温度对高浓度SDS水溶液泡沫稳定性及分离的影响

高浓度表面活性物质的分离是泡沫分离过程的难题,也是制约泡沫分离技术应用于工业化生产的瓶颈.为了解决高浓度表面活性物质泡沫分离的难题,以阴离子表面活性剂十二烷基硫酸钠(SDS)水溶液为体系,研究了在其临界胶束浓度(CMC)附近时,温度对SDS水溶液气泡直径、泡沫稳定性、富集比及回收率的影响.结果表明:温度对高浓度表面活性物质的泡沫分离有显著影响.当SDS水溶液浓度分别为1.2、2.3、3.5g·L-1,温度从30℃升高到70℃时,泡沫稳定性先增大后减小,在pH 6.9、表观气速2.4×10-3 m·s-1、装液量200 mL的操作条件下,气泡直径先减小后增大,富集比提高了3～5倍,回收率降低了34％～65％.     

糖-蛋白质混合体系泡沫分离过程研究

利用环流泡沫分离技术对若干糖 -蛋白质 (牛血清白蛋白 )混合模拟体系进行了分离实验 ,研究了 p H值对溶液表面张力和分离效果的影响 ,在综合考虑蛋白质泡沫夹带量、去除率、糖的损失率及分离因子的基础上 ,得到了泡沫分离的最优 p H值。研究结果表明 ,采用环流泡沫分离技术可以实现糖与蛋白质的分离 ,是生物多糖与蛋白质初级分离的一种有效方法     

高稳定水基泡沫技术应用及其研究进展

水基泡沫技术在水成膜泡沫灭火、泡沫排水、泡沫分离等领域中应用广泛,又因具有广谱、非燃爆、无毒和持续时间长等特点,而使得泡沫的军事应用前景也十分广阔。综述了水基泡沫技术的研究进展和应用现状,提出了技术研发的方向,对水基泡沫的深入研究和推广应用有一定的参考作用。     

泡沫分离法的应用与发展

综述了近年来泡沫分离法的研究进展,并对非泡沫分离,泡沫分离进行文献评述,主要介绍了泡沫分离在固体粒子,溶液中的离子,分子以及生物产品的分离方面的应用,指出了泡沫分离目前存在的问题及发展方向。     

含铜和含锌稀溶液的吸附泡沫分离技术的研究

运用自制的泡沫分离塔,以十二烷基硫酸钠为表面活性剂对泡沫吸附分离含铜及含锌溶液的操作参数进行了研究。考察了料液浓度、pH值、气体流量、表面活性剂浓度等因素对含铜和含锌溶液泡沫分离效果的影响。结果表明：最佳操作参数为pH值5．0,料液浓度0．125mmol／L,进料流速50mL/min,气体流量100mL/min,表面活性剂浓度0．25mmol／L。同时从理论上推算出泡沫吸附分离铜离子的最佳pH值范围为5．0左右。实验还通过改变孔板的孔径大小以改变气泡的尺寸,特别研究了泡沫尺寸对泡沫吸附分离的影响。     

泡沫分离技术的实验研究——回收废液中的金

<正>泡沫分离是一种新的分离技术,在国外研究工作已取得了不少成果.Jorne和Rubin在研究金属离子泡沫分离的基础上,提出的Goug chapman扩散双电层理论,阐述了利用相反电荷的金属离子与表面活性剂离子之间的静电吸引作用,达到金属离子的泡沫分离.Rubin和Lapp、Charewicz和Grives等人通过对泡沫分离金属离子的研究表明:pH值是一个重要的影响因素.同时,离子强度可以改变表面活性剂的选择性.Bruner和Stephan采用泡沫分离方法脱除洗涤剂厂排放的一级及二级污水中的表面活性剂,试验结果表明:塔式泡沫分离装置比槽式装置有更高的脱除率.     

