Hollow Fiber Membrane Extraction Research Articles

Upcycling wastewater nitrate into ammonia fertilizer via concurrent electrocatalysis and membrane extraction

Electrocatalytic upcycling of nitrate (NO3−) in wastewater into the valuable ammonium-based fertilizer has been considered as a green and appealing alternative to biological nitrogen removal or the industrial ammonia (NH3) production processes. This work investigated an innovative and energy-efficient electrolysis flow-through cell consisting of a porous activated iron nickel (FeNi) alloy cathode and a hollow polypropylene fiber membrane extraction unit to realize the electrochemical NO3− reduction and simultaneous upcycling to ammonium sulphate salts ((NH4)2SO4). Cathodic and anodic electrochemical half-reactions were coupled to enable NO3− reduction to ammonia and in-situ acid/base productions to promote the membrane stripping of NH3. Our results show that after electrolysis operation for 14 h for a synthetic wastewater containing 150 mM NO3− under a cathodic current density of 30 mA·cm−2, 99 % of NO3− removal efficiency, 98 % of ammonia selectivity, 93 % of Faradic efficiency and 97 % of total ammonia nitrogen (TAN) recovery were achieved respectively. A NH3 recovery flux and a specific energy consumption reached 2050 g-(NH4)2SO4·m−2·d−1 and 11 kWh·kg−1-(NH4)2SO4, respectively, which outcompetes many reported processes. Direct electron transfer was the main mechanisms of electrochemical NO3− reduction to ammonia. Interfacial reaction thermodynamics and kinetics analysis of key intermediates (e.g., *NO3, *NO2, and *NO) shows that the NiFe2O4 (3 1 1)-Ni site on the thermally activated FeNi alloy surface exhibited higher reactivity and specificity toward electrochemical NO3− reduction to ammonia over nitrogen (N2) or hydrogen (H2) generation. Ultimately, this study aims to promote sustainable nitrogen nutrient recovery and ammonia fertilizer synthesis from wastewater treatment.

Novel Chiral Drug Recovery and Enantioseparation Method: Hollow Fiber Membrane Extraction and In Situ Coupling of Back-Extraction with Crystallization

A novel method was developed for the recovery and enantioseparation of the active pharmaceutical ingredient (S)-amlodipine from pharmaceutical wastewater: hollow fiber membrane extraction and in si...

Simultaneous determination of 11 phthalate esters in bottled beverages by graphene oxide coated hollow fiber membrane extraction coupled with supercritical fluid chromatography

Phthalate esters (PAEs) are a group of serious environmental pollutants, which lead to carcinogenicity or tumorigenicity in human body. In this study, a rapid, sensitive and green method by graphene oxide coated hollow fiber membrane extraction (GO-HFME) coupled with supercritical fluid chromatography (SFC) was proposed for the determination of 11 phthalate esters in bottled beverages. Graphene oxide (GO) was prepared and coated onto a porous hollow fiber membrane (HFM) to reinforce the efficiency of membrane extraction. The modified hollow fiber membrane was employed for the extraction of phthalate esters from bottled beverages prior to the determination by the supercritical fluid chromatography with UV detection. To achieve the maximum extraction efficiency, several parameters were investigated including GO concentration, extraction time, desorption solution and desorption time. SFC variables including stationary phase, modifier composition and percentage, column temperature, flow rate and backpressure were studied to improve the separation conditions. Under these optimized conditions, all the studied 11 phthalate esters were well separated and simultaneously determined in 7 min by SFC. The performance of the developed method was evaluated. Good linearity was observed (R ≥ 0.999) in the range of 0.02–10.0 μg/mL with limit of detection (LOD, S/N = 3) ranging from 1.5 to 3.0 ng/mL. Recoveries of all the PAEs for the spiked samples were between 92.1% and 99.3% with satisfactory relative standard deviations (RSD) less than 5.9%. The proposed method is time-saving, green, simple and robust, which will be an alternative way to the analysis of PAEs in real samples.

Hollow Fiber–Stir Bar Sorptive Extraction and Gas Chromatography–Mass Spectrometry for Determination of Organochlorine Pesticide Residues in Environmental and Food Matrices

A method of hollow fiber–stir bar sorptive extraction (HF–SBSE) coupled with gas chromatography–mass spectrometry was proposed to explore the migration of eight organochlorine pesticide residues in environmental and biological matrices. HF–SBSE was a configuration for solid–phase microextraction purposes, combining the features of SBSE and hollow fiber membrane extraction technology. Variables affecting the extraction (salt addition, extraction temperature, and time) and desorption (microwave time, eluted solvent) have been evaluated. Under the optimal conditions, good linearity (r > 0.999) of all calibration curves was obtained in validation experiments. The recoveries in different sample matrices were in the range from 69.0 to 114.1% with RSD% less than 10.2%. The bio-accumulation of OCPs was tested in samples of soil, underground water, forage grass, and raw milk. It was indicated that HF-SBSE could be applied in simultaneous extraction of hazardous substances in different matrices without sample clean-up.

