Ion-imprinted Polymer Research Articles

Combining synergistic interaction and ion imprinting to improve adsorption capacity for selective uranium extraction from seawater

Abstract To ensuring the demand for uranium by utilizing unconventional uranium resources, the development of materials for selective capturing uranyl ions is increasingly important. Hence, the ion-imprinted polymer (IIP) based on specific binding sites was designed and prepared for selective enrichment of uranium from seawater. The existence of specific adsorption sites and the corresponding adsorption mechanism were confirmed by a series of experimental analyses and supported by density functional theory (DFT) calculations. Under the influence of seawater environment, the maximal uranium uptake of IIP reached 58.31 mg g−1. Significantly, the mass ratio of U and V (Sr or Ni) adsorbed by IIP was greater than 15, and the adsorption capacity did not change obviously after five cycles of use. The strategy combining ion imprinting and synergistic interaction is expected to improve uranium extraction performance.

Preparation and application of a new ion-imprinted polymer for nanomolar detection of mercury(II) in environmental waters

This study introduces a novel ion-imprinted polymer for the ultrasensitive detection of mercury(II) in water. The ion-imprinted polymer was synthesized via a simple bulk polymerization process using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, morpholine-4-carbodithioic acid phenyl ester as the chelating agent, and ammonium persulfate as the initiator. The electrochemical mercury(II) sensing capability of the ion-imprinted polymer was studied via the modification of a cost-effective carbon paste electrode. A stripping voltammetric technique was utilized to quantify the analyte ions following open-circuit enrichment. Critical experimental parameters, including the nature and concentration of the eluent, solution pH, preconcentration duration, ion-imprinted polymer dosage, sample solution volume and reduction potential, were systematically studied and optimized. Under optimal conditions, the sensor exhibited a linear response in the range of 1.0 to 240.0 nM, with a low detection limit of 0.2 nM. The sensor demonstrated remarkable selectivity against potential interfering ions, including lead(II), cadmium(II), copper(II), zinc(II), manganese(II), iron(II), magnesium(II), calcium(II), sodium(I) and cobalt(II). The practical applicability of the developed method was successfully validated through the analysis of real water samples, suggesting its potential for environmental monitoring applications.

Adsorption and detection of praseodymium ion by ion-imprinted polymer with ultra-low sensitivity.

A novel kind of carbon dot (CD) was prepared by one-step hydrothermal microwave assisted method using L-tryptophan and L-tartaric acid as raw materials. Monodisperse poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres were utilized as the matrix, with praseodymium (Pr) ion (Pr3+) as the template, methacrylic acid as the functional monomer, and 5-amino-8-hydroxyquinoline (5-AHQ) acts as the ligand. A composite microsphere of ion-imprinted polymer (IIP) and CD (noted CD@IIP) was prepared by surface-initiated atom transfer radical polymerization (SI-ATRP). For comparison, IIP without CD (Pr-IIP) and non-imprinted polymer (NIP) were also prepared. Through static adsorption experiments, it was determined that the saturated adsorption amount of CD@IIP is 47.19mgg-1, that of Pr-IIP is 54.49mgg-1, while that of NIP is only 24.32mgg-1. Dynamic adsorption experiments showed that the equilibrium of three kinds of materials wasreached within 30min. Particularly, CD@IIP could emit two fluorescence peaks at 325nm and 421nm under ultraviolet irradiation, and exhibited excellent selectivity and fluorescence quenching effect on Pr3+. The fluorescence response of Pr3+ in the range 0-400μmol L-1 was determined by ratiometric fluorescence method, offering a two-stage model and robust linear regression coefficient. These results demonstrated that CD@IIP exhibited selective adsorption ability for Pr3+, and a sensitive, rapid and simple method for detection of Pr3+ was successfully developed.

Fabrication of ultrasound/microwave co-assisted ruthenium temperature-sensitive ion-imprinted polymer microspheres and evaluation of its selective adsorption performances

Ruthenium recovery from secondary sources is necessary to secure the supply of ruthenium because of the increasing demand for ruthenium in industrial applications and the generation of ruthenium-containing secondary sources. In this work, a integration technique that combining imprinted technology, temperature-sensitivity technology, multi-field coupling technology and Pickering emulsion technology was proposed to prepare a green and efficient ruthenium temperature-sensitive ion-imprinted polymer microsphere under ultrasound/microwave co-assisted conditions for the specific separation and purification of ruthenium in complex environments. The structures and morphologies of the obtained hollow temperature-sensitive imprinted microspheres were characterized. Their adsorption/desorption performances, reusability and application in secondary resources were also studied and evaluated. The adsorption mechanism was studied by adsorption kinetic studies and isothermal adsorption studies. The results showed that the structure of US/MW-Ru(IV)-TIIPM was responsive to external temperature changes, reaching a maximum adsorption of 16.2105 mg/g at 33 °C and a maximum desorption rate of 76.30 % at 25 °C. US/MW-Ru(IV)-TIIPM has good reusability and demonstrates good separation and purification capabilities when applied to platinum catalyst leach solutions.