含十二烷基苯磺酸钠废水的多级泡沫分离研究

采用多级泡沫分离装置对水中十二烷基苯磺酸钠(SDBS)进行分离富集,考察了表面活性剂溶液的浓度、离子强度、pH值、分离时间、气体流速等因素对水中十二烷基苯磺酸钠脱除率的影响。进一步采用四因素三水平正交实验进行分离条件的优化,结果表明溶液浓度为20 mg/mL,气体流速为20L/min,pH=10,离子强度为2×10-5mol/L时,分离5 min,可使SDBS的脱除率最高达到97%,三次平行试验SDBS的脱除率分别为96.61%、97.04%和93.93%。与单级环流泡沫分离塔(其脱除率为82%)相比,多级泡沫分离装置具有能耗比低、分离效率高的优点,具有更好的推广应用价值。     

pH对酪蛋白/十二烷基硫酸钠体系泡沫性能及泡沫分离酪蛋白的影响

为强化表面活性剂对起泡性差的蛋白质泡沫分离,以酪蛋白/十二烷基硫酸钠(SDS)为研究体系,用吊环法和Ross-Miles法分别研究了pH对酪蛋白/SDS体系表面张力、泡沫性能的影响,在此基础上考察了pH对SDS辅助酪蛋白泡沫分离效果的影响。结果表明,20℃条件下,随着pH下降,酪蛋白/SDS体系的表面张力下降,起泡高度变大,泡沫半衰期增长。在气速为120mL·min-1,SDS浓度为0.03g·L-1,酪蛋白浓度为0.05g·L-1,装液量为850mL条件下,SDS辅助酪蛋白泡沫分离的最佳pH为3.4,偏离了酪蛋白的等电点(pI=4.8),在此条件下酪蛋白泡沫分离的富集比为96.37,回收率为25.12%。     

阻尼分布式泡沫分离塔处理合成洗涤剂生产废水的研究与应用

研究了气液返混对泡沫分离的影响并采用阻尼分布构件改善了气液两相流动状态,提高了分离效率。在合成洗涤剂厂生产废水脱除LAS的分离中在一定的间径比、开孔率、气液比、孔径的条件下,阻尼分布式泡沫分离塔比空塔分离效率提高了近一倍,取得了很好的效果。     

泡沫分离技术在蛋白质多元体系分离中的应用

综述了泡沫分离蛋白质与糖,蛋白质与表面活性剂以及不同蛋白质的混合体系的研究进展,分析了泡沫分离技术在蛋白质分离中应用的前景并提出了需要解决的问题。     

连续泡沫分离蛋白质

本文以空气-明胶水溶液体系为研究对象，较为详细地考察了通气量、进料流量、进料浓度、进料位置、泡沫高度、溶液pH值等因素对连续泡沫分离明胶过程中明胶富集度变化的影响．     

泡沫分离回收水中低浓度磷酸三丁酯

以吐温系列表面活性剂采用泡沫法回收水中的微量磷酸三丁酯．实验结果表明，在本实验条件下，泡沫法可以回收水中的磷酸三丁酯，磷酸三丁酯的提浓率与残留率与起始磷酸三丁酯浓度、起始表面活性剂浓度和表面活性剂种类有关。     

Production of porous polylactic acid monoliths via nonsolvent induced phase separation

Polylactic acid (PLA) is one of the most promising polymers for use as the matrix of a bone scaffold. In this work, porous PLA monoliths are fabricated via nonsolvent induced phase separation using dichloromethane as a solvent and hexane as a nonsolvent. The PLA-dichloromethane-hexane compositions which undergo liquid–liquid phase separation followed by gelation are shown to allow for the production of high quality foams. Solvent exchange with methanol after aging the gel is found to substantially reduce shrinkage during drying. Using this simple, versatile and template-free method we produced PLA foams with porosities as high as ∼90.8%, specific surface area up to 54.14 m²/g, crystallinity up to 62.6% and compressive modulus ranging from 1.8 to 57 MPa. Depending on ternary mixture concentration and standing temperature a range of mesoporous and combined meso/macroporous morphologies suitable for use as a bone scaffold are produced.     

Structure–properties relations in flexible polyurethane foams containing a novel bio-based crosslinker

The structure, morphology and properties of PU foams containing the novel bio-based crosslinker 3-hydroxy-N,N-bis(2-hydroxyethyl)butanamide (HBHBA) were investigated in comparison with PU foams containing the conventional crosslinker diethanolamine (DEOA). FTIR results indicate that HBHBA increases the degree of microphase separation in the foam and hydrogen bond concentration in the hard domains, suggesting that the incorporation of HBHBA produces better ordering of hard domains as compared with DEOA-crosslinked foam. Uniquely, the tri-functional crosslinker, HBHBA, can act as a chain extender due to the presence of a low reactivity secondary hydroxyl, reducing the crosslink density of the HBHBA foam vs. that of DEOA foam. Concerning foam morphology, the lower reactivity of HBHBA tends to favor larger cell sizes and more complete cell opening as compared to the more reactive DEOA. This behavior may in turn be related to the onset of phase separation and the rate of viscosity build-up. Mechanical properties measurements indicate that the elongation at break and the tensile strength of the HBHBA foam are ∼33% and 41% higher than the DEOA foam, respectively. The HBHBA foam also exhibits 40% greater tear strength and 10% greater compression strength without any loss in resilience. These results indicate that this bio-based crosslinker enhances properties and has clear potential in molded foam applications.     

