A new recycling system for expanded polystyrene using a natural solvent. Part 1. A new recycling technique

A new recycling technique has been developed which uses a natural solvent, d limonene, to shrink expanded polystyrene (EPS). d-Limonene is a natural vegetable oil which is extracted from the rinds of citrus fruits and is a good solvent of EPS. Limonene has almost the same solubility as toluene at room temperature. This technique reduces the volume of EPS to about 1/20th of the original. Contracted EPS is recyclable with almost no molecular weight degradation because d-limonene acts as an antioxidant of polystyrene during the heating process. © 1998 John Wiley & Sons, Ltd.     

EPDM／PA高性能弹性体的某些性能研究

研究了EPDM/PA共混物的流变性能，耐油性、耐化学溶剂性、吸水性及动态生热。结果表明，随PA用量增多，共混物的假塑性变得不明显，呈现出宾汉流体的行为；共混物的表观粘度随剪切速率的增加而降低，表现出假塑性；PA分散于基体EPDM中，大幅度提高了基体的耐油性；虽然PA难溶于二甲苯；但共混物中的PA易于被二甲苯刻蚀；尽管共混物含30份的PA，但仍具有优良的耐吸水性，与近似硬度的EPDM过氧化物硫化胶相比，共混物的生热有大幅度降低。     

济阳坳陷渤南洼陷页岩油气形成条件研究

通过大量地震、钻井、测井、矿物、地球化学、物性资料分析,认为济阳坳陷渤南洼陷古近系沙一段、沙三下和沙四上亚段页岩分布面积广,有机质丰度高,有机质类型以Ⅰ—Ⅱ型为主,有机质成熟度分布范围宽,具备形成大量页岩油气的物质基础,三套泥页岩全岩矿物组成中粘土矿物含量低,脆性矿物含量高,以碳酸盐含量为主,利于页岩油气的开采。页岩中压力系数高,各类微孔隙、微裂缝发育,从而容易形成网状的油气储存体系,利于页岩油气的保存。含油、水饱和度分析资料显示,渤南洼陷沙三下亚段12上—13上层组页岩中具有较高的单位岩石含油气量,是页岩油气勘探的有利层段,其中的纹层状泥质灰岩是最有利的岩石类型,具有较好的页岩油气勘探前景。     

天然生物质材料吸油性能研究

采用小麦秸秆、玉米秸秆、锯末、中药渣作为吸油材料,重点研究了吸附材料粒径、吸附时间以及不同油品对这4种天然生物质材料的吸油性能的影响。同时,研究对比了这4种材料的吸水性能和保油能力。在对原油进行吸附实验时,发现锯末和小麦秸秆在0.25～0.83mm粒径范围内具有较好的吸油性能,吸油量分别为5.79和6.02g/g,其次为玉米秸秆,0.15～0.18mm之间的材料吸油量最大能达到5.02g/g,而中药渣在0.18～0.20mm之间的吸油量仅为2.37g/g。比较4种材料对有机物甲苯及植物油的吸附性能发现,其对原油的吸附效果优于植物油和甲苯。材料均有一定的保油能力,而锯末的保油能力最高,其油水比>11。由于天然生物质材料属固体废物,其吸油后可直接作为燃料使用,可达到以废治废的目的,因此在含油污水处理领域具有较好的开发和应用前景。     

Optical switching behavior of azobenzene/PMMA blends with high chromophore concentration

In this article, the authors will present a simple way to produce thin solid organic films, with a content of more than 60 wt% photoactive molecules dispersed in a polymeric matrix showing an almost complete and fully reversible photoisomerization. These high filling factors could be achieved by using branched side chains in the molecules, which prevent crystallization. The chromophores were codissolved with the polymer Polymethylmethacrylate (PMMA) of different M _w in toluene in various concentrations and spin casted onto the substrate. The effect of the M_w of PMMA on the switching kinetics and the agglomeration tendency of different molecule configurations were investigated.     

