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膨润土对亚甲基蓝的吸附性能研究 总被引:13,自引:0,他引:13
为将膨润土作为消化道粘膜保护剂提供依据,本文研究了钠质,钙质膨润土对亚甲基蓝的吸附性能。研究了在20℃下的吸附动力学,测试了肿附速率常数,绘制了20℃下各型膨润土的吸附等温线,并求得其饱和吸附量。结果表明,20℃时钠质膨润土的吸附速率要快于钙质膨润,各型膨润土的吸附行为符合Langmuir方程,钠质膨润土的饱和吸附量qm为86.51mg/g,与粘膜保护剂思密达比较接近,而钙质膨润土吸附能力相对较弱。 相似文献
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Phenylsulfonic acid functionalized mesoporous silica was synthesized by condensation of tetraethylorthosilicate with phenyltrimethoxysilane, and then sulfonation using 30% fuming sulfuric acid. The material was characterized using FT‐IR, DSC, XPS, TEM and N2 adsorption/desorption measurements. DSC revealed that sulfonic acid group of the catalyst was decomposed at 354.8°C, indicating that the catalyst exhibited high thermal stability. XPS showed that there existed three kinds of different silicon species on surface of the catalyst. The catalytic performance of the catalyst was evaluated using transetherification of alcohols with dimethoxymethane. It was found that among primary alcohols, the selectivities of the two long‐chain alcohols for n‐dedocanol and n‐tetradecyl alcohol were higher than 97.0% at the conversions of 43.6% and 65.3%, respectively, while the selectivities of the short‐chain alcohols except for n‐hexanol were less than 90.0% at the conversions of over 80.0%. Due to steric barrier, the secondary alcohols such as iso‐butanol and cyclohexanol afforded conversions of 79.4% and 60.5%, and the selectivities of the two alcohols were more than 90.0%. The sequence in conversion of the substituted phenols is as follows: p‐nitrophenol>p‐fluorophenol≥p‐bromophenol>p‐cresol>m‐cresol. 相似文献
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为考察溶质浓度对三碳多元醇水溶液氢键作用以及不同物质玻璃态形成能力的影响,采用1H NMR外标法研究不同浓度的1-丙醇(NPA),2-丙醇(IPA),1,2-丙二醇(PG),1,3-丙二醇(PD)和丙三醇(glycerol)的水溶液在室温常压下质子化学位移.结果表明:具有CH3CH(OH)一基团的PG烷基质子的化学位移变化趋势与其他几种醇相比有较大差异.醇羟基质子与水分子的氧形成较强O-H…O氢键.相同摩尔分数下,羟基数的增加导致水质子和羟基质子的化学位移降低,而且羟基位置不同也会导致水质子和羟基质子化学位移差异.这几种三碳多元醇碱性强弱的顺序和降低冰的均相成核温度能力的顺序一致,即glycerol>PG>PD>IPA>NPA,1H NMR技术表明glycerol和PG更适合用作低温保护剂. 相似文献
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单电子还原电位是辐射保护和敏化中“电荷转移”的根本判据,采用时间分辨脉冲电子辐解瞬态吸收光谱装置,在pH=7.0的磷酸缓冲溶液中,以杜醌(-244mV)为参比,准确地测定了茶多酚类化合物表儿茶素没食子酸酯(ECG)、表没食子酸儿茶素(EGC)、表儿茶素(EC)的单电子还原电位值E7^1分别为-324、-320、-326mV;并通过与DNA碱基胸腺嘧啶的单电子还原电位(-1100mV)作比较,从热力 相似文献
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铑矿石是获取铑的重要来源,但矿石中的铑含量极低,且分布不均匀,准确测定其含量一直是分析测试中的难题。本研究建立了一种可高效富集矿石中铑元素的铅试金——石墨炉原子吸收光谱分析方法。采用金作保护剂,铅试金分离富集矿石中的铑,形成的金-铑合金用王水溶解,石墨炉原子吸收光谱法进行测定。实验结果表明:熔剂配比m(硼砂):m(纯碱):m(黄丹粉):m(淀粉)=5:5:10:1,加入15mg金做为保护剂,灰吹温度900℃,可完全富集50 μg铑。用石墨炉原子吸收光谱仪进行检测,方法的相对标准偏差RSD(n=11)为6.97%~11.23%,线性范围为0.17~50 μg?L-1,加标回收率为99.36%~100.94%,10倍于铑的其他共存贵金属对测定无干扰。方法准确、可靠、简便,可用于矿石样品中铑的日常分析。本研究对铑资源勘探开采及铑矿物的综合利用研究具有重要意义。 相似文献