Clarification of suspensions by colloidal gas aphrons

Colloidal gas aphrons (CGAs), generated from dilute solutions of four surfactants, were used to clarify palm oil mill effluent (POME), suspensions of microalgae and suspensions of three inorganic minerals. In POME and the algal suspensions, each CGA was most effective at a pH value close to the pK value of the surfactant concerned. This effect was not tested in the inorganic suspensions. The efficiency of air utilization was directly related to the concentration of solids in the suspensions, the size, density and nature of the solids having secondary effects. Comparison with data in the literature led to a general correlation embracing a variety of suspensions and flotation systems. Shedding of collected material from the foam layer was also a direct function of solids concentration. CGAs offer advantages over other systems of air-assisted flotation in relation to the requirements for equipment and to the management of process operations.     

Harvesting of Saccharomyces cerevisiae using colloidal gas aphrons

Adsorptive bubble separation using Colloidal Gas Aphrons (CGA) can be used for harvesting of microorganisms. The effect of various operating parameters, for example pH, biomass loading, dispersed and continuous phase velocity, surfactant type and concentration, has been studied on the recovery of Saccharomyces cerevisiae. The operating conditions were optimised for maximum separation. The results obtained have been compared with the prediction of an model earlier.     

一种新型胶质液体泡沫的制备及其在处理含油污泥中的应用研究

经过两步反应合成了一种新型的磺酸盐型阴离子表面活性剂。应用红外光谱、元素分析等手段对中间体、最终产品进行了结构表征;应用电导法测定了自制的新型磺酸盐型阴离子表面活性剂cmc,运用两相滴定法测定了新型磺酸盐型阴离子表面活性剂的有效含量。接着,应用新型磺酸盐型阴离子表面活性剂构筑了一种新型的胶质液体泡沫(CLA)体系。实验发现,胶质液体泡沫(CLA)的粒径及稳定性主要受相比影响。利用电导率仪对胶质液体泡沫体系的稳定性进行初步研究。应用光学显微技术对胶质液体泡沫体系的结构进行了表征。最后,应用胶质液体泡沫体系进行含油污泥的原油脱除研究,并对脱除的原油进行了回收,并应用光学显微镜技术对原油脱除机理进行了初步探讨。正交实验的结果表明:自制的、稳定的、胶质液体泡沫体系可以有效地脱除含油污泥中的原油,最佳条件是:含油污泥处理量0.5g,稀释比为10∶1,处理温度45℃,处理时间20min,最佳条件下含油污泥中原油的脱除率可达99.60%。     

The influence of system parameters on the stability of colloidal liquid aphrons

An investigation was carried out on the effect of process parameters involved in Pre‐Dispersed Solvent Extraction (PDSE) on the stability and interactions in dilute dispersions of Colloidal Liquid Aphrons (CLAs). The aim of this work was to derive empirically‐based engineering relationships that could be used in the design of PDSE processes. For this investigation, CLAs were formulated with an Aliquat 336/n‐octanol/Softanol 120 solvent phase, and a Synperonic A20 aqueous phase. These CLAs were intended for use in the reactive pre‐dispersed solvent extraction of polar solutes such as phenylalanine. Light scattering measurements over a range of continuous aqueous and CLA phase conditions were used as a method of obtaining a measure of the rate of disappearance of CLAs from dispersion (a measure of stability), and a comparison of stability under different conditions. Two forms of CLA interaction occurring by independent mechanisms were identified – CLA break‐up, and CLA flocculation. Break‐up was found to be a first order process, allowing CLA stability to be characterised by a first order half‐life (typical half‐life 15–40 min). This was proposed to occur on collision of CLAs with sufficient energy to overcome the stabilising forces provided by the surfactants at the interfaces of the CLAs. It was shown that flocculation occurred at high ionic strengths (>0.1 M NaCl), and that it was not part of the break‐up mechanism. An apparent size dependent CLA half‐life was proposed to be due to smaller particles having a lower collision energy on average. The data suggested that the resistance to CLA break‐up was not charge repulsion, but derived from an interaction between molecules of one of the surfactants making up the aqueous ‘shell’ of the CLAs (Synperonic A20). Finally, the basis for a semi‐empirical design equation for prediction of CLA half‐life developed from the Arrhenius equation was proposed. © 1999 Society of Chemical Industry     

