A solid–solid extraction

When a vessel containing two equal-sized particle species is subjected to vibration with an acceleration significantly greater than 1g, the particle bed sometimes separates into two clear-cut layers, the bottom layer consisting only of the lighter particles. This paper shows that the above inverse density segregation can be used to perform a solid–solid extraction. A mixture of equal-sized glass and steel beads (1290 μm in mean diameter) did not separate into two layers under vibration. However, when equal-sized lead beads were added to the mixture and the three-component mixture was subjected to vibration the bed separated into two clear-cut layers, the top layer being the mixture of the three components, the bottom layer consisting only of glass beads. The scale effect and the underlying mechanisms of this solid–solid extraction are discussed.     

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     

Simultaneous extraction and purification of myricetin from Chamaecyparis obtusa by multi‐phase extraction with ionic liquid‐modified mesoporous MCM‐41

BACKGROUND: Multi‐phase extraction is a novel method for the simultaneous extraction and separation of myricetin from Chamaecyparis obtusa . In this research, an amino ionic liquid‐modified MCM‐41 was used as the sorbent and the sample was packed with it into a cartridge. A fixed volume of solvent was then use to extract the target compound with several repetitions and to remove the myricetin to the sorbent. The washing and elution of solvent were investigated. RESULTS: FT‐IR and element contents tests confirmed that the ionic liquid groups were successfully immobilized on MCM‐41. 0.184 mg myricetin was extracted with five repetitions of 1.0 mL methanol. Then 2.0 mL n‐hexane and water were removed all the interference and 1.0 mL methanol was purified 0.1 mg myricetin from 0.2 g ionic liquid‐modified MCM‐41. CONCLUSION: Base on a comparison with traditional extraction methods, the low deviation error (3.16%), small amount of solvent required, highly selective separation and stability of the proposed method justify continuing its development. Copyright © 2011 Society of Chemical Industry     

Structure–process–yield interrelations in nanocrystalline cellulose extraction

In order to improve the extraction of nanocrystalline cellulose (NCC) from sulfuric acid hydrolysis of chemical pulps, we have studied the effect of hydrolysis conditions on the degree of polymerization (DP), the extent of sulfation, morphological, and solid‐state characteristics of the extracted materials vis‐à‐vis yield. Our results demonstrate that sulfation plays a significant role in (i) determining the yield of, and (ii) imparting the unique solid‐state characteristics to, the extracted, H₂O‐insoluble cellulose nanomaterial from sulfuric acid hydrolysis. The hydrolysis process is itself proven to be highly reproducible, and NCC with high crystallinity (>80%) and a yield between 21% and 38% could be extracted from a fully bleached, commercial softwood kraft pulp using 64 wt.% sulfuric acid at 45–65°C after freeze drying. The NCC aggregates, with iridescent patterns typical of chiral nematic materials, are parallelepiped rod‐like structures which possess cross‐sections in the nanometer range and lengths orders of magnitude larger, resulting in high aspect ratios. The Ruland–Rietveld analysis was employed to precisely resolve X‐ray diffraction patterns and obtain information on crystallite size, crystalline and amorphous areas, and crystallinity of the extracted materials.     

Complexation chemistry in liquid–liquid extraction of rhenium

This review addresses the dearth of knowledge about the interaction of rhenium species with organic solvents during the liquid–liquid extraction of rhenium. To describe such interactions, the aqueous chemistry of rhenium in unlike media, the extraction mechanism and the salient role of thermodynamic properties are also discussed. Formation of a rhenium‐complexed species inorganic phase and competition between the extracted species during extraction is described by inner and outer sphere coordination. Emergence of a stabilized complex in a hydrophobic environment is greatly affected by the interaction of electrostatic and/or H‐bonding. The chemistry of liquid–liquid extraction of rhenium that can further assist future studies in this area is also relevant to other metal ion systems. © 2015 Society of Chemical Industry     

Polymer‐supported iminodiacetamides for selective mercury extraction

A new polymeric resin with iminodiacetamide functions has been prepared for the selective extraction of mercuric ions. This polystyrene sulfone amide‐based resin with a 9.6 mmol g^?1 amide content is able to selectively sorb mercury over many metal ions, including Cd(II), Zn(II), Fe(III), and Pb(II). Among these, Cd(II) and Zn(II) ions are not sorbed at all, and Fe(III) and Pb(II) ions show only trace absorptions (0.58 and 0.17 mmol/g, respectively) under the same conditions. The selectivity of the resin, its high mercury loading capacity (4.23 mmol g^?1), and its ability to regenerate via acetic acid make it a promising material for the large‐scale selective separation of mercuric ions from aqueous mixtures. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1316–1321, 2003     

