Organic Solvent Phase Research Articles

Harvesting microalgae using ionic polyelectrolytes in an aqueous-organic two-phase system: Screening of separation parameters using model algal particles

Abstract Separation and recovery of microalgae from the aqueous medium that they reside in is difficult as a result of the nature of the algal cells, i.e., small cell size, density close to water, low concentration, and ability to stay suspended in water due to surface potential. In this study, an easy technique that can separate microalgae from aqueous phase to a water-immiscible organic phase utilizing the natural zeta potential of microalgae is reported. The technique involves the addition of the positively charged electrolyte, Mono/Poly-(diallyl dimethyl ammonium chloride, DADMAC), which then interacts with the negatively charged biomass. The particle-bound electrolyte results in the formation of a hydrophobic ensemble which in turn migrates the particles from the aqueous phase to hydrophobic organic solvent phase. Approximately 80–85% of cellulose beads (model particles) and 80–82% of algae cells were displaced into hexane phase. Studies also indicated that the technique could be used to extract lipids without subjecting algal cells to disruption. The results pave the way for developing a low-cost method to dewater and separate whole algal cells by utilizing the inherent charges they carry. We anticipate the results being a starting point for the development of new separation technology targeting bioprocessing industry.

Aromatic solvent-assisted interfacial polymerization to prepare high performance thin film composite reverse osmosis membranes based on hydrophilic supports

We report an aromatic solvent-assisted interfacial polymerization (IP) method to prepare high performance thin film composite reverse osmosis (RO) membranes based on a polyacrylonitrile support. The use of toluene and xylene as an organic solvent phase led to excellent water flux and unprecedentedly high NaCl rejection (∼99.9%), exceeding both the control membrane prepared using a conventional aliphatic solvent (n-hexane) and commercial RO membranes. The membrane prepared using n-hexane had a thick and moderately dense PA layer, due to the limited amine monomer diffusion, accounting for its relatively low performance. In contrast, the membranes fabricated using toluene/xylene had roof-like structures covering a thin and highly dense basal PA layer, which was formed by increased amine diffusion and an expanded miscible interface zone resulting from the enhanced miscibility of toluene/xylene with water. The excellent membrane performance achieved using toluene/xylene can be attributed to the thin and highly cross-linked basal PA layer.

Electrochemical monitoring of the co-extraction of water with hydrated ions into an organic solvent

An electrochemical cell based on the interface between two immiscible electrolyte solutions (ITIES) was designed and used to study the co-extraction of water with hydrated chloride ions from the aqueous to the organic solvent phase. The interfacial potential was controlled by the distribution of a common tetralkylammonium (TAA+) ion. Transfer of hydrated chloride ions is accompanied by the transfer of TAA+, decreasing its concentration on the aqueous side of the interface. Changes in the TAA+ concentration at the interface were monitored by measuring the open circuit potential (OCP). The proposed mechanism of TAACl transport involves a follow-up reaction with the co-extracted water molecules, leading to the formation of clusters of water containing TAACl in the organic phase.

Partitioning of Cs+ and Na+ ions by dibenzo-18-crown-6 ionophore in biphasic aqueous systems of octanol and ionic liquid

Abstract Molecular dynamics (MD) simulations were carried out to obtain molecular level insights on the behavior of Cs+/Na+ ions at the water–ionic liquid and water–octanol interface in the presence of dibenzo-18-crown-6 (DB18C6) ionophore with an aim to compare an ionic liquid (IL) to a octanol as receiving organic solvent phase. It was observed that the rate of phase separation for the octanol system was rapid as compared to the IL system. The free crown ethers (CE) were found to be highly solvated by the IL phase. A dual cationic exchange mechanism was observed at the [BMIM]/water interface. The [BMIM]+ cation was found to exchange with both the metal ions in aqueous phase as well as with the metal ion aided by the ionophore. The self-diffusion coefficient of the 1:2 complex (0.07×10−9 m2/s) at the octanol/water interface were found to be smaller than that of 1:1 complex (0.37 and 0.14×10−9 m2/s). It was observed that the surface tension of ILs decreased in the presence of complexes and free CE, whereas the surface tension of water was found to increase in presence of salts (Cs+NO3 − and Na+NO3 −). The experimentally determined value of D Cs was found to be quite high in IL phase (1.595) compared to the octanol phase (0.139) in presence of CE. The kinetics of Cs+ was found to be very fast having rate with values of k 1 ^ $\widehat {{k_1}}$ =1.79×10−12 s−1 and k 2 ^ $\widehat {{k_2}}$ =0.205×10−12 s−1 in IL and water phase, respectively. The present results may help us in understanding the role of diluents in the assisted metal ion extraction but also in the future design of diluents and ionophore.

