钙基膨润土的酸化改性研究

研究了高温灼烧、酸种类，硫酸浓度，反应时间、温度和粒度等，对钙基土制备酸性膨润土的工艺条件的影响。     

不锈钢在湿法磷酸中腐蚀行为研究

本文采用腐蚀实验和电化学测试方法对不锈钢在湿法磷酸中的腐蚀行为进行了研究，并进行钝化膜的组成与结构分析。研究表明，磷酸中加入ＳＯ４＾２＾－，ｃＬ＾－，Ｆ＾－均提高合金的维钝电流密度和致纯电流浓度，加速材料的腐蚀，这些杂质共存时腐蚀性更大。湿法磷酸中存在的Ｓｉ＾４＾＋，Ａｌ＾３＾＋，Ｍｇ＾２＾＋和Ｆｅ＾３＾＋起缓蚀作用。不锈钢纯化膜主要由Ｃｒ和Ｆｅ的氧化物组成，表面形成致密稳定的Ｃｒ２Ｏ３保护膜是提     

Acid rain effects on the exterior durability of architectural coatings on wood

Acid rain is an important consequence of pollutants generated by modern industrial societies and is known to cause damage to ecological systems, construction materials and cultural artifacts. The assessment of the damage caused to paint films has included laboratory, exposure chamber, and exterior weathering experiments. This study uses visual assessment of paints applied directly to southern yellow pine and exposed at 30° south to either natural acid rain or deionized water spray sites in North Carolina and Ohio to determine damage by acid rain. An acrylic latex paint with a pigment volume concentration (PVC) of 52 and a volume solids (VS) of 35% was formulated with calcium carbonate or sodium potassium alumino-silicate extenders. This high PVC paint formulation is one known to stress the binding capacity of the latex and thus produce early grain cracking failures over bare wood. Major effects observed include severe yellowing and increased mildewing of the carbonate containing paints exposed to acid rain. While acid rain can damage exterior paints, much of the damage can be minimized by careful selection of the polymers and pigments used in the formulation.     

Effect of calcination temperature on the characteristics of SO<Emphasis Type="Italic">sk</Emphasis>4/2-/TiO<Subscript>2</Subscript> catalysts for the reduction of NO by NH<Subscript>3</Subscript>

The catalytic activity of sulfated titania (ST) calcined at a variety of temperatures has been investigated for selective catalytic reduction (SCR) of NO by NH₃. The NO removal activity of ST catalyst mainly depends on its sulfur content, indicating critical role of sulfur species on the surface of TiO₂. The role of sulfur is mainly the formation of acid sites on the catalyst surface. The presence of both BrØnsted and Lewis acid sites on the surface of sulfated titania has been identified by IR study with the adsorption of NH₃ and pyridine on ST. The reduction of the intensity of IR bands representing BrØsted acid sites is more pronounced than that revealing Lewis acid sites as the calcination temperature increases. It has been further clarified by IR study of ST500 catalyst evacuated at a variety of temperatures. The NO removal activity also decreases with the increase of the catalyst calcination temperature. It simply reveals that BrØnsted acid sites induced by sulfate on the catalyst surface are primarily responsible for the enhancement of catalytic activity of ST catalyst containing sulfur for NO reduction by NH₃.     

Interactions Between Ozone,Halogens and Organic Compounds

During drinking-water treatment, ozone used as a preoxidant and chlorine required for final disinfection, lead to competing chemical reactions, in the case of raw water containing both organic compounds and inorganic salts (such as bromides and ammonia).

The study of the interactions between those reactants has been made according to the following main topics :

As for THM formation, experiments conducted on simple organic compounds or on natural fulvic acids show important decreases in THM or TCAA formation after ozonation. It may be noticed, however, that the ozonation of surface waters may induce the formation of haloform precursors, usually with a low level of reactivity.

In water supplies containing bromide ions, oxidation of the latter through hypobromous acid may take place during the ozonation stage. Failing preozonation treatment, hypobromous acid is generated very rapidly during chlorination, thus inducing the formation of chloro- brominated organic compounds.

During the ozonation of fulvic acid solutions, the presence of small amounts of bicarbonate was found to improve precursor removal significantly.

It can be concluded that the partial analogy of the action of ozone or chlorine on aromatic structures, whether simple or complex (such as humic and fulvic acids), seems to indicate that the consequence of preozonation is the destruction, at least in part, of the most reactive sites for THM production, thus leading to a decrease of the volatile organochlorinated compounds formed during the post-chlorination. However, some ozonation products of natural waters are THM precursors, though of low reactivity. Then, in the presence of bromide ions, the formation of volatile organobrominated compounds may be observed during ozonation.     