页岩灰与催化裂化催化剂细粉旋风分离性能的对比试验研究

试验测定和对比页岩灰和流化催化裂化三旋灰(FCC三旋灰)的旋风分离器性能,考察入口气速、入口浓度对分离效率和分离器压降的影响.结果表明,在相同操作条件下,同一台旋风分离器上,粒度小于75 μm的页岩灰与FCC三旋灰的分离效率和分离器压降曲线差别显著;页岩灰的分离效率与分离器压降都明显低于FCC三旋灰,且入口浓度增大,页岩灰分离器压降的下降幅度高于FCC三旋灰;页岩灰分离效率最高的入口气流速度也低于FCC三旋灰.颗粒特性对旋风分离器的分离性能有明显影响,页岩灰和三旋灰的颗粒特性与形状差别是导致其旋风分离特性不同的一个基本原因;油页岩旋风分离器的设计应当考虑油页岩颗粒特性的影响.     

不同分解方法对聚乙烯分解行为的影响

综述了有关聚乙烯(PE)热分解和超临界水分解的研究情况，对PE的两种分解过程进行了对比。考察了分解产物的分子量、油转化率、催化剂的作用、反应机理等内容。对比结果表明，超临界水分解时不使用催化剂、反应温和、具有较高的油转化率，同时，产物分子量分布宽，组成复杂。超临界水分解对于热分解过程中产生的炭化现象有很好的抑制作用，因而具有广阔的工业应用前景。     

Systematic bias in the measurement of water in oils by tubular oven evaporation and azeotropic distillation.

Water in oil has been measured by tubular oven evaporation and by azeotropic distillation into a coulometric moisture analyzer. The results of these measurements were compared to the results obtained by volumetric titration of water in oil. The volumetric measurements were consistently higher than the measurements made by tubular oven evaporation or azeotropic distillation. A mass balance study was performed by volumetric Karl Fischer titration of the water in the oil that remained in the tubular oven and in the distillation apparatus. This study indicated that measurable amounts of water were not removed after exhaustive evaporation or distillation. The sum of the water removed by distillation from toluene and that remaining in the distillation chamber was equal to the amount of water measured in the oil by the volumetric method. The data are consistent with the existence of an oil-water azeotrope that does not release water upon evaporation at 160 degrees C or upon dissolution in toluene and distillation of the water-toluene azeotrope. These results were obtained for oils varying in viscosity from 8 to 850 m2/s, and the amount of water remaining associated with the oil appears to be dependent upon the composition of the oil and the method of analysis.     

Preparation and characterization of silica aerogels from oil shale ash

The silica aerogels were successfully synthesized using oil shale ash which is a by-product of oil shale processing via ambient pressure drying. The physical and textural properties of the silica aerogels have been investigated and discussed. The results showed that the organic modification of hydrogels was a crucial step during the processing which preserved mesopores in ambient pressure drying. The unmodified hydrogel underwent tremendous shrinkage during the drying and yielded microporous silica aerogel. Using this novel route, it could produce silica aerogel with low tapping density of 0.074 g/cm³, high specific surface (909 m²/g) and cumulative pore volume of 2.54 cm³/g. From the industrial point of view, the present process is quite suitable for a large scale production of powdered silica aerogel. Furthermore, it provides a new way to solve the problem of oil shale ash pollution.     