Simultaneous Cell Disruption Extraction and Purification Followed by Two-phase Derivatization Procedure for the Determination of Organotin Compounds in Wet Biological Samples by GC–MS

Freeze-dried biological samples used for the determination of organotin compounds (OTCs) involve complicated or tedious pretreatment (e.g., freeze-drying) that may result in loss of analyst or contamination. In the present study, a rapid and accurate method for determination of five kinds of OTCs—monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPhT) and triphenyltin (TPhT) in fresh biota samples—was developed and further compared with freeze-dried tissues. It involved a sample preparation method of simultaneous extraction and purification of OTCs in fresh biological samples, which was developed with ultrasonic cell disruption and primary secondary amine (PSA) adsorption, and followed by two-phase (organic solvent and cell membrane phases) derivatization before the analysis by gas chromatography–mass spectrometry. The extraction efficiency from biota matrices was relatively better with the acetate/acetic acid and tropolone into methanol as extraction agents and primary secondary amine as grease-removing agents. The retention of cell membrane-like materials as well as 25% of ethyl acetate as co-extraction reagents used after centrifugation improved the targeted OTCs’ recoveries. The proposed method, under the optimal condition, has shown satisfactory performance in wet biological samples. The limits of detection obtained were less than 10 ng Sn g−1 ww (wet weight) for all analytes. Spiked recoveries were within the range 89–118% and the relative standard deviations were less than 7% (n = 5) when quantified by matrix-matched calibration curves. Finally, the applicability of this new method was further verified by comparing the results from wet and freeze-dried oyster tissues collected from two coastal cities in China.

Determination of N-nitrosodiphenylamine in meat canned food for children by the method of chromato-massspectrometry

This study demonstrates the results obtained from the GC/MS experimental determination of low concentrations of N-nitrosodiphenylamine in meat canned baby food in the concentration range of 0.027-3.89 mg/kg. The perfect conditions of sample preparation (extraction with organic solvent and solid phase extraction) as well as the application of the chromatography-mass spectrometry allowed us to detect N-nitrosodiphenylamine in samples of the meat canned baby food with high selectivity in concentrations ranged from 0.016 to 5 mg/kg when an error of 23% was assumed. The use of the reaction of transesterification of fatty acids by potassium methylate, the removal of the ester generated from the samples of canned meat by organic solvent (hexane), concentrating of N-nitrosodiphenylamine in the aqueous layer on the cartridges of an automatic solid-phase extraction system provided 99.94% extraction of N-nitrosodiphenylamine from the canned meat samples. The experiment has made evident the presence of N-nitrosodiphenylamine in the samples of canned meat (beef + chicken) with the help of mass-spectrometry method in the mode of full ion scanning using the AMDIS automatic mass-spectral identification system.

Integration of laminar flow extraction and capillary electrophoretic separation in one microfluidic chip for detection of plant alkaloids in blood samples

