Ion-Imprinted Polymeric Materials for Selective Adsorption of Heavy Metal Ions from Aqueous Solution.

The introduction of selective recognition sites toward certain heavy metal ions (HMIs) is a great challenge, which has a major role when the separation of species with similar physicochemical features is considered. In this context, ion-imprinted polymers (IIPs) developed based on the principle of molecular imprinting methodology, have emerged as an innovative solution. Recent advances in IIPs have shown that they exhibit higher selectivity coefficients than non-imprinted ones, which could support a large range of environmental applications starting from extraction and monitoring of HMIs to their detection and quantification. This review will emphasize the application of IIPs for selective removal of transition metal ions (including HMIs, precious metal ions, radionuclides, and rare earth metal ions) from aqueous solution by critically analyzing the most relevant literature studies from the last decade. In the first part of this review, the chemical components of IIPs, the main ion-imprinting technologies as well as the characterization methods used to evaluate the binding properties are briefly presented. In the second part, synthesis parameters, adsorption performance, and a descriptive analysis of solid phase extraction of heavy metal ions by various IIPs are provided.

Sustainable Multi-Network Cationic Cryogels for High-Efficiency Removal of Hazardous Oxyanions from Aqueous Solutions.

It is still a challenge to develop advanced materials able to simultaneously remove more than one pollutant. Exclusive cationic composite double- and triple-network cryogels, with adequate sustainability in the removal of Cr2O72- and H2PO4- oxyanions, were developed in this work starting from single-network (SN) sponges. Chitosan (CS), as the only polycation originating from renewable resources, and poly(N,N-dimethylaminoethylmethacrylate) (PDMAEMA) and polyethyleneimine (PEI), as synthetic polycations, were employed to construct multi-network cationic composite cryogels. The properties of the composites were tailored by the cross-linking degree of the first network (SN5 and SN20, which means CS with 5 or 20 mole % of glutaraldehyde, respectively) and by the order of the successive networks. FTIR, SEM-EDX, equilibrium water content and compressive tests were used in the exhaustive characterization of these polymeric composites. The sorption performances towards Cr2O72- and H2PO4- anions were evaluated in batch mode. The pseudo-first-order, pseudo-second-order (PSO) and Elovich kinetics models, and the Langmuir, Freundlich and Sips isotherm models were used to interpret the experimental results. The adsorption data were the best fitted by the PSO kinetic model and by the Sips isotherm model, indicating that the sorption mechanism was mainly controlled by chemisorption, irrespective of the structure and number of networks. The maximum sorption capacity for both oxyanions increased with the increase in the number of networks, the highest values being found for the multi-network sponges having SN5 cryogel as the first network. In binary systems, all sorbents preferred Cr2O72- ions, the selectivity coefficient being the highest for TN sponges. The high sorption capacity and remarkable reusability, with only a 4-6% drop in the sorption capacity after five sorption-desorption cycles, recommend these composite cryogels in the removal of two of the most dangerous pollutants represented by Cr2O72- and H2PO4-.

Polysaccharide-Based Composite Hydrogels as Sustainable Materials for Removal of Pollutants from Wastewater.

Nowadays, pollution has become the main bottleneck towards sustainable technological development due to its detrimental implications in human and ecosystem health. Removal of pollutants from the surrounding environment is a hot research area worldwide; diverse technologies and materials are being continuously developed. To this end, bio-based composite hydrogels as sorbents have received extensive attention in recent years because of advantages such as high adsorptive capacity, controllable mechanical properties, cost effectiveness, and potential for upscaling in continuous flow installations. In this review, we aim to provide an up-to-date analysis of the literature on recent accomplishments in the design of polysaccharide-based composite hydrogels for removal of heavy metal ions, dyes, and oxyanions from wastewater. The correlation between the constituent polysaccharides (chitosan, cellulose, alginate, starch, pectin, pullulan, xanthan, salecan, etc.), engineered composition (presence of other organic and/or inorganic components), and sorption conditions on the removal performance of addressed pollutants will be carefully scrutinized. Particular attention will be paid to the sustainability aspects in the selected studies, particularly to composite selectivity and reusability, as well as to their use in fixed-bed columns and real wastewater applications.

Optimization of Arsenic Removal from Aqueous Solutions Using Amidoxime Resin Hosted by Mesoporous Silica.

