Chelating Membrane Research Articles

Mechanism of selective transportation of metal ions across chelating membranes in electrodialysis

The presented research explains the mechanism of selective transportation mass in electrodialysis by chelating membrane according to the electrosorption and specific diffusivity. The Nernst-Planck equation was applied for modelling and defining the character of mass transportation. The chelating membrane is developed by the chemical grafting of hydroxyquinoline (HQ), which guarantees selectivity. The investigation of mass transportation was determined using a single-component solution of transition metal cations like Co2+, Mn2+and Ni2+, as well as from alkaline metal classes like Li+ and Mg2+. Finally, the multi-component solutions were tested to confirm the chelating membrane's specific character and mass transportation mechanism. The chemical and electrochemical investigations like FTIR and EIS confirmed the appearance of the chelating reactions between membrane and cobalt cations only. According to the creation of aqua complexes of HQ and Co2+, the PAN-5C8Q membrane could transport in a significant majority only Co2+ against other mono- and divalent cations. The transport number against the Mn2+, Ni2+, Mg2+ and Li+ for Co2+got over 0.6.

Ultra-selective chelating membranes for recycling of cobalt from lithium-ion spent battery effluents by electrodialysis

The recovery of valuable resources from spent effluents is critical to ensure sustainable growth and reduce commodity shortages at global levels. Spent batteries are largely untapped resources containing multiple high-value metal ions that may be harnest and resued indefinitely to develop a circular battery economy. Challenges however lay with the cost of purification and recovery strategies and the limited selectivity of existing processes. This work presents the development of selective cation exchange membranes suitable for the selective recovery of cobalt from mixtures of lithium, cobalt, and nickel from spent battery effluents. Efficient cation exchange membranes were generated by modifying poly(vinyl chloride) films with ethylene diamine followed by grafting of 5-chloro-8-hydroxyquinoline (5C8Q) chelating agents and two synthesis routes were compared including surface and bulk grafting and the membrane separation properties were benchmarked against CIMS Neosepta. Besides being stable across a pH range between 2 and 8, relevant to spent battery lixiviat, the surface grafted membranes exhibited the lowest energy of sorption in comparison to bulk membranes, which was ten times lower than that of the commercial CIMS Neosepta reference membranes. The transfer of ions from model single salt solutions across the surface grafted membranes allowed for over 60 % of cobalt recovery within 1 h, while nickel and lithium were transferred only up to 18 % and 0.2 %, respectively. In addition, the electrodialysis-based separation of multi-component solutions remained very cost-effective with cobalt ion removal amounts up to 58 %, leading to Co/Li separation factors as high as 247. This novel chelating agent strategy opens avenues for the development of highly efficient and selective membrane materials, which are able to operate in extreme pH environments and supporting ultra-selective ionic transfer.

Effect of Pollutant Species on the Performance of Chelating Membranes for Wastewater Treatment

AbstractA chelating membrane was fabricated to simultaneously remove metal ions and proteins from simulated wastewater. For a mixture consisting of a single ion and protein, the chelating membrane exhibited overall good separation performance (except for Cd2+), with both ion removal and protein rejection surpassing 90 %. The removal of metal ions highly depends on the chelation of amidoxime groups with ions rather than the complexation of proteins with ions. An increase in the content of metal ions has a detrimental impact on the protein rejection efficiency owing to the damaging effect of heavy metals on the protein. Similarly, increasing the amount of protein adversely affects the removal of ions due to the weakened chelation of amidoxime groups with metal ions.

Amidoxime functionalized PVDF-based chelating membranes enable synchronous elimination of heavy metals and organic contaminants from wastewater.