Modified Soxhlet apparatus for high‐temperature extraction

Modification of a Soxhlet apparatus widely used for extraction is suggested. This modification is aimed at overcoming the main disadvantage of the Soxhlet apparatus for extraction, that the extraction takes place at around room temperature. The modified apparatus allows extraction to be performed with boiling solvent, which has obvious advantages when working with polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2013–2014, 2006     

A model for liquid-liquid extraction column performance — The influence of drop size distribution on extraction efficiency

A precise model for predicting liquid-liquid extraction column efficiency based upon assumed hydrodynamic, axial mixing and mass transfer behaviour has been formulated and solved numerically. The complex nature of the dispersed phase can be better described by drop-size-dependent residence time distribution (RTD). Both the variation of axial velocities due to drops of different sizes, i.e. forward mixing, and the axial dispersion for the drops of the same size have been considered in this model. The computed results reveal that the effects of both varying velocities and dispersion of drops on extraction efficiency are appreciable and cannot be neglected, and the efficiency may be overestimated if only a forward mixing model is adopted. The comparison of the experimental values of N_ODP with those predicted shows that the mass transfer data obtained in RDC agree well with the values predicted by the present model for the case of solute transfer in c→d direction, and are slightly higher than the predicted ones for the transfer in d→c direction.     

Natural colorant extraction from Cinnamomum camphora tree leaves of different maturities and its ultrasonic‐assisted extraction process

This study investigated natural colorant extraction from camphor tree leaves using a green and effective process. Ethanol, acetic acid, aqueous sodium carbonate and an aqueous solution of cellulase enzyme were used to examine the extraction performance, with and without the assistance of ultrasonics. Results showed that when subjected to changes in frequency and extraction time, ultrasonics is able to accelerate the extraction process and achieve a better yield for chlorophyll and anthocyanin extraction from fresh leaves compared with a traditional heating bath at similar temperatures. However, when an alkaline solvent was used to extract dark brown colorant from the old leaves, a traditional heating bath was found to be more effective than ultrasonic extraction. Cellulase enzyme failed to show its effectiveness in this study when serving as a colorant‐extracting solvent, regardless of the use of ultrasonics.     

Selective solid‐phase extraction of metal for water decontamination

Metal‐contaminated industrial effluent is a major concern for human health. Therefore, the removal of metal is of primary importance. In this study, metals were selectively extracted from water. Selective metal recovery was studied with a crown‐ether‐based polymer, wherein the selectivity was observed for strontium over lead. Parameters influencing the metal recovery, such as the contact time, adsorbent dosage, and metal‐ion concentration, were evaluated. Interestingly, the adsorption rate of strontium was exponentially increased for the initial 4 h, and lead was adsorbed exponentially after 6 h. Notably, 98% strontium adsorption and 64% lead adsorption were obtained in 24 h. The Langmuir adsorption isotherm was in good agreement and demonstrated that the reactive sites of the adsorbent were homogeneous with monolayer metal adsorption with an adsorbent. The Freundlich adsorption isotherm was not obeyed by both metals. The pseudo‐first‐order and pseudo‐second‐order kinetics indicated that strontium was adsorbed by chemisorption and lead was adsorbed by physisorption. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42849.     

liquid–liquid extraction of lactic acid with Alamine 336

The extraction of lactic acid (HL) from aqueous solutions by Alamine 336 (B) dissolved in toluene was studied. Experiments were performed in the temperature range of 25–60°C and for two amine concentrations of 20 and 40% (v/v) in toluene. The extent to which the organic phase (amine + toluene) may be loaded with lactic acid is expressed as a loading ratio, Z = C_HL /C_B. Z values are independent of the amine concentration and, hence, the extracted complex contains only one molecule of amine. Z decreases with increasing temperature. Experimental results indicate that the system presents overloading, i.e. Z > 1. The extraction equilibrium may be interpreted as a result of consecutive formation of three acid–amine species with stoichiometries of 1:1, 2:1 and 3:1.     

