共查询到20条相似文献,搜索用时 78 毫秒
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茶梗木质纤维素对儿茶素类吸附动力学研究 总被引:4,自引:1,他引:3
以茶梗为原料制备木质纤维素,通过静态吸附,研究茶梗木质纤维素在绿茶提取物溶液中对儿茶素类的吸附动力学。结果表明,茶梗木质纤维素对儿茶素类总量的吸附等温线符合Freundlich经验方程,随着温度的升高,茶梗木质素纤维素对儿茶素类的平衡吸附量降低;动力学研究数据用拟一级速率方程和拟二级速率方程模拟,其中拟二级速率方程拟合程度更高,在不同温度下利用拟二级速率方程计算的总儿茶素类饱和吸附量与实测值吻合。随着温度的升高,速率常数k1和k2提高,而总儿茶素类的初始吸附速率降低。 相似文献
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通过静态吸附、静态解吸及吸附动力学研究,对比分析了ADS-7、ADS-17、聚酰胺树脂、超高交联树脂和酚醛型树脂等5种大孔吸附树脂对橡胶乳清中白坚木皮醇的分离效果,同时探讨了ADS-17树脂在25℃下的等温吸附过程,并用Langmuir吸附等温线模型和Freundlich模型分别对吸附数据进行拟合。结果表明:5种树脂中,中极性的大孔吸附树脂ADS-17对白坚木皮醇的吸附效果最佳,吸附平衡时间约4 h,吸附量可达5.8 mg/g干树脂;且白坚木皮醇在ADS-17树脂上的吸附符合Langmuir吸附等温线模型,为单分子层吸附。 相似文献
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为了解钠基蒙脱石(sodium montmorillonite, Na-MMT)在油脂脱胶过程中的吸附行为以及吸附机理,采用钠化方法将钙基蒙脱石制备成Na-MMT,并对其进行X射线衍射和热重分析;利用Na-MMT对菜籽油中的磷脂(phospholipids, PL)进行吸附,探讨PL在Na-MMT上的静态吸附平衡、吸附动力学和吸附热力学。结果表明,Na-MMT对PL的最大理论吸附量为833.3mg/g;Na-MMT对PL的吸附是属于优惠吸附,吸热且自发进行。Freundlich吸附模型能够较好地拟合其静态吸附行为;同时拟二级吸附动力学模型适用于描述Na-MMT吸附PL的动力学特性。
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茶园土壤对氟的吸附与解吸特性 总被引:11,自引:1,他引:10
研究了我国主要砖茶产区湖南省和湖北省茶园土壤对氟的吸附与解吸特性。茶园土壤氟的吸附可由Freundlich方程描述 ,Langmuir方程只在低浓度 (初始氟浓度 0 5 - 2 0mmol/L)时适用 ,且拟合程度不如Freundlich方程 ,Temkin方程不能描述茶园土壤对氟的吸附特征。氟的解吸率随加入氟浓度而变化 ,在高浓度下吸附的氟更易被解吸。解吸率与Freundlich吸附方程的k值成显著或极显著负相关 ,与Langmuir方程参数的相关系数因加入氟浓度而变化 ,低浓度时 ,氟的解吸率与结合 相似文献
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利用大孔树脂从大豆糖蜜中回收大豆异黄酮 总被引:1,自引:0,他引:1
以大豆糖蜜为原料,以Ca(OH)2为絮凝剂去除大豆蛋白质,利用大孔树脂分离大豆异黄酮.测定了大豆异黄酮在ADS-7型树脂上的吸附饱和曲线,并研究了大豆异黄酮的洗脱条件.结果表明,用浓度为70%的乙醇洗脱大豆异黄酮,得到产品的纯度最高为63.51%,收率为93.40%. 相似文献
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蔗渣基生物质炭的制备、表征及吸附性能 总被引:6,自引:0,他引:6
以甘蔗渣为前驱物,采用持续升温限氧法在350、450、550℃温度下制备生物质炭(分别标记为BC350、BC450、BC550),并对其结构和组成进行表征。结果表明,3种生物质炭的产率分别为25.27%、22.28%、18.20%,pH值分别为5.97、6.45、7.96,比表面积为110.52、160.36、298.40 m2/g,阳离子交换量为:42.87、52.69、108.53 cmol/kg。此外,通过对生物质炭进行元素分析,生物质炭中含量最高的是碳元素,通过Boehm滴定测定,生物质炭表面含氧官能团含量随着制备温度的升高而逐渐减少。在3种温度下制备的3种生物质炭对诺氟沙星具有较好的吸附性能,其log(Kf)值大小顺序为:BC550(13.74)BC450(11.47)BC350(4.52)。可用作去除水和土壤中诺氟沙星的吸附功能材料。 相似文献
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大豆糖蜜上清液中除大豆低聚糖(蔗糖、棉子糖和水苏糖)外,还含有色素、无机盐、含氮组分和有机酸等杂质。本文主要研究了离子交换树脂纯化脱色糖蜜上清液过程中去除杂质的机理并优化了纯化工艺。结果显示:脱色上清液中主要的含氮组分有5种游离氨基酸(天冬氨酸、谷氨酸、天冬酰胺、丙氨酸、酪氨酸)和1种二肽(谷氨酸-酪氨酸)。用离子交换树脂直接处理脱色上清液的效率很低,含氮组分在3倍柱体积处理量时穿透;而离子交换树脂对纯含氮组分的吸附能力很强,处理量约为40倍柱体积。因此,无机盐(Na~+、K~+和Cl~-)和有机酸(柠檬酸)成为了树脂吸附含氮组分的制约因素。用电渗析法脱除无机盐后,阳离子交换树脂对含氮组分的吸附效果显著改善,处理量升高到35倍柱体积;继续用阴离子交换树脂吸附阳离子树脂流出液中的有机酸,即可获得高纯度的大豆低聚糖。同时通过拟合Thomas方程,分别计算了阳离子交换树脂吸附含氮组分和阴离子交换树脂吸附柠檬酸的最大固相吸附浓度。 相似文献
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Sabrine AlilaFadhel Aloulou Wim ThielemansSami Boufi 《Industrial Crops and Products》2011,33(2):350-357
Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 μmol g−1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles. 相似文献
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Spent grain, the major by-product of the brewing industry, was magnetically modified by contact with water-based magnetic fluid. The prepared material has been used as a new inexpensive magnetic adsorbent for the removal of water-soluble dyes. The dye adsorption could be described both with the Langmuir and Freundlich isotherms. The maximum adsorption capacities reached the value up to 72.4 mg of dye (Bismarck brown Y) per g of dried magnetically modified spent grain. 相似文献
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Macroporous PVA/HAp composite cryogel was studied for cadmium removal in a fixed-bed column. The cryogel was made through
a freeze-thawing process. The morphology of the cryogel was measured. The adsorption performance of the cryogel in the column
was examined by varying bed height and HAp amount in PVA cryogel. The maximum adsorption capacity and exhaustion time were
determined from the breakthrough curves. The experimental data was described using Adams-Bohart model. Bed height did not
exert a large influence on the maximum adsorption capacity and exhaustion time. The kinetic rate constant and the adsorption
capacity of the bed were found to be affected by HAp amount. 相似文献