Aiming at the synchronous elimination of heavy metals and organic contaminants from wastewater, the amidoxime functionalized PVDF-based chelating membrane was fabricated in this study. The structure and morphology of the chelating membrane were characterized using infrared spectroscopy (FT-IR), nuclear magnetic resonance spectrometer (NMR) and scanning electron microscopy (SEM). The SEM results show that the chemical modification with amidoxime groups did not damage the structure of the PVDF-based membrane. The chelating membrane has a high removal efficiency for Cu2+ (77.33%) and Pb2+ (79.23%) owing to the chemisorption through coordination bonds. However, the chelating membrane exhibits a low removal efficiency for Cd2+ (29.88%) due to the physical adsorption. The chelating membrane has a high rejection efficiency of BSA (95.17%) and lysozyme (70.09%), which is attributed to the sieving effect and increased hydrophobicity. Furthermore, the membrane performance for simultaneously removing metals and proteins from simulated wastewater was examined. The interaction of metal ions with proteins (BSA and lysozyme) can enhance the ion removal efficiency of the chelated membrane, but decrease the protein rejection efficiency due to the destructive effect. The amidoxime functionalized PVDF-based chelating membrane has a high potential for application in wastewater treatment.

Influence of pollutant concentration on the separation efficiency of chelating membranes for removing simultaneously metal ions and proteins from simulated industrial wastewater

AbstractBACKGROUNDA novel chelating membrane was fabricated for removing simultaneously metal ions (Cd2+, Pb2+ and Cu2+) and proteins (bovine serum albumin and lysozyme) from simulated industrial effluent. The purpose of the study was to investigate the influence of pollutant concentration on the separation efficiency of the chelating membrane for pollutants.RESULTS(i) The removal of metal ions mainly relies on the adsorption capacity of the chelating membrane, and seems to be independent of the concentration of protein. (ii) The retention of proteins depends mainly on their concentration in solution. (iii) When the wastewater contains high concentration of metal ions (C = 100 mg L−1) and low concentration of proteins (C = 10 mg L−1), the chelating membrane exhibits overall poor separation performance, with a low ion removal efficiency (55–70%) and a low protein rejection rate (ca 60%). (iv) When the wastewater contains low concentration of metal ions (C = 10 mg L−1) and high concentration of proteins (C = 100 mg L−1), the chelating membrane exhibits overall excellent separation performance, with ion removal rates of higher than 90% (except for Cd2+) and protein rejection rates of higher than 90%.CONCLUSIONSThe separation efficiency of the chelating membrane for metallic and organic pollutants greatly depends on the pollutant concentration in the wastewater. This study provides a theoretical basis for membrane technology for removing simultaneously heavy metals and organic pollutants in wastewater. © 2022 Society of Chemical Industry (SCI).

PAN/PVDF chelating membrane for simultaneous removal of heavy metal and organic pollutants from mimic industrial wastewater

The polyacrylonitrile/polyvinylidene fluoride (PAN/PVDF) chelating membrane with amidoxime groups was prepared to simultaneously remove metallic and organic pollutants from mimic industrial wastewater. The main purpose of this study is to investigate the interaction between metal ions and protein molecules, and synergistic effects on the pollutant removal efficiency through the chelating membrane. Lysozyme and bovine serum albumin (BSA) were used as organic pollutants and Cu2+, Pb2+ and Cd2+ were used as metal components in this study. As one of the metal ions (Cu2+, Pb2+ or Cd2+) and one of the proteins (lysozyme or BSA) are present in the solution, the metal removal rate is improved due to the interaction of metal ions with protein, to form a metal-protein complex. At the same time, the lysozyme rejection efficiency decreases, but the BSA rejection efficiency increases. For the mixture consisting of one metal ion and two proteins, the metal removal rate is higher than that for the case (one metal ion + lysozyme), but lower than that for the case (one metal ion + BSA). Meanwhile, the protein retention efficiency decreases, since the interaction between lysozyme and BSA disturbs the retention efficiency of each protein. As three metal ions and two proteins are present in the solution, the ion removal efficiency is significantly improved, and the protein retention efficiency is increased as well, which is due to the fact that there are much more chances for forming metal-protein complexes.

