共查询到19条相似文献,搜索用时 225 毫秒
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研究了超声微波法制备维生素M-β-环糊精包合物的最佳工艺条件,以维生素M-β-环糊精包合率为指标,通过单因素(超声功率、超声时间、配料比等)实验和正交实验优化包合工艺参数,紫外分光光度计测定吸光度,根据维生素M包合前后的吸光度来计算包合率。单因素实验结果表明:在25℃,维生素M的量为0.02g时,进行超声波辅助-β-环糊精包合维生素M,超声最佳时间为30min,最佳超声功率为200w,β-环糊精饱和溶液体积最佳为15mL。正交实验结果表明:在25℃,维生素M与β-环糊精包合物的包合率在超声时间为40min、超声功率为200w、β-环糊精饱和溶液为10mL时达到最大值2.36%。超声功率对包和率的影响最大,其次是β-环糊精饱和溶液的体积,影响最小的是超声时间。 相似文献
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尝试采用超声波技术对铬黑T及亚甲基蓝两种模拟染料废水进行降解实验。以脱色率为指标,分别考察pH值、超声功率强度、超声时间和温度等因素对两种模拟染料废水脱色作用的影响。结果表明:超声波技术对铬黑T及亚甲基蓝两种模拟染料废水具有一定的脱色能力,随着pH值的增大,脱色能力减弱。常温下,在pH=1.79附近、超声时间120min,超声功率0.7kw时,亚甲基蓝模拟染料废水的脱色率为27.60%,铬黑T模拟染料废水的脱色率为20.33%。进一步地采用超声波与水合二氧化锰联用技术,可以极大提高有机染料的降解效率,水合二氧化锰投加量为40mg/L时,亚甲基蓝模拟染料废水的脱色率达到92.48%。 相似文献
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超声波提取元宝枫叶总黄酮方法研究 总被引:75,自引:3,他引:75
利用超声波以水为溶剂提取元宝枫叶黄酮 ,对超声功率 ,超声作用时间 ,水量等因素进行研究。其较佳条件为 :超声功率中挡 ,作用时间 15min ,固液比为 1∶2 0 ,提取次数 2次 相似文献
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通过氧化反应与溶剂萃取分离相结合的方法对催化裂化柴油氧化脱硫。在催化氧化溶剂抽提的基础上,同时又用功率超声作用于该过程,开辟了一条全新的柴油氧化脱硫技术。考察氧化剂油比、氧化剂与催化剂的体积比、氧化温度、反应时间等因素对脱硫效果的影响。实验结果表明:在超声频率为28kHz作用下,以H2O2为氧化剂,甲酸为催化剂,萃取剂为DMF,萃取剂油比(体积比)为1:1,一次萃取20min,萃取次数为2次时氧化剂油比(体积比)为1:10,H2O2:甲酸体积比为1:1,氧化温度为50℃,反应时间为10min为最佳,其脱硫率达到93.2%。 相似文献
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Atmospheric freeze drying is a highly attractive process for the dehydration of thermosensitive products, like food, due to the fact that water is removed at low temperature by sublimation. Unfortunately, drying times can be very long because of the internal resistance of the product to vapor diffusion: power ultrasound can be an effective means of accelerating the process, thus reducing the operating cost. The aim of this study was to assess the effect of air temperature and velocity, ultrasound power and sample size on the drying kinetics of eggplant (Solanum melongena L.) samples and, afterward, to analyze in silico an industrial process. Experiments were performed under various conditions regarding air temperature (?5, ?7.5, ?10°C), velocity (2 and 5?m?s?1), power ultrasound (0, 10.3, 20.5?kW?m?3, 21.9?kHz), and sample size. Drying rate was measured experimentally. The air velocity showed no relevant effects on the drying kinetics, and the effect of air temperature was slight when compared to the marked reduction in the drying time obtained when ultrasound was applied. The uniformly retreating interface model was modified to account for the cubic shape of the samples and used to establish the kinetic parameters, in particular to evaluate water diffusivity in the dried product, searching for the best fit between measured and calculated moisture content. The model was finally used to optimize the process in silico, considering an industrial unit as test case. In this case, it appeared that power ultrasound can increase the productivity of a tunnel dryer up to four or five times, and it allows the operational and fixed costs of the plant to be reduced significantly. 相似文献
