Partitioning,solubility and solubilization of limonene into water or short-chain phosphatidylcholine solutions

Using headspace solid-phase microextraction (HS–SPME), equilibrium distributions could be determined for hydrophobic solutes in closed systems containing vapor and aqueous solution, either in the absence or presence of two short-chain phospholipids, dihexanoyl-phosphatidylcholine (diC₆PC) and diheptanoyl-phosphatidylcholine (diC₇PC). Without phospholipid, HS–SPME with short extraction times was used to measure water–vapor partition coefficients for d-limonene at five temperatures within 15–40°C, with results in good agreement with existing literature. The temperature dependence of yielded the enthalpy of volatilization 34.5 kJ/mol for limonene. At 25°C, solubility values for d-limonene, 1-octanol, and n-decane were obtained using similar measurements above aqueous solutions of various solute concentrations. Short-time HS–SPME extraction of limonene in closed vials containing diC₆PC or diC₇PC micelles was also used to evaluate distributions of solute between vapor, aqueous dissolution, and micelles, for various surfactant concentrations at 15–40°C. Resulting vapor phase concentrations were analyzed using a mass balance and measured values, to obtain micelle–water partition coefficients and critical micelle concentrations. in diC₆PC solutions (1–2 mM⁻¹) weakly increased with temperature, but decreased significantly with increased temperature for diC₇PC micelles (2–4 mM⁻¹). Solubilization in short-chain PC micelles has previously received little attention, and our results show that the extent of partitioning into these diacyl (i.e., two-tailed) lipids is comparable to that for single-tailed anionic or nonionic surfactants.     

Al-4％Cu合金定向凝固枝晶／胞晶转变速率的研究

通过实验和理论对比研究Al-4%(质量分数)Cu合金定向凝固胞晶/枝晶转变过程,得到胞晶/枝晶转变发生在尖端半径变化的拐点处。采用KGT模型与非平衡效应研究与胞晶/枝晶转变过程相对应的高速枝晶/胞晶转变特征。结果表明:尖端半径和界面温度均随抽拉速率的增加而减小,到达临界值后又急速增大。枝晶/胞晶转变发生在尖端半径和界面温度的拐点处,即在尖端半径和界面温度最小时发生转变;溶质截留在枝晶/胞晶转变过程中作用明显,大大减小了微观偏析。     

络合萃取技术在极性有机物稀溶液中的应用进展

简要总结了近3年来络合萃取技术在萃取Lewis酸、Lewis碱、两性有机物稀溶液及其在废水处理方面的应用状况,同时也介绍了一些新的技术,并就其应用开发前景提出了自己的看法。     

The marangoni effect and enhanced oil recovery Part 1. Porous media studies

The use of partitionable solutes, e.g., aliphatic alcohols, to enhance the recovery of trapped oil in reservoir rock, has been simulated using a ballotini-packed column initially flooded with kerosene, and subsequently lowered to an irreducible value by a water drive. Introduction of a “slug” of an alcohol effected an increased recovery, with n-propanol and sec-butanol giving the highest yields. Previous workers attributed such increased recovery to the formation of a “soluble front”, in which both oil and connate water are completely dissolved. However, we obtained similar recoveries using slugs with initial compositions lying on the miscibility boundary, which could not form soluble fronts. It was therefore concluded that Marangoni-induced oscillation of the trapped drops is the more likely explanation of the enhanced recovery.     

Al-1.5Cu-3Zn合金的溶质分凝因数的实验和模型研究

采用液态金属冷却技术淬火得到了温度梯度在80K／cm时Al-1．5Cu-3Zn合金的固液界面,使用光学显微镜观察了界面形貌,发现在生长速度为0．1和7．1pμm／s时试样分别为胞状生长界面和枝晶生长界面。用SEM和EDS测量了溶质分配,计算出了A1-1．5Cu-3Zn合金中Cu和Zn的平衡分凝因数为0．31和0．58。采用活度模型和浓度模型进一步计算了平衡分凝因数,发现两个模型计算出的Cu和Zn的平衡分凝因数一致,并讨论了模型计算值和试验值之间的差异。     