Adsorption of lead ion by a polyether sulphone-type chelating membrane bearing aminophosphonic acid functional groups

Adsorption of lead ion by a polyether sulphone-type chelating membrane bearing aminophosphonic acid functional groups

Adsorption of Pb(II) by a polyvinylidene fluoride membrane bearing chelating poly(amino phosphonic acid) and poly(amino carboxylic acid) groups

Pb(II) can cause a hazardous effect on ecosystem and public health due to its high biotoxicity. A polyvinylidene fluoride-type membrane bearing both poly(amino phosphonic acid) and poly(amino carboxylic acid) functional groups was fabricated for the purpose of Pb(II) removal from the aqueous solutions. The adsorption behaviors of the fabricated chelating membrane toward Pb(II) were studied by the series of static and continuous adsorption experiments. When the pH, adsorption equilibrium time, initial Pb(II) concentration, and temperature were 5.1, 300 min, 1.0 mmol g−1, and 298 K, respectively, Pb(II) uptake of the membrane was 1.1 mmol g−1. The presence of coexisting metal ions and complexing reagents decreased the Pb(II) uptake. The adsorption kinetic and isotherm adsorption followed pseudo-second-order equation and Langmuir model, respectively; this adsorption process showed a spontaneous and exothermic feature. The bed depth service time and Thomas models were suitable for describing obtained breakthrough curves.

PAN chelating membranes for simultaneous removal of metallic ions and organic pollutants from aqueous solution

PAN chelating membranes for simultaneous removal of metallic ions and organic pollutants from aqueous solution

DFT Investigation of the Effects of Coexisting Cations and Complexing Reagents on Ni(II) Adsorption by a Polyvinylidene Fluoride-Type Chelating Membrane Bearing Poly(Amino Phosphonic Acid) Groups

A polyvinylidene fluoride (PVDF)-type chelating membrane bearing poly(amino phosphonic acid) groups, denoted as ethylenediamine tetra(methylene phosphonic acid) (EDTMPA)-tetrabutyl orthotitanate (TBOT)/PVDF, was employed to remove Ni(II) from the aqueous solution. The effects of coexisting Ca(II), Pb(II), citrate, nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA) on the Ni(II) adsorption by this chelating membrane were revealed using density functional theory (DFT) calculations. Pb(II) showed a more detrimental effect than Ca(II) on the Ni(II) uptake; EDTA interfered with the capture of Ni(II) more remarkably than citrate and NTA. The results derived from DFT calculations were consistent with the experimental data. Ni(II) and Pb(II) showed more excellent affinity to the EDTMPA-TBOT/PVDF membrane than Ca(II). The stabilities between Ni(II) and the [EDTMPA-TBOT]7− chelating ligand of the membrane and those between Ni(II) and the three aforementioned complexing reagents followed the sequence: [Ni(II)-(EDTMPA-TBOT)]5− > Ni(II)-EDTA > Ni(II)-NTA > Ni(II)-citrate. The complexation between Ni(II) and the chelating membrane was prominent with the presence of citrate, NTA and EDTA.

Adsorption of Ni(II) by a polyvinylidene fluoride-type chelating membrane bearing poly(aminophosphonic acid) groups

Adsorption of Ni(II) by a polyvinylidene fluoride-type chelating membrane bearing poly(aminophosphonic acid) groups

Effect of Ca(II), Fe(II), and Fe(III) on Cu(II) adsorption by a polyvinylidene fluoride-based chelating membrane from Cu(II)–EDTA complex solution

ABSTRACTA polyvinylidene fluoride-based membrane bearing the diethylenetriaminepentaacetic acid chelating group was employed to recover Cu(II) from the Cu(II)-ethylenediaminetetraacetic acid complex aqueous solution. Effects of Ca(II), Fe(II), and Fe(III) on Cu(II) uptake were investigated by static batch adsorption tests and dynamic adsorption filtration. Isotherms, kinetics, and breakthrough curves of Cu(II) uptakes in the presence of the three cations at concentrations of 1 mmol L−1 were elucidated. The three cations showed a positive effect on the Cu(II) uptake; the stimulative roles were in the order of Fe(III) > Fe(II) > Ca(II). They did not alter the adsorption behavior of the membrane; adsorption isotherms and kinetics could be described by Langmuir and Lagergren second-order models, and Cu(II) adsorption was a spontaneous and exothermic process. The presence of Ca(II), Fe(II), and Fe(III) increased the sorption capacity of the membrane stack by 1.3, 1.9, and 3 times. Breakthrough time and the exhaustion time of membrane stacks were also extended.