胶质液体泡沫的研究进展及其在分离工程中的应用

概述了胶质液体泡沫（CLAs）的研究发展现状；讨论了CLAs的制备及影响CLAs形成的因素；分析了CLAs内部结构特征，稳定机理及其影响因素；并就胶质液体泡沫在分离工程中的应用，特别是预分散溶剂萃取（PDSE）分离，进行了总结和评述。重点分析了CLAs内部结构的本质，对该领域的研究前景作了展望；指出了有关CLAs结构探讨的研究方向和手段。     

电导法研究胶质液泡稳定性

应用电导法考察了溶剂极性和溶液离子强度对胶质液泡稳定性的影响,并提出了胶质液泡的稳定性模型。测量得到的电导率值k_t随时间t的变化曲线出现a、b和c三个明显不同的区域。由增比电导率值k_r随时间变化关系曲线的陡峭程度和a区所占时间,分析了溶剂种类和溶液离子强度对胶质液泡稳定性的影响。根据电导率值变化敏感的b区的动力学分析,结合胶质液泡液滴的上升、聚并和破乳等体系不稳定因素提出了胶质液泡稳定性模型。胶质液泡体系模型拟合值与稳定性实验测量数据的符合程度是令人满意的。     

Factors influencing the stability of a novel enzyme immobilisation support – colloidal liquid aphrons (CLAs)

A key factor in the immobilisation of enzymes is the stability of the support. An investigation was carried out on the stability of colloidal liquid aphrons (CLAs) in dilute dispersion, looking particularly at the effects of process parameters and CLA composition. CLAs were formulated from a Softanol 30/decane solvent phase and sodium dodecyl sulfate (SDS)/β‐galactosidase aqueous phase. The aim of this work was to gain an understanding of the mechanisms stabilising CLAs, and to characterise the effects of process parameters on stability such that the knowledge gained could be used in the design of a membrane bioreactor. CLA stability was measured using a light scattering technique (defined by a first order CLA half‐life). It was proposed that CLA break‐up occurred by the collision of CLAs with sufficient energy to overcome the forces stabilising the CLAs. Stability was found not to be dependent on the bulk aqueous phase ionic strength, but increasing the concentration of the ionic surfactant increased stability, indicating that stability was influenced by charge repulsion. Stability was also found to increase for increasing enzyme (β‐galactosidase) concentration, indicating steric interactions and elastic effects were also important. Finally, the effect of process parameters (reactor temperature, CLA concentration and circulation velocity) were assessed, and their effect was explained in terms of their influence on collision energy and the activation energy necessary for CLA break‐up; increasing CLA concentration was found to improve stability considerably. © 2000 Society of Chemical Industry     

A model for harvesting of microorganisms using colloidal gas Aphrons

A theoretical study of the harvesting of microorganisms using Colloidal Gas Aphrons (CGA) is presented. A model for predicting the separation factor of the CGA contactor is proposed which involves parameters that may be estimated through simple experiments.     

Extraction of Lipids from Aqueous Protein‐Rich Streams using Near‐Critical Dimethylether

An extraction process for obtaining lipids from aqueous protein/lipid mixtures has been developed using near‐critical dimethylether (DME) as the solvent. The process has been demonstrated on fresh and reconstituted egg yolks, and on selected dairy by‐product streams. The lipid yield is dependent on the processing temperature, solids content and feed ratio of solvent to liquid. The extent of protein denaturation is also dependent on these parameters. The phase equilibria of DME‐water‐phospholipid mixtures are presented with modeling of the DME‐water system using the Peng‐Robinson equation of state.     