Selective Capture of Germanium from Water by a Hydrotalcite-Based Ion-Imprinted Polymer: Performance and Mechanism

Selective Capture of Germanium from Water by a Hydrotalcite-Based Ion-Imprinted Polymer: Performance and Mechanism

A novel composite electrochemical sensor doped ion-imprinted polymer based on N-methacryloyl-L-histidine/ethylene glycol dimethacrylate for ultrasensitive determination of copper (II) ions in food supplements

A novel composite electrochemical sensor doped ion-imprinted polymer based on N-methacryloyl-L-histidine/ethylene glycol dimethacrylate for ultrasensitive determination of copper (II) ions in food supplements

Reel silk from cocoons: Optimized fabrication of chitosan-sodium tripolyphosphate imprinted polymers for high-efficiency and selective capture of hexavalent chromium

The structure–function relationship of ion-imprinted polymers for toxic hexavalent chromium (Cr(VI)) is poorly understood. In this study, a series of Cr(VI)-imprinted chitosan (CS)-sodium tripolyphosphate (STPP) composites were prepared by sol–gel method using different alkali/acid combinations and drying modes. The elution of CS-STPP polymer with 1 M NaOH+5 mM HNO3 followed by freeze drying produced the optimal IIP-B+5A-fd material. The distinct structural stabilities and surface charges of imprinted CS-STPP composite determined their disparate Cr(VI) sorption abilities. The Cr(VI) sorption ratio on IIP-B+5A-fd kept higher than 97 % at pH<7, while that on non-imprinted NIP-B+5A-fd decreased from ∼ 73 % to ∼ 28 % as the solution pH rose from 4 to 7. The Cr(VI) sorption kinetics on IIP-B+5A-fd reached equilibrium after 12 h, faster than 24 h on NIP-B+5A-fd. The maximum Cr(VI) sorption capacity of IIP-B+5A-fd (41.29 mg/g) surpassed those of NIP-B+5A-fd (26.00 mg/g) and various previously reported adsorbents. IIP-B+5A-fd exhibited a much better Cr(VI) sorption efficiency (∼83 %) than NIP-B+5A-fd (∼20 %) in the presence of mixed aqueous components. The Cr(VI) sorption mechanism on IIP-B+5A-fd was electrostatic attraction–redox–inner-sphere complexation. Overall, the prepared IIP-B+5A-fd polymer holds a promising potential for highly efficient and selective removal of Cr(VI) from a polluted water environment.

Advanced fiber optic sensors for quantitative nitrite detection: Comparative analysis of plasmonic tilted fiber Bragg gratings and fiber optic tips with ion-imprinted polymers

The presence of nitrite, a prevalent contaminant in natural environments, presents a significant environmental and human health concern. Hence, it is imperative to develop a sensor with the ability to quantitatively detect nitrite. This study focuses on the design and development of i) probe 1: tilted fiber Bragg gratings (TFBGs) and ii) probe 2: fiber optic tip-based plasmonic sensors utilizing ion-imprinted polymers. The concentration of nitrite was assessed at various levels using both sensing configurations. The outcomes indicated that the TFBGs-based sensor exhibited a sensitivity and limit of detection (LOD) of 0.469 nm/ln(μg/mL) and 0.142 μg/mL in the linear detection range of 0.5–50 μg/mL. The fiber optic tip-based sensor exhibited a sensitivity and LOD of 1.16 nm/ln(μg/mL) and 0.176 μg/mL within the 1–50 μg/mL linear detection range. The obtained sensing results reveal that the sensors presented in this study are able to accurately detect nitrite at various concentrations in a quantitative manner. Moreover, an assessment was conducted to examine the selectivity and reusability of the sensor individually, yielding satisfactory results.