Microcapsules for Enhanced Cargo Retention and Diversity

Prevention of undesired leakage of encapsulated materials prior to triggered release presents a technological challenge for the practical application of microcapsule technologies in agriculture, drug delivery, and cosmetics. A microfluidic approach is reported to fabricate perfluoropolyether (PFPE)‐based microcapsules with a high core‐shell ratio that show enhanced retention of encapsulated actives. For the PFPE capsules, less than 2% leakage of encapsulated model compounds, including Allura Red and CaCl₂, over a four week trial period is observed. In addition, PFPE capsules allow cargo diversity by the fabrication of capsules with either a water‐in‐oil emulsion or an organic solvent as core. Capsules with a toluene‐based core begin a sustained release of hydrophobic model encapsulants immediately upon immersion in an organic continuous phase. The major contribution on the release kinetics stems from the toluene in the core. Furthermore, degradable silica particles are incorporated to confer porosity and functionality to the otherwise chemically inert PFPE‐based polymer shell. These results demonstrate the capability of PFPE capsules with large core–shell ratios to retain diverse sets of cargo for extended periods and make them valuable for controlled release applications that require a low residual footprint of the shell material.     

超疏水石墨烯/甲醛-三聚氰胺-亚硫酸氢钠共聚物海绵的制备及其在油水分离中的应用

采用两步法合成了石墨烯（GE）改性的超疏水超亲油甲醛-三聚氰胺-亚硫酸氢钠（FMS）共聚物海绵,首先在FMS海绵基质上进行GE原位聚合,然后通过聚甲基苯基硅氧烷构筑超疏水结构。采用FTIR、SEM、TGA、光学接触角测量仪对海绵结构进行表征分析。结果表明,GE成功地修饰了FMS海绵,制备出的GE/FMS共聚物海绵的接触角达158.9°。将GE/FMS共聚物海绵用于油水分离,经20次对机油吸附-解吸附测定后仍能保持稳定的超疏水性质。改性后的GE/FMS海绵具有良好的可重复利用性且对油和有机溶剂具有高度选择吸收性,对氯仿和机油的吸收量分别达到自身质量的约125倍和90倍,对油或有机溶剂的回收率达到87%以上。进一步对油或有机溶剂与水的分离进行了应用模拟,结果表明:改性后的GE/FMS海绵可以高效快速地将油或有机溶剂从水中分离出来,对于投入生产及吸附应用具有实际意义。      

Recovery of nitrotoluenes from wastewater by solvent extraction enhanced with salting-out effect

Toluene extraction enhanced by salting-out effect was employed to recover dinitrotoluene isomers and 2,4,6-trinitrotoluene (2,4,6-TNT) from wastewater of toluene nitration processes (e.g. dinitration or trinitration). The batchwise experiments were conducted to elucidate the influence of various operating variables on the extracting performance, including concentrations and species of inorganic salts, such as NaCl, KCl, Na(2)SO(4), K(2)SO(4) and MgSO4, acidity of wastewater, volume ratios of solvent versus wastewater and extraction stages in existence of inorganic salts. It was found that recovery of total organic compounds (TOC) was significantly elevated with increasing concentrations of salts, whose promoting effects were in the following order: NaCl>Na(2)SO(4)>K(2)SO(4)>MgSO4>KCl on the weight basis of wastewater. Besides, high volume ratio of toluene/wastewater (ca. 2.0) was more suitable for recovery of TOC from wastewater with or without addition of NaCl, of which extractable priority was as follows: 2,6-DNT>2,4-DNT>2,4,6-TNT. It is remarkable that TOC in wastewater would be almost completely recovered by sequential four stages toluene extraction, promoted continuously by salting-out effect.     

Synthesis of mono-dispersed nano-scale fullerene (C60) crystals

Fullerene (C60), which has a unique molecular structure, was used in the preparation of crystalline organic nano-crystals. Fullerene was dissolved in toluene and this fullerene solution was mixed with water drastically. During this process, fullerene transferred from toluene to water phase. The significantly different solubility of fullerene in a toluene/water solvent system played an important role in the self-assembly of single fullerene nano-crystals, as it is called drowning-out crystallization. In addition, pH of water was controlled to carry out the interfacial transference of fullerene. An optical spectrum analysis showed that the fullerene was transferred by a hydrolysis reaction from toluene to water, depending on the pH and toluene involved in the crystal structure. During the interfacial transference, the growth of nano-scale fullerene occurred at pH > 7. Importantly, fullerene nanocrystals were formed with a mono-dispersed square structure on a nano-scale (104 nm average size and 1.03 +/- 0.24 aspect ratio) at pH 10.     