Nanomicellar Extraction of Polyphenols—Methodology and Applications Review

The selection of the appropriate extraction method is crucial, especially for the receiving of active substances from plant material. The extraction using supercritical liquids and micellar-mediated extraction (MME) is the most advantageous among the alternative methods to classical solid–liquid extraction. However, the latter seems to be the best solution when the desired actives are polar. The following article presents a comprehensive review of the micellar-mediated extraction method in the last decade. The theoretical principle of the process was also refreshed and the current state of knowledge on the applications for analytical and manufacturing purposes was summarized.     

Equilibrium and Kinetics of the Extraction of Propionic Acid Using Tri‐n‐Octylphosphineoxide

Organophosphorous compounds have been widely used in inorganic analysis for the extraction and separation of inorganic acids or metal species. Since these compounds can form hydrogen bonds to proton donors, they can also be used for the extraction of acidic organic compounds. Therefore, the reactive extraction of propionic acid using tri‐n‐octylphosphine oxide (TOPO) in hexane was studied. Equilibrium and kinetics experiments were performed. The extraction of propionic acid using n‐heptane, light liquid paraffin, heavy liquid paraffin and hexane was studied and hexane was found to be most suitable diluent. The equilibrium complexation constant for the propionic acid‐TOPO complex was determined to be 0.702 m³/kmol. The extraction was found to be first order in propionic acid and first order in TOPO with the overall rate constant as 46.91 (m³/kmol)²/s.     

Extraction equilibria and separation of phenylalanine and aspartic acid from water with di(2‐ethylhexyl)phosphoric acid

The distribution equilibria of single and binary L ‐phenylalanine and L ‐aspartic acid between water and a kerosene solution of di(2‐ethylhexyl)phosphoric acid (D2EHPA) were studied. It was shown that the distribution ratios of phenylalanine generally increased with increasing aqueous pH (2–5) in the D2EHPA concentration range 0.1–0.5 mol dm^?3, but those of aspartic acid decreased with increasing solution pH. Different reaction stoichiometries were proposed for the extraction of phenylalanine and aspartic acid under the conditions studied. The extraction equilibrium constants were obtained. Competitive extraction in binary systems was more apparent in the pH range where the cationic form of amino acids was not predominant. The present results indicated that selective separation of phenylalanine to aspartic acid was possible with this cationic extractant when they were extracted at higher pH and stripped using higher acidity of HCl solution. Copyright © 2006 Society of Chemical Industry     

Preparation and properties of water‐soluble polyester surfactants. I. Preparation and surface activity of poly(ethylene glycol)‐dimethyl 5‐sulfo‐isophthalate sodium salt polyester surfactants

The reaction of poly(ethylene glycol) (PEG, number‐average molecular weight M_n = 400‐2000) and dimethyl 5‐sulfoisophthalate sodium salt (SIPM) synthesized a series of anionic polymeric surfactants having a range of molecular weights. ¹H‐NMR, FTIR, and elemental analysis were employed to characterize the structures of these compounds. Also, the influences of the PEG segment lengths of PEG/SIPM copolymers on the surface tension, foaming properties, wetting power, and dispersant properties were investigated. The experimental results indicated that the solution that contained the PEG/SIPM copolymer surfactants exhibited excellent surface‐active properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2727–2731, 2002     

表面活性剂强化提取黄姜中薯蓣皂苷的研究

对7种表面活性剂强化提取薯蓣皂苷的效果进行了比较,筛选出对该提取过程具有较好强化作用的表面活性剂——十二烷基硫酸钠(SDS)。通过正交实验、单因素实验考察了提取温度、提取时间、w(SDS)、提取溶剂用量对薯蓣皂苷提取率的影响,获得了优化的提取条件:黄姜粉末5 g,提取温度70℃,提取溶剂用量12 mL/g黄姜,提取时间2 h,w(SDS)=3%,获得皂素92.59 mg。实验结果表明,SDS对水提取黄姜中薯蓣皂苷(7.74mg)有明显强化作用,提取效率高于传统的甲醇/水溶液(75.08 mg),接近索氏提取(95.67 mg)。     

