Near critical and supercritical water. Part I. Hydrolytic and hydrothermal processes

The potential of hot and supercritical water in applications to produce useful products, or to process unwanted compounds into environmentally compatible materials is reviewed. The potential of hot and supercritical water is high. Water changes its character from a solvent for ionic species at ambient conditions to a solvent for non-ionic species at supercritical conditions. Water at temperatures higher than ambient boiling temperature can be applied for extraction. At modest temperatures, ionic and polar species will be extracted. At higher temperatures, in particular approaching the critical temperature, nonpolar substances are readily dissolved and extracted. Hot pressurized water has a high reactivity. The reactions are commonly summarized as “hydrolysis reactions” which are catalyzed by acids, or may arise from simply hydrothermal transformations. Since CO₂, dissolved in water increases the availability of protons, the addition of CO₂ to liquid water catalyses hydrolysis reactions. Hydrolysis of natural plant materials provides a route to obtain fuel from non-food plant material. However, difficulties associated with operating conditions have so far limited the large scale implementations.     

Extraction and HPLC Characterization of Chlorogenic Acid from Tobacco Residuals

Abstract

Chlorogenic acid is a highly valuable natural polyphenol compound used in medicine and industries. Its current commercial sources are from plant extracts of Lonicera japonica Thunb and Eucommia ulmoides Oliver. These sources are limited and expensive. On the other hand, tobacco residuals contain chlorogenic acid and other natural polyphenol compounds. Large quantities of tobacco residuals are produced each year as waste materials from tobacco manufacturing, potentially providing an alternative commercial source of chlorogenic acid and other valuable compounds. In this paper, microwave and ultrasound extractions of chlorogenic acid with mixed solvent were studied. Total polyphenol concentrations in extract solutions obtained with different extraction methods were analyzed with the method of ferrous tartrate and UV‐Vis spectrophotometry and compared. The extraction solutions were also characterized for polyphenol compositions with the method of HPLC. Experimental results indicated that high extract concentrations of chlorogenic acid were obtained with a mixed solvent of acetone and water (1:2 v/v). A total polyphenol concentration of up to 4.87 mg/ml and a chlorogenic acid concentration of up to 2.12 mg/ml were achieved. The application of microwave and ultrasound significantly increased the extract concentrations. The extraction time needed was also much reduced. HPLC analysis indicated that acetone water mixed solvent extraction achieved much higher relative concentrations of chlorogenic acid to other compounds in the extract solutions. These results indicted that fast and effective extraction of chlorogenic acid from tobacco residuals were achieved.     

Restoring Solvent for Nuclear Separation Processes

Abstract

Solvent extraction separation processes are used to recover usable nuclear materials from spent fuels. These processes involve the use of an extractant/diluent (solvent) for separation of the reusable actinides from unwanted fission products. The most widely used processes employ tributyl phosphate as an extractant diluted with a normal-paraffin hydrocarbon. During use, the solvent is altered due to hydrolysis and radiolysis, forming materials that influence product losses, product decontamination, and separation efficiencies. In most processes, the solvent is recycled after cleaning. Solvent cleaning generally involves scrubbing with a sodium carbonate solution. Studies at the Savannah River Laboratory have shown that carbonate washing, although removing residual solvent activity, does not remove more solvent-soluble binding ligands (formed by solvent degradation), which hold fission products in the solvent. Treatment of the solvent with a solid adsorbent after carbonate washing removes binding ligands and significantly improves recycled solvent performance. Laboratory work to establish the advantage of adsorbent cleaning and the development of a full-scale adsorption process will be described The application of this process for cleaning the first cycle solvent of a Savannah River Plant production process will be discussed.     

