Extraction Efficiency Of Phenolics Research Articles

Determination of Phenols Isomers in Water by Novel Nanosilica/Polydimethylsiloxane-Coated Stirring Bar Combined with High Performance Liquid Chromatography-Fourier Transform Infrared Spectroscopy

A novel nanosilica/polydimethylsiloxane (SiO2/PDMS) coated stirring bar was adopted in the sorption extraction (SBSE) of phenols in water, and the high performance liquid chromatography-fourier transform infrared spectroscopy (HPLC-FTIR) was subsequently used to determination of phenol concentration. The SiO2/PDMS coating was prepared by sol-gel method and characterized with respect to morphology and specific surface area. The results of field-emission scanning electron microscope (FE-SEM) and N2 adsorption-desorption as well as phenol adsorption experiments denoted that SiO2/PDMS has larger surface area and better adsorption capacity than commercial PDMS. The extraction efficiency of phenol with SiO2/PDMS coated stirring bar was optimized in terms of ion strength, flow rate of phenol-involved influent, type of desorption solvent and desorption time. More than 75% of phenol desorption efficiency could be kept even after 50 cycles of extraction, indicating the high stability of the SiO2/PDMS coated stirring bar. Approximately 0.16 mg/L 2, 5-dimethylphenol (2, 5-DMP), which was 34-fold more toxic than phenol, was detected in water through HPLC-FTIR. However, 2, 5-DMP could be oxidized to 5-methy-2-hydroxy benzaldehyde after disinfection in drinking water treatment process. Therefore, the proposed method of SiO2/PDMS-SBSE-HPLC-FTIR is successfully applied in the analysis of phenols isomers in aqueous environment.

The use of a multilayer perceptron (MLP) for modelling the phenol removal by emulsion liquid membrane

Extraction of phenol from aqueous solution was studied using emulsion liquid membrane (ELM). In this study, due to the extreme complexity and non linearity of ELM process, a multilayer perceptron (MLP) was developed to predict the extraction efficiency of phenol. The effect of operational parameters such as: the ratios of volume ratio of internal phase to organic phase, volume ratio of emulsion to aqueous external phase, the emulsification speed and time, the surfactant concentration, the extractant and sodium hydroxide concentrations were studied to optimize the conditions for maximum removal of phenol. The results showed that a network with 3 hidden neurons was highly accurate in predicting the extraction efficiency (more than 98%). This accuracy was reflected by high correlation coefficient R=0.99 and a root mean square error below 0.5. The result indicated that the MLP model explained in this study is an applied tool to predict the extraction efficiency of phenol by ELM.

Demulsification of Remaining Waste (Water In Oil Emulsions) After Removal Of Phenol In Emulsion Liquid Membrane Process

The aim of present work is to study the removal of phenol present in aqueous feed solution by the emulsion liquid membrane technique using kerosene as a diluent, sodium hydroxide as a stripping agent, and sorbitan monooleate (Span 80) as a surfactant. The parameters studied were: surfactant concentration, volume ratio of membrane phase to internal phase, and stirring speed. It was found that more than 98% of phenol can be removed at the conditions were surfactant concentration 2% (v/v), volume ratio of membrane phase to internal phase 5:1 and stirring speed 400 rpm. Maximum phenol extraction efficiency at 7 minutes of process time was observed. It was found that there was a good agreement between the standard kerosene and the upper layer that resulted after the demulsification of the remaining waste by applying centrifuge. Thus, it is possible to reuse this layer to prepare a new emulsion of the membrane phase.
 

Solvent extraction of phenol from aqueous solution with benzyl 2‐ethylhexyl sulfoxide as a novel extractant

In this paper, we synthesized a novel structure of sulfoxide, benzyl 2‐ethylhexyl sulfoxide (BSO), and evaluated its performance for extracting phenol. The influences of several variables on phenol extraction were investigated, including equilibrium time, pH value, temperature, and salts in the aqueous phase. It was found the BSO dissolved in kerosene was an effective extractant for the recovery of phenol from an aqueous solution at pH = 2. The transfer mechanism of phenol into the organic phase was proved to be the solvation reaction by BSO through hydrogen bonds as a phenol: BSO 1:1 complex. The temperature variation tests showed that the extraction process is exothermic, and phenol extraction efficiency decreased with increased reaction temperature. Phenol could be efficiently stripped from the loaded organic phase with a sodium hydroxide solution. The results obtained establish that the BSO/kerosene system has potential for practical applications in the recovery of phenol from aqueous solutions.