The design, construction and testing for integration of liquid-liquid extraction (EX) and capillary electrophoretic (CE) separation on one glass microchip was reported. In this EX-CE chip, a 1.5 cm-long and 200 μm-wide EX channel was used for extraction based on the two-phase laminar flow, followed by a single-cross CE unit for on-line analysis without any auxiliary devices. One side of the EX channel surface for the organic solvent phase was selectively modified to be hydrophobic while the surface of the other side for the aqueous phase remained hydrophilic, and the extraction product reservoir is also used as the sample reservoir for the subsequent chip separation in the CE channel. With the surface-directed liquid flow behavior and liquid level adjustment in various reservoirs of the EX-CE chip, no disturbance occurred between the extraction (EX) and capillary electrophoretic (CE) units. A small heating block was placed under the chip to accelerate solvent evaporation after liquid-liquid extraction. Sanguinarine (SAN), a plant alkaloid, was used as a model analyte to evaluate the performance of the EX-CE chip. The influences of organic solvent type and liquid flow speed on the extraction efficiency were investigated. Rhodamine 123 (Rh123) was used as an internal standard for quantification of Sanguinarine (SAN) in a physiological buffer (e.g. PBS) or blood samples. A good linearity in the concentration range of 0.05 μg mL−1 to 0.1 mg mL−1 for SAN in PBS was obtained, with the detection limit of 0.5 ng mL−1. Good repeatibilities for migration times (RSD of SAN is 0.63%, Rh123 is 0.91%, n = 5) and peak area ratio of SAN to Rh123 (RSD is 1.3%, n = 5) were obtained. For blood sample analysis, only 20 μL of sample was needed, and the whole analysis was finished in 17 min. In addition to the advantages in fast analysis speed, minimum sample handling, potential automation, the reported method showed an on-line sample pre-concentration capability.

An effective pathway for 5-brominemethylfurfural synthesis from biomass sugars in deep eutectic solvent

Background As a novel platform molecule, 5-bromomethylfurfural (5-BMF) has great potential in the production of varieties of value added chemicals as well as biofuels. Result To overcome the toxicity of the previous 5-BMF preparation process and environment issues, a brand new 5-BMF synthesis pathway was presented in this study. In a biphasic Deep Eutectic Solvent (DES)/MIBK reaction system, reactants and catalysts were enriched in the DES phase and the produced 5-BMF was continuously in-situ extracted to the organic solvent phase, which brought a 5-BMF yield of up to 50%(mass yield)from fructose. This biphasic reaction system for 5-BMF synthesis is of prominent advantages such as green and solvent recyclability. Conclusion This research may provide a new access and alternative for the production of platform chemicals and enriches the map of bio refinery concept.

Metal nanoclusters stabilized by pH-responsive microgels: Preparation and evaluation of their catalytic potential

Unstabilized, pH-responsive soluble crosslinked polymers (microgels) bearing pendant trialkylamino or pyridyl groups and containing size-controlled Au or Pd nanoclusters have been prepared by radical copolymerization in dilute solution, followed by loading with HAuCl4 or Pd(OAc)2 and chemical reduction. The hydrodynamic volume, the solubility and the partition between immiscible solvents of the microgels and of the resulting microgel-metal nanocomposites have been investigated, together with the variation of these parameters with the solution pH: separation of our microgel-containing metal nanoclusters from aqueous solutions can be accomplished by precipitation or by extraction into an organic solvent phase upon pH change, thus enabling their potential recovery. The catalytic performance of the microgels in the aerobic oxidation of benzyl alcohol (Au) and in Sonogashira coupling reactions (Pd) has been determined. The microgel-Au nanocomposites exhibit poor catalytic activity, whereas better results have been obtained in the copper-free Sonogashira reaction with microgel-Pd nanocomposites as precatalysts.

Identification of antifungal substances secreted by Bacillus subtilis Z-14 that suppress Gaeumannomyces graminis var. tritici

ABSTRACTBacillus subtilis strain Z-14 has biological control activity against the take-all fungus Gaeumannomyces graminis var. tritici (Ggt). In Petri dishes, the crude extract from B. subtilis Z-14 culture filtrate reduced take-all severity in roots of wheat seedlings by 91.3% and potted plants by 69.8% compared to the Ggt-inoculated control. Treatment with the crude extract also significantly (P < .05) increased growth of roots’ average length, and fresh weight in comparison with those of the Ggt-inoculated control. B. subtilis Z-14 culture filtrate was relatively thermally stable with 88.2% of the antifungal activity being retained after being heated at 100°C for 30 min. Meanwhile, the antifungal activity remained almost unchanged (>95%) when the culture filtrate was exposed to a pH ranging from 3 to 8, but significantly reduced in basic conditions. This activity was not transferred to the organic solvent phase after treatment with organic extraction agents. B. subtilis Z-14 culture filtrate exhibited a broad spectrum of antifungal activities against various phytopathogenic fungi. Three homologs of iturin A (C14–16) were characterised by liquid chromatography-mass spectroscopy (LC-MS) and electrospray ionisation mass spectrometry/mass spectrometry collision-induced dissociation (ESI-MS/MS CID).

