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Metal ion binding properties of poly(N‐vinylimidazole) hydrogels
Abstract
The ability of poly(N-vinylimidazole) hydrogels to bind Cu(II), Co(II), Ni(II), Zn(II), Cd(II), Pb(II), Hg(II), Na(I) and Ca(II) cations, as well as uranyl, vanadium, rhenium, and molybdenum complexes, was studied by a batch equilibrium procedure using atomic absorption spectroscopy and UV-Vis spectrophotometry. The optimum pH for ion adsorption was determined in any case. The influence of the crosslinking degree of the hydrogel on the sorption kinetics and the sorption capacity at equilibrium were also studied. Sorption from the binary mixture Cu(II) + U(VI) was also analyzed at the optimum pH. Elution of the ions adsorbed from single and binary solutions was achieved in all cases. A selective desorption of loaded hydrogels with two types of ions was attained. The general conclusion is that poly(N-vinylimidazole) hydrogels are excellent materials for retention of all the ions studied here [except for Pb(II), Na(I), and Ca(II)]. The elution, which can be selective, allows regeneration of the hydrogel. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1109–1118, 1998
... Allí se discutió el trabajo de Kida y colaboradores, [125] donde emplean un silano modificado con un grupo imidazólico (3-(2-imidazolin-1-il)propiltrietoxisilano), denominado como IPTES, empleándolo de forma similar a la utilizada para los films basados en APTES, discutidos en el capítulo 3. Desde una perspectiva ahora tridimensional, es posible encontrar también el uso de hidrogeles de vinilimidazol, capaces de coordinar cationes metálicos. [198] Por estos motivos, se exploró el uso de brushes de poli(1-vinilimidazol), en adelante PvIm, como plataforma para la nucleación heterogénea de ZIF-8 y su posterior crecimiento. Los brushes fueron sintetizados mediante la técnica ATRP (Atom-Transfer Radical Polimerization) mediada por cobre, desarrollada por Krzysztof Matyjaszewski. ...
RESUMEN:
La Tesis se centró en el uso de ZIF-8, una Red Metal-Orgánica (MOF) en una configuración de film delgado sobre superficies electroactivas. Se analizó su crecimiento, estabilidad y propiedades funcionales, así como el efecto de diversas modificaciones tanto en el sustrato (uso de capas de silanos, monocapas autoensambladas de tioles y brushes poliméricos) como en los films desarrollados (inclusión de polielectrolitos).
ABSTRACT:
The focus of this thesis was the use of ZIF-8, a Metal-Organic Framework (MOF) in thin-film configuration, as a modifier of electroactive surfaces. It includes the analysis of the growth, stability, and functional properties of the native films. Additionally, the effect of different chemical modifications of the substrate (silane layers, thiol Self-Assembled Monolayers, and polymer brushes) and the final films (polyelectrolyte inclusion) was also studied.
... The obtained QDMAC5 was precipitated by crystallization from the solution. The solid separated by filtration was washed with diethyl ether to remove excess unreacted C5 and dried under vacuum at room temperature for 2 days (Rivas et al., 1998). ...
Olive mill wastewater, also known as olive wastewater, contains biologically active components with various beneficial effects on health. The development of novel adsorbent materials for the recovery of these biologically active substances is important area of research. In this study, copolymeric hydrogels based on N-vinylimidazole (VIm), a new material that has never been used as an adsorbent in the separation of phenolic components, were synthesized. The hydrogels synthesized in this study is copolymer structures based on N-vinylimidazole (VIm) containing [2- (methacryloxy) ethyl] dimethylpentylammonium bromide (QDMAC5) in different moles. QDMAC5 was obtained by quaternization of 2- (dimethylamino) ethyl methacrylate (DMA) with 1-bromopentane (C5). The production of copolymer hydrogels was carried out by free radical solution polymerization. The syntheses were carried out only by changing the monomer composition so that the crosslinker ratio remained constant (1.2 mol%). The QDMAC5 content in the copolymers was 5, 10, 20, 30, and 50 mol%. So, the resulting structures were named PVQ-5%, PVQ-10%, PVQ-20%, PVQ-30%, and PVQ-50%, respectively. Functional group characterizations of hydrogels were made by Fourier Transform Infrared Spectrometry (FTIR). The surface of the hydrogels was analyzed by Scanning Electron Microscopy (SEM). Finally, thermogravimetric analyzes (TGA) were performed to investigate the thermal degradation behavior. The recovery of the rutin present in olive mill wastewater has been investigated as a model study. Kinetic data has been represented by the selected models (pseudo-first order, pseudo-second order, and intraparticle diffusion) convincingly (R² > 0.76), while the equilibrium findings have fitted well to Langmuir, Freundlich, and Temkin equations (R² > 0.77). Rutin adsorption process on N-vinylimidazole (VIm) based copolymeric hydrogels has been found as exothermic and spontaneous chemisorption process depending on the thermodynamic analysis.
... VI copolymers readily form complexes with transition metal ions. Cu 2 + and Zn 2 + are present in blood plasma at concentrations of 10-20 M [11] , and the equilibrium dissociation constants reported for complex formation with cross-linked polyVI gels are in the range of 0.5-1 mM [12] , which is much higher than the ion's concentrations in plasma. Some withdrawal of transition metal ions from plasma can thus be anticipated, though the VI-units of the copolymers will probably be far from saturation. ...
N-vinylimidazole-divinylbenzene (VI-DVB) copolymer beads with a N-vinylimidazole (VI) weight content ranging from 7% to 15% were studied as possible adsorbents for hemoperfusion and compared with the cross-linked polystyrene beads from commercial devices. All the beads had a large volume fraction of mesopores with diameters of 2–50 nm, quantified by nitrogen adsorption, and BET areas from 500 to 1000 m²/g. Metal-chelate adsorption of copper (II) ions on VI-DVB was high in 0.15 M NaCl (up to 40 μmol/mL), and low in blood plasma (< 1 μmol/mL). Reversible adsorption of blood plasma proteins was high (> 100 mg/mL beads) on all the bead types. Irreversibly adsorbed proteins eluted by 2% SDS included albumin, fibrinogen, fibronectin, and transferrin. Metal chelating contributed to the irreversible adsorption. Unlike the beads from commercial devices, VI-DVB beads adsorbed the LPS endotoxin from plasma. Adsorption of bilirubin and IL-6 was high on all the beads tested, but VI-DVB beads were better adsorbents of bile acids. VI-DVB are promising as components of multifunctional devices for blood purification applicable to treatment of diseases where conventional devices have lower or negligible adsorption capacity.