Influence of Ozone on the Photocatalytic Oxidation of Organic Compounds

Heterogeneous photocatalytic oxidation processes using titanium oxide as a photocatalyst are widely discussed topics in research for water and waste water treatment. Oxygen fed into the systems is normally used as oxidizing agent. However few investigations exist concerning the use of ozone as an additional oxidant. In this work the influence of ozone on the photocatalytic degradation of organic compounds are described. The results are compared with those by using ozone, UV/O₃ and UV/TiO₂/O₂. The oxidation reactions were performed at pH 3 and 7.

In this research compounds of the different classes were used: glyoxal, pyrrole-2-carboxylic acid, p-toluenesulfonic acid and naphthalene-1,5-disulfonic acid. Depending on the classes of compounds in some cases the elimination rates of the initial compounds is enhanced by using UV/TiO₂/O₃ compared to UV/O₃ or O₃ alone. But in all cases greatest DOC elimination is achieved by using UV/TiO₂/O₃.     

Decolorization of organic dyes on Pilkington Activ™ photocatalytic glass

The air–solid photocatalytic degradation of organic dye films Acid Blue 9 (AB9) and Reactive Black 5 (RBk5) is studied on Pilkington Activ™ glass. The Activ™ glass comprises of a colorless TiO₂ layer deposited on clear glass. The Activ™ glass is characterized using atomic force microscopy (AFM) and X-ray diffraction (XRD). Using AFM, the TiO₂ average agglomerate particle size is 95 nm, with an apparent TiO₂ thickness of 12 nm. The XRD results indicate the anatase phase of TiO₂, with a calculated crystallite size of 18 nm.

Dyes AB9 and RBk5 are deposited in a liquid film and dried on the Activ™ glass to test for photodecolorization in air, using eight UVA blacklight-blue fluorescent lamps with an average UVA irradiance of 1.4 mW/cm². A novel horizontal coat method is used for dye deposition, minimizing the amount of solution used while forming a fairly uniform dye layer. About 35–75 monolayers of dye are placed on the Activ™ glass, with a covered area of 7–10 cm². Dye degradation is observed visually and via UV–vis spectroscopy.

The kinetics of photodecolorization satisfactorily fit a two-step series reaction model, indicating that the dye degrades to a single colored intermediate compound before reaching its final colorless product(s). Each reaction step follows a simple irreversible first-order reaction rate form. The average k₁ is 0.017 and 0.021 min⁻¹ for AB9 and RBk5, respectively, and the corresponding average k₂ is 2.0 × 10⁻³ and 1.5 × 10⁻³ min⁻¹. Variable light intensity experiments reveal a p = 0.44 ± 0.02 exponent dependency of initial decolorization rate on the UV irradiance. Solar experiments are conducted outdoors with an average temperature, water vapor density, and UVA irradiance of 30.8 °C, 6.4 g water/m³ dry air, and 1.5 mW/cm², respectively. For AB9, the average solar k₁ is 0.041 min⁻¹ and k₂ is 5.7 × 10⁻³ min⁻¹.     

Alkyd emulsions

Various aspects of alkyd emulsion technology have been investigated. The influence of alkyd oil length, acid value and hydroxyl number and type of surfactant used as emulsifier, on shear stability of alkyds emulsions have been studied. It was found that the acid value was the most important alkyd parameter, the stability increasing with increasing oil length. It is also shown that anionic surfactants give emulsions with small droplet sizes at lower concentrations than do nonionics. Polymerizable nonionic surfactants have been tested as emulsifiers and compared with conventional surfactants of the same hydrophilic lipophilic balance (HLB). It was found that surfactants capable of participating in the autoridative curing process give faster drying and improved film hardness compared with nonreactive surfactants. The distribution of driers between the alkyd phase and the water phase has been investigated. It was found that low pH and the use of hydrophilic anionic surfactants, such as sodium dodecyl sulphate, favour partitioning of cobalt into the aqueous phase which is unfavourable with respect to drying properties.     

高铁酸盐降解偶氮染料酸性橙Ⅱ的研究

为研究高铁酸盐对废水的处理效果,以试验的方式研究了高效净水剂高铁酸盐对偶氮染料酸性橙Ⅱ的脱色效果,考察了紫外光照射、高铁酸钠浓度、pH值、添加剂对脱色效果的影响.结果表明,在原水样浓度为50 mg/L,高铁酸盐含量10 mg/L,NaHCO3浓度0.01 mol/L,在中性条件下处理30 min,脱色率可以达到94%左右.紫外光照射能有效提高染料的脱色速率;相同条件下脱色率可达97%以上,表明紫外光和高铁酸盐联合使用对染料的降解速率大大提高,产生了明显的协同作用.     

建南气田水平井酸压工艺及效果分析

针对建南气田"低孔隙度、低渗透率、低压和非均质性强"的储层特征,采用水平井是高效开发的必要手段。经过综合分析12井次的水平井酸压效果,认为以胶凝酸为主的全程伴氮酸压工艺,适用于建南水平井的开发,达到了提高单井产能、提升开发效果的目的。