打印温度对3D打印用黄芪药渣/聚乳酸材料性能的影响

为了探究黄芪药渣/聚乳酸(APS/PLA)材料3D打印过程中打印温度参数对产品性能的影响,以熔融挤出法制备了黄芪药渣/聚乳酸复合材料(APS/PLA-CM)线材,采用熔融沉积成型(FDM)-3D打印工艺打印试样,研究了打印温度对复合材料力学性能及热性能的影响.通过力学测试及扫描电子显微镜(S EM)观察层间结合情况发现...     

纤维素酶法提取竹叶黄酮的传质动力学

采用纤维素酶法提取竹叶中的总黄酮类化合物,讨论了温度、原料尺寸、转速及纤维素酶用量对传质速率的影响,并用扫描电镜观察了水提和酶提取后样品的细胞结构变化。结果表明,竹叶黄酮的提取动力学符合平板型Fick第二定律,提取过程主要受内扩散控制;纤维素酶不改变传质动力学机理,它只破坏细胞壁,从而降低扩散阻力使溶质的传质速率和表观扩散系数D′提高。实验还得到了D′与提取温度、竹叶几何尺寸之间的关系,在30～60℃,酶提时的D′为1.95×10 13～6.85×10 13m2·s-1,水提时的D′为1.73×10 13～6.05×10 13m2·s-1;酶提时的活化能Ea为11.853kJ·mol-1,比水提时降低了9.59%。该研究为酶法提取竹叶黄酮的工艺设计及工业化应用提供了理论依据。     

黄芪多糖提取、分离纯化工艺研究

用水提取黄芪多糖,比较了TCA法、Sevag法和鞣酸法3种脱蛋白方法对黄芪多糖提取液脱蛋白效果的影响,以D101大孔吸附树脂纯化黄芪多糖。结果显示,黄芪多糖的最佳提取工艺为:100℃下用水加热回流提取2次,60 min/次,料液比为1∶10 g/mL,提取率达3. 570%;鞣酸法脱蛋白效果最好; D101大孔吸附树脂分离纯化黄芪多糖的工艺为:处理100 mL浓度1. 8 mg/mL的黄芪粗多糖溶液时,采用4 BV,50%乙醇为洗脱剂,以1 mL/min的流速进行洗脱,可获得纯度为65. 07%的黄芪多糖。     

水提醇沉法提取黄芪中黄芪多糖的工艺优化及含量测定

为得到高效的黄芪多糖提取方法,以提高黄芪多糖的提取效率。采用全面实验法,研究黄芪多糖提取时的温度和时间,以及醇沉时乙醇的浓度对提取率的影响;并用液相色谱法测定黄芪多糖的纯度。实验发现提取黄芪多糖最佳的工艺条件是:温度100℃,水提取2 h,醇沉时乙醇体积分数为90%,黄芪多糖粗提物的质量含量是42.9 mg/g(4.29%),纯度为31.2%。实验结果表明,黄芪多糖的提取效率有所提高,对黄芪多糖的工业化提取奠定了基础。     

黄芪多糖提取、分离纯化工艺研究

用水提取黄芪多糖,比较了TCA法、Sevag法和鞣酸法3种脱蛋白方法对黄芪多糖提取液脱蛋白效果的影响,以D101大孔吸附树脂纯化黄芪多糖。结果显示,黄芪多糖的最佳提取工艺为:100℃下用水加热回流提取2次,60 min/次,料液比为1∶10 g/mL,提取率达3. 570%;鞣酸法脱蛋白效果最好; D101大孔吸附树脂分离纯化黄芪多糖的工艺为:处理100 mL浓度1. 8 mg/mL的黄芪粗多糖溶液时,采用4 BV,50%乙醇为洗脱剂,以1 mL/min的流速进行洗脱,可获得纯度为65. 07%的黄芪多糖。     

偏二甲肼水溶液在3A分子筛上的吸附平衡与动力学研究

采用气相色谱(GC)法测定了偏二甲肼(UDMH)水溶液中各组分的相对含量,通过静态吸附实验及吸附动力学实验测得UDMH水溶液在3A分子筛上的吸附平衡和动力学,用Langmuir方程和Freundlich方程对吸附等温线进行拟合。采用Dünwald-Wagner方法解析吸附动力学数据求得有效扩散系数D′i,研究了温度、初始水含量(C0)和分子筛粒径(dp)对D′i的影响。结果表明,在15℃下C0为2.298%、dp为250~420μm时D′i为1.49×10-7cm2/s,并随着温度的升高或水含量的增加而增大,但受分子筛粒径的影响较小。UDMH水溶液在3A分子筛上的吸附动力学参数为:活化能E为3.341×104 J/mol,指前因子D0为0.169 5cm2/s。     

氯化钠熔浸钾长石提钾过程

对熔融氯化钠浸取钾长石的提钾过程进行了研究. 结果显示，最佳反应条件是：反应温度890~950℃；氯化钠与钾长石的质量配比为1；钾长石的粒径为0.208 mm以下. 动力学分析显示，过程由Na+和K+在钾长石内部的离子扩散控制，扩散系数与反应温度之间的关系服从Arrhenius公式，即Deff=D0exp(–Ea/RT)，其中，Ea=81.42 kJ/mol，D0=0.324 mm2/h.     