Influence of the experimental conditions on porosity and structure of adsorbents elaborated from Moroccan oil shale of Timahdit by chemical activation

This study records experiments undertaken to determine the suitable conditions for the use of the oil shale of Timahdit, as an adsorbent for water treatment. A simple process was proposed based on chemical activation. The preparation has been carried out by carbonization after impregnation of the precursor with phosphoric acid. The effect of different conditions of preparation on the specific surface area is discussed. These parameters are H3PO4/shale weight ratio, carbonization temperature, carbonization time and concentration of H3PO4. The properties and surface structure of the adsorbent were investigated by XPS and FT-IR. Their total surface acidity and basicity were also determined. The retention process of methylene blue (MB) by adsorbents has been studied. It was found that MHP2 and MHP7 have relatively high retention ability as compared to activated carbons.     

Determination of the analytical performance of a headspace capillary gas chromatographic technique and karl Fischer coulometric titration by system calibration using oil samples containing known amounts of moisture

Over the past few years, concerns have been raised in the literature about the accuracy of the Karl Fischer (KF) method for assessing moisture in transformer mineral oils. To better understand this issue, the performance of a static headspace capillary gas chromatographic (HS-CGC) technique was compared to that of KF coulometric titration by analyzing moisture in samples containing known amounts of water and various samples obtained from the National Institute of Standards and Technology (NIST). Two modes of adding samples into the KF vessel were used: direct injection and indirect injection via an azeotropic distillation of the moisture with toluene. Under the conditions used for direct injection, the oil matrix was totally dissolved in the anolyte, which allowed the moisture to be titrated in a single-phase solution rather than in a suspension. The results have shown that when HS-CGC and combined azeotropic distillation/KF titration are calibrated with moisture-in-oil standards, a linear relation is observed over 0-60 ppm H(2)O with a correlation coefficient better than 0.9994 (95% confidence), with the regression line crossing through zero. A similar relation can also be observed when calibration is achieved by direct KF addition of standards prepared with octanol-1, but in this case an intercept of 4-5 ppm is noted. The amount of moisture determined by curve interpolation in NIST reference materials by the three calibrated systems ranges from 13.0 to 14.8 ppm for RM 8506 and 42.5 to 46.4 ppm for RM 8507, and in any case, the results were as high as those reported in the literature with volumetric KF titration. However, titration of various dehydrated oil and solvent samples showed that direct KF titration is affected by a small bias when samples contain very little moisture. The source of error after correction for the large sample volume used for the determination (8 mL) is about 6 ppm for Voltesso naphthenic oil and 4 ppm for toluene, revealing a matrix effect on the measurement. Finally, the results revealed that HS-CGC is a good technique for measuring moisture in oil samples and that the use of azeotropic vapors for introducing moisture into the titrator almost completely eliminates the matrix effect observed with the oil components. Direct KF injection could also be used provided the system is calibrated with moisture-in-oil standards prepared in the same matrix which is to be used for the determination.     

Application of microwave-assisted extraction to the analysis of PCBs and CBzs in fly ash from municipal solid waste incinerators

Polychlorinated biphenyls (PCBs) and chlorobenzenes (CBzs) are two classes of dioxin precursors formed in municipal solid waste incinerators (MSWIs) producing negative health effects similar to those of dioxins. Reducing the analytical time required for determining the concentrations of these compounds in MSWIs is important for quickly evaluating their importance and associated health risks. In the present study, microwave-assisted extraction (MAE) is compared with traditional Soxhlet extraction (SE) to determine the extraction efficiencies attained for PCB and CBz analysis. The efficiencies of MAE are compared with those of SE under various experimental conditions, using fly ash spiked with standards. Water is used as a safe and environmentally friendly solvent in MAE for PCB and CBz analyses and MAE has high extraction efficiency for spiked fly ash compared with that of SE. Furthermore, the extraction time and organic solvent consumption are reduced with MAE compared with SE. The optimum conditions for MAE established in this study are using a 30-ml volume of toluene/acetone (1/1) or a 15-ml volume of toluene, samples with less than 60% water content (WC), and an irradiation time of 15 min.     