The paper reports on the performances of cross-linked amidoxime hosted into mesoporous silica (AMOX) in the removal of As(III) and As(V). The optimum pH for sorption of As(III) and As(V) was pH 8 and pH 5, respectively. The PFO kinetic model and the Sips isotherm fitted the best the experimental data. The thermodynamic parameters were evaluated using the equilibrium constant values given by the Sips isotherm at different temperatures and found that the adsorption process of As(III) and As(V) was spontaneous and endothermic on all AMOX sorbents. The spent AMOX sorbents could be easily regenerated with 0.2 mol/L HCl solution and reused up to five sorption/desorption cycles with an average decrease of the adsorption capacity of 18%. The adverse effect of the co-existing inorganic anions on the adsorption of As(III) and As(V) onto the sorbent with the highest sorption capacity (AMOX3) was arranged in the following order: H2PO4 - > HCO3 - > NO3 - > SO4 2-.

New Polymeric Adsorbents Functionalized with Aminobenzoic Groups for the Removal of Residual Antibiotics.

In this paper, we present the synthesis of new polymeric adsorbents derived from macroporous chloromethylated styrene-divinylbenzene (DVB) copolymers with different cross-linking degrees functionalized with the following aminobenzoic groups: styrene-6.7% DVB (PAB1), styrene-10% DVB (PAB2), and styrene-15% DVB (PAB3). The new polymeric products, PAB1, PAB2, and PAB3, were characterized by FTIR spectroscopy, thermogravimetric analysis, and EDX, SEM, and BET analysis, respectively. The evolution of the functionalization reaction was followed by FTIR spectroscopy, which revealed a decrease in the intensity of the γCH2Cl band at 1260 cm-1, and, simultaneously, the appearance of C=O carboxylic bands from 1685-1695 cm-1 and at 1748 cm-1. The thermal stability increased with the increase in the cross-linking degree. The data obtained from the EDX analysis of the novel cross-linked copolymers confirmed the functionalization with aminobenzoic groups through the presence and content of nitrogen, as follows: PAB1: N% = 0.47; PAB2: N% = 0.85; and PAB3: N% = 1.30. The adsorption performances of the novel polymeric adsorbents, PAB1, PAB2, and PAB3, were tested in the adsorption of three antibiotics, tetracycline, sulfamethoxazole, and amoxicillin, from aqueous solutions, by using extensive kinetic, equilibrium, and thermodynamic studies. The best adsorption capacity was demonstrated by the tetracycline. Amoxicillin adsorption was also attempted, but it did not show positive results.

Chitosan-Based Polyelectrolyte Complex Cryogels with Elasticity, Toughness and Delivery of Curcumin Engineered by Polyions Pair and Cryostructuration Steps.

Chitosan (CS)-based drug delivery systems (DDSs) are often stabilized by chemical cross-linking. A much more friendly approach to deliver drugs in a controlled manner is represented by polyelectrolyte complexes (PECs) physically stabilized by spontaneous interactions between CS and natural or synthetic biocompatible polyanions. PECs with tunable structures, morphologies, and mechanical properties were fabricated in this paper by an innovative and sustainable strategy. Carboxymethyl cellulose (CMC) or poly(2-acrylamido-2-methylpropanesulfonate sodium salt) were used as aqueous solutions, while CS microparticles were evenly dispersed in the polyanion solution, at pH 6.5, where CS was not soluble. Cryostructuration of the dispersion in two steps (5 min at -196 °C, and 24 h at -18 °C), and freeze-drying at -55 °C, 48 h, conducted to pre-PEC cryogels. Next step was rearrangement of complementary polyions and the complex formation inside the pore walls of cryogels by exposure of the pre-PECs at a source of H+. PEC cryogels with impressive elasticity and toughness were engineered in this study by multiple-cryostructuration steps using CMC as polyanion with a molar mass of 250 kDa and an optimum concentration of polyanion and polycation. The performances of PEC cryogels in sustained delivery of anti-inflammatory drugs such as curcumin were demonstrated.

Preparation and Characterization of Semi-IPN Cryogels Based on Polyacrylamide and Poly(N,N-dimethylaminoethyl methacrylate); Functionalization of Carrier with Monochlorotriazinyl-ß-cyclodextrin and Release Kinetics of Curcumin.

Curcumin (CCM) is a natural hydrophobic polyphenol known for its numerous applications in the food industry as a colorant or jelly stabilizer, and in the pharmaceutical industry due to its anti-inflammatory, antibacterial, antioxidant, anti-cancer, and anti-Alzheimer properties. However, the large application of CCM is limited by its poor solubility in water and low stability. To enhance the bioavailability of CCM, and to protect it against the external degradation agents, a novel strategy, which consists in the preparation of semi-interpenetrating polymer networks, (s-IPNs) based on poly(N,N-dimethylaminoethyl methacrylate) entrapped in poly(acrylamide) networks, by a cryogelation technique, was developed in this work. All s-IPN cryogels were characterized by SEM, EDX, FTIR, and swelling at equilibrium as a function of pH. Functionalization of semi-IPN cryogel with monochlorotriazinyl-ß-cyclodextrin (MCT-ß-CD) led to IPN cryogel. The release profile of CCM from the composite cryogels was investigated at 37 °C, in pH 3. It was found that the cumulative release increased with the increase of the carrier hydrophobicity, as a result of increasing the cross-linking degree, the content and the molar mass of PDMAEMA. Fitting Higuchi, Korsmeyer-Peppas, and first order kinetic models on the CCM release profiles indicated the diffusion as the main driving force of drug release from the composite cryogels.