Development of Nanoparticulate Hydrogel Loaded with Crossandra infundibuliformis Extract

Objective: Present study is aimed at formulation of hydrogel containing PLGA nanoparticles loaded with of Crossandra infundibuliformis (CI) extract. Leaf extract of Crossandra infundibuliformis has been reported to possess antibacterial, antifungal activity hence an attempt was done to improve the efficacy of the extract by formulating into nanoparticulate hydrogel which can be used as a feasible alternative to conventional formulations of Crossandra infundibuliformis extract with dual benefit of sustained release and advanced permeation characteristics for transdermal application. Methodology: In this study, the active ingredients present in the leaves of Crossandra infundibuliformis (CI) were extracted by cold maceration using ethanol. The crude extracts were developed into polymeric nanoparticles by nanoprecipitation method using PLGA as polymer, polyvinyl alcohol as surfactant and dimethyl sulphoxide as organic phase solvent. Polymeric nanoparticles were incorporated into gel matrix containing HPMC K4M as gel matrix base. Results: Polymeric nanoparticles showed nearly spherical shape with z-average 143-325nm, PDI in the range of 0.235- 0.299 and -2.08 mV to -3.58mV zeta potential with maximum % drug entrapment of 69%. Nanoparticulate hydrogel formulations showed high viscosity, neutral pH with good spreadability which is suitable for transdermal application. In vitro drug release showed initial burst release of 28.56 ± 0.93 % with prolonged drug release of 90.06± 0.93 % from optimized formulation up to 24 h. Conclusion: Nanoparticulate hydrogel can be used as carrier for transdermal delivery of extract of Crossandra infundibuliformis. Key words: Crossandra , Nanoparticle, hydrogel

Study of 3-Ethylamino-but-2-enoic acid phenylamide as a new ligand for preconcentration of lanthanides from aqueous media by liquid-liquid extraction prior to ICP-MS analysis

In the present work the potential of a new ligand 3-Ethylamino-but-2-enoic acid phenylamide (representing the class of enaminones) for selective preconcentration of lanthanides (La, Ce, Eu, Gd and Er) from aqueous medium is examined. Liquid-liquid extraction parameters, such as pH of the water phase, type and volume of organic solvent, quantity of ligand and reaction time are optimized on model solutions. Recovery of lanthanides by re-extraction with nitric acid makes the LLE procedure compatible with Inductively Coupled Plasma Mass Spectrometry. Spectral and non-spectral interferences are studied. Two isotopes per element are measured (with exception of La) for dynamic evaluation of the potential risk of spectral interference in variable real samples. The selectivity of complex formation reaction towards concomitant alkali and alkali-earth elements eliminates the interferences from sample matrix. Subjecting the standards to the optimized extraction procedure in combination with Re as internal standard is recommended as calibration strategy. The accuracy of developed method is approved by analysis of CRM Bush branches and leaves (NCS DC 73348) and recovery of spiked water and plant samples. The method's limits of detection for both studied objects are in the ranges from 0.2 (158Gd) to 3.7 (139La) ngl−1 and 0.02 (158Gd) to 0.37(139La) ngg−1 for waters and plants respectively. The studied compound is an effective new ligand for preconcentration/separation of lanthanides from aqueous medium by LLE and subsequent determination by ICP-MS.