Mixed Matrix PVDF Membranes With in Situ Synthesized PAMAM Dendrimer-Like Particles: A New Class of Sorbents for Cu(II) Recovery from Aqueous Solutions by Ultrafiltration.

Advances in industrial ecology, desalination, and resource recovery have established that industrial wastewater, seawater, and brines are important and largely untapped sources of critical metals and elements. A Grand Challenge in metal recovery from industrial wastewater is to design and synthesize high capacity, recyclable and robust chelating ligands with tunable metal ion selectivity that can be efficiently processed into low-energy separation materials and modules. In our efforts to develop high capacity chelating membranes for metal recovery from impaired water, we report a one-pot method for the preparation of a new family of mixed matrix polyvinylidene fluoride (PVDF) membranes with in situ synthesized poly(amidoamine) [PAMAM] particles. The key feature of our new membrane preparation method is the in situ synthesis of PAMAM dendrimer-like particles in the dope solutions prior to membrane casting using low-generation dendrimers (G0 and G1-NH2) with terminal primary amine groups as precursors and epichlorohydrin (ECH) as cross-linker. By using a combined thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) casting process, we successfully prepared a new family of asymmetric PVDF ultrafiltration membranes with (i) neutral and hydrophilic surface layers of average pore diameters of 22-45 nm, (ii) high loadings (∼48 wt %) of dendrimer-like PAMAM particles with average diameters of ∼1.3-2.4 μm, and (iii) matrices with sponge-like microstructures characteristics of membranes with strong mechanical integrity. Preliminary experiments show that these new mixed matrix PVDF membranes can serve as high capacity sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration.

Influence of Co(II), Ni(II), tartrate, and ethylenediaminetetraacetic acid on Cu(II) adsorption onto a polyvinylidene fluoride-based chelating membrane

A 3-aminopropyltrimethoxysilane-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (APTMS-DTPA/PVDF) chelating membrane was employed to remove Cu(II) from an aqueous solution. The influence of Co(II), Ni(II), tartrate, and ethylenediaminetetraacetic acid (EDTA) on the sorption of Cu(II) was investigated by a series of dynamic adsorption tests and by density-functional theory (DFT) calculations. Isotherms and kinetics of the membrane sorption process towards Cu(II) in the presence of the two other cations and the two complexing reagents were elucidated. The DFT descriptors, such as chemical potential, electronegativity, electrophilicity index and charge transfer, and the complexation energy, were calculated. Cu(II) showed higher electrophilicity than Co(II) and Ni(II), and the sorption of Cu(II) by the chelating membrane in the absence of tartrate and EDTA was stronger than in their presence. Ni(II) tended to form a more stable complex with the complexing ligand than Co(II). EDTA interfered more strongly with Cu(II) uptake than tartrate. Adsorption isotherms and adsorption kinetics were fitted to the Langmuir and the Lagergren second-order models. The [Cu(APTMS-DTPA)]2− complex exhibited higher charge transfer and a more negative complexation energy than [Co(APTMS-DTPA)]2−, [Ni(APTMS-DTPA)]2−, Cu-tartrate, and Cu-EDTA.

Adsorption performance of APTMS-DTPA/PVDF chelating membrane toward Ni(II) with the presence of Ca(II), NH4+, lactic acid, and citric acid

The 3-aminopropyltrimethoxysilane-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (APTMS-DTPA/PVDF) chelating membrane was prepared to remove Ni(II) from the solutions. The adsorption performance of the membrane toward Ni(II) was investigated by the adsorption experiments and density functional theory (DFT) calculations, considering the existence of Ca(II), NH4+, lactic acid, and citric acid. Ca(II) tended to form more stable complex with the APTMS-DTPA ligand of the chelating membrane than NH4+. Citric acid showed a larger interference on Ni(II) uptake than lactic acid. Lagergren second-order equation and Langmuir model were competent for descriptions of the adsorption kinetics and the isotherms, respectively. The negative ΔG° and ΔH° indicated the spontaneous and exothermic nature of Ni(II) adsorption. The results of DFT calculations were consistent with the experimental data. The complexing sequences of the metal ions with the APTMS-DTPA ligand were in the order of NH4+ < Ca(II) < Ni(II). The stabilities of the Ni(II)–organic complexes followed the order of Ni(II)–lactic acid < Ni(II)–citric acid < Ni(II)–(APTMS-DTPA). Therefore, the complexation between Ni(II) and APTMS-DTPA ligand of the membrane was prominent.