Highly efficient chiral separation of amlodipine enantiomers via triple recognition hollow fiber membrane extraction

In this study, a triple recognition chiral extraction process has been developed to separate (S)-amlodipine from racemic raw medicine, based on the combination of molecularly imprinted hollow fiber membrane and cross-flow biphasic recognition extraction. The chiral separation process was operated in a dismountable hollow fiber module coated with molecularly imprinted polymer, and the cross-flow extraction was applied with d-tartaric acid in feed phase and sulfobutyl ether-β-cyclodextrin in stripping phase. The synergistic effect of molecularly imprinted polymer and dual chiral additives was investigated, and excellent enantioseparation ability with a selectivity factor of 1.98 was obtained. Mathematical model of S/R=0.598e0.150NTU for racemic amlodipine separation by molecularly imprinted hollow fiber membrane extraction was established. The optical purity for amlodipine is up to 90% when 4 hollow fiber membrane modules of 25cm in length in series are used. The triple recognition process strongly enhanced the separation selectivity; therefore it may bring about the potentially application for large-scale production of pure enantiomeric compound.

Comparison of hollow fiber membrane and solvent extraction techniques for extraction of cerium and preparation of ceria by stripping precipitation

AbstractBACKGROUNDThe extraction of cerium by hollow fiber supported liquid membrane using tri‐octyl methyl ammonium chloride (TOMAC) as mobile carrier was studied and the result was compared with solvent extraction data. The effect of different parameters such as pH, flow rates, extractant concentration, metal ion concentration and strip solution concentration on cerium extraction was investigated.RESULTSThese parameters were optimized for maximum cerium flux and were found to be: pH 1.0, 0.1 mol L−1 TOMAC, 290 mL min−1 feed solution flow rate, 150 mL min−1 strip solution flow rate and 0.9 mol L−1 H2SO4 as strip solution. The parameters were also optimized for solvent extraction study. The number of stages and Aqueous:Organic (A:O) ratio for extraction and stripping were determined from McCabe–Thiele diagrams. The extracted species was determined to be (R3NCH3)2Ce(SO4)3. The selective separation of cerium in presence of various other metal ions such as iron, copper, zinc, cobalt, nickel and manganese using a hollow fiber supported liquid membrane (HFSLM) was carried out and the separation factor values were found to be in the order α Ce/Fe <αCe/Cu < αCe/Mn < αCe/Zn < αCe/Co < αCe/Ni. Finally highly pure (99.99%) CeO2 was prepared by stripping precipitation with oxalic acid and thermal decomposition at 900°C for 1 h.CONCLUSIONThe efficiency of hollow fiber supported liquid membrane was greater than that of solvent extraction for the extraction of cerium for the present system. © 2014 Society of Chemical Industry

Separation of vanadium using both hollow fiber membrane and solvent extraction technique – A comparative study

A comparative study between solvent extraction and hollow fiber membrane technique has been carried out for the extraction of V (V) from an aqueous chloride solution. LIX 84I has been used as carrier/extractant. Also the extraction of vanadium in presence of various other metals, such as iron, copper, zinc, cobalt, nickel and manganese using hollow fiber supported liquid membrane (HFSLM) has been studied. Effect of different parameters such as pH of feed solution, flow rate, extractant concentration, metal ion concentration and strip solution concentration on vanadium extraction has been investigated. With increase of pH, extractant concentration and flow rate, the flux value increased up to certain level and then decreases. The flux increased from 1.0 to 1.82×10−5, 0.97 to 1.82×10−5 and from 0.6 to 1.82×10−5mol/m2.s with increase of pH, [extractant] and flow rate from 1.0 to 1.75, 0.08 to 0.32M and from 105 to 290mL/min, respectively. The extracted species was determined to be VO2R·RH. Vanadium was extracted selectively and separated completely from a multi metal bearing solution by using hollow fiber membrane module and the separation factor values were found to be in the order of αV/Cu<αV/Fe<αV/Zn<αV/Co<αV/Mn<αV/Ni. The data generated from the hollow fiber study were compared with that of conventional mixer-settler study. High purity (99%) V2O5 was produced from the strip solution by precipitation with H2SO4 at pH around 2.0.

