polymerization are the favorable conditions to obtain exfoliated nanocomposites based on modified BMI matrix. The exfoliated structure favored the improvement in impact strength.     

环境危害物质的分类与评估

目前,环境危害物质还没有确切的定义,GHS将危害水生环境物质和危害臭氧层物质一同归类为环境危害物质。介绍了环境危害物质的分类,包括危害水生环境物质和危害臭氧层物质的分类,并对如何评估环境危害物质进行了阐述。     

有机物在介孔分子筛合成中的作用

随着对介孔分子筛研究的深入，有机物在合成中不仅作为模板剂，而且在作为模板剂萃取剂、表面修饰剂、溶剂等方面也发挥着越来越重要的作用。本文对有机物在介孔分子筛研究中诸方面的作用及其发展情况和应用前景进行了综述。     

Correction to: Synthesis and Characterization of MoO3 for Photocatalytic Applications

Journal of Inorganic and Organometallic Polymers and Materials - A correction to this paper has been published: https://doi.org/10.1007/s10904-021-02038-6     

Synthesis, Characterization and Catalytic Applications of Organized Mesoporous Aluminas

The synthesis of organized mesoporous aluminas has opened a very interesting area for application of this type of materials, particularly as catalysts or catalyst supports. This review focuses on the individual synthesis routes to produce organized mesoporous aluminas with large surface areas and narrow pore size distributions, and on the evaluation of their textural, chemical and thermal properties and outlines examples of catalytic applications of organized mesoporous alumina-based catalysts. We tried to rationalize the synthetic approaches to prepare organized mesoporous aluminas, to relate their properties to synthetic procedures used as well as to their catalytic behavior in different reactions. Utilization of various structure-directing agents for “cationic,” “neutral,” “anionic,” “nanocasting,” and special approaches leading to scaffolding and lathlike organized mesoporous aluminas is discussed in the first part of this review, as well as textural and structural characterization and thermal stability of mesoporous aluminas synthesized by different synthetic approaches. In the second part, catalytic applications of organized mesoporous aluminas described in the open literature are evaluated from the standpoint of the importance of these reactions for technological applications.     

Synthesis,Characterization and Catalytic Applications of Organized Mesoporous Aluminas

The synthesis of organized mesoporous aluminas has opened a very interesting area for application of this type of materials, particularly as catalysts or catalyst supports. This review focuses on the individual synthesis routes to produce organized mesoporous aluminas with large surface areas and narrow pore size distributions, and on the evaluation of their textural, chemical and thermal properties and outlines examples of catalytic applications of organized mesoporous alumina‐based catalysts. We tried to rationalize the synthetic approaches to prepare organized mesoporous aluminas, to relate their properties to synthetic procedures used as well as to their catalytic behavior in different reactions. Utilization of various structure‐directing agents for “cationic,” “neutral,” “anionic,” “nanocasting,” and special approaches leading to scaffolding and lathlike organized mesoporous aluminas is discussed in the first part of this review, as well as textural and structural characterization and thermal stability of mesoporous aluminas synthesized by different synthetic approaches. In the second part, catalytic applications of organized mesoporous aluminas described in the open literature are evaluated from the standpoint of the importance of these reactions for technological applications.