Thermodynamic and kinetic investigations of a chelating membrane bearing polyaminecarboxylate groups towards Ni(II)

Melamine-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (MA-DTPA/PVDF) chelating membrane bearing polyaminecarboxylate groups was used to remove Ni(II) from the solutions. The adsorption characteristic of the membrane towards Ni(II) was investigated in Ni(II)–Ca(II), Ni(II)–, and Ni(II)–Fe(III) binary systems. The organic complex systems including Ni(II)–lactic acid, Ni(II)–succinic acid, and Ni(II)–citric acid were also considered. The effects of the aforementioned coexistent cations and organic acids were determined based on the experimental data. Lagergren second-order equation and Langmuir model were competent for descriptions of the adsorption kinetics and the isotherms, respectively. The chemical chelation predominated the adsorption process. In the binary systems with the presence of coexistent cations, Ca(II) tended to form a more stable complex with MA-DTPA ligand of the membrane than and Fe(III), and Ca(II) could interfere with the formation of Ni(II)–MA-DTPA complex. The stabilities of Ni(II)–organic acid complexes followed the order of lactic acid < succinic acid < citric acid, but they cannot be comparable to that of Ni(II)–MA-DTPA complex. Therefore, the chelating membrane had a potential Ni(II) recovery from wastewater of the electroless nickel plating and electroplating industries.

Characterisation of metal-complexing membranes prepared by the semi-interpenetrating polymer networks technique. Application to the removal of heavy metal ions from aqueous solutions

Novel chelating membranes for heavy metal ions were prepared by the semi-interpenetrated polymer networks technique. The matrix is a crosslinked network of poly(vinyl alcohol) (PVA) that immobilises a commercial or synthetic chelating polymer (CP). The membranes were characterised for the effectiveness of the crosslinking by measurement of swelling ratio and infra-red spectrometry, thermal stability, exchange and sorption capacities. In this paper, the removal of Hg(II), Pb(II), Cd(II) and Cu(II) ions by the most versatile membrane, the PVA/poly(ethyleneimine) (PEI) membrane was studied. The effects of parameters such as temperature, water hardness, the presence of complexing chloride anions and of other metal cations were investigated. The dissolution of the PVA/PEI membrane in water was slow and limited to 5% after two months, showing the efficiency of the crosslinking process. The sorption isotherms obey the Langmuir model and show high retention capacities for Pb(II), Cd(II) and Cu(II) ions. The sorption capacity was greater for metal ions that hydrolyse easily. The maximum sorption capacities of the membrane were 0.729mmolg−1 for Pb(II), 0.692mmolg−1 for Cu(II) and 0.525mmolg−1 for Cd(II), whereas the theoretical and experimental exchange capacities were 9.30mmolg−1 and 2.78mmolg−1, showing that most internal complexing sites of the membrane were not accessible for sorption of ions. Sorption experiments using mixtures of 2, 3 or 4 metal ions showed the selectivity order: Hg(II)>Cu(II)>Pb(II)>Cd(II). The thermodynamical sorption parameters showed a large entropic effect. The retention ratios were remarkably insensitive to the presence of calcium or chloride ions, which suggest possible use for the purification of real wastewaters by filtration.