Modeling and Transport Analysis of Silver Extraction in Porous Membrane Extractors by Computational Methods

A comprehensive two-dimensional mathematical model was developed for the transport of \( {\text{Ag(CN)}}_{ 2}^{ - } \) ions through porous membrane extractors. Extraction of \( {\text{Ag(CN)}}_{ 2}^{ - } \) with n-heptane solution of N,N-bis(2-ethyl hexyl) guanidine as extractant (LIX79) was investigated theoretically. Simulations were done using computational fluid dynamics of momentum and mass transfer in all subdomains of a hollow-fiber membrane extractor by COMSOL Multiphysics software. The latter uses finite element method for numerical simulations. Parabolic velocity profile was used for the aqueous feed in the tube side and the solvent flow in the shell side that was characterized by Happel’s equation. The distribution of concentration was obtained for the solute in the membrane module. Simulation results indicated that increasing feed flow rate reduces the extraction efficiency of silver from aqueous phase to organic phase. Dimensionless concentration distribution (C/C0) of silver ions in the tube side of membrane extractor in axial and radial direction shows that it moves to the membrane due to the concentration difference, and then it is swept by the moving extractants in the shell.

Determination of trace aromatic amines in waste water using microextraction combined with ion chromatography

The aim of this work is to develop a simple, selective, sensitive and inexpensive analytical method for the simultaneous determination of several aromatic amines. In this work, a new method for the determination of trace aromatic amines, including o-toluidine and 4-chloroaniline in waste water was developed by hollow fiber membrane extraction with ion chromatography. The optimal extraction conditions were as follows: by using 1-octanol as the organic phase with 500 g/L NaCl and 0.01 mol/L NaOH as the donor phase, and 0.1 mol/L HCl as the acceptor phase, the extraction was performed at a stirring rate of 430 r/min for 30 min. The linear range of both of o-toluidine and 4-chloroaniline was 0.005 - 0.1 mg/L, with correlation coefficients larger than 0. 999. The detection limits of o-toluidine and 4-chloroaniline were 0.2 microg/L and 0.5 microg/L with the relative standard deviations (RSDs) of 0.85% and 3.38%, respectively. The method has been applied to the simultaneous determination of trace aromatic amines including o-toluidine and 4-chloroaniline in the waste water.

Simultaneous speciation and preconcentration of ultra trace concentrations of mercury and selenium species in environmental and biological samples by hollow fiber liquid phase microextraction prior to high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry

Nowadays, hollow fiber membrane extraction techniques are widely used due to the high enrichment factors obtained with many different types of analytes and samples. In this paper, we propose a new analytical method that allows the simultaneous extraction of methylmercury, inorganic mercury and Se4+ and determination by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC–ICP-MS). The detection limits obtained are very low (110–230ng/L) with relative standard deviations below 15% for all the analytes and averaged recoveries in fortified samples in the range of 71–99%. The precision of the analytical method is very good which overcomes one of the most important shortcomings of membrane extraction techniques. Several variables were studied to get optimal extraction conditions for the analytes. This method has been validated with real world samples such as water (tap, river and estuarine) and human blood plasma.

Hollow-Fiber Membrane Extraction of Copper from Aqueous Nitrate Media by LIX® Reagents: Comparison of Extraction Efficiency and Fractional Resistances

Extraction of copper from nitrate/nitric acid aqueous solutions was studied using a HF Membrane Module and four LIX reagents (LIX® 860N-I, LIX® 984N, LIX® 84-I, and LIX® 65N) containing different active compounds (ketoximes and/or salicylaldoximes). Kinetic experiments varying the flow rates of both phases, aqueous and organic, and the extractant concentration were carried out to compare the extraction rate and efficiency from nitrate-aqueous media. A mathematical model based on the “aqueous extraction mechanism” in which the chemical reaction takes place in an aqueous-reaction zone was applied to determine the individual resistances of the copper mass-transfer process. It was found that the fractional resistance due to chemical reaction in the aqueous reaction zone, which varied from 92.5% to 95.8% in the order LIX® 860N-I < LIX® 984N < LIX® 84-I < LIX® 65N, controlled the total rate of the hollow-fiber copper extraction from nitrate aqueous media.