Optimization of Cr(VI) ion-imprinted polymer with imidazole derivatives as functional monomers and its binding mechanism

Cr(VI) is a representative heavy metal which has significant toxicity to biological organisms. Ion-imprinted polymers (IIPs) have been recognized as effective adsorbents to remove Cr(VI) from environment. Among them, imidazole derivatives are expected to serve as potential monomers for Cr(VI)-IIPs, but the binding mechanisms of monomers with Cr(VI) remain unclear, which makes Cr(VI)-IIPs design having rare sound theory to be guideline. In this work, the suitable functional monomer of Cr2O72--IIPs was screened among five imidazole derivatives (adenine, cytosine, uric acid, l-histidine, 1-methacryloyl imidazole) with a target-monomer binding affinity guide strategy, and the optimal self-assembling conditions were investigated using theoretical calculations and experimental methods. Adenine exhibited the highest potential among the five candidate monomers, followed by cytosine. The optimal ratio of target and monomer was determined to be 2:3. Furthermore, a 5:5 mixture of ethanol and cyclohexane was identified as the most suitable solvent for the pre-polymerization environment, while epichlorohydrin acted as the most appropriate crosslinker. Additionally, the binding nature of non-covalent interaction between target and monomer was identified to be electrostatic-dominated hydrogen bonding. These mechanistic insights provide valuable theoretical support for the rational design of Cr2O72--IIPs, which are significant for IIPs development as adsorbents for contaminants detection and removal from environment.

Advances in the selection of functional monomers for molecularly imprinted polymers: A review.

Molecularly imprinted polymers, a type of special polymer materials, are widely used in biosensing and other fields due to their ability to specifically recognize target molecules, often called "artificial receptors.". Nowadays, researchers are constantly exploring new design and synthesis methods for molecularly imprinted materials to improve the selectivity and sensitivity of molecularly imprinted materials. Among them, the selection of functional monomers has attracted great attention. This review comprehensively analyzes and discusses the selection methods of functional monomers. The most commonly used functional monomers among different types of templates are screened based on the structural properties of the template molecules, including the selection of functional monomers among ion-imprinted polymers, protein-imprinted polymers, and bacterial imprinted polymers. The rich binding sites and functional group types of multifunctional monomers are also highlighted to advance the development of molecular imprinting technology. The article further explores the current challenges and prospects in the selection of functional monomers and emphasizes multiplex experiments and computer simulations as important directions for future research. This review provides comprehensive information and constructive guidelines for researchers in selecting functional monomers in areas such as analytical chemistry and biosensors.

Recent Advances in Synthesising and Applying Magnetic Ion-Imprinted Polymers to Detect, Pre-Concentrate, and Remove Heavy Metals in Various Matrices

Magnetic ion-imprinted polymers (MIIPs) are an innovative material that combines the selectivity of ion imprinting with the ease of separation provided by magnetic properties. Recent advancements in MIIPs have shown that they have higher selectivity coefficients compared to non-imprinted materials. The synthesis of MIIPs involves creating specific recognition sites for target ions in magnetic nanomaterials. Various nanomaterials, such as graphene oxide, carbon nanotubes, and silica, have been incorporated into the IIPs to improve their analytical performance for different environmental applications, including metal extraction, monitoring, detection, and quantification. This review stresses the need to develop new monomers with a high affinity for the target analyte and to find supporting materials with groups that facilitate the effective removal of the target analyte. It also explores the influence of experimental parameters on metal determination.

Application Prospect of Ion-Imprinted Polymers in Harmless Treatment of Heavy Metal Wastewater.

With the rapid development of industry, the discharge of heavy metal-containing wastewater poses a significant threat to aquatic and terrestrial environments as well as human health. This paper provides a brief introduction to the basic principles of ion-imprinted polymer preparation and focuses on the interaction between template ions and functional monomers. We summarized the current research status on typical heavy metal ions, such as Cu(II), Ni(II), Cd(II), Hg(II), Pb(II), and Cr(VI), as well as metalloid metal ions of the As and Sb classes. Furthermore, it discusses recent advances in multi-ion-imprinted polymers. Finally, the paper addresses the challenges faced by ion-imprinted technology and explores its prospects for application.