Continuous Droplet-Based Liquid-Liquid Extraction of Phenol from Oil

Multiphase droplet-based and continuous liquid-liquid extraction (LLE) of phenol from oil is studied in a low width-to-height aspect ratio polymethylmethacrylate (PMMA)-based microchannel reactor. The extraction efficiency of phenol from the dispersed phase consisting of silicone oil to the external continuous water phase is studied as a function of the flow rate ratio of the two immiscible phases. This paper demonstrates that for enhancing the extraction efficiency of phenol from silicone oil to water in droplet-based microfluidic reactors, a low flow rate ratio of the external continuous phase, Qc, to dispersed oil phase, Qd, is preferable.

Phenolic composition, antioxidant and anti-inflammatory activities of extracts from Moroccan Opuntia ficus-indica flowers obtained by different extraction methods

The objectives of this study were to compare the phenolic extraction efficiency of four extraction procedures, to explore the extract phenolic profile by HPLC-DAD-ESI-MS and to evaluate the antioxidant and anti-inflammatory activities of cactus flowers from Morocco. accelerated solvent extraction (ASE) with 80% acetone in water at 80°C gave rise to extracts with higher yields of total polyphenols, procyanidins and flavonoids. The qualitative analysis of the phenolic composition showed that these extracts were composed mainly by flavonol glycosides in addition to hydroxycinnamic acids which were detected in the extracts for first time. Our study also revealed the high antioxidant and anti-inflammatory potential of cactus pear flower extracts. In light of the obtained results, cactus flowers are a good source of polyphenols that could be used in foods, cosmetics or pharmaceutical products, thus contributing to diminish the environmental impact of cactus by-products and to its valorization.

Operating Conditions of Hollow Fiber Supported Liquid Membrane for Phenol Extraction from Coal Gasification Wastewater

The extraction and recycling of phenol from high concentration coal gasification wastewater has been studied using polypropylene (PP) hollow fiber membrane and polyvinylidene fluoride (PVDF) hollow fiber membrane as liquid membrane support, the mixture of tributyl phosphate (TBP) and kerosene as liquid membrane phase, and sodium hydroxide as stripping agent in the process of extraction. The experiments investigated the effect of the operating conditions of the hollow fiber supported liquid membrane, such as aqueous phase temperature and the connection forms of membrane modules, on the extraction efficiency of phenol from high concentration coal gasification wastewater. The conclusions obtained from lab scale experiments provided guidance for scale-up experiments. So, in the scale-up experiments, three membrane modules connected in parallel, then three membrane modules connected in series were used to increase the treatment capacity and improve the treatment effect, under the operating conditions of wastewater temperature 20 ˚C, PH 7.5~8.1, flow rate 100 L/h and the concentration of stripping phase 0.1 mol/L, stripping phase flow rate 50 L/h, the extraction efficiency of the PP-TBP supported liquid membrane system was 87.02% and the phenol concentration of effluent was 218.14mg/L. And the phenol concentration of effluent met the requirements of further biodegradation treatment.

Effect of extraction method on phenolic content and antioxidant activity of mistletoe extracts from Viscum album subsp. abietis

AbstractThe total content of polyphenols and flavonoids determined in the same plant and their corresponding antioxidant activities may vary widely, depending on the extraction conditions applied. This study was conducted to optimise the extraction conditions of phenolics and flavonoids from the mistletoe plant. Various extraction methods, i.e. ultrasound-assisted extraction technology, maceration, maceration with stirring, accelerated solvent extraction (ASE), and extraction under reflux were evaluated for their percentage extraction of polyphenols (TPC) and flavonoids (TFC) from Viscum album subsp. abietis. In addition, the anti-radical activity of extracts was analysed using the 2,2-diphenyl-1-picrylhydrazyl method. The effects of temperature, solvent type, and concentration on the phenolic extraction efficiency and antioxidant activity were studied using chemometric and statistical methods. The results showed that the extracts of V. album subsp. abietis contained large amounts of polyphenols and flavonoids (up to 57.673 mg g−1 and 9.955 mg g−1 of dry extract, respectively) and exhibited potent antioxidant activity, hence representing promising sources of powerful antioxidants. Due to its high extraction efficiency and considerable saving of time and solvent, ASE was more effective than the other extraction techniques. Extracts prepared with water-polar solvent mixtures displayed the highest TPC, TFC, and antioxidant activity, while organic polar solvents were the least efficient extractants.