星点设计-响应面法优化黄芪多糖提取工艺实验研究

建立黄芪多糖最佳提取工艺.通过单因素试验与正交设计试验,应用Box-Behnken中心组合试验设计和响应面(RSM)分析法,以黄芪多糖得率为响应值,回归分析黄芪多糖提取的影响因素,优选黄芪多糖提取工艺.结果表明正交设计与响应面法优化结果接近,所得黄芪多糖的最佳提取条件为:提取时间40min,水提取温度100℃,液料比(...     

响应面法优化黄芪-葛根药对多糖的超声提取工艺及其抗氧化活性研究

以黄芪-葛根药对多糖提取率为评价指标,在单因素实验的基础上,采用响应面法优化黄芪-葛根药对多糖的超声提取工艺,并通过测定其对羟基自由基、DPPH自由基、超氧阴离子自由基的清除率评价其抗氧化活性。结果表明,最佳超声提取工艺为：液料比17∶1(mL∶g)、提取时间30 min、提取温度57℃,在此条件下,黄芪-葛根药对多糖提取率为13.78%;黄芪-葛根药对多糖具有一定的抗氧化活性,对黄芪-葛根药对多糖进行脱蛋白处理后,可以有效改善其抗氧化活性。     

专利快递

Z05065箬叶多糖的提取方法公开号:CN1468868A,公开日:2004.1.21从箬叶中提取多糖或箬叶硒多糖的方法。箬叶(或含硒箬叶)在pH值为2～11水中,温度为0～80℃下用纤维素酶(或含纤维素酶的混合酶)酶促反应提取数次,合并提取液浓缩、去沉淀,澄清液加入酒精沉淀24h以上,分出多糖沉淀、脱水、真空干燥即得箬叶多糖(或箬叶硒多糖)。在本发明中采用蛋白酶法除蛋白,蛋白酶(或含蛋白酶的混合酶)可以在提取时与纤维素酶一同加入、或在提取中加入、或在三次提取液的浓缩液中加入,无论在哪一工序加入蛋白酶,均需在pH值为2～11,温度为0～80℃下酶促反应。…     

Removal of Cu2+ from Water Using Liquid-Liquid Microchannel Extraction

The very good extraction selectivity of Cu²⁺ from water was demonstrated with a new microchannel equipment, by employing di-(2-ethylhexyl)phosphoric acid (D2EHPA) as an extractant and kerosene as a solvent. The effects of different experimental parameters on the extraction efficiency E, the volumetric mass transfer coefficient K_La, and the entrainment were experimentally investigated. The results showed that the extraction efficiency increased with increasing temperature, extractant concentration, phase ratio (organic/aqueous), and pH. The total flow rate, phase ratio, and pH were found to have a great effect on the mass transfer, whereas the temperature and the extractant concentration showed little effect.     

超临界二氧化碳萃取生姜油实验研究与数值模拟

1 INTRODUCTION Supercritical fluid extraction (SFE) as an alter- native to conventional processes, such as solvent ex- traction and steam distillation for obtaining essential oils, is a novel technique especially attractive to the food, cosmetics and Pharmaceuticals industries. The extracts from SFE are free of solvent residues. In ad- dition, the process can be conducted at low tempera- ture, which is very important to preserve the quality of heat-sensitive products[1,2]. Ginger (Zing…     

超临界CO_2萃取过程的数学模拟

对超临界CO_2萃取β-胡萝卜素的过程进行了模拟研究,考察了压力(10～32MPa)、温度(0～60℃)、空塔气速(0.25～1.00m/s)和颗粒直径(0.0005～0.01m)等各种工艺操作条件对萃取得率和过程经济性的影响,得出了超临界CO_2萃取β-胡萝卜素的最佳工艺条件;提出了一种研究超临界CO_2萃取技术的新思路:采用计算机模拟技术优化萃取过程的工艺条件以减小操作条件的探索工作量。     

磷酸三丁酯萃取硝酸的动力学

在改进的恒界面池内研究了磷酸三丁酯（ＴＢＰ）－正庚烷（ｎＣ７Ｈ１６）萃取硝酸的宏观动力学。采用热力学方法处理实验数据，计算了两相内组份的传质系数及传质阻力。研究结果表明，萃取过程的传质阻力主要在有机相内。根据动力学研究实验结果，进而分析了磷酸三丁酯萃取硝酸过程的机理，并以被萃组份的活度差为传质推动力作为计算基准建立了萃取速率的数学模型：模型计算结果与实验结果的平均相对偏差为２．５％。实验结果和理论分析表明，此萃取过程为有机相内的扩散控制机制，扩散阻力主要来自有机相内ＴＢＰ和萃合物ＨＮＯ３·ＴＢＰ分子的扩散。     

填料塔中牛血清清蛋白在聚乙二醇-硫酸铵双水相系统中的传质特性

研究了填料塔中牛血清清蛋白在聚乙二醇－硫酸铵双水相系统中的传质特性,测定了分散相含率和传质系数,用修正的Ｈａｎｄｌｏｌｓ－Ｂａｒｏｎ模型对实验数据进行关联,得到了相应的关联式,关联值与实验值相比,偏差小于５％。     

