EMD与KOH溶液的相互影响

利用滴定分析、热失重分析以及XRD方法研究了EMD和KOH溶液混合后的变化。结果表明:碱与MnO2可以相互作用并导致体系温度的升高,碱浓度的下降,EMD中形成Mn3O4以及MnO2中结合水的损失。相互作用的结果与所加KOH溶液的浓度、EMD中的水含量、二者用量的比例关系以及体系的温度有关。     

Development of correlation between potassium hydroxide number and conductivity of concentrated natural rubber latex

Increase in the ion concentration in the medium was found to increase conductivity and potassium hydroxide number (KOH No) in natural rubber latex (NRL). Addition of long chain fatty acids can increase the ion concentration in the medium and stability of NRL. A series of concentrated natural rubber latex samples from three different areas with different soils and climatic conditions were tested for the parameters such as KOH No and conductivity. They have been measured over a period of 62 days, upon addition of soap to natural rubber latex concentrate. The result showed that there was a strong positive linear correlation between conductivity and KOH No. The regression equation to express the relationship between the variables has also been found. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

金属离子对车载制氢机制氢效率的影响

针对向车载制氢机加水带入的金属离子导致制氢效率偏低的问题,在制氢测试系统实验台上研究加入含不同Zn2+、Fe3+和Cu2+质量浓度的溶液对制氢效率的影响.在电解电流为30 A,初始温度为19.7℃,压力恒为0.1 MPa条件下,电解2 L质量分数为30%的KOH溶液与其对应加入50 mL含不同金属离子质量浓度溶液做比较.试验结果表明：随着电解的进行,加入溶液所含的金属离子质量浓度越高,KOH溶液的电解电压越高,制氢速率越低,制氢效率越低.     

大豆油脂肪酸甲酯化条件的研究

氢氧化钾-甲醇甲酯化是用气相色谱法测定植物油脂肪酸组成的常用衍生方法,通过采用单因素试验及正交试验,以大豆油中亚油酸为主要考核目标,同时观察其他主要脂肪酸含量变化,研究氢氧化钾-甲醇法甲酯化的优化条件。     

The effect of isopropyl alcohol concentration on the etching process of Si-substrates in KOH solutions

In this paper the process of silicon anisotropic etching in KOH solutions containing isopropyl alcohol in a wide concentration range is extensively studied. Though the alcohol does not take part in the etching process itself, it strongly affects the etching results. Both etch rates and the roughness of etched surfaces depend on the alcohol concentration in the etching solution, which is connected with the adsorption phenomena on the etched surface. The surface coverage with alcohol depends on the level of saturation of the etching solution and crystallographic orientation of an etched surface. It was observed that the best morphology of (1 1 0) surface was achieved just below saturation level with IPA whereas the (1 0 0) surfaces were improving above the saturation. A model, which explains these phenomena, was proposed. Based on this model, a simple way of selection of the composition of KOH solutions with alcohol additives, assuring optimization of etching results was suggested. The method is restricted to surface tension measurements and allows one to avoid elaborated etching experiments.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Preparation of activated carbon with low ash content and high specific surface area from coal in the presence of KOH

An activated carbon with ash content less than ]0% and specific surface area more than 1600 m^2/g was prepared from cool and the effect of K-containing compounds in preparation of cool-based activated carbon was investigated in detail in this paper. KOH was used in co-carbonization with coal, changes in graphitic crystallites in chars derived from carbonization of coal with and without KOH were analyzed by X-ray diffraction (XRD) technique, activation rates of chars with different contents of K-containing compounds were deduced, and resulting activated carbons were characterized by nitrogen adsorption isotherms at 77 K and iodine numbers. The results showed that the addition of KOH to the coal before carbonization can realize the intensive removal of inorganic matters from chars under mild conditions, especially the efficient removal of dispersive quartz, an extremely difficult separated mineral component in other processes else. Apart from this, KOH demonstrates a favorable effect in control over cool carbonization with the goal to form nongraphitizable isotropic carbon precursor, which is a necessary prerequisite for the formation and development of micro pores. However, the K-containing compounds such as K2CO3 and K20 remaining in chars after carbonization catalyze the reaction between carbon and steam in activation, which leads to the formation of macro pores. In the end an innovative method, in which KOH is added to coal before carbonization and K-containing compounds are removed by acid washing after carbonization, was proposed for the synthesis of quality coal-based activated carbon.     

KOH／SBA-15负载型固体碱催化剂的合成、表征及催化性能

采用后合成法制备出固体碱催化剂KOH／SBA-15,利用X射线衍射法（XRD）、N2吸附-脱附（BET）、透射电镜（TEM）、化学吸附剂表面碱性测定（COz—TPD）等对其进行表征。考察了其在大豆油酯交换反应制备生物柴油中的催化性能。结果表明,在相同反应条件下,与CaO／SBA-15和MgO／SBA-15相比,KOH／SBA-15在催化活性和孔扩散上都具有较大的优越性,催化制备生物柴油产率最高（83．56％）。     

氢氧化钾活化石油焦制备高比表面积活性炭

研究了以石油焦为原料,用氢氧化钾为活化剂制备高比表面积活性炭方法。通过正交实验与进一步的单因素实验考察了碱焦比、活化温度和活化时间对活性炭碘吸附值和活化收率的影响。实验结果表明碱焦比对活性炭碘吸附值影响最显著,增大碱焦比、延长活化时间和选择合适的活化温度能提高碘吸附能力。在碱焦比为4∶1,活化温度750℃和活化时间120 min条件下制备的活性炭BET比表面积可达2775 m2/g,总孔容为2.888 cm3/g。     

KOH/SBA-15催化大豆油酯交换反应制备生物柴油

通过后合成法制备了KOH/SBA-15负载型固体碱催化剂,以大豆油和甲醇为原料,进行酯交换反应合成生物柴油。考察醇油比、反应温度、反应时间、活性组分负载量和催化剂用量等因素对生物柴油收率的影响。结果表明,当醇油摩尔比为16：1、反应温度为60 ℃、反应时间为8 h、活性组分KOH负载量（w）为15 %、催化剂用量为原料油质量的5％条件下,生物柴油收率为85.32 %。