Separation of Phenols from Oil Using Imidazolium-Based Ionic Liquids

Phenolic compounds, which are important substances in industry, are mainly derived from coal liquefaction oil, coal tar, and petroleum, and also from biomass via pyrolysis. However, the traditional process of separation of phenols from oil using water, NaOH, and H2SO4 causes serious environmental problems. In this work, imidazolium-based ionic liquids (ILs) were used to extract phenol from a model oil of hexane and phenol in order to reduce environmental risk. It was found that these ILs could successfully separate phenols from hexane, and a small amount of [Bmim]Cl, equimolar to that of phenol in hexane, was enough to extract phenol with a high extraction efficiency of 99%. Anions of imidazolium-based ILs have a significant influence on the phenol extraction efficiency, which follows the order: Cl– > Br– > BF4– > PF6–. But the cation of these ILs shows a relatively small influence on the extraction. Particularly, [Bmim]Cl shows best performance in terms of phenol extraction efficiency. Furthermore, it is not sensitive to temperature changes and can be performed at ambient temperature. The extracted phenol in ILs could be recovered by evaporation, and the regenerated ILs could be reused for four cycles with no obvious loss in the phenol extraction efficiency. [Bmim]Cl was also used to extract phenols from real coal liquefaction oil, and the extraction efficiency of phenols could reach 90%.

Characterization of Phenol and Alkyl Phenols in Organic Matrixes with Monoethylene Glycol Extraction and Multidimensional Gas Chromatography/Mass Spectrometry

The use of monoethylene glycol as an extraction medium for removing phenol and alkyl phenols in organic matrixes such as hydrocarbons is introduced and combined with a practical analytical multidimensional gas chromatography approach. The analytical approach has been successfully developed for the characterization of phenol, cresols, xylenols, and alkyl phenols like 4-ethylphenol and 2,3,5-trimethylphenol. The technique employs a single-step extraction of the analytes with monoethylene glycol and sonication, followed by multidimensional gas chromatography with mass spectrometry in selected ion monitoring mode for the detection and quantitation. Extraction efficiency of phenol approached 100% while cresols, xylenols, and 4-ethylphenol were 97% or higher and 2,3,5-trimethylphenol was better than 91% under the analytical conditions used. With the technique described, a complete analysis can be conducted in less than 16 min. Reproducibility of area counts at two levels, namely, 5 ppm(w) and 50 ppm(w) over a period of 2 days were found to be less than 4% (n = 20). The analytes of interest was found to be linear over a range from 100 ppb(w) to 250 ppm(w) with correlation coefficient of at least 0.999 and detection limit of 50 ppb(w) . Spike recoveries from 500 ppb(w) to 250 ppm(w) for all analytes range from 96 to 102%.

Distribution of almond polyphenols in blanch water and skins as a function of blanching time and temperature

The distribution of polyphenols in blanched almond skins and blanch water, as a function of time and temperature, was quantified using negative ion electrospray time-of-flight mass spectrometry (ESI TOF MS). Almonds were blanched in 25° (RT) and 100°C (HW) water for up to 10min. At 10min, ∼30% (25°) and 90% (100°C) of the polyphenols quantified had leached from the skins into the blanch water. Many of the compounds precipitated from the blanch water due to limited water solubility, as evidenced by a logarithmic fit to kinetic data (1st order kinetics). The rate of procyanidin degradation into smaller polymeric units (e.g., catechin and epicatechin) also increased as a function of time and temperature. Finally, hydration in RT water increased the extraction efficiency of phenolics by 25%. This work shows that the blanch water, in particular the 100°C blanch water, was rich in polyphenols and supports exploration of alternative uses for blanch water.