... [16][17][18] In previous reports, many researchers have focused on the specific introduction of various metal ions into the catechol-metal system. [19,20] It provided a new opportunity for various applications, such as water purification, biomedical engineering, wearable device, and responsible sensor. ...
Catechol plays an important role in many systems by interacting with organic (e.g., amino acids) and inorganic (e.g., metal ions, metal oxides) compounds. Catechol cross‐linked polymer networks exhibit significant mechanical strength, good adhesiveness, and life‐like characteristics. Recently, catechol–metal coordination materials have aroused increasing interest in multifunctional applications. Numerous influential studies have demonstrated that the type of metal ions and the structure of phenolic (such as natural phenolic (e.g., tannic acid, gallic acid, and lignin) or synthetic catechol‐containing polymers) play important roles in the formation of catechol–metal coordination complexes. Although catechol–metal‐based materials have been successfully prepared, the cross‐linking chemistry between catechol and metal ions is still an important topic. To achieve catechol–metal‐based materials with controllable and superior performance like living organisms, an in‐depth understanding of the cross‐linking mechanism is crucial. This review summarizes some studies on the coordination of catechol–metal‐based materials, as well as the chemical mechanism behind the cross‐linking of metal ions and catechol‐containing molecules. The pathways and parameters that can affect the cross‐linking are also discussed. Their advanced applications in the energy strategy, environmental filtration, biomedical, mechanical, adhesive, and some emerging fields, together with the current trends are also explored. This review summarizes the currently proposed mechanisms for the catechol–metal coordination, covering a variety of metal ions as well as natural or synthetic catechol, and some applications in the energy strategy, environmental filtration, biomedical, mechanical, adhesive, and some emerging fields.
... HCO 3 − ) or carbamate forms. Polymers formed from 1-vinylimidazole (and related derivatives such as 1-vinyl-2-methylimidazole) have been extensively researched within homo-or copolymers for use in applications including gas separation, 11,12 gene delivery, 13 metal binding and removal, [14][15][16][17][18][19] hydrogels, 12 flame retardation, 20 wearable technology 21 and for grafting or surface modification of other materials 22,23 as well as the various applications for poly(ionic liquid)s formed from vinylimidazolium salts. ...
1‐Vinylimidazole has been extensively utilized by the polymer science community, due to its high reactivity for free radical polymerization and the variety of uses for both neutral polyvinylimidazole and cationic polyvinylimidazolium forms. While much rarer, 4‐vinylimidazoles and 2‐vinylimidazoles are less synthetically accessible. In comparison to conventional methods for the synthesis of vinylimidazole derivatives from energy‐intensive reaction conditions utilizing hazardous, gaseous precursors, herein we demonstrate a simple and versatile two‐step method applied to the synthesis of seven 1‐vinylimidazoles with different substituents as well as an initial demonstration of a facile method to synthesize the rare compound 1‐methyl‐2‐vinylimidazole. The process relies upon the synthesis of N‐hydroxyethylimidazole precursors via a ring‐opening reaction from substituted imidazoles with ethylene carbonate, a ‘green’ substance formed from CO2 and ethylene oxide. For the synthesis of 1‐methyl‐2‐vinylimidazole, the hydroxyethylimidazole intermediate is conveniently formed from 1,2‐dimethylimidazole and paraformaldehyde. These hydroxyethylimidazoles are subsequently dehydrated to the corresponding 1‐ or 2‐vinylimidazole forms using a base‐catalyzed reactive distillation. The optimization of process conditions is discussed, and properties of the vinylimidazole derivatives were computationally studied using density functional theory calculations. This work reveals scalable synthetic methods for previously inaccessible vinylimidazole compounds which can enable the design of new polymers. © 2020 Society of Chemical Industry
... Poly(4-vinylphenol) is used in electronics applications due to its dielectric and photoresist properties, whilst poly(4-vinylguaiacol) is antimicrobial and potentially biodegradable (Hatakeyama et al., 1977). 4-vinylimidazole (4VI) is another styrene analog that can form polymers with potentially novel properties, such as the absorbance of heavy metal ions (Rivas et al., 1998). Styrene and its derivatives are produced industrially from the unsustainable use of petrochemical feedstocks (Cavani and Trifir, 1995). ...
Bio-based production of industrial chemicals using synthetic biology can provide alternative green routes from renewable resources, allowing for cleaner production processes. To efficiently produce chemicals on-demand through microbial strain engineering, biomanufacturing foundries have developed automated pipelines that are largely compound agnostic in their time to delivery. Here we benchmark the capabilities of a biomanufacturing pipeline to enable rapid prototyping of microbial cell factories for the production of chemically diverse industrially relevant material building blocks. Over 85 days the pipeline was able to produce 17 potential material monomers and key intermediates by combining 160 genetic parts into 115 unique biosynthetic pathways. To explore the scale-up potential of our prototype production strains, we optimized the enantioselective production of mandelic acid and hydroxymandelic acid, achieving gram-scale production in fed-batch fermenters. The high success rate in the rapid design and prototyping of microbially-produced material building blocks reveals the potential role of biofoundries in leading the transition to sustainable materials production.
... Moreover, 4VP-based materials or polymers have been used as antimicrobial materials, detoxifying agents for environmental applications, and as template and reactor for the synthesis of metal nanoparticles and applications in catalysis [10]. The third of these monomers, 1-vinyl-1H-imidazole (VIM), is a monomer with properties suitable for use in hydrogel synthesis and modifications [11]. VIM-based materials or polymers have attracted the attention of researchers due to aromatic structure and pH response and are used in metal-ion complexation, water purification, catalytic agent, redox reactions, photoinduced hydrogen generation, counter ion and dye binding, corrosion inhibitors [12][13][14][15]. ...