Fish protein concentrate: A new source of dietary protein

The concept of fish protein concentrate (FPC) is based on the more efficient use of our fishery resource by converting under-utilized fish to acceptable products for human consumption. FPC is not a single product. It is rather a family of products produced by different processes. Each member in the family of products has different characteristics and can be used for different purposes. Although a variety of processes has been developed, most have been based on solvent extraction of whole fish to remove lipids and water. FPC produced by solvent extraction of fish of several different species contains between 75% and 95% protein, which is particularly high in quality. This type of product can be used in foods to improve markedly their nutritional quality without significantly changing their other characteristics. FPC produced by some solvent extraction methods, however, has limited functional properties. New processes are being developed which use enzymes, various solvents, or a combination of enzymes and solvents. Products from some of these processes have improved functional properties and these FPCs appear to be particularly promising for use in foods for their functional attributes. Several problems still remain to be solved and research is needed to determine how FPCs can be produced and utilized most efficiently and effectively. There is, however, a commercial industry emerging and indications are that FPCs will find a significant place in the market. One of 16 papers being published from the Symposium, “Oilseed Processors Challenged by World Protein Needs,” presented at the ISF-AOCS World Congress, Chicago, September 1970. National Marine Fisheries Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce.     

超临界CO_2萃取浓缩大豆粗磷脂的研究

以浓缩大豆粗磷脂作为液态物料的模型材料进行了超临界CO2萃取研究。通过实验考察了萃取温度、压力、时间和溶剂流量等对萃取效果的影响,确定了对于该种物质萃取的最佳操作条件。通过与传统的水蒸汽蒸馏法和有机溶剂萃取法生产的产品进行对比(酸碱度、含水量、有机溶剂残余量、色泽、气味等方面),表明了超临界流体萃取技术用于热不稳定物质的萃取所具有的独特优势。     

水辅助溶剂法提取油砂中的沥青

开发了一种水辅助溶剂法从油砂中提取沥青的技术。该方法通过在油砂固相与有机溶剂间介入水层提取油砂中的沥青。以内蒙古扎赉特旗油砂矿为研究对象,考察了温度、剂砂质量比、提取时间、甲苯在复合溶剂中的含量及溶剂的种类与性质对沥青回收率高低的影响,结果表明：最佳提取条件为提取温度50℃,剂砂质量比1∶1,提取时间25min。沥青回收率与提取溶剂的性质紧密相关,水层介入有效降低了固体微粒组分在有机相中的含量,且便于后续的有机相与泥砂相的分离。通过对各种溶剂提取的沥青进行组分分析,发现各种溶剂对沥青提取能力的差异性源于溶剂的化学组成和结构不同。本文相关研究结果对溶剂法提取油砂中沥青技术及溶剂种类的选择具有指导作用。     

Rückgewinnung von Metallen aus niedrigkonzentrierten Lösungen

Recycling of metals from low concentrated solutions. A review is given of processes used for the separation of metals from aqueous solutions, especially low concentration waste waters. Purification processes for waste water used only to reach values set by law are compared with processes that allow recovery of metals. Precipitation with and without additives, adsorption, processes with ion exchange resins, solvent extraction and membrane processes, especially liquid membrane permeation, are described. As a result of these considerations, a qualitative comparison of all the described processes becomes possible. For the separation of zinc from a waste water stream, a special economic comparison is also shown between precipitation processes and the liquid membrane permeation process. Finally, the latest developments in the fields of solvent extraction and liquid membrane permeation are discussed.     

Electroreductive Stripping of Silver in the (C6H5)3 P-Na2S2O3 Two-Phase System

Abstract

The increasing application of hydrometallurgical alternatives for the treatment of complex ore materials has caused remarkable development in solvent extraction processes (1). The success of solvent extraction for the purification of metals depends both on the efficiency and selectivity of the chosen solvent, as well as on the suitability of the stripping solution. Electrolysis of this latter aqueous phase is then necessary to produce the metal in its final form (2). The recovery of precious metals from different sources is of economic

The recovery of precious metals from different sources is of economic interest, and several solvent extraction studies, either from a technological (3) or from a scientific point of view (3, have appeared. A detailed survey on this subject indicates an effective affinity of this class of metals for sulfur-and/or phosphorous-containing extractants (4–6).

The aim of this work is to emphasize the viability of the direct produc-tion of a metal, namely silver, by a two-phase electrolysis. The conven-tional operations of metal stripping and subsequent electrowinning are, in this way, replaced by a one-step technique (7).     