Supercritical Fluid Extraction of Pentachlorophenol from Pressure-Treated Wood

Abstract

The extraction of pentachlorophenol (PCP) from pressure-treated wood wafers with supercritical carbon dioxide (SC-CO₂) was studied in a continuous-flow extractor. PCP extraction rates were determined as a function of pressure (17.5–25 MPa), temperature (313–353 K), flow rate (1–3 mL/min at supercritical conditions), and sample size (0.8 × 10 × 50 mm and 2.2 × 10 × 50 mm) by measuring PCP concentrations in the extractor effluent intermittently. The rate of extraction increased with an increase in solvent pressure and a decrease in particle size. A fundamental model was developed which includes rates of intraparticle diffusion, external film mass transfer, linear desorption isotherms, and initial distribution of PCP between pore volume (cell lumen) and pore surfaces (cell wall) of wood wafers. The overall mass transfer coefficient and the rate of extraction increased with an increase in solvent pressure, temperature, and flow rate. The adsorption equilibrium coefficients of PCP with wood substance were very small, and more than 80% of the PCP was found to be in the cell lumen initially.     

Extraction rates of amino acids by an emulsion liquid membrane with tri-n-octylmethylammonium chloride

The extraction rates of amino acids from alkaline aqueous solution into an emulsion liquid membrane containing tri-n-octylmethylammonium chloride as a carrier and Paranox 100 as an emulsifier were measured using a stirred transfer cell. The effects of agitation speed (0·33–0·66 rev s⁻¹), amino acid concentrations (0·5–50 mol m⁻³) and temperature (10–45°C) on the extraction rates were examined. The results were analyzed by a double-film model. The mass transfer coefficients of amino acids (0·26–1·58×10⁻⁵ m s⁻¹) and their complexes (0·60–1·72×10⁻⁵ m s⁻¹) were found to correlate well with the hydrophobicities of the amino acids. It was found that the surfactant layer influenced the mass transfer processes of both amino acids in the aqueous film and their complexes in the organic film. The permeation of amino acids with a large hydrophobicity through the emulsion liquid membrane was promoted by both high distribution and larger mass transfer rates. © 1998 Society of Chemical Industry     

Ethanol-Assisted Aqueous Enzymatic Extraction of Peony Seed Oil

An ethanol-assisted aqueous enzymatic extraction was performed for peony seed oil (content of 30%). This method included cooking pretreatment, pectinase hydrolysis, and aqueous ethanol extraction, and the corresponding variables in each step were investigated. The changes in viscosity and dextrose equivalent values of the reaction medium as a function of changing enzymatic hydrolysis time were compared to the oil yield. The microstructures of peony seeds were analyzed using confocal laser scanning microscopy to understand the process of oil release as a result of cooking and grinding. The highest oil yield of 92.06% was obtained when peony seeds were cooked in deionized water with a solid–liquid ratio of 1:5 (w/v) at 110°C for 1 hour, ground to 31.29 μm particle size, treated with 0.15% (w/w) pectinase (temperature 50°C, pH 4.5, time 1 hour), and then extracted with 30% (v/v) aqueous ethanol (temperature 60°C, pH 9.0, time 1 hour). After processing with pectinase followed by ethanol extraction, the residual oil content in water and sediment phase decreased to 5% and 3%, respectively. The quality of the oil obtained by ethanol-assisted aqueous enzymatic extraction was good, complying with the Chinese standard.     

Hydrotropic Extraction of Reserpine from Rauwolfia vomitoria Roots

Aqueous solutions of sodium cumene sulfonate give quantitative and faster extraction of reserpine from Rauwolfia vomitoria as compared to the extraction using methanol. The extraction rate is influenced by intraparticle diffusion and increases with increasing temperature and hydrotrope concentration. The dynamic extraction data were fitted in a mass transfer model to evaluate diffusion coefficient of reserpine in the solid plant matrix. Amongst all hydrotropes, sodium cumene sulfonate, gave the best extraction and extraction rates of reserpine. The reserpine crystals recovered from aqueous hydrotrope solutions were much smaller in size and showed different morphology than those from methanol.     

G/O/W微分散体系实现甲酸/三辛胺-正辛醇体系萃取分离

以络合萃取法实现了稀溶液中甲酸的富集。确定了高分配系数的萃取体系。根据传质基本方程建立了传质模型,计算并分析了油/水体系中的传质过程,确定传质控制步骤为甲酸自水相至水/油界面的传质。计算了分散尺寸对体系传质性能的影响,结果表明,由于水/油相比高,体系的传质系数低,界面积小,以油/水微分散乳液实现萃取过程,传质效率仍不高。引入惰性气体,并构建气/油/水体系,计算并分析了气/油/水体系中的传质过程并优化了气相加入量,结果表明,气相的加入可以有效促进传质过程。设计了双重膜分散设备,制备了微米尺度的气/油/水双重乳液,并以此实现了稀溶液中甲酸的高效富集。