A new bubbling extraction tower: Toward liquid–liquid solvent extraction at large aqueous‐to‐oil phase ratios

Enrichment and recovery of valuable components in industrial waste waters by traditional liquid–liquid solvent extraction is not economic due to extremely low concentrations of those targets. Large‐phase‐ratio extraction exhibits potential advantages for recovery of small quantities of target components from large volume of aqueous solutions. A novel bubbling extraction tower is proposed toward performing solvent extraction at large aqueous‐to‐oil phase ratios in this work. Organic extractants were covered onto surface of gas bubbles to form a layer of organic liquid membrane and the dispersed organic phase in tower could be small enough. The target components are extracted from aqueous feed solution onto the surface of the bubbles, and the enrichment ratios could be extremely high. We develop a feasible methodology to calculate tower height and operation phase ratios of the bubbling extraction tower, which is essential for future industrial scale‐up. Experimental results in pilot test are highly consistent with calculations. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3889–3897, 2015     

Deep oxidative–extractive desulfurization of fuels using benzyl‐based ionic liquid

Four benzyl‐based ionic liquids (ILs) were synthetized and used for deep desulfurization of model oil and real diesel fuel. The removal efficiencies of benzothiophene (BT) and dibenzothiophene (DBT) with [Bzmim][NTf₂] and [Bzmim][SCN] as extractants are higher than that with [Bzmp][NTf₂] and [Bzmp][SCN] as extractants. The desulfurization capability follows the Nernst's Law. A reactive extraction mathematical model for desulfurization was established. An oxidative‐extractive two‐step deep desulfurization method was developed. DBT was first oxidized by H₂O₂ with CH₃COOH as catalyst and then the unoxidized DBT and uncrystallized dibenzothiophene sulfoxide (DBTO₂) in model oil were extracted by [Bzmim][NTf₂], and finally the removal efficiency was 98.4% after one‐stage extraction. Besides, the removal efficiency of 4,6‐DMDBT was 96.4% after oxidation and one‐stage extraction processes. Moreover, the oxidative‐extractive two‐step deep desulfurization method was also effective for desulfurization of diesel fuel. The removal efficiency of sulfur reached up to 96% after oxidation and three‐stage cross‐current extraction processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4023–4034, 2016     

Membrane‐liquid emulsion membrane process using a liquid emulsion membrane process using methane sulfonic acid as a strippant

The application of a liquid emulsion membrane (LEM) process in the recovery of zinc from aqueous solutions is discussed. The role of a stripping agent is very important in the LEM extraction process. Various stripping agents, such as hydrochloric, sulfuric, nitric and methane sulfonic acids, were tested for the stability of membrane. Methane sulfonic acid outperforms the other acids as a strippant. Further importance was given to the stability of the liquid emulsion membrane during the extraction process. The important variables affecting the LEM permeation process of zinc in a mechanically agitated contactor (MAC), such as residence time for extraction, speed of agitation, organic diluents, surfactant concentration and internal strip acid concentration, were systematically investigated. Emulsion swelling and breakage that occurred during these investigations were also described. Finally, the static mixer (SM) device was shown to have a very good potential for LEM extraction of zinc as it outperforms MAC.     

A Multi‐Stream Microchip for Process Intensification of Liquid‐Liquid Extraction

Solvent extraction is a critical step in many industrial mineral‐processing circuits and is affected by chemical (e.g., metal ions, extractant, pH, reaction rate) and physical (e.g., interfacial phenomena, mass transport, temperature) factors. Here, a new type of microfluidic contactor is presented that enables higher volumetric throughputs and straightforward counter‐current operation compared with Y‐Y chips. A single chip design can handle a wide range of organic/aqueous phase ratios, thereby enabling stable operation for non‐ideal solutions and fluctuating flow. An expression defining this widened operational window has been derived based on the relative stream geometries and liquid viscosities. A two‐stage counter‐current circuit is demonstrated for the extraction of platinum(IV) chloride.