This paper describes the theoretical comparison of the reactivity as comonomers of some nitrogen-containing monomers. Theoretical calculations of monomers commonly used as comonomer in preparation of micro- or nano-gels were carried out by using CAM-B3LYP/6-31+G and B3LYP/6-311G+ (d,p) basis sets of density functional theory. The vibrational frequencies and chemical shifts were calculated by both methods and compared with each other. VEDA 4 program was used for detailed frequency analysis. HOMO and LUMO analysis, electronic properties and NBO analysis are also determined using the same methods and compared. NBO analysis confirms the delocalization of electron density within the monomers. In addition, molecular electrostatic potential maps were generated for each monomer to identify reactive regions. Finally, thermodynamic functions and Mulliken atomic charges were calculated, and the results calculated by both methods matched well.
... The strength of sorbed metal ion has been determined by titrating the remaining metal ions. The results of sorption behaviour of -carrageenan and its grafted polymer with N-(hydroxymethyl) acrylamide has been determined in terms of different parameters (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998) ...
... The strength of sorbed metal ion has been deter- mined by titrating the remaining metal ions. The results of sorption behaviour of k-carrageenan and its grafted polymer with N-vinyl-2- pyrrolidone have been determined in terms of different parameters (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998), i.e. per- cent ion uptake (P u ), partition coefficient (K d ), retention capacity (Q r ). ...
... Filtrates of the solution were analyzed for concentration of unabsorbed ions by titrametri- cally (Bassette, Denney, Jeffery, & Mendham, 1978). Different rela- tionships were used to express sorption behavior are as follows (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998). ...
... The strength of sorbed metal ion has been determined by titrating the remain- ing metal ions. The results of sorption behaviour of partially carboxymethylated guar gum and its graft polymer synthesized (partially carboxymethylated guar gum-g-N-vinyl-2-pyrrolidone) have been investigated in terms of different parameters i.e. per- cent ion uptake (P u ), partition coefficient (K d ), retention capacity (Q r ) (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998 ...
... The strength of sorbed metal ion has been determined by titrating the remaining metal ions. The results of sorption behaviour of -carrageenan and its grafted polymer with N-(hydroxymethyl) acrylamide has been determined in terms of different parameters (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998) ...
... The strength of sorbed metal ion has been determined by titrating the remaining metal ions. The results of sorption behaviour of j-carrageenan and its grafted polymer with N-vinyl formamide has been determined in terms of different parameters (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998), i.e., percent ion uptake (P u ), partition coefficient (K d ), retention capacity (Q r ). ...
... The strength of sorbed metal ion has been determined by titrating the remaining metal ions. The results of sorption behaviour of sodium carboxymethyl cellulose and its grafted polymer with vinyl sulfonic acid have been determined in terms of different parameters (Rivas, Maturana, Molina, Gomez- Anton, & Pierola, 1998) ...
... The strength of sorbed metal ion has been determined by titrating the remaining metal ions. The results of sorption behaviour of xanthan gum and its grafted polymer with 2-Acrylamidoglycolic acid have been determined in terms of differ- ent parameters (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998) ...
... The strength of sorbed metal ion has been determined by titrating the remaining metal ions. The results of sorption behavior of partially carboxymethylated guar gum and its grafted polymer with 2-acrylamidoglycolic acid have been deter- mined in terms of different parameters (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998) i.e., percent ion uptake (P u ), parti- tion coefficient (K d ), retention capacity (Q r ). Retention capacity (Q r ) = amount of metal ion in the polymer (mEq.) ...
... Filtrate solution was analyzed for concentration of unabsorbed ions by titrametrically (Bassett, Denney, Jeffery, & Mendham, 1978). Different relationships were used to express sorption behaviour and are as follows (Rivas, Maturana, Molina, Gomez-Anton, & Pierola, 1998). Amount of metal ion in the polymer (mEq) Weight of dry polymer (g) ...
... Adsorption of metals was performed by immersing the grafted hydrolysed or non-hydrolysed samples (0.1 g) in a solution (50 ml) containing 25 ppm of Cr 6þ or Cu 2þ ions for 24 h. After filtration, the remaining metal ions in the filtrate were determined using ICP spectrometer and the percent uptake was calculated, equation (2) (Rivas et al., 1998). Percentage uptake of metal ions by the Hydrogel: ...
Purpose – The purpose of this paper is to prepare and optimize the preparation conditions of some new hydrogels and in addition, evaluate their water
absorbance at different mediums and their ability to remove ions from aqueous solutions.
Design/methodology/approach – Cellulose was extracted from depithed bagasse at two different pulping conditions; 3 and 6 hours cooking times,
pulp (I) and (II), respectively. These pulps, in addition to cotton linter for comparison, were grafted with acrylamide followed by cross-linking with
glutaraldehyde. The networks were partially hydrolyzed and the structures of products (before and after hydrolysis) were studied using FTIR, SEM, TGA
and X-ray. The optimum preparation conditions were identified, before and after hydrolysis, to achieve maximum absorbance and the ability of prepared
hydrogels to remove ions from solutions was investigated.
Findings – Maximum level of absorption was recorded using hydrogels prepared with monomer concentration ¼ 0.8 mol/l, cross-linker
concentration ¼ 0.01 mol/l, reaction time ¼ 2 hours and temperature ¼ 658C. Hydrogels prepared using pulp (I) showed the best absorbance
behavior and a tendency to remove ions from water.
Research limitations/implications – The ability of the prepared gels to remove ions from water could be further investigated to evaluate the ability
of their use in a multi-filtration system for water treatment.
Practical implications – This piece of work has suggested a simple way to convert an agricultural waste to hydrogel able to remove metal ions from
water.
Social implications – Consuming this type of waste reduces the risks resulting from its burning in some countries, such as Egypt, that produce large
amounts of it.
Originality/value – In this paper, low cost hydrogels, with expected value in water treatment, were prepared using agricultural wastes. They have
shown better reactivity than gels prepared using pure cellulosic materials (cotton linter).