A review on the micro- and nanoporous polymeric foams: Preparation and properties

A great number of studies on new synthetic materials have been focused on the preparation of different porous polymers. This review explains the principles and techniques of polymeric foam formation and their features followed by an overview of papers on polymeric porous materials. Physical blowing agent, phase separation, leaching, etching, and thermal decomposition are the main techniques for foam formation that are briefly described. This discussion covers different polymeric foams with various morphologies, pore sizes, and properties. These polymeric foams can be applied for various purposes, including tissue engineering, membranes in separation process, electrical and thermal insulators, packaging, and scaffolds.     

Competitive foam separation of rare earth elements from aqueous solutions using a cationic collector

ABSTRACT

Competitive foam separation of two rare earth elements (REEs), Eu(III) and Tb(III), are investigated in this study in presence of ethylenediaminetetraacetic acid (edta) using cetylpyridinium chloride (CPC). The effects of pH, [edta]/Σ[REEs] and [CPC]/[edta] molar ratio, frother concentration, ionic strength and air-flow rate on the foam separation efficiency are also evaluated. At the optimal experimental condition, Eu(III)/Tb(III) separation factor of 141.56 is obtained. The kinetic data obtained at all the studied parameters are analyzed by the flotation first-order and second-order kinetic models. Eventually, a schematic flow-sheet for Eu(III)/Tb(III) separation is proposed.     

Separation of oil contaminants by surfactant-aided foam fractionation

The separation of oily contaminants out of aqueous/non-aqueous phases using foam fractionation with a surfactant was investigated. In the separation of the light oil (hexadecane), the eluted amount of oil and the o/w (oil/water) ratio increased with the weight percentage of SDS (sodium dodecyl sulfate); and the ratio actually remained the same above the CMC (critical micelle concentration) point (0.23 wt% of SDS). Most of the oil was eluted even at 49:1 initial o/w ratio with the surfactant. For the heavy oil (carbon tetrachloride), the eluted o/w ratio and the oil recovery had maxima at 0.05 and 0.1 wt% of SDS solution, respectively, even though the overall recovery of 20–30 % was much lower than that of 80–100 % in the light oil. It was speculated that emulsion formation might affect oil entrapment in the foams. Higher gas flow rates, in general, increased the oil recovery, but did not increase the o/w ratio in the effluents.     

Unstable Operation in an Acetaldehyde Purification Tower

There are many reasons, such as an inappropriate control system, improper hydraulic design, and operational faults, which can make a tower unstable. In this case, with the aid of simulation and checks on the control system, it has been confirmed using the foaming test that instability is due to foaming in the system. The method described in this article can be used for any separation system with instability problems.     

泡沫分离技术及其发展现状

探讨了泡沫分离技术的原理、泡沫分离设备及泡沫分离技术的研究进展。泡沫分离过程的性能受很多因素的影响 ,例如 ,进料液浓度、气泡尺寸、气体流量、泡沫的排液、进料位置、聚并、温度等。阐述了现有的几种新技术 ,如低重力条件操作、通过压力梯度而提高分离效率。此外 ,还简要介绍了泡沫分离塔中传质单元数和传质单元高度的概念。     

BUBBLE AND FOAM SEPARATION OF EMULSIFIED BITUMEN FROM TAR SAND WASTEWATER

Process waters generated by the steam purging of tar sand deposits in Vernal, Utah, were treated by means of second-stage foam separation and air flotation operations. Among the independent process variables considered were hydraulic detention time, air flowrate. temperature, and polymer or surfactant addition level. System performance evaluations were based on second-stage effluent levels of total organic carbon (TOC), chemical oxygen demand (COD), suspended solids (SS). total solids (TS), and turbidity. The results indicated that the most effective second-stage system studied was air flotation aided by polymer addition. Removals of TOC, COD, and SS accomplished by this system exceeded 98 percent.