Vanadium speciation using magnetic multi-walled carbon nanotubes coated with ion-imprinted polymer and electrothermal atomic absorption spectrometry

ABSTRACT For selective extraction of vanadium (V) from water and food samples, ion-imprinted polymer was synthesised on magnetic multi-walled carbon nanotubes. For this purpose, the complex of V(V)-8-hydroxyquinoline, 4-vinylpyridine, ethylene glycol dimethacrylate, and magnetic multi-walled carbon nanotubes were used as the template of V(V), functional monomer, cross-linker, and the core, respectively. The prepared sorbent was characterised by FTIR spectroscopy, scanning electron microscopy, X-ray diffraction, energy-dispersion X-ray, and vibrating sample magnetometer. The extracted vanadium (V) was assessed by electrothermal atomic absorption spectrometry. The total vanadium in the solution was extracted and determined after oxidation of V(IV) to V(V) by hydrogen peroxide. Under optimised conditions, limits of detection and quantification of 2.9, and 10.0 ng L−1 were obtained, respectively. The maximum capacity of sorbent was 44.1 mg g−1. The method was successfully employed for the extraction and quantification of vanadium species in different water samples and total vanadium in food samples.

Tailoring of ionic imprinted polymer-based polyeugenol as a selective adsorbent of Fe(III) ions

ABSTRACT An imprinted polymer has been successfully synthesized using polyeugenol and polyethylene glycol dimethacrylate (PEGDMA) crosslinker for selective adsorption of Fe3+ ions. The synthesized imprinted polymer is milled to obtain a polymer with high adsorption performance. This work aims to determine the effect of milling on ionic imprinted polymer (IIP) and non-ionic imprinted polymer (NIP) as selective adsorbents of Fe3+ ion against competing metal ions. Adsorbent synthesis was carried out by adding polyeugenol with the crosslinking agent ethylene glycol dimethacrylate (EGDMA) in chloroform solvent and with the initiator 2,2’-Azobis(2-methyl propionitrile) (AIBN). IIP and NIP were used as adsorbents in the adsorption selectivity test of Fe3+ on the binary metals Fe3+/Cu2+, Fe3+/Zn2+, Fe3+/Ag+, and Fe3+/Cd2+. SEM (Scanning Electron Microscope) shows a more identical and smaller particle surface morphology in the milled IIP. Surface area analysis using the BET method (Brunauer-Emmett-Teller) showed an increase in the surface area of IIP after milling treatment. The adsorption capacity and selectivity of Fe3+ metal ions on milled IIP were greater than that of IIP. The selectivity of Fe3+ adsorption is greater in the binary metal ion mixture Fe3+/Cu2+ and Fe3+/Zn2+ than in the Fe3+/Cd2+ and Fe3+/Ag+ solutions.

Simple distance-based thread analytical device integrated with ion imprinted polymer for Zn2+ quantification in human urine samples.

This article presents the development of a distance-based thread analytical device (dTAD) integrated with an ion-imprinted polymer (IIP) for quantitative monitoring of zinc ions (Zn2+) in human urine samples. The IIP was easily chemically modified onto the thread channel using dithizone (DTZ) as a ligand to bind to Zn2+ with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as well as 2,2-azobisisobutyronitrile (AIBN) as cross-linking agents to enhance the selectivity for Zn2+ detection. The imprinted polymer was characterized using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). Under optimization, the linear detection range was from 1.0 to 20.0 mg L-1 (R2 = 0.9992) with a limit of detection (LOD) of 1.0 mg L-1. Other potentially interfering metal ions and molecules did not interfere with this approach, leading to high selectivity. Furthermore, our technique exhibits a remarkable recovery ranging from 100.48% to 103.16%, with the highest relative standard deviation (% RSD) of 5.44% for monitoring Zn2+ in human control urine samples, indicating high accuracy and precision. Similarly, there is no significant statistical difference between the results obtained using our method and standards on zinc supplement sample labels. The proposed method offers several advantages in detecting trace Zn2+ for point-of-care (POC) medical diagnostics and environmental sample analysis, such as ease of use, instrument-free readout, and cost efficiency. Overall, our developed dTAD-based IIP method holds potential for simple, affordable, and rapid detection of Zn2+ levels and can be applied to other metal ions' analysis.

18-Crown-6-ether assembly of cesium ion-imprinted polymer enabling efficiently selective separation of cs(I) from aqueous solution

18-Crown-6-ether assembly of cesium ion-imprinted polymer enabling efficiently selective separation of cs(I) from aqueous solution

Construction of hyperbranched imprinted nanomaterials for selective adsorption of cadmium (II).

