氧化钙和氟化钾负载高岭土固体碱催化制备新型生物柴油

以高岭土为载体,利用浸渍法制备了氧化钙和氟化钾负载高岭土固体碱(GCK);利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、红外光谱(FT-IR)和哈密特指示剂法等技术手段对催化剂进行表征;考察了KF负载量和反应条件对月桂酸甲酯(ML)与乙二醇单甲醚(EGME)酯交换反应制备新型生物柴油产率的影响。 结果表明,GCK碱强度(H_)在7.2~18.4之间,KCaF₃为主要活性组分,当氟化钾负载量为25%、EGME与ML摩尔比3.0、催化剂用量相对于ML的质量分数为4.5 %、120 ℃下反应2 h,新型生物柴油的收率高达97.1%。 最后对催化剂的重复利用性能进行了考察。     

Surface modification of highly dispersed rubber fillers and pigments by titanate proadhesive and hydrophobic compounds

A method of modifying silicate and carbonate fillers with titanate coupling agents and proadhesive agents was worked out. The modification aimed at hydrophobization of filler surface by introduction to the surface of functional groups with chemical affinity to polymers. Optimum amounts of modifying substances and appropriate conditions for performing the modification process were established. The obtained fillers showed a high degree of hydrophobicity.The modified fillers were applied in rubber mixtures based on butadienestyrene or natural rubber, in polyurethanes, in PVC, and as pigments in oil dyes of high corossive resistance.     

The zeta potential of kaolin suspensions measured by electrophoresis and electroacoustics

The zeta potentials of kaolin dilute and concentrated suspensions were monitored using the techniques of electrophoresis and electroacoustics, respectively. The effect of addition of salt (KCl), a polymer material (Triton X-100), and an anionic surfactant (sodium dodecyl sulphate, SDS) on the suspension properties was investigated by electrophoresis. Electroacoustics was employed for the measurement of zeta potentials for the highest possible kaolin content in suspension and the effect of dilution. The effect of aging of a freshly prepared sample and kaolin isoelectric point was also studied. Using both techniques it was noted that there was no isoelectric point, just a maximum value in the magnitude of the kaolin suspension zeta potential. These maxima were observed also in the presence of Triton X-100 and SDS. An increase of the concentration of KCl and SDS in suspension shifted the maxima towards more acidic values, while in the presence of Triton X-100 the position of the zeta potential maxima remained constant. Electroacoustic techniques revealed that a freshly prepared concentrated suspension requires about six hours to equilibrate to achieve a steady zeta potential. Diluting the concentrated suspensions led to decrease of the zeta potential as ions bound to the surface desorbed and screened the surface charge. The zeta potential maxima remained unchanged even after heating the powder in an oven at 200°C (to remove any organic material) thereby suggesting that the most likely explanation for the maxima is isomorphic substitution.     

Influence of catalyst binder on the acidity and activity/selectivity of Ga/H-ZSM-5 zeolite in propane aromatization

The acidity and initial and time-on-stream activity in propane aromatization (at 550°C, space velocity of 3100 cm³g⁻¹ _(zeolite)h⁻¹) of Ga-impregnated H-ZSM-5 zeolite without or with binders (50 wt%), such as silica, alumina and kaolin, have been investigated. Both the acidity and catalytic activity of the zeolite are influenced by the presence of binder in the catalyst, depending upon the binder. The influence is found to be lowest for alumina and highest for kaolin. Among the binders, alumina is the most preferred binder for the zeolite catalyst.     

Removal of Malachite Green Dye from Aqueous Solution by Catalytic Wet Oxidation Technique Using Ni/Kaolin as Catalyst

In this study, natural Algerian kaolin was used as a support and impregnated with nickel at different loading amounts (2 wt.%, 5 wt.%, and 7 wt.%) in order to prepare a supported catalyst. The wet impregnation technique was used in this preparation; nickel oxide (NiO) was the active phase precursor of the catalyst, and the catalysts were designated as follows: 2%, 5%, and 7% Ni/kaolin. These catalysts were put to the test in catalytic wet peroxide oxidation (CWPO) for degrading the organic contaminant malachite green dye (MG). Analytical techniques such as FTIR spectroscopy, X-ray diffraction, BET, and X-fluorescence were used to examine the structure, morphology, and chemical composition of the support and the produced catalysts. Several parameters, including temperature, catalytic dose, metal loading, hydrogen peroxide volume, and kinetic model were systematically investigated. The combination of improved parameters resulted in a significant increase in the catalytic activity, achieving a high removal rate of MG dye of 98.87%.     