Evaluation of phosphate adsorption by porous strong base anion exchangers having hydroxyethyl substituents: kinetics, equilibrium, and thermodynamics.

Phosphate anions are recognized as the main responsible for the eutrophication of surface waters. In this work, two strong base anion exchangers having either N,N-dimethyl 2-hydroxyethylammonium (SBAEx.2M) or N,N-diethyl 2-hydroxyethylammonium (SBAEx.2E) functional groups, as highly efficient sorbents in the removal of phosphate anions, are presented. The influence of the main parameters (pH, contact time, initial concentration of phosphate, temperature) on the adsorption performances was investigated in batch mode. Modeling the kinetics data by Lagergren, Ho and McKay, and Elovich kinetic models indicated chemisorption as the main mechanism of sorption. The sorption at equilibrium was modeled with Langmuir, Freundlich, Sips, Dubinin-Radushkevich, and Temkin isotherm models. The experimental isotherms were the best fitted by Langmuir and Sips isotherms, the maximum sorption capacity for phosphate anions being 233.88 mg g-1 SBAEx.2M and 223.5 mg g-1 SBAEx.2E, at pH 3, and 23 °C. Adsorption of phosphate anions in competitive conditions showed that the interference with co-existing anions was low in the case of Cl- ions and much higher with SO42- ions, the ion exchange having an important contribution in the adsorption process. The adsorption was spontaneous and endothermic, the degree of spontaneity increasing with the increase of temperature. The high level of reusability, the adsorption capacity decreasing with only ~ 7% in the case of SBAEx.2E and with ~ 9% in the case of SBAEx.2M, after five sorption/desorption cycles, recommends these SBAEx as promising adsorbents for phosphate removal.

Superadsorbents for Strontium and Cesium Removal Enriched in Amidoxime by a Homo-IPN Strategy Connected with Porous Silica Texture.

In light of the fact that two with good compatibility are better than one, the homo-interpenetrating polymer network (IPN) strategy was used in this work to design novel amidoxime (AOX)-interpenetrating networks into porous silica (PSi) with the final aim to enhance the sorption performances of composite sorbents toward Cs+ and Sr2+. To achieve this goal, first, a homo-IPN of poly(acrylonitrile) (PAN) was constructed inside the channels of two kinds of porous silica, one mesoporous (PSi1) and one macroporous (PSi2), the textural properties of silica being exploited in controlling the sorption performances of the composites. The novel composites were fully characterized by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and the nitrogen sorption/desorption isotherms (Brunauer-Emmett-Teller (BET) analysis). The sorption properties of the PSi1/AOX and PSi2/AOX composite sorbents for Sr2+ and Cs+ were investigated in the batch mode to determine the effect of solution pH, contact time, initial metal ion concentration, temperature, and the presence of competitive ions on the adsorption performances. The fast kinetics of sorption was supported by the fact that ∼80% of Sr2+ and ∼65% of Cs+ were adsorbed in the first 30 min, the kinetic data being better described by the pseudo-second-order kinetic model. The experimental isotherms were well fitted by the Langmuir and Sips isotherm models. The superadsorption of Sr2+ and Cs+ is demonstrated by the values of the maximum sorption capacity of the best sorbent constructed with mesoporous silica (PSi1/IPN-AOX), which were 344.23 mg Cs+/g and 360.23 mg Sr2+/g. The sorption process was spontaneous and endothermic for both metal ions. The presence of interfering cations (Na+, K+, Ca2+, and Mg2+), at a concentration of 10-2 M, only slightly influenced the sorption capacity for the main cation. The composite sorbents were still highly efficient after five sorption/desorption cycles.

Erratum: Dragan, E.S., et al., Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores. Molecules 2020, 25, 1249.

The authors wish to make a change to the published paper [...].

Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores.

Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica (PSi), was cross-linked with either N,N,N',N'-tetramethyl-1,2-ethylenediamine (TEMED) or N,N,N',N'-tetramethyl-1,3-propanediamine, followed by the reaction of the free -CH2Cl groups with N,N-diethyl-2-hydroxyethylamine to generate strong base anion exchangers (ANEX) inside the pores. The PSi/ANEX composite sorbents were deeply characterized by FTIR spectroscopy, SEM-energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water uptake. The sorption performances of composites against Cr(