Polyether-segmented nylon hemodialysis membranes. IV. Membrane morphologies and permeability characteristics of dialysis membrane composed of poly(ethylene oxide)-segmented Ny69/M10

Dialysis membrane was prepared by a phase inversion method using a new polyether-segmented nylon which dissolves in common organic solvents such as dimethylsulfoxide. The polyether-segmented nylon contained poly(ethylene oxide) block and nylon block (random copolyamide: Ny69/M10) prepared by sebacic acid, azelaic acid, m-xylenediamine, and hexamethylenediamine. The morphologies and permeability characteristics of the membranes were investigated. It was shown by scanning electron microscope observation that the membrane had a fingerlike structure when dimethylsulfoxide was used as a polymer solvent, and a spongelike structure when an additive such as calcium chloride was added to the polymer solution. The high permeability for the solutes such as urea and vitamin B₁₂ were observed in comparison with the polyether-segmented Ny610 membranes prepared by a phase inversion method. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1731–1737, 1997     

TG6钛合金冷却过程的块状转变机制研究

在近α型TG6钛合金两相区淬火过程中,对初生α相αP周围形成的块状组织αm进行表征研究,块状组织αm与αP存在明显的界面,合金元素Al、Sn和Zr浓度介于αP和β基体之间,EBSD分析结果表明αm取向与αP保持一致。在冷却过程中,αP周围β基体中合金元素扩散受到限制,进而在局部过渡成分区域通过扩散转变形成αm组织。当固溶温度从1040℃提高至1060℃,同时保温时间从30 min减少为5 min,溶质元素扩散受限,αm体积分数从5.2%提升至30.7%。     

正渗透过程中水与溶质的传递现象

正渗透是一种利用渗透原理的新兴膜技术,近年来在国内外受到了广泛的关注。解析该过程中溶剂水的传递和驱动溶质的反向传递对其发展和应用至为关键。首先开展了两种膜的取向下,正渗透过程中的水通量和溶质反向摩尔通量的实验研究。当驱动溶液在膜分离层侧时,水通量更高,而溶质反向摩尔通量更低,表明水的传递对溶质的反向传递有限制作用。而后分别考察了不同的单一溶质和二元混合溶质作为驱动溶质时,水和溶质的传递现象。当单一中性溶质或电解质作为驱动溶质时,水通量和溶质反向摩尔通量均随驱动溶液浓度的升高而增大;在相同操作条件下,驱动溶质的扩散系数越小,溶质反向摩尔通量越小;中性溶质与电解质混合溶液为驱动溶液时,溶质分子之间存在耦合传递效应。     

稀土浸出过程溶质传递的格子Boltzmann模拟

采用耦合传质的格子Boltzmann方法模拟风化壳淋积型稀土矿中稀土浸出的溶质传递过程,在验证模型有效性的前提下,获得了稀土矿填充孔隙中流体流动的速度分布和伴随流动过程的溶质浓度分布. 通过考察浸取流速对溶质传递过程的影响,得到最佳浸取流速,约为0.25~0.35 mm/s,使溶质传递效率最高. 浸取流速小于0.2 mm/s导致浸取周期过长、浸取剂消耗量大;浸取流速大于0.4 mm/s引起沟流,导致稀土不能有效地浸出. 此外,模拟所得传质舍伍德数Sh随雷诺数Re的变化关系与经验关系式吻合,表明提出的模型可用于预测稀土浸出过程的溶质传递规律.     

Investigation of effect of constitutional supercooling and solute segregation in CZT-LPVB with finite element analysis method

Crystal growth of Cd_0.9Zn_0.1Te (CZT) using the Liquid-phase Vertical Bridgman method (LPVB) is numerically simulated and analyzed using the simulation software of Comsol Mutiphysics. The influence of curvature on the solid-liquid interface is studied, and the radial solute segregation is calculated for three kinds of growth method. The energy dispersive X-ray (EDX) detector of an SEM was used to test the concentration of Zinc. And all the calculated data are in agreement with the results of the experiments numerically. The diffusion transported mechanism during supercooling of CZT crystal growth was studied and the freezing point curve and the thickness of the boundary layer for different values of G (temperature gradient) and v (growing rate) are discussed.