Polypyrrole/graphene composite‐coated fiber for the solid‐phase microextraction of phenols

A polypyrrole (Ppy)/graphene (G) composite was developed and applied as a novel coating for use in solid-phase microextraction (SPME) coupled with gas chromatography (GC). The Ppy/G-coated fiber was prepared by electrochemically polymerizing pyrrole and G on a stainless-steel wire. The extraction efficiency of Ppy/G-coated fiber for five phenols was the highest compared with the fibers coated with either Ppy or Ppy/graphene oxide (GO) using the same method preparation. Significantly, compared with various commercial fibers, the extraction efficiency of Ppy/G-coated fiber is better than or comparable to 85 μm CAR/PDMS fiber (best extraction efficiency of phenol, o-cresol, and m-cresol in commercial fibers) and 85 μm polyacrylate (PA) fiber (best extraction efficiency of 2,4-dichlorophenol and p-bromophenol in commercial fibers). The effects of extraction and desorption parameters such as extraction time, stirring rate, and desorption temperature and time on the extraction/desorption efficiency were investigated and optimized. The calibration curves were linear from 10 to 1000 μg/L for o-cresol, m-cresol, p-bromophenol, and 2,4-dichlorophenol, and from 50 to 1000 μg/L for phenol. The detection limits were within the range 0.34-3.4 μg/L. The single fiber and fiber-to-fiber reproducibilities were <8.3 (n=7) and 13.3% (n=4), respectively. The recovery of the phenols spiked in natural water samples at 200 μg/L ranged from 74.1 to 103.9% and the relative standard deviations were <3.7%.

Extraction of phenol from aqueous solutions by means of supported liquid membrane (MLS) containing tri- n-octyl phosphine oxide (TOPO)

This paper deals with the liquid–liquid extraction and the facilitated transport through a supported liquid membrane (SLM) system of aqueous phenol using tri -n-octyl phosphine oxide (TOPO) dissolved in an appropriate organic solvent. Phenol has been quantitatively extracted from aqueous acidic solutions using TOPO dissolved in kerosene as organic phase. The effect of TOPO concentration dissolved in kerosene on the extraction efficiency reveals that TOPO combined with phenol in the ratio of 1:1. Using a flat-sheet SLM (FSSLM) system, more than 65% of the initial phenol content in the feed phase was extracted and stripped in a NaOH aqueous receiving phase. The important operational variables affecting the facilitated transport of phenol through the FSSLM system studied are concentration of TOPO, membrane viscosity, feed phase pH, initial phenol concentration, polymeric support type and membrane stability. Regardless of its comparatively low extraction efficiency of phenol, the SLM based on TOPO exhibits higher long-term stability as compared to tributyl phosphate (TBP). Elaborated SLM system retained its stability and initial performance during the 5 days long experiment contrary to the TBP-SLM system where a time dependent negative tendency (transport efficiency decline) was observed.

Phenolic composition and antioxidant properties of some traditionally used medicinal plants affected by the extraction time and hydrolysis

Polyphenolic phytochemicals in traditionally used medicinal plants act as powerful antioxidants, which aroused an increasing interest in their application in functional food development. The effect of extraction time (5 and 15 min) and hydrolysis on the qualitative and quantitative content of phenolic compounds and antioxidant capacity of six traditionally used medicinal plants (Melissa officinalis L., Thymus serpyllum L., Lavandula officinalis Miller, Rubus fruticosus L., Urtica dioica L., and Olea europea L.) were investigated. The content of total phenols, flavonoids, flavan-3-ols and tannins was determined using UV/Vis spectrophotometric methods, while individual phenolic acids, flavones and flavonols were separated and detected using HPLC analysis. Also, to obtain relevant data on the antioxidant capacity, two different assays, (2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging and ferric reducing/antioxidant power (FRAP) assays were used. The extraction efficiency of phenolics, as well as the antioxidant capacity of plant extracts, was affected by both prolonged extraction and hydrolysis. The overall highest content of phenolic compounds was determined in hydrolyzed extract of blackberry leaves (2160 mg GAE/L), followed by the non-hydrolyzed extract of lemon balm obtained after 15 min of extraction (929.33 mg GAE/L). The above extracts also exhibited the highest antioxidant capacity, while extracts of olive leaves were characterized with the lowest content of phenolic compounds, as well as the lowest antioxidant capacity. The highest content of rosmarinic acid, as the most abundant phenolic compound, was determined in non-hydrolyzed extract of lemon balm, obtained after 15 min of extraction. Although the hydrolysis provided the highest content of polyphenolic compounds, longer extraction time (15 min) was more efficient to extract these bioactives than shorter extraction duration (5 min). The distribution of detected phenolic compounds showed a wide variability with regard to their botanical origin. Examined medicinal plants showed to be a valuable supplement to a daily intake of bioactive compounds.