... Poli(N-vinilimidazol) (p(VIm)) hidrojel ilk olarak Chapiro ve Mankowski tarafından organik bir çözücüde sentezlenmiş [23], ardından 1998 yılında Rivas ve arkadaşları tarafından N,N'-methylenebisacrylamide (BAAm) çapraz bağlayıcısı varlığında sulu ortamda sentezlenmiştir [24]. p(VIm) hidrojeller nötral yapıya sahip olmakla birlikte yapılarındaki imidazol gruplarından dolayı zayıf baz olarak davranırlar ve asidik çözeltilerde kolaylıkla protonlanırlar. ...
... They are introduced into the environment during industrial processes, refining of ores, mining, disposal of industrial and domestic waters, etc. Pollution in water concern to worldwide due the toxic effect on humans hence it needs the immediate attention of researchers and environmentalists [12,13]. Polymer resins and hydrogels bearing electron donor groups have the ability to bind metal cations [15][16][17][18][19][20]. Mercury is generally considered to be one of the most toxic metals found in the environment [21] and that is why the discharge limit of waste water streams has been fixed by law in very small values. ...
... Our previous work on polymer electrolytes suggested that the polymer electrolytes can form complexes with lithium, leading to a negative shift in the TiO 2 conduction band and an increase in the open circuit voltage Lau, 2011, 2010;Smolin et al., 2015). It has been shown that PVIZ can coordinate strongly with metal ions, and therefore it has the potential to bind well to lithium ions present in the DSSC electrolyte (Pekel et al., 2002;Rivas et al., 1998). This is a possible explanation for why the open circuit voltage is higher in the PVIZ integrated DSSC. ...
... All the adsorption experiments were carried out at room temperature during 24 h by mixing the solution with the hydrogel in an orbital shaker a slow rate. Likewise, the adsorption of heavy metal was estimated by calculating the removal percentage, P r , the partition coefficient, K d , and the retention capacity, Q r , as follows: [9,37,38] P r ¼ Amount of metal ion in the polymer mg ð ÞFigure 2 shows the FTIR spectra of native starch, NS, and the oxidized starches with the lower and higher oxidation, OS-1 and OS-3, respectively. During the oxidation reaction, hydroxyl groups of glucose are initially oxidized to carbonyl groups and thereafter to carboxyl groups. ...
Superabsorbent materials based on natural products have been synthesized by free radical oxidation of corn starch using a redox system consisting of potassium permanganate and sodium bisulfite. The resulting oxidized starches were characterized by analyzing the variation of carbonyl and carboxyl contents. The swelling ability of these samples has been determined by gravimetric method in water and in saline solutions. The effect of oxidant concentration and bleaching procedure on the water absorption capacity has been studied. The ability to remove heavy metals in water solution has been tested against Cd2+, Ni2+, Pb2+ and Zn2+ ions, showing higher percentage of remotion for the unbleached oxidized starches, in particular against nickel ions. Copyright © 2014 John Wiley & Sons, Ltd.
There are many advantages of using membranes in the separation of wastewater, but their uses are limited because they are not reusable due to blockages in the membrane. In this study, alginate‐based poly(ethyl‐methacrylate) (PEMA) polymeric membranes containing previously synthesized IOS, which are known to be selective against Fe³⁺, were prepared and their permeability against heavy metals such as Cd²⁺, Co²⁺, Cu²⁺, Fe³⁺, Hg²⁺ and Pb²⁺ were investigated. The properties of membranes characterized by UV‐Vis and FT‐IR spectrophotometry, were investigated with analysis techniques such as SEM, contact angle measurements, TG‐DTG, DSC and AFM. As a result of the measurements taken from the UV spectrophotometer of the filtrates passed through various aqueous ion solutions of the membranes as mentioned above, it was concluded that the ion to which the membrane was most selective was the Fe³⁺ ion. Moreover, it could be said that thanks to the repeated filtration processes the membrane prepared retained some Fe³⁺ ion in each measurement and could be used many times in the filtration process. Resultantly, it is possible to say that the polymeric Fe³⁺ membrane sensor produced may be suitable for use when it is necessary to remove Fe³⁺ ion from a polluted aqueous environment.
Poly(acrylic acid/Kryptofix 23-Dimethacrylate) superabsorbent polymer [P (AA/Kry23-DM) SAP] was synthesized by solution polymerization to remove Co, Ni, Cu, Cd, Mn, Zn, Pb, Cr, and Fe ions in water and improve the quality of the water. Kry23-DM cross-linker (1,4,7,13,16-Pentaoxa-10,19 diazo cyclohexene icosane di methacrylate) was synthesized using Kry23 and methacryloyl chloride. The characterization of the molecules was done by FTIR, TGA, DSC, and SEM techniques. The effects of parameters such as pH, concentration, and the metal ion interaction on the heavy metal ions uptaking of SAP was investigated. It was observed that P (AA/Kry23-DM) SAP has maximum water absorption, and the absorption increases with the pH increase. Adsorption rates and sorption capacity, desorption ratios, competitive sorption (qcs), and distribution coefficient (log D) of P(AA/Kry23-DM) SAP were studied as a function of time and pH with the heavy metal ion concentration. Langmuir and Freundlich isotherms of the P (AA/Kry23-DM) SAP were investigated to verify the metal uptake. Molecular mechanic (MM2), Assisted Model Building with Energy Refinement (AMBER), and optimized potentials for liquid simulations (OPLS) methods. were used in quantum chemical calculations for the conformational analysis of the cross-linker and the SAP. ΔH0f calculations of the cross-linker and the superabsorbent were made using Austin Model 1(AM1) method.
This work reports on a novel and versatile approach to control the structure of metal–organic framework (MOFs) films by using polymeric brushes as 3D primers, suitable for triggering heterogeneous MOF nucleation. As a proof‐of‐concept, this work explores the use of poly(1‐vinylimidazole) brushes primer obtained via surface‐initiated atom transfer radical polymerization (SI‐ATRP) for the synthesis of Zn‐based ZIF‐8 MOF films. By modifying the grafting density of the brushes, smooth porous films were obtained featuring inherently hydrophobic microporosity arising from ZIF‐8 structure, and an additional constructional interparticle mesoporosity, which can be employed for differential adsorption of targeted adsorbates. It was found that the grafting density modulates the constructional porosity of the films obtained; higher grafting densities result in more compact structures, while lower grafting density generates increasingly inhomogeneous films with a higher proportion of interparticle constructional porosity.