带分散网的屈尼塔的萃取实验研究

将微分散技术运用于萃取工艺,设计出带分散网的屈尼萃取塔实验装置。以水/粗磷酸/TBP+煤油为实验体系,研究该装置在湿法磷酸萃取净化过程中的应用,考察了转速、停留时间、相比对萃取和反萃过程的影响。实验得到最佳萃取工艺条件：转速为250 r/min、停留时间为20 min、相比为4∶1。在此条件下,磷酸萃取率为46.84%,萃取速率为0.281 5 g/s,全塔效率为25%,塔的理论当量高度为0.24 m。在最佳萃取和反萃操作条件下,磷酸的有效利用率为36.57%,Fe2+、F-、SO42-等3种杂质离子的去除率较高,均在95%以上。     

Simulation of hydrodynamics in RDC extraction columns using the simulation tool “ReDrop”

ReDrop is a simulation tool which can predict the behaviour of pulsed extraction columns on pilot-plant scale. Because it follows a certain number of drops during their entire lifetime in an extraction column, it can be seen as a Monte-Carlo solution of drop-population balances. ReDrop is based on single-drop models which have system-specific parameters. These parameters are determined from lab-scale experiments with single drops. In this study, ReDrop is extended to RDC extraction columns and simulations are carried out for the standard test systems toluene (d) + water (c) + acetone (c → d) and n-butyl acetate (d) + water (c). The calculated hold-up and Sauter mean diameter show good agreement with the experimental data obtained in pilot-plant scale experiments.     

Enzyme‐assisted water‐extraction of oil and protein from rice bran

Enzymatic water‐extraction of oil and proteins from rice bran was studied in a laboratory‐scale set‐up. The effects of the following enzymes – Celluclast 1.5L, hemicellulase, Pectinex Ultra SP‐L, Viscozyme L, Alcalase 0.6L and papain – on oil and protein extraction yields, and the level of reducing sugars in the extract were investigated. The results showed that Alcalase was most effective in enhancing oil and protein extraction yields. Papain was found to be superior to all carbohydrase enzymes but it gave lower yields than Alcalase. Celluclast 1.5L, hemicellulase, Pectinex Ultra SP‐L and Viscozyme L did not affect yields significantly but increased the level of reducing sugars in the extract. © 2002 Society of Chemical Industry     

Solvent extraction — the challenges of a “mature” technology

The solvent extraction area is perceived by some chemical engineers as being mature and fully developed. The present review shows that this is not the case. Many chemical engineering problems must be solved before equipment can be confidently designed from first principles. The review also outlines progress in extraction process chemistry, and in new techniques such as membrane extraction.     

Particle size effects on supercritical CO<Subscript>2</Subscript> extraction of oil-containing seeds

Rosehip seeds were milled, sieved, and extracted with 26.3 g/g substrate/h of supercritical carbon dioxide (CO₂) at 40°C and 300 bar. The extraction kinetics were characterized by an initial solubility-controlled period (8.78 g oil/kg CO₂ at 40°C and 300 bar), followed by a transition period to a final mass transfer-controlled process. The integral yield of oil approached an asymptotic value that was dependent on the particle size of the substrate: 57.1 g oil/kg dry oil-free substrate (large particles), 171.0 g/kg (medium-size particles), or 391.5 g/kg (small particles). Based on gravimetric determinations and microscopic analysis, our size-classification process segregated seed parts having different oil contents. Particles ≥0.85 mm were mainly composed of tough, lignified testa fragments devoid of oil, whereas particles ≤0.425 mm contained mostly brittle, oil-rich germ fragments. The segregation of seed in fractions with different oil contents may be a common occurrence in supercritical extraction experiments, especially for seeds with thick and/or hard testa and small germ, whose fractions can be separated by sieving.     

Separation of isopropanol from aqueous solution by salting‐out extraction

A novel salting‐out extraction process has been developed to separate isopropanol from aqueous solution. Potassium carbonate was experimentally shown to be effective in modifying the liquid–liquid equilibrium (LLE) of an isopropanol/water/hexane system in favour of the solvent extraction of isopropanol from an aqueous solution with hexane, particularly at suitable salt concentrations. Potassium carbonate enlarged the area of the two‐phase region. This effect essentially increased the distribution coefficient of isopropanol between hexane and water and increased the separation factor for isopropanol vs water, which is an important consideration in designing a solvent extraction process. The effects of potassium carbonate concentration, temperature and pH on the LLE were studied. Finally, a ?30 mm × 1200 mm reciprocating plate column (RPC) was tested to separate isopropanol from an aqueous solution. When isopropanol in an aqueous solution with composition of isopropanol/water = 1:0.95 (wt/wt) was extracted by hexane assisted with 30% (wt%) potassium carbonate aqueous solution, the alcohol–water ratio increased to 11:1 in the extract. © 2001 Society of Chemical Industry