One-pot preparation of polyimide/Fe3O4 magnetic nanofibers with solvent resistant properties

A series of solvent resistant magnetic polyimide/Fe3O4 (PI/Fe3O4) nanofibers were prepared by electrospinning the polyamide acid/ferric acetylacetonate (PAA/Fe(acac)3) mixed solutions and followed by a thermal treatment procedure. Samples were fully characterized in terms of FTIR, SEM, TEM, XRD and vibrating sample magnetometer (VSM). PI/Fe3O4 nanofibers structure and performance can be tuned by varying the thermal treatment procedure and Fe(acac)3 loading amount as well. Results revealed the complete transformation from PAA to PI after thermal treatment procedure, and the Fe3O4 particles dispersed relatively well, and mainly in the outer sphere of PI nanofibers under optimal conditions. VSM results showed that the saturation magnetization of PI/Fe3O4 nanofibers with a Fe(acac)3 loading amount of 21% can reach up to 10.46 emu/g. The one-pot prepared magnetic PI/Fe3O4 nanofibers were stable in most common organic solvents. This methodology can be scaled up and the obtained nanofibers could be an encouraging candidate for the template of adsorption, separation and catalysis, especially in the organic solvent phase.

Microreactor Mixing-Unit Design for Fast Liquid-Liquid Reactions

Abstract Based on previous work studying complex microreactors, it was desired to further improve the mixing efficiency by varying the mixing unit design for fast liquid-liquid reactions. Different flow regimes were studied, including slug flow, parallel flow, and drop flow. The two-phase hydrolysis of 4-nitrophenyl acetate in sodium hydroxide solution was used to evaluate the overall volumetric mass transfer coefficients (K org a) as a function of the average rate of energy dissipation (ε) for each microreactor design and all flow regimes. The liquid-liquid systems investigated used n-butanol or toluene as the organic phase solvent and a 0.5-M NaOH aqueous solution. The use of surfactant was also investigated with the toluene- water system. All microreactor geometry designs were based on contraction–expansion repeating units with asymmetric obstacles to aid the breakup of slugs and desynchronize the recombination of split streams. The investigated designs were chosen to avoid the formation of the parallel flow regime, contrary to curvature-based mixing-unit designs. The microreactor design can then be optimized to reduce the ε required to reach drop flow, since K org a has been found to be constant at equal ε for a given solvent system in this flow regime, regardless of the reactor selection. Additionally, the “3/7th” scaleup rule was applied and confirmed with the LL-Triangle mixer. It was found that, for low interfacial-tension systems (i.e., n-butanol-water), the onset of drop flow occurred at a lower ε for the LL-Triangle mixer when compared with the Sickle or LL-Rhombus mixers.

ChemInform Abstract: The Photodegradation of Polybrominated Diphenyl Ethers (PBDEs) in Various Environmental Matrices: Kinetics and Mechanisms

AbstractReview: 126 refs.

Brönsted and Lewis acid ZSM-5 zeolites for the catalytic dehydration of glucose into 5-hydroxymethylfurfural

Three different acid ZSM-5 zeolites (H-, Fe- and Cu-ZSM-5) have been prepared and tested in the catalytic dehydration of glucose into 5-hydroxymethylfurfural (HMF). A commercial NH4-ZSM-5 zeolite (MFI) was modified by thermal or ion-exchange treatments in order to create Brönsted and Lewis acid sites. The zeolitic structure is preserved, and the resulting acid zeolites have demonstrated to be active in the glucose dehydration. The influence of different experimental variables, such as reaction time and temperature, substrate:catalyst molar ratio, volume of the organic solvent and aqueous phase, as well as the density and nature of acid sites, on the catalytic behaviour was investigated. Under the optimal reaction conditions, by using a biphasic NaCl (20wt%) aqueous solution/methyl isobutyl ketone (MIBK) system, a glucose conversion of 80% and a HMF yield of 42% were achieved at 195°C, after only 30min, using H-ZSM-5, which has the lowest Lewis/Brönsted molar ratio among the prepared zeolites. The reutilization of this catalyst was also examined.