Removal of Lead by Merlinoite Prepared from Sugarcane Bagasse Ash and Kaolin: Synthesis,Isotherm, Kinetic,and Thermodynamic Studies

This study introduces a merlinoite synthesized from sugarcane bagasse ash (SBA) and kaolin and evaluates its application as an adsorbent to remove lead from wastewater. The synthesis was performed via the hydrothermal method, and optimal conditions were determined. The adsorption of Pb by merlinoite was also optimized. Determination of the Pb²⁺ remaining in the aqueous solution was determined by atomic absorption spectroscopy (AAS). Adsorption isotherms were mainly studied using the Langmuir and Freundlich models. The Langmuir model showed the highest consistency for Pb adsorption on merlinoite, yielding a high correlation coefficient (R²) of 0.9997 and a maximum adsorption capacity (q_max) of 322.58 mg/g. The kinetics of the adsorption process were best described by a pseudo-second-order model. Thermodynamic studies carried out at different temperatures established that the adsorption reaction was spontaneous and endothermic. The results of this study show that merlinoite synthesized from kaolinite and SBA is an excellent candidate for utilization as a high-performance adsorbent for lead removal from wastewater.     

合成A型分子筛的矿物原料中石英的转化与活化

合成Ａ型分子筛的矿物原料中石英的转化与活化赵经贵，张斌，刘景茂，张新，霍丽华，陈耐生（黑龙江大学化学系哈尔滨１５００８０）（福州大学化学系福州）关键词　石英，高岭土，转化，活化，分子筛由高岭土、煤矸石合成Ａ型分子筛［１～３］，其中所含石英杂质影响分子...     

Effect of sulfadiazine on biological model membranes

Summary In this paper the optimization of the kaolin calcination is studied, aiming at using the produced metakaolin as supplementary cementitious material. Representative samples of poor Greek kaolin (Milos island) and a high purity commercial kaolin were tested. Samples were heated at different temperatures during different times. The optimization of calcination conditions was studied by DTA-TG and XRD analysis of the raw and thermal treated kaolin samples, by pozzolanic activity analysis of metakaolins and finally by strength development analysis of cement-metakaolin mixtures. This approach showed that heating at 650°C for 3 h is efficient to convert poor kaolins with low alunite content to highly reactive metakaolins. However in the case of kaolin with a high alunite content, thermal treatment at 850°C for 3 h is required in order to remove undesirable SO₃. Evidence was found that poor kaolins can be efficiently used for the production of highly reactive metakaolins.     

In Situ Synthesis of NaY Zeolite with Coal—Based Kaolin

NaY zeolites were in-situ synthesized form coal-based kaolin via the hydrothermal method. The effects of various factors on the structure of the samples were extensively investigated.The samples were characterized by N2 adsorption,XRD,IR and DTG-DTA methods,and the results show that the crystallization temperature and amount of added water play an important role in the formation of the zeolite structure.The 4A and P zeolites are the competitive Phaes present in the resulting product.However,NaY zeolites wiht a higher relative crystallinity,excluding impure crystals and the well hydrothermal stapore size distribution,and this means that optimization of this process might result in a commercial route to synthesize NaY zeolites form coal-based kaolin.     

Effects of kaolin on the thermal stability and flame retardancy of polypropylene composite

Kaolin clay was introduced into an intumescent flame retardant (IFR) system containing ammonium polyphosphate as an acid source and pentaerythritol as a carbonization agent in order to improve the thermal stability and flame retardancy of polypropylene (PP) composite. The flame retardancy and smoke suppression was evaluated by the limiting oxygen index, vertical burning UL‐94, and cone calorimeter (CONE) tests. The limiting oxygen index value was increased from 30 to 33 at the presence of 2 phr kaolin. The peak heat release rate value decreased from 1002 kW/m² of neat PP to 318 kW/m² of PP/40 phr IFR and then to 222 kW/m² of PP/38 phr IFR/2 phr kaolin. The time of the peak heat release rate was significantly prolonged after the introduction of kaolin. The morphology of char after combustion was characterized by a scanning electron microscope, and it revealed more compact char structure that was obtained at the presence of kaolin. The mechanism of kaolin on improving the retardancy and smoke suppression of PP/IFR composite was proposed on the basis of X‐ray photoelectron spectroscopy analysis. Copyright © 2014 John Wiley & Sons, Ltd.