Evaluation of the extraction efficiency for polyphenol extracts from by‐products of green kiwifruit juicing

SummaryThe health benefits of fruits are attributable in part to their bioactive components such as phenolics and pectic polysaccharides. By‐products derived from kiwifruit processing can be a good source of such bioactive compounds. Extracts were produced using different concentrations of ethanol in water (0%, 30%, 50%, 74% and 96% v/v) from by‐products (skin, residue and pulp) of the green‐fleshed kiwifruit (Actinidia deliciosa‘Hayward’) juicing process. The amounts of phenolic compounds and uronic acid (UA) as well as the phenolic composition in each extract were determined. Results show that different by‐products contained different concentrations of phenolics and pectic polysaccharides. Based on total phenolic contents, 96% v/v ethanol appeared to be the best extraction medium. The 30% or 74% ethanolic dilution was the second best medium for phenolic extraction from skin and pulp/residue, respectively. Water was a good medium for extracting satisfactory quantities of phenolics as well as the highest concentration of pectic polysaccharides. Phenolic profiling by high‐performance liquid chromatography (HPLC) was used to detect individual phenolic compounds in an extract. Results using HPLC showed that alkali pre‐treatment has improved the extraction efficiency of phenolics as a function of alkali concentration, fruit tissue type, extraction media, by‐product preparation method, and class of polyphenols. As a result more efficient methods for both extraction and characterisation of polyphenols could be evaluated.

Phenolic content and antioxidative capacity of green and white tea extracts depending on extraction conditions and the solvent used

The efficiencies of different solvents in the extraction of phenolics from bagged and loose leaves of white and green tea, after different extraction times, as well as the antioxidative capacity of the obtained extracts, were investigated. The developed HPLC method has the potential to separate and determinate 17 phenolics widely distributed in plants, but in investigated tea extracts only four catechins and traces of three flavonols and one flavone were separated and detected based on comparison with authentic standards. The extraction efficiency of phenolics depended strongly on the time of extraction and the solvents used. The extraction of catechins from green tea was significantly affected by the form (bagged or loose) of the tea, whereas this effect was shown not to be statistically significant for white tea. Green tea was a richer source of phenolics than was white tea. The extraction of phenolics from white tea by water could be accelerated by the addition of lemon juice. Aqueous ethanol (40%) was most effective in the prolonged extraction of catechins. The antioxidative capacity of the investigated tea extracts correlated with their phenolic content.

Optimization of phenolics and dietary fibre extraction from date seeds

This work was conducted to optimise extraction conditions of phenolics and dietary fibre from date seeds. The effects of solvent to sample ratio, temperature, extraction time, number of extractions and solvent type on phenolic extraction efficiency were studied. At two-stage extraction, each stage 1h duration at 45°C with a solvent to sample ratio of 60:1, is considered optimum. Acetone (50%), and butanone were the most efficient solvents for extraction and purification, increasing the yield and phenolic contents of seed concentrate to 18.10 and 36.26g/100g, respectively. The total dietary fibre of seeds (57.87g/100g) increased after water and acetone extractions to 83.50 and 82.17g/100g, respectively. Nine phenolic acids (free and liberated) were detected in seeds with p-hydroxybenzoic (9.89mg/100g), protocatechuic (8.84mg/100g), and m-coumaric (8.42mg/100g) acids found to be among the highest. After extraction and purification, total phenolic acid content increased significantly from 48.64 to 193.83mg/100g. Protocatechuic, caffeic and ferulic acids were the major phenolic acids found in the concentrates. Based on this study, we believe date seed concentrates could potentially be an inexpensive source of natural dietary fibre and antioxidants and possibly used as a functional food ingredient.

Recovery of Phenols Using Liquid Surfactant Membranes Prepared with Newly Synthesized Surfactants

Abstract Extraction and stripping equilibrium of phenol, p-cresol, and p-chlorophenol were studied with an organic solution containing a newly synthesized surfactant and an aqueous alkaline solution as a stripping phase. A cationic surfactant showed the highest extraction ratio of phenol among several surfactants used in this study. The magnitude of phenol extracted from water was in the order phenol < p- chlorophenol < p-cresol. The stripping of phenol extracted in the organic solution was quantitatively accomplished with an alkaline solution of high concentration except for the case of cationic surfactants. Extraction of phenol and its derivatives by liquid surfactant membranes containing a newly synthesized surfactant as an emulsifier was carried out in a stirred cell. The effects of various parameters (such as a surfactant and alkaline concentration, the kind of surfactant, and the alkali composition) on the extraction efficiency of phenol were examined along with demulsification of W/O emulsions. On ...