Near-Critical Extraction of the Fermentation Products by Membrane Contactors: A Mass Transfer Simulation

A 2D mathematical model was developed to study liquid extraction by membrane contactors. The extraction system included a hollow-fiber membrane extractor, an aqueous solution of ethanol and acetone as the feed, and a near-critical phase of carbon dioxide as the solvent. Axial and radial diffusions of the ethanol and acetone within the tube side, through the membrane, and within the shell side of the contactor were considered in the model. The equations of the model were solved by a numerical method based on the finite element method (FEM). The predicted results of the extraction for ethanol and acetone show an average difference of 15.66% and 2.55% with the experimental data, respectively. Simulation results for extraction of acetone are more accurate than those for ethanol mostly due to a better estimation of the transport properties within the aqueous phase, which controls extraction of this solute. The developed mass transfer model is more accurate than the other few provided models in the literature and represents a general approach which can be applied for similar membrane separation systems.

Simultaneous Extraction and Concentration in Carbon Nanotube Immobilized Hollow Fiber Membranes

Analytical enrichment during continuous hollow fiber membrane extraction involves the movement of analytes from the sample to the extractant. At the same time, a second preconcentration mechanism is provided by out-diffusion of the extracting solvent. These effectively combine extraction and concentration into one step. In this paper, we demonstrate for the first time that the presence of carbon nanotubes (CNTs) can enhance both these phenomenon leading to superior performance in terms of higher enrichment factors and extraction efficiency. The CNTs were immobilized in the pores of a polypropylene hollow fiber and led to nearly 250% enrichment enhancement over the unmodified parent membranes. The detections limits for polycyclic aromatic compounds were between 0.042 and 0.25 microg/L.

Determination of inorganic anions in ethyl acetate by in-line hollow fiber membrane extraction with ion chromatography

In this work, a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water. Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time. Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfactory linear range, limits of detection and good repeatability were obtained. The procedure was applied to analyze inorganic anions in two commercial ethyl acetate samples.

Modeling extraction separation of Cu(II) in hollow-fiber modules

The mass transfer problems in the hollow-fiber membrane extractor module with concurrent- and countercurrent-flow were investigated theoretically and experimentally in this study. A two-dimensional mathematical model of the hollow-fiber membrane extractor module was developed theoretically and the shell side flow described by Happel's free surface model was taken into account. The analytical solution is obtained using an eigenfunction expansion in terms of the power series and an orthogonal expansion technique. The theoretical predictions were represented graphically with the mass-transfer Graetz number ( Gz), flow pattern and packing density ( φ) as parameters and the theoretical results were also compared with those obtained by experimental runs. The highest extraction rate, extraction efficiency and mass transfer efficiency can be achieved by arranging the packing density φ=0.3. The results show that the device performance of the countercurrent-flow device is better than that of the concurrent-flow device. The experiments of the extraction of Cu 2+ by using D2EHPA with PVDF hollow fibers is also set up to confirm the accuracy of the theoretical predictions. The accuracy of the theoretical predictions for concurrent- and countercurrent-flow are 5.87 × 1 0 - 2 ≤ E 1 ≤ 6.69 × 1 0 - 2 and 2.46 × 1 0 - 2 ≤ E 1 ≤ 3.48 × 1 0 - 2 , respectively, for G z a = 40.8 .

Selective recovery of nickel ions from wastewater of stainless steel industry via HFSLM

High concentration of heavy metal ions in all kinds of effluents, especially in wastewater is of great concern for hazardous pollution due to their high toxicities and wide environmental spreading. The selective stripping or recovery of nickel ions from wastewater of the stainless steel-cold rolled plate process by hollow fiber supported liquid membrane was studied. The optimum conditions were examined in a batch process. The pH of feed, types and concentrations of the extractants, concentration of the stripping solution (sulfuric acid), flow rates of feed and stripping solutions, and volumetric ratio of feed to stripping solutions were investigated. The extractants, i.e., D2EHPA, Cyanex 301, Cyanex 272 and LIX 860-I were dissolved in kerosene as a membrane solution, which was supported by a microporous hydrophobic hollow fiber membrane extractor. Consequently, two consecutive modules of hollow fiber were applied to recover more nickel ions. The results showed that LIX 860-I was the most effective to selectively retrieve nickel ions from wastewater at a feed pH of 4. The percentage of the recovery and selectivity of nickel ions increased in accordance with an increase in the concentration of LIX 860-I and decreased after the concentration of LIX 860-I was higher than 0.8 M. It was found that the percentage of recovery of nickel ions increased with sulfuric acid concentration and lower flow rates of feed and stripping solutions. Higher nickel ions were obtained at the flow rates of feed and stripping solutions of 100 ml/min and reduced when the flow rates increased. In addition, in this study it is recommended to use equal volume of feed and stripping solutions of 3500:3500 (ml:ml) to attain more nickel ions recovery. For a single-module operation, the percentage of recovery of nickel ions was 58%, and 87% by double-module operation.