Utilization of oil shale in the production of Portland clinker

Oil shale can potentially be utilized in manufacturing the Portland cement. In addition to the utilization of the spent oil shale after combustion, it can also reduce the required temperature for the clinkering reactions during the production of Portland clinker. A study on the Jordanian oil shale was performed to maximize the use of oil shale ash in the manufacturing of Portland cement. It was found that Jordanian oil shale can be used up 15% with the typical raw materials to produce Portland clinker without altering its principle properties. The corresponding temperature required to generate the required liquid for the clinkering reactions as well as the essential ingredients for clinker was found to be around 1300 °C. The optimized blend ratio obtained was equal to of 16% oil shale ash, 18% kaolinite, and 66% calcite. The operating temperatures for this optimized blend ratio were found to be between 1300 and 1350 °C. The resulting Portland clinker from this ratio will need further testing in accordance with international standards for Portland cement to examine properties like strength, setting time, etc.     

Time-resolved total internal reflection fluorometry study on polarity at a liquid/liquid interface

The polarity of a water/oil (oil: cyclohexane, carbon tetrachloride, toluene, chlorobenzene, o-dichlorobenzene, or 1,2-dichloroethane) interface was investigated by means of time-resolved total-internal-reflection (TIR) fluorescence spectroscopy of a polarity-sensitive probe: sulforhodamine B (SRB). In bulk solutions, the nonradiative decay rate constant of SRB increased with an increase in a solvent polarity parameter [ET(30)], and this relationship was used to estimate the polarities of water/oil interfaces. For the oil having a relatively low solvent polarity [ET(30) < 35 kcal/mol], the polarity of the water/ oil interface agreed with that of the arithmetic average of the polarities of the two phases [ET(30)calc]. For water/odichlorobenzene and water/1,2-dichloroethane interfaces [ET(30) of the oil > 35 kcal/mol], on the other hand, the interfacial polarity determined by TIR spectroscopy was lower than the ET(30)calc. The results are discussed in terms of thickness/roughness of the water/oil interface.     

In Vitro Dissolution Profile of Theophvlline Lorded Ethvl Cellulose Microspheres Preprred by Emulsificrtion Soluent Eurporrtion

Abstract

Theophylline was entrapped in ethyl cellulose microspheres by a water/oil/water emulsification-solvent evaporation method. Aqueous solution of drug was emulsified into a solution of ethyl cellulose in toluene, containing polyisobutylene as protective colloid, followed by emulsification of this primary emulsion into an external aqueous phase to form a water/oil/water emulsion. Microspheres was formed after solvent evaporation and precipitation of ethyl cellulose. In vitro dissolution profile and effect of polyisobutylene on it were studied.     

A Supercritical Fluid Chromatograph for Physicochemical Studies

A supercritical fluid chromatograph has been designed and constructed to make physicochemical measurements, while retaining the capability to perform chemical analysis. The physicochemical measurements include diffusion coefficients, capacity ratios, partition coefficients, partial molar volumes, virial coefficients, solubilities, and molecular weight distributions of polymers. In this paper, the apparatus will be described in detail, with particular attention given to its unique features and capabilities. The instrument has recently been applied to the measurement of diffusion coefficients of toluene in supercritical carbon dioxide at a temperature of 313 K, and pressures from 133 to 304 bar (13.3–30.4 MPa). The data are discussed and compared with previous measurements on similar systems.