In situ ultrasound enhancement of octanoic acid directional solvent extraction for seawater desalination

The low yield and high salinity of the water product have limited the use of directional solvent extraction desalination method to the treatment of only low salinity water. In this research, in situ ultrasound enhancement of octanoic acid solvent extraction desalination is reported. The pre-prepared 3.5% (w/w) of saltwater solution and octanoic acid were mixed at five different temperatures which resulted in two phases. The performance of extraction for each set was evaluated based on salinity, yield of the recovered water, and solvent residual in the product water. The calculated yield of pure water under the ultrasound effects was higher than that without the ultrasound. This is due to the role of ultrasound in weakening the intermolecular interaction to dissociate water from salt, increasing the solvent efficiency in extracting water. The recovered water salinity was lower by using the ultrasound which can be explained as result of increasing the water yield.     

甲基丙烯酸甲酯-甲醇-水共沸体系萃取分离工艺模拟

针对甲基丙烯酸甲酯?甲醇?水共沸体系,分别选择水、正己烷和水?正己烷双溶剂为萃取剂建立分离流程进行模拟, 建立单溶剂、双溶剂萃取工艺过程进行全流程模拟,采用灵敏度分析优化工艺过程的溶剂比和操作温度. 结果表明,双溶剂萃取工艺比水、正己烷单溶剂萃取工艺能耗分别降低15.1%和34.9%. 采用绿色度评价方法量化3种分离工艺对环境的影响,水、正己烷、水?正己烷双溶剂萃取工艺的绿色度分别为–7.25, –21.3和–6.75 gd.     

水产品副产物胶原蛋白制备方法及应用

胶原蛋白（Collagen）作为动物体内重要的大分子蛋白质，是参与动物组织和器官机械保护的重要细胞外蛋白。水产品副产物作为近年胶原蛋白行业关注的重点，传统蛋白提取方式在提取率、环保等方面缺点逐渐显现。本文综述了胶原分子构成机理、类型、胶原蛋白来源以及前处理方法对胶原蛋白提取工艺的影响；比较了原料、传统提取工艺（酸、碱、酶）对胶原蛋白产量与功能的影响；对水产品胶原蛋白在食品品质、食品保鲜、医药领域的应用现状以及新型胶原蛋白提取方法（亚临界水、超临界流体萃取）的工业可行性进行分析。对蛋白提取效率低、原料结构影响大的副产物提出“物理/生物-酸-复合酶”的水产胶原蛋白工艺优化方案，旨在为水产品资源高值化利用提供理论支撑。     

From laboratory to scale-up by modelling in two cases of β-carotene extraction from vegetable products

The laboratory investigation of β-carotene separation from rose hip fruits (RHFs) powder and carrot noodles (CNs) was analyzed by means of mathematical modelling, in order to develop models for process scale-up. The developed models contain parameters characterizing species transport inside and outside of vegetal material particle as well as species interphase equilibrium distribution. The model parameters were estimated by experimental data capitalization. The solvent type, liquid–solid ratio and extraction temperature were selected as process factors in β-carotene extraction. Having a significant influence on the process yield, these factors determined the values of model parameters. A model based on process control by external diffusion of extracted species and particle swelling was adopted for β-carotene extraction from RHFs, whereas an internal diffusion one was chosen to describe the process in the case of β-carotene extraction from CNs. The model parameters were identified by least squares method using theoretical and experimental data characterizing the dynamics of species extraction yield. The scale-up of counter current multistage extraction was performed through analysis of the processes studied at laboratory level.     

Waste water treatment by solvent extraction

A review is presented of the application of solvent extraction to the treatment of waste waters. Methods of extraction, solute-solvent separation and water — solvent separation are described. Phenol removal, oily water treatment, desalination, metal recovery by “liquid ion exchange” and miscellaneous other applications are described/ Available economic data are discussed. Possible future applications are outlined and it is suggested that greatest potential is in the treatment of oily waste water and of relatively concentrated streams containing valuable or noxious materials     

The use of an ionic liquid in a Karr reciprocating plate extraction column

Ionic liquids offer an alternative to volatile organic solvents for extraction of a range of materials. This work examines the mass transfer performance of a Karr reciprocating plate column with an ionic liquid as an alternative solvent for the extraction of phenol from water. The results indicate that ionic liquids can be used in existing solvent extraction equipment and that existing correlations and models can be used to predict mass transfer performance.     