A hyperbranched ion-imprinted polymer (IIP) material containing multiple selective adsorption sites was synthesized using halloysite nanotubes, methyl acrylate, and ethylenediamine in the presence of a template ion [i.e. Cd (II) heavy metal]. The successful preparation of the Cd-IIP composition was confirmed by FT-IR, XRD, TEM, TGA, and elemental analysis. The polymers exhibited good adsorption of Cd (II) with a maximum adsorption capacity of 64.37 mg·g-1. The imprinting factor (α) for Cd (II) was 2.62 and the selection factor (β) was 1.78, indicating a specific adsorption of Cd (II) ion. The selection coefficients of Cd-IIP for Cd (II)/Pb (II), Cd (II)/Cu (II), Cd (II)/Ni (II), Cd (II)/Cr (III), and Cd (II)/Na (I) also indicated an excellent selectivity of the hyperbranched polymers for Cd (II) in the presence of competitive ions. The removal efficiency remained more than 75% after five cycles of desorption/adsorption. We envision that the HNTs based Cd-IIP has promising applications in the removal of Cd (II) from wastewater.

Synthesis of Ion Imprinted Polymers (IIPs) Adsorbent Materials Using Fe(III) Leaching Process with Variation of Hydrochloric Acid Solvent Concentration and Heat Treatment

Fe(III)-IIPs material was prepared using a cooling-heating method with different leaching variations. The synthesis process used several chemical components, including EGDMA, MAA, and BPO as the crosslinker, functional monomer, and initiator. This study focused on the template formation process of IIPs with leaching variations, using parameters such as molarity concentration, solution mixture, and temperature to influence the amount of template formed in the polymer body. The spectra of XRD showed a widening value of FWHM as higher molarity was applied during the leaching process, with the widest one at 0.163 rad for IIPs 3 M. Fe(III) peak is located at 680-610 cm−1 or 1386-1350 cm−1 within the unleached sample, according to FTIR spectra. It also can be traced at minimum intensity in leached samples. SEM data processing showed that higher concentrations were essential in releasing Fe(III) ions from the polymer body. Meanwhile, heat treatment did not strongly impact the template formation sites of IIPs. Synthesized Fe(III)-IIPs materials had adsorption capacity, optimum time, and efficiency of 9.35 mg.g−1, 40 minutes, and 93.48%, respectively. Based on the results, Fe(III)-IIPs materials had great potential as adsorbents for removing metal pollutants from water.

Progress and Prospect of Ion Imprinting Technology in Targeted Extraction of Lithium.

Ion Imprinting Technology (IIT) is an innovative technique that produces Ion-Imprinted polymers (IIPs) capable of selectively extracting ions. IIPs exhibit strong specificity, excellent stability, and high practicality. Due to their superior characteristics, the application of IIPs for lithium resource extraction has garnered significant attention. This paper discusses the following aspects based on existing conventional processes for lithium extraction and the latest research progress in lithium IIPs: (1) a detailed exposition of existing lithium extraction processes, including comparisons and summaries; (2) classification, comparison, and summarization of the latest lithium IIPs based on different material types and methods; (3) summarization of the applications of various lithium IIPs, along with a brief description of future directions in the development of lithium IIP applications. Finally, the prospects for targeted recovery of lithium resources using lithium IIPs are presented.

Use of the dummy approach for the synthesis of ion imprinted polymers with Ni(II) or Zn(II) as template ion for the solid-phase extraction of Cu(II).

There is a strong interest in monitoring copper in environmental waters, but its direct analysis suffers from strong matrix interferences. This is why, a sample pretreatment based on solid-phase extraction (SPE) is often used but conventional sorbents usually lack specificity. It is overcome with ion-imprinted polymers (IIPs). This work evaluates for the first time the use of the dummy approach for the synthesis of Cu(II)-targeting IIPs. Two analog ions Ni(II) and Zn(II) were tested as templates and the resulting IIPs were packed in SPE cartridges. The SPE procedure was designed by optimizing a washing step following the sample percolation, to eliminate the interfering ions retained on the IIP by non-specific interactions. To optimize the washing step, solutions at different pH or containing tris(hydroxymethyl)aminomethane as a complexing agent at different concentrations were tested and combined. Zn-IIP appeared more promising than Ni-IIP, showing excellent specificity and a high selectivity. Its retention capacity was determined to be 100µg/g, and different isotherm models were evaluated to fit with the adsorption data. Finally, applications to mineral and sea waters were successfully completed and led to high and repeatable extraction recoveries for Cu(II) (88±1% and 83±3%, respectively).