DFT investigation of Ni(II) adsorption onto MA-DTPA/PVDF chelating membrane in the presence of coexistent cations and organic acids

Melamine-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (MA-DTPA/PVDF) chelating membrane bearing polyaminecarboxylate groups was used to remove Ni(II) from nickel plating effluents. Adsorption experiments were conducted to study the adsorption of the membrane towards Ni(II) in Ni(II)–Ca(II), Ni(II)–NH 4 +, Ni(II)–Fe(III) binary systems, and Ni(II)–lactic acid, Ni(II)–succinic acid and Ni(II)–citric acid complex systems. For the ternary nickel plating processes, the effects of 3d transition metals including Fe(II), Co(II), Cu(II) and Zn(II) on Ni(II) adsorption were evaluated. The influences of the aforementioned coexistent cations and organic acids were elucidated by the continuum solvation model (COSMO)-corrected density functional theory (DFT) method. Geometries and complexation energies were analyzed for metal–MA-DTPA and Ni(II)–organic acid complexes. DFT results accord with the experimental data, indicating that DFT is helpful to evaluate the complexation between the membrane and metal cations. The coexistent Ca(II) tends to form more stable complex with MA-DTPA ligand than NH 4 + and Fe(III), and can interfere with the formation of Ni(II)–MA-DTPA complex. The complexing sequence of 3d metals with MA-DTPA ligand is Zn(II) < Co(II) < Ni(II) < Fe(II) < Cu(II). Therefore, both Fe(II) and Cu(II) have the considerable competition with Ni(II). The stabilities of Ni(II)–organic acid complexes follow the order of lactic acid < succinic acid < citric acid, but cannot be comparable to that of Ni(II)–MA-DTPA complex.

Adsorption characteristics of Ni(II) onto MA–DTPA/PVDF chelating membrane

The melamine-diethylenetriaminepentaacetic acid/polyvinylidene fluoride (MA–DTPA/PVDF) chelating membrane bearing polyaminecarboxylate groups was prepared for the removal of Ni(II) from wastewater effluents. The membrane was characterized by SEM, 13C NMR and FTIR techniques. Quantitative adsorption experiments were performed in view of pH, contact time, temperature, the presence of Ca(II) and lactic acid as the controlling parameters. Adsorption kinetics and equilibrium were examined regarding the single Ni(II) system, binary Ni(II) and Ca(II) system and nickel–lactic acid complexes system. The desorption efficiency was also evaluated, and the adsorption mechanism was suggested based on experimental data. The results show that the sorption kinetics fit well to Lagergren second-order equation and the isotherms can be well described by Langmuir model. At 298 K, the second-order rate constant is calculated to be 4.171, 11.39, 6.203 cm 2/(mg min) and the equilibrium uptake is 0.0264, 0.0211 and 0.0216 mg/cm 2 in the aforementioned three systems. The distribution coefficient of Ni(II) slowly decreases from 4.27 to 2.72, and the separation factor ( f Ni(II)/Ca(II)) increases from 3.10 to 8.46 when the initial Ca(II) concentration varies from 20 to 200 mg/L. This reveals the chelating membrane shows more affinity for Ni(II) than Ca(II) ions. In the studied range of lactic acid concentration, Ni(II) uptake decreases with the maximum ratio of 10%. Chemical bonding (chelation) dominates in the adsorption process, and the negative Δ G° and Δ H° indicate the spontaneous and exothermic nature of adsorption.

Empore™ membrane vs. Chelex 100: Thermodynamic and kinetic studies on metals sorption

The sorption of several metal ions on a solid, iminodiacetic based material, the Empore™ chelating membrane, is considered. Determination of the acid-base properties, kinetic of metal sorption and complexing properties, in solutions with different composition is undertaken. The results are compared with those obtained using the classical iminodiacetic resin Chelex 100 in beads. In particular, Cd(II), Fe(III), Pb(II), and Zn(II) are considered. The Gibbs–Donnan, the usual model we used to explain the protonation and the metal sorption on chelating sorbent, is applied also in the present study. On the other hand, the kinetic models selected to describe our data are the two widely applied for fitting ion-exchange data: the Homogeneous Particle Diffusion Model and the Sharing Core (Shell Progressive) Model. In general no significant differences between membrane and resin are found in the thermodynamic properties, but for some metals the kinetics of the sorption on the membrane is slower.