Chitosan adhesive hydrogels have attracted interest because of their unique properties. However, it is still a challenge to use simple and unmodified chitosan to synthesize multifunctional hydrogels with adhesive, self-healing and strain sensing properties. Here, a multifunctional hydrogel of Ca²⁺-chitosan/polyacrylamide（Ca²⁺- CS/PAAm）with adhesive self-healing and strain sensing properties was carried out by one-step preparation method. The hydrogel has the ability to adhere to a variety of materials, wherein the adhesion strength to rubber surface is 48.4 kPa. The hydrogel has excellent strain sensing capability on finger bending or cyclic stretching, the sensitivity factor is 0.41 ± 0.015. The cut hydrogel healed completely at room temperature within 4 hours, and the healing hydrogel can be stretched to 5 times of its original length. This makes Ca2+-CS/PAAm hydrogel to be great potential in the application of strain sensors, wound dressing and skin adhesives.
Two shot solution polymerized natural rubber/polyethylene oxide (NR/PEO) block copolymers are used as chelating exchanger for the metal ions Mn(II) and Fe(II). The polymer - metal ion chelates are prepared via solution batch adsorption method and are subjected to various characterisation techniques. Adsorption studies shows 96 and 63 % complexation for Mn(II) and Fe(III) ions, respectively. The 72 helical conformation of PEO and metal-etheric oxygen coordination are confirmed by FT-IR spectroscopy. The XRD results revealed the complete miscibility of metal ions and semi-crystalline nature of samples. The EDX analysis confirmed the presence of metal ions in the polymer chelates. Surface morphology is also studied using SEM and TEM techniques.
Metal-ligand coordination bonding is a non-covalent interaction that has been extensively studied as an effective way to improve the mechanical properties of hydrogels or to generate novel supramolecular self-healing gels. In this study, biodegradable polyaspartamide derivatives conjugated with histamine were synthesized and used to prepare the metal-coordinated supramolecular gel with several different metal-ions such as Cu(II), Ni(II), and Zn(II) in an aqueous solution. The resulting gels showed high adhesive properties on glass and plastics substrates, and the adhesive strength could be modulated by using different metal-ion species as well as the concentration and medium pH. In particular, the Cu(II)-coordinated gel exhibited a reversible self-healing behavior and good antibacterial activity. These wholly bio-based supramolecular polymer gels have potential for various biomedical applications with their multifunctional properties comprising adhesive, self-healing and antimicrobial properties in wet gel state.
Developing ultrasensitive chemical sensors with small scale and fast response through simple design and low‐cost fabrication is highly desired but still challenging. Herein, a simple and universal sensing platform based on a hydrogel interferometer with femtomol‐level sensitivity in detecting (bio)chemical molecules is demonstrated. A unique local concentrating effect (up to 109 folds) in the hydrogel induced by the strong analyte binding and large amount of ligands, combined with the signal amplification effect by optical interference, endows this platform with an ultrahigh sensitivity, specifically 10^−14 M for copper ions and 1.0 × 10^−11 mg mL−1 for glycoprotein with 2–4 order‐of‐magnitude enhancement. The specific chemical reactions between selected ligands and target analytes provide high selectivity in detecting complex fluids. This universal principle with broad chemistry, simple physics, and modular design allows for high performance in detecting wide customer choices of analytes, including metal ions and proteins. The scale of the sensor can be down to micrometer size. The nature of the soft gel makes this platform transparent, flexible, stretchable, and compatible with a variety of substrates, showing high sensing stability and robustness after 200 cycles of bending or stretching. The outstanding sensing performance grants this platform great promise in broad practical applications.
In the present work, graft copolymers of acrylamide onto guar gum were synthesized by free radical polymerization using potassium bromate/thiourea redox initiating system. The guar gum and guar gum-g-polyacrylamide were characterized by infrared spectroscopy and thermogravimetric analysis. It was found that the guar gum-g-polyacrylamid was thermally more stable than pure guar gum. The grafting ratio, grafting efficiency, add-on, and conversion increased with the concentration of bromate and acrylamide, whereas they decreased with increasing the concentration of guar gum. The grafting ratio and grafting efficiency showed maximum value at the concentration of thiourea and hydrogen ions of 3.2×10⁻³ mol dm⁻³ and 4.0×10⁻³ mol dm⁻³, respectively, but decreased with further increasing the thiourea and hydrogen ions concentrations. The increase in temperature from 30 to 45 °C resulted in increasing the grafting ratio while decreasing the conversion. The optimum reaction time for the graft copolymerization was found to be 2 h. Compared to the parent guar gum, the graft copolymer showed higher water swelling capacity and metal ion sorption, as well as better flocculant behaviors.
Poly (N-vinyl imidazole) hydrogel (p-VIm) and its partially quaternized analogue (p-VIm-Ar) were prepared and used for the removal of Orange II (OII). A Fourier transform infrared spectrophotometer, scanning electron microscope with an energy dispersive X-ray spectrometer attached, thermogravimetric analyzer, zeta potential analyzer and drop shape analyzer were used for the characterization of the hydrogels. The influence of some experimental parameters, such as pH of the OII solution, contact time and initial OII concentration on the adsorption process, was examined, and the obtained data were used to calculate the isotherm and kinetic parameters. Adsorption processes of OII onto adsorbents were coherent with the Langmuir isotherm and pseudo-second-order kinetic models. The quaternized analogue exhibited remarkable adsorption performance in the pH range of 2–12, while the effective adsorption with p-VIm occurred only at pH 2.0. The maximum adsorption capacity values of adsorbents were determined as 2331 (for p-VIm) and 1327 mg g−1 (for p-VIm-Ar) at pH 2.0 and 132 (for p-VIm) and 1357 mg g−1 (for p-VIm-Ar) at pH 6.0.