Extraction of p-coumaric acid from agricultural residues and separation using ‘sugaring out’

We investigated the extraction of para-coumaric acid (pCA) from different agriculture residues (corn stover, sugarcane bagasse, sorghum stalk, pearl millet stalk, green gram shell, groundnut shell, sesame shell) using sugarcane bagasse alkaline hydrolysis and separation of pCA using sugaring out - a new phase separation method. Primary screening of different feed stocks was by alkaline hydrolysis with 2M NaOH for 6 h at room temperature. Sugarcane baggase resulted into significant amount of pCA (1.1 g/L) and small amount of ferulic acid (FA) (0.23 g/L). The optimized alkaline hydrolysis conditions (2 M NaOH and 16 h) resulted into maximum pCA release of 2.0 g/L. The pCA was separated from alkaline hydrolysate using sugaring out, a two phase separation method that results in aqueous phase and the organic solvent (acetonitrile) phase. Sugaring-out separated more than 90% of the pCA from the alkaline hydrolysate. Results of HPLC using standard pCA and FA showed that the main component of the separated top (organic solvent) phase was pCA rather than FA.

Extraction of Picric Acid from Wastewater by a Secondary Amine (Amberlite LA2) in Octan-1-ol: Equilibrium, Kinetics, Thermodynamics, and Molecular Dynamics Simulation

The paper deals with the equilibrium and kinetic studies on the reactive extraction of picric acid (HPc: 0.021–0.061 kmol·m–3) using Amberlite LA2 (ALA2; 0.235–1.175 kmol·m–3), a secondary amine, dissolved in an active diluent, octan-1-ol. On the basis of the values of the loading factor (Z < 0.5), the interaction between the molecules of HPc and ALA2 takes place by forming 1:1 solvates in the organic solvent phase and was confirmed from Fourier transfoem infrared analysis. The effect of the temperature (298.2, 308.2, and 318.2 K) on the performance of extraction is evaluated, and the thermodynamic parameters (entropy and enthalpy) are determined. The mass-transfer coefficient (kL = 7.12 × 10–4 m·s–1) of picric acid in octan-1-ol is estimated experimentally to establish the kinetics of the reaction. The Hatta number is found to be in the range of 0.009–0.011, suggesting a very slow extraction reaction occurring in the bulk of the solvent phase. The reaction order is 1.2 with respect to HPc and 0.7 order w...

Separation of Switchgrass Bio-Oil by Water/Organic Solvent Addition and pH Adjustment

Applications of bio-oil are limited by its challenging properties including high moisture content, low pH, high viscosity, high oxygen content, and low heating value. Separation of switchgrass bio-oil components by adding water, organic solvents (hexadecane and octane), and sodium hydroxide may help to overcome these issues. Acetic acid and phenolic compounds were extracted in aqueous and organic phases, respectively. Polar chemicals, such as acetic acid, did not partition in the organic solvent phase. Acetic acid in the aqueous phase after extraction is beneficial for a microbial-electrolysis-cell application to produce hydrogen as an energy source for further hydrodeoxygenation of bio-oil. Organic solvents extracted more chemicals from bio-oil in combined than in sequential extraction; however, organic solvents partitioned into the aqueous phase in combined extraction. When sodium hydroxide was added to adjust the pH of aqueous bio-oil, organic-phase precipitation occurred. As the pH was increased, a bi...

Novel mode of liquid-phase microextraction: A magnetic stirrer as the extractant phase holder.

In the present study, a novel configuration of liquid-phase microextraction was proposed, in which a magnetic stirrer with a groove was used as the extractant phase holder. It was termed as magnetic stirrer liquid-phase microextraction. In this way, the stability of the organic solvent was much improved under high stirring speed; the extraction efficiency was enhanced due to the enormously enlarged contact area between the organic solvent and aqueous phase. The extraction performance of the magnetic stirrer liquid-phase microextraction was studied using chlorobenzenes as the probe analytes. A wide linearity range (20 pg/mL to 200 ng/mL) with a satisfactory linearity coefficient (r(2) > 0.998) was obtained. Limits of detection ranged from 9.0 to 12.0 pg/mL. Good reproducibility was achieved with intra- and inter-day relative standard deviations <4.8%. The proposed magnetic stirrer liquid-phase microextraction was simple, environmentally friendly and efficient; compared to single-drop microextraction, it had obvious advantages in terms of reproducibility and extraction efficiency. It is a promising miniaturized liquid-phase technology for real applications.