Using water and organic solvents in extraction processes: A review

The molecular interactions in binary systems consisting of water and organic solvent are considered. The use of water with organic solvents in the extraction and purification of organic materials in the coke, oil, and chemical industries is reviewed, in Russia and elsewhere.     

鲜花精油和浸膏的超临界CO_2萃取进展

该文对国内外植物精油和浸膏的提取方法作了概述,包括传统方法(水蒸馏法和有机溶剂浸提法)和新型清洁方法〔微波诱导法、吸附法、水扩散法、分子蒸馏、超临界水萃取、液体CO2萃取和超临界CO2(SC CO2)萃取〕。介绍了SC CO2萃取的原理和优势,详细地说明了SC CO2对精油选择性萃取的较优条件、蜡和精油的传质机理、多级萃取除蜡等。重点将现有的SC CO2萃取强化方法———快速降压法、夹带剂法和溶胀预处理法进行较详细的总结。引用文献34篇。     

Converting of Bulk Polymers Into Nanosized Materials With Controlled Nanomorphology

The peculiarities of nanomaterials arise mainly from their sizes and for this reason the search of methods for their preparation is of increasing importance. For polymers the most common method is electrospinning but the final nanofibrillar non-woven textile has limited applications. The concept of nanofibrillar composites solves the same problem being free from the disadvantages of the electrospinning. Starting from blend of non-miscible polymers after extrusion and cold drawing, followed by extraction of the dominating component, nanofibrils (of 50–250 nm thickness) of the minor component can be separated. These neat nanofibrils can be used as scaffolds in tissue engineering, micro- and nanofilters in industry, as starting materials for single polymer composites, and others. They are obtained if H-bonding between blend partners is missing. In the opposite case the nanomorphology represents a nanofibrillar nanoporous 3-D network. In this way, H-bonding is a tool for governing the final morphology using water as the only solvent.     

萃取法制备磷酸二氢钾

以氯化钾和磷酸为原料,利用有机溶剂萃取法制备磷酸二氢钾的新工艺。选择了萃取率高、易回收的有机萃取剂三正丁胺作为萃取剂。考察了原料液中加水量、萃取时间、萃取剂用量、萃取温度对产品产率和纯度的影响。实验结果表明：较好的工艺条件为萃取剂用量为40 mL,萃取时间为40 min,用水量为20 mL,萃取温度为30℃,得到的磷酸二氢钾产品的产率高达96.426%和纯度高达98.252%。     

溶剂萃取法回收废弃含能材料的研究现状

废弃含能材料主要来源于退役武器和超过存储期弹药,是特殊性质的危险品,必须妥善处理。综述了废弃含能材料组分的提取技术,并介绍了改善方法（即加速溶剂萃取法和超临界流体萃取法）。当设计合理时溶剂萃取法可以做到处理过程安全、操作简单,所用溶剂可回收再利用,无三废排放,是一种处理和利用废弃含能材料的较优途径。     

Temperature and solvent effects on polyphenol extraction process from chestnut tree wood

Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol unit or building block per molecule. Polyphenols are generally divided into hydrolysable tannins (gallic acid esters of glucose and other sugars) and phenylpropanoids, such as lignins, flavonoids, and condensed tannins.They are widely found in natural products, nowadays they are extensively used in food and beverage industry and in pharmaceutical and nutraceutical industry for their positive effects on human health.In conventional processes polyphenols are extracted from vegetable material using water as solvent in a temperature range from 40 to 90 °C.The aim of this work is to characterize chestnut tree wood in terms of total extractable polyphenols and assess the temperature and solvent type effects on the polyphenol extraction process. To this end, experimental data on equilibrium distribution of polyphenols between solid and liquid phases for different temperatures (ranging from 60 to 80 °C) and different solvent solutions (water and ethanol-water solutions) are reported. The obtained results have been correlated by means of Freundlich isotherm.Experimental data are also reported about the batch extraction kinetics of polyphenols from solid phase and analysed by a mathematical model to estimate the polyphenol diffusion coefficient inside the chestnut wood particles and the mass transfer coefficient in the liquid phase.