A membrane process to recover extractant D2EHPA in aqueous phase

A membrane adsorption–extraction process to recover di-(2-ethylhexyl) phosphate (D2EHPA) from the raffinate is developed, i.e. a hollow fiber membrane extraction module, in which raffinate flows in the tube side and n-heptane used as the “extractant” flows in the shell side. The emulsion with D2EHPA, n-heptane and Triton X-114 was used as the simulated raffinate, and it was proved that both the affinity of membrane for oil droplets and the extraction of D2EHPA by n-heptane contribute to the method. Via recycling the feed, the final recovery efficiency of D2EHPA could be as high as 90%. The effects of two main operating conditions, tube side velocity and shell side velocity, were investigated. The tube side velocity was found to be an essential operation factor, while the shell side velocity had a slight influence.

New liquid membrane technology for simultaneous extraction and stripping of copper(II) from wastewater

In this paper, a new liquid membrane technique, hollow fiber renewal liquid membrane (HFRLM), is presented, which is based on the surface renewal theory, and integrates the advantages of fiber membrane extraction, liquid film permeation and other liquid membrane processes. The results from the system of CuSO 4 + D 2 EHPA in kerosene + HCl show that the HFRLM process is very stable. The liquid membrane is renewed constantly during the process, the direct contact of organic droplets and aqueous phase provides large mass transfer area. These effects can significantly reduce the mass transfer resistance in the lumen side. Then the mixture of feed phase and organic phase flowing through the lumen side gives a higher mass transfer rate than that of stripping phase and organic phase, because the aqueous layer diffusion of feed phase is the rate-controlling step. The overall mass transfer coefficient increases with increasing flow rates and D2EHPA concentration in the organic phase, and with decreasing initial copper concentration in the feed phase. The overall mass transfer coefficient also increases with increasing pH in the feed phase, and reaches a maximum value at pH of 4.44, then decreases. Also, there is a favorable w / o volume ratio of 20:1 to 30:1 for this process. Compared with hollow fiber supported liquid membrane and hollow fiber membrane extraction processes, HFRLM process has a high mass transfer rate. Mathematical model for the HFRLM process based on the surface renewal theory is developed. The calculated results are in good agreement with experimental results under the conditions studied.

Comparison of membrane extraction with traditional extraction methods for biodiesel production

AbstractThree traditional methods for the refining step in biodiesel production were compared: (i) washing with distilled water; (ii) washing with acid (HCl); and (3) dissolving and extracting in a solvent (hexane or petroleum ether) and then washing with distilled water. Biodiesel with a high purity (97.5%) could be obtained by all three methods, but serious emulsification occurred during the refining processes, which led to high refining losses. A novel refining method was developed by using hollow fiber membrane extraction, and polysulfone was selected as the most suitable membrane. This process effectively avoided emulsification during refining and decreased the refining loss. The purity of the biodiesel obtained was about 99%; and other properties, such as density, kinematic viscosity, water content, and acid value, conformed to the standards.

Guidelines for the application of a stationary model in the prediction of the overall mass transfer coefficient in a hollow fiber membrane contactor

A dynamic model describing the behavior of a hollow fiber membrane extractor, working as a closed system, is developed. Plug flow of both the aqueous and organic phases inside the fiber module is supposed while the reservoirs are considered to be perfectly mixed. The resistances to mass transfer between the phases, inside the module, are lumped in an overall mass transfer coefficient. This dynamic model shows that the system behavior is controlled by five dimensionless parameters: one equilibrium, one mass transfer, two volume ratios and one ratio of space times. A parametric study is conducted and the influence of each parameter on the system behavior is assessed independently. When a pseudo-steady state approximation is made, considering the module in steady state, the currently used stationary model is obtained [N.A. D’Elia, L. Dahuron, E.L. Cussler, Liquid–liquid extraction with microporous hollow fibers, J. Membr. Sci. 29 (1986) 309–319]. The operating region for the determination of the global mass transfer coefficient between the aqueous and organic phases using this simplified model is identified by the comparison of the histories of solute concentrations inside the respective reservoirs, obtained by the solutions of both the dynamic and the stationary models. Based on this comparison, guidelines for the application of the simplified model are given both in terms of the dimensionless parameters and of the operating variables.