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以异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇、二羟甲基丙酸(DMPA)、三羟甲基丙(烷TMP)等为原料,合成了遇水膨胀型聚氨酯。用FTIR对该聚氨酯进行了结构表征,并对其遇水体积膨胀率和力学性能进行了研究。结果表明:NCO/OH摩尔比(异氰酸酯指数)为1.3~1.4时试样遇水体积膨胀率较高;随着DMPA用量的增加,试样的遇水体积膨胀率增大,拉伸强度保持率降低;加入TMP后,聚氨酯形成化学交联,拉伸强度保持率得到改善但,是试样的体积膨胀率随着TMP用量的增加而降低。 相似文献
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湿法炼锌产出的中和沉铁渣作为重要的二次资源,含有大量的铁、锰、锌等有价金属,具有较高的综合回收利用价值。回收有价金属前需对中和铁渣进行脱水预处理,基于回转窑干燥法存在干燥时间长、干燥效率低、二次污染等问题,本文开展了微波干燥湿法炼锌中和铁渣实验研究,考察了微波功率、物料量对中和铁渣温升行为的影响,表明微波干燥湿法炼锌中和铁渣是可行的;实验考察了微波功率、物料量和干燥时间对中和铁渣脱水率的影响。研究结果表明:在一定程度上,中和铁渣脱水率与干燥时间和微波功率成正比,与物料量成反比。实验控制微波功率为1000W、物料量为50g、微波干燥时间为9min时,中和铁渣脱水率达98.55 %;X射线衍射、红外光谱分析展示微波干燥中和铁渣自由水脱除较为完全,但仍含有部分的结晶水;扫描电镜分析显示微波干燥较常规干燥更为均匀;与常规干燥工艺相比,微波干燥具有干燥时间短、水脱除率高、干燥均匀、清洁无污染等优势。 相似文献
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Ultrasonically Assisted Extraction of Isoflavones from Stem of Pueraria lobata (Willd.) Ohwi and Its Mathematical Model 总被引:1,自引:0,他引:1 下载免费PDF全文
Ultrasonically assisted extraction of isoflavones from the stem of Pueraria lobata (Willd.) Ohwi has been carried out with an ultrasonic extracting apparatus (20kHz, electrical power input to the transducer in 0-650W). The influence of the electrical power input and extraction time on the'extraction yield is investigated in water, n-butanol, and 95% (by volume) and 50% (by volume) ethanol aqueous solution. The experimental results indicate that the yields of total isoflavones are higher in ultrasonically assisted extraction than those obtained from con-ventional extraction.Moreover,a mathematical model is proposed,by introducing the electrical power input to index the ultrsound intensity,to describe the behavior of ultrasonically assisted extraction.It is found that the model calcuations are in good agreement with the experimental data. 相似文献
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Von H. Schuller 《大分子材料与工程》1968,2(1):64-70
A dilatometer is described which does automatically the following work essential in kinetic investigations of polymerizations: Registering and plotting of the volume contraction of the sample (proportional to conversion) as a function of time, differentiation of the conversion-time curve and logarithmic plotting of the resulting rate of polymerization against time. Some examples are given to demonstrate the efficiency of the experimental set-up. 相似文献
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The agglomeration of two TiO2 pigments (0.2-1.0μ) dispersed in an agitated 1% saline solution has been studied by a sequential count method using a Coulter counter. A model based on collision frequency due to the turbulent motion in a stirred vessel predicts the second order rate constant k to be proportional to agglomerate volume and to stirrer speed to the power 3/2. Experimental values of k were proportional to threshold volume to the power 0.79, stirrer speed to the power 1.3, and independent of TiO2 concentration 相似文献
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微波辅助萃取油页岩工艺条件的研究 总被引:3,自引:0,他引:3
以CS2-NMP为溶剂,在微波辅助的条件下对依兰油页岩进行了萃取,采取了四因素、四水平的正交实验,并对正交实验的结果进行了分析。实验结果表明,微波萃取的最佳工艺条件为粒度0.119mm、溶剂量55ml(矿样5±0.25%)、时间15min、功率600W;萃取率可以达到10.9%;各因素对萃取率影响关系为溶剂量〉粒度〉功率〉时间,并且粒度、溶剂量和功率对萃取率均有显著影响。 相似文献