Given the increasing heavy metal pollution issue, fast preparation of polymeric hydrogels with excellent adsorption property toward heavy metal ions is very attractive. In this work, a series of poly(N-vinylimidazole-co-acrylamide) (poly(VI-co-AM)) hydrogels were synthesized via laser-ignited frontal polymerization (LIFP) for the first time. The dependence of frontal velocity and temperature on two factors monomer ratios and initiator concentrations was systematically investigated. Poly(VI-co-AM) hydrogels with any self-supporting shapes can be synthesized by a one-step LIFP in seconds through the application of 3D templates. These shape-persistent hydrogels are pH-responsive and exhibit excellent adsorption/desorption characteristics toward Mn(II), Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) ions, and the adsorption conformed to the pseudo-second-order kinetic model. The reusability of the hydrogels toward mental ions adsorption was further researched, which suggested that the hydrogels can be reused without serious decrease in adsorption capacity. This work might open a promising strategy to facilely prepare shape-controllable hydrogels and expand the application of LIFP.
The present paper deals with the synthesis of chitosan-g-methacrylic acid by free radical polymerization using potassium peroxymonosulphate/cyclohcxanone as a redox pair in an inert atmosphere. The reaction conditions have been optimized by varying the reaction variables, including the concentration of methacrylic acid from (12 × 10-2 to 36 × 10-2) mol dm-3, peroxymonosulphate (0.6 × 10-2 to 1.2 × 10-2) mol dm-3, cyclohexanone (0.8 × 10 -2 to 1.6 × 10-2) mol dm-3, sulphuric acid (2 × 10-3 to 6 × 10-3) mol dm -3, chitosan (0.6 to 1.4) g dm-3 along with time duration and temperature. It has been observed that the maximum grafting ratio has been obtained at time 120 min, temperature 35°C and at 2.2 × 10 -2 mol dm-3 concentration of peroxymonosulphate. Metal ion sorption, and flocculation properties have been studied along with swelling property of graft copolymer. It has been found that graft copolymer shows enhancement in these properties and is thermally more stable than parent polymer The graft copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis.
Crude metallothionein (MT) extracts from Scchizosaccharomyces pombe entrapped in sol-gels were investigated for the removal of heavy metals such as cadmium and zinc. The sol-gel provided a robust immobilization matrix for the protein extract. Adsorption and desorption isotherms were developed for both cadmium and zinc. Both metals were recovered from the sol-gel by desorption using a 1 M NaCl solution. The adsorption kinetic studies showed that cadmium and zinc adsorption followed the Langmuir isotherm. The distribution factors for cadmium and zinc were found to be 5.43 L/mg and 2.88 L/mg, respectively. Greater than 60% of Zn2+ was also removed using MT sol-gels. The experiments demonstrated that MT has a greater capacity for Cd than polyethyleneimine immobilized in the sol-gels. The adsorption capacity of MT was found to be 588.2 mg of cadmium and 434.8 mg of zinc per gram of immobilized MT, which is significantly higher than with nonbiological chelators such as polyethyleneimine or EDTA.
Cu(II)-Poly(N-vinylimidazole) complex (Cu(II)-PVI) was synthesized and employed to catalyze the oxidative polymerization of 2,6-dimethylphenyl (DMP) in water. Compared with the conventional Cu(II)-EDTA catalyst, the Cu(II)-PVI complex catalyst shows an enhancement in the catalytic efficiency, which is nearly ten times higher than that of Cu(II)-EDTA complex. In order to elucidate the reason of the high catalytic efficiency of Cu(II)-PVI complex, N,N'-methylenebisacrylamide was used as a crosslinking agent and PVI hydrogel was prepared by radical copolymerization of N-vinylimidazole and N,N'-methylenebisacrylamide. UV-vis spectrophotometer was used to monitor the change of the adsorption of DMP in PVI hydrogel with time. It was found that DMP concentration in water firstly decreases with the increase of time, while DMP concentration in PVI hydrogel increases with time and finally maintains an equilibrium, which confirms the concentration effect of PVI for DMP. The high catalytic efficiency of Cu(II)-PVI complex can be ascribed to the concentration effect of PVI for both substrate and catalyst during the oxidative polymerization of DMP in water.
The polymeric ligand (resin) was prepared from 2-hydroxy-4-methoxybenzophe- none with 1,3-butane diol in presence of polyphosphoric acid as a catalyst at 160°C for 13 h. The poly[(2-hydroxy-4-methoxybenzophenone) 1,3-butylene] H(HMBP-1,3-BD) forms, 1:2 metah:ligand chelates with La(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), and Dy(III). The polymeric ligand and its polychelates were characterized on the basis of elemental analyses, electronic spectra, magnetic susceptibilities, thermogravimetric analysis, and NMR and IR spectroscopies results. The molecular weight was determined using number average molecular weight (Mn) by the vapour pressure osmometry (VPO) method. All the polychelates are paramagnetic in nature. The resin and their polychelates were tested for antimicrobial activity against E. coli, B. substilis, and S. aureus (bacteria) and S. cerevisiae (yeast). It is found that the synthesized polychelates can be used as antibacterial agents.
A number of ion-exchange resins have been synthesized by reacting 8-Hydroxyquinoline with dithiooxamide and formaldehyde in presence of 2M HCl as catalyst, proved to be selective chelating ion-exchange resin for certain metals. Chelation ion-exchange properties of the terpolymer resin was studied for Fe3+, Cu2+, Ni2+, Zn2+, Cd2+ and Pb2+ ions. A batch equilibrium method has been employed in the study of the selectivity of metal ions uptake involving the measurement of the distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ions strengths. The terpolymer showed higher selectivity for Fe3+, Cu2+, and Ni2+ ions than for Co2+, Zn2+, Cd2+ and Pb2+ ions.
Graft copolymer of alginate and acrylamide was synthesized by grafting acrylamide chains on to alginate by free radical polymerization using potassium bromate/ thiourea redox system in an inert atmosphere. The reaction conditions for maximum grafting have been optimized by varying the reaction variables, including the concentration of acrylamide (3.0×10(2) - 9.3×10(2) mol dm(-3)), potassium bromate (8×10(-3) - 16×10(-3) mol dm(-3)), thiourea (1.6×10(-3) - 4.8×10(-3) mol dm(-3)), sulphuric acid (3.0×10(-3) - 7×10(-3) mol dm(-3)), alginate (0.6-1.6g dm(-3)) along with time duration (60-180min) and temperature (30-50°C). Water swelling capacity, metal ion sorption, flocculation and resistance to biodegradability studies of synthesized graft copolymer have been performed with respect to the parent polymer. The grafted polymers were characterized by FTIR spectroscopy and thermo gravimetric analysis.
Monomers Polymerization and Fabrication Properties Applications Suppliers and Commercial Grades Safety
Polymerized ionic liquids and polyelectrolytes play a major role in a broad range of biological applications including antimicrobials, nonviral gene delivery, synthetic enzymes, metal chelation, and drug delivery. Ammonium- and phosphonium-containing macromolecules will be reviewed with a focus on the literature that examines structure-property relationships of these polyelectrolytes for biological applications. Imidazole-containing macromolecules also receive significant focus due to their natural occurrence in nature and their ubiquitous use in nanomedicine. Special attention to imidazole- and imidazolium-containing polymers will focus on vinylimidazole regioisomers in particular.
Water-soluble and crosslinked water-insoluble polymers having suitable functional groups are capable to retain metal ion pollutants through ion exchange or complexation, allowing their remove from contaminated water streams. The polymeric sorbents can be obtained by polymerization of monomers containing the functional groups or by post-functionalization, also, with the aim to enhance their performance, the sorbents can be loaded with inorganic (nano)particles or coupled with membrane processes. This paper is an overview of the versatile polymer materials containing different functional groups at the main or side chain to remove hazardous inorganic species. These materials include water-insoluble, nanocomposite and water-soluble polymers. Water-insoluble polymers and nanocomposites are used in adsorption and ion exchange processes, whereas water-soluble polymers are employed with ultrafiltration membranes in the liquid-phase polymer-based retention technique.
Hydrogels of N-vinylimidazole are polymerized in molds of different materials (acidic glass, basic glass, silanized glass, nylon, Teflon, pvc) to study the influence of the material on the gel properties. Molds are cylinders of very narrow diameter (2-8 mm) to enhance the influence of the wall. Confocal microscopy, glass transition, and degree of swelling are used to characterize the gels. A border with more dense polymer is formed close to the wall in all the materials. The hydrogels obtained in Teflon and pvc have higher glass transition, higher degree of swelling, and higher density of cross-links than the gels obtained in glass. Also, the reaction yield is lower in Teflon and pvc than in glass. For the narrower molds, the gels swell more in the direction normal to the wall than in the direction parallel to the wall, and this departure from isotropy is more noticeable in Teflon and pvc than in glass.
Heavy metal pollution represents an important environmental problem due to the toxic effects of metals. The accumulation of heavy metals throughout the food chain leads to serious ecological and health problems. Mercury is universally recognized as one of the most toxic and dangerous non-biodegradable inorganic pollutants present in aquatic systems. Mercury is present in many products and processes in common use (for example, chloro-alkali production, pharmaceutical and cosmetic preparations, combustion of fossil fuels, electrical and electronics manufacturing plants, metal processing, metal plating, metal finishing, and pulp and paper industries), resulting in the contamination of aquatic systems.
Imidazole-containing network polymers have been prepared via quaternization of linear poly(1-vinylimidazole). Owing to the affinity for water, crosslinked poly(1-vinylimidazole) is capable of limited swelling in water and concomitant formation of polyelectrolyte hydrogels. Imidazole-containing hydrogels can be doped with different metal ions and can serve as matrixes for stabilization of particles obtained via reduction of nanosize metals.
Monomers N, N-(dimethyl) amine ethyl methacrylate (DMAEMT) and N-[3 - (dimethylamine) propyl] methacrylamide (DMAPMD) were co-polymerized with 1-vinylimidazole (VI) in different proportions and crosslinked with N,N′-methylenebisacrylamide (BIS) in aqueous phase, to yield highly resistant hydrogels. The polymeric products were studied by swelling kinetics, solvent diffusion within the crosslinked network, thermal decomposition, infrared spectroscopy (FTIR), variable pressure scanning electron microscopy (VP-SEM), and mechanical and rheological tests. The incorporation of VI in the polymerization reaction led to beneficial changes in the properties of the final materials such as improvement in the resistance of the materials and increase in the percentage of deformation capable of withstanding elongation before breaking. All VI-containing products were mechanically strong with respect to homo-polymers (DMAPMD 100% and DMAEMT 100%). The most resistant products were DMAPMD-co-VI 60% and DMAEMT-co-VI 60%. A synergistic effect with the addition of VI is revealed by Young’s modulus that increases 5 and 10 times regarding the hydrogels yielded from pure monomers, respectively.
A series of random copolymers of acrylamide and N-vinylimidazole, poly(AAm-co-NVI), with various compositions were prepared using redox copolymerization. The influence of environmental conditions such as pH, temperature, and ionic strength on the swelling behavior of the copolymeric hydrogels was investigated. The hydrogels exhibited the highest equilibrium swelling in basic medium at high temperature. Equilibrium swelling decreased with rising ionic strength at pH 5.0. As pH increased, equilibrium swelling of the hydrogels increased at pH 11.0 and I = 0.20 M. Swelling kinetics of the hydrogels was found to be non-Fickian at 25°C. The process tended to be Fickian at higher pH and temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1783–1788, 2005
Interest in the potential use of constructed and naturally-occurring wetland systems as a low-cost, low-maintenance method for the treatment of metal-polluted water has increased considerably in recent years. Because metal cation binding to organic matter represents one mechanism by which metals are retained in wetlands, laboratory studies were conducted of the binding of metal cations to Sphagnum peat and sawdust, two substrates used in wetland construction for treatment of metal-polluted waters. The two substrates differed in initial cation exchange characteristics, organic matter fractionation, affinities for ten different metal cations, and metal binding capacities. Results suggest a simple method for quantitatively assessing the potential for different types of organic substrates to retain metals by binding when exposed to metal-polluted water of a particular chemical composition. For metals that are retained in wetlands principally by binding to organic matter, application of the method could lead to an improved ability to formulate a priori cost-benefit analyses for contemplated wetland treatment of metal-polluted waters.
Resins with retention properties for copper(II) and uranium(VI)were synthesized by crosslinking of polyethyleneimine with 1,9-dibromononane and 1,10-dibromodecane, and subsequent alkylation with dimethylsulphate. The effect of the pH on the retention, elution assays in acid and basic medium, and maximun capacity of load were determined. Moreover, the thermal behaviour was studied.
The successive association constants of the cadmium-imidazole complex have been determined potentiometrically by the method of Bjerrum. At 25° log k1 = 2.80, log k2 = 2.10, log k3 = 1.55 and log k4 = 1.13. From measurements at other temperatures ΔH1 is estimated to be -5 ± 2 kcal./mole. The value of log k1 is identical with the logarithm of the intrinsic association constant of cadmium with the imidazole groups of serum albumin.
A crosslinked poly(ethylene imine), using epichlorohydrin as crosslinker, was prepared and subsequently modified in order to obtain the corresponding N-methylated, N-carboxymethylated and N-phosphonomethylated derivatives. The sorption characteristics of these functionalized resins were studied by a batch equilibration technique, for uptake of Cu(II), Fe(II), Fe(III) and uranyl ions from aqueous solution. Resins with tertiary amine or ammonium groups show negligible sorption for Fe(II), Fe(III) and Cu(II) at pH 1, in contrast with high sorption for U(VI), which is readily eluted with sodium carbonate.Polyethylenimin wurde mit Epichlorhydrin vernetzt und anschließend zu den entsprechenden N-Methyl-, N-Carboxymethyl- und N-Phosphonomethyl_Derivaten umgesetzt. Die Sorptionseigenschaften der funktionalisierten Harze für die Aufnahme von Cu(II)-, Fe(II)-, Fe(III)- und Urany-(UO)-Ionen aus wässeriger Lösung wurden untersucht. die Aufnahme von Fe(II), Fe(III) und Cu(II) bei pH 1 ist bei Harzen mit tertiären Amin-oder Ammoniumgruppen vernachlässigbar, während U(VI) leicht aufgenommen und mit Natriumcarbonatlösung ebenso leicht wieder eluiert wird.
PAA networks have been prepared by crosslinking copolymerization of acrylamide (AA) and N,N′-methylen-bis-acrylamide (BA) in water. The degree of swelling was measured in the range v2=0–0.16 as a function of crosslinker proportion, C (%w/w) and total concentration, CT (g/100 ml). The swelling of two networks with BA contents of 3% and 10% were measured as a function of temperature in the range 10–30°C. The interpretation of elastic and swelling data in terms of the scaling law |fph*|=Av2m, shows a transition from a good solvent regime to a collapsed state for the polymer chains, when the crosslinker proportion is around 5 to 7%. Results of elastic and swelling measurements were used to determine the χ parameter. A different dependence of χ with v2 was found for gels with BA contents below and above 5–7%. The enthalpic contribution to the interaction parameter χH was calculated from swelling experiments as a function of temperature. The results show that when the BA proportion is increased, the enthalpic interaction parameter at infinite dilution gets closer to the one of poly(N-methyl-acrylamide).
A synthetic gel obtained by bulk polymerization of sucrose acrylate and incorporating glutaraldehyde crosslinking was used to remove heavy metal ions from aqueous and organic solutions through chelation. The influences of pH, concentration, swelling index, temperature, and solvent on the gel's chelation tendencies towards CuCl2, Pb(NO3)2, HgCl2, Ca(OH)2, NiSO4, UO2Ac2 and Hg(AcO)2 are described in this paper.
Strong and weak resins were prepared by crosslinking branched polyethyleneimine with three dihalo-aliphatic derivatives and subsequent N-methylation. All the resins were insoluble in water and common organic solvents. It was found that the N-methylated resins showed the highest adsorption ability for uranium. The morphology and the thermal stability were also examined.
The interaction of human serum albumin with zinc ions has been studied in unbuffered solutions of the isoionic protein in 0.15 M sodium nitrate to which varying quantities of sodium hydroxide and zinc chloride were added. The results nave been interpreted to show that zinc ions bind to the imidazole group of the histidine residues in the albumin, approximately in the proportion of one zinc ion to one imidazole group. Treating the binding of zinc ions and of hydrogen ions as a competition for the imidazole groups, an intrinsic binding constant for zinc ions has been calculated. This constant was found not to vary over a considerable range of values for the number of moles of zinc ions bound per mole of protein. The value of the constant is unchanged by guanidination or diazo-esterification of the albumin, and was identical with the first association constant determined for the interaction of zinc ions with imidazole.
A polarographic study has been made of the effect of pH upon the interaction between a number of metals and bovine serum albumin. It is concluded that the principal sites on the protein molecule responsible for metal binding are the imidazole groups. Approximate values of the logarithms of the intrinsic association constants with these groups are: Cu ++ (in 0.15 M KNO3) 3.7, Zn ++ (in 0.15 M KCl) 2.9, Cd ++ (in 0.15M KCl), 2.8, Pb++ (in 0.15 M KNO3) < 2.3, Tl + (in 0.15 M KCl) < 0. Weak binding also occurs at carboxyl groups. The extent of binding at these sites is determined largely by the competitive effect of other anions present in solution.
Weak and strong basic resins were synthesized by crosslinking with 1,7-dibromoheptane and 1,12-dibromododecane and subsequent N-methylation reaction of branched and linear polyethyleneimine. All the resins are insoluble in water. It was found that the N-methylated resins showed the highest retention ability for uranium. The resins do not retain significatively iron (> 10%), and only two of them retain copper above 80% at optimum pH. Elution assays with sulphuric acid, sodium carbonate, and thermal stability were also carried out.
Resins with retention properties for copper (II), and uranium (VI) have been synthesized by crosslinking of polyethyleneimine with 1,4-dibromo-2-butene and subsequent alkylation with dimethyl sulphate. The influence of pH on the retention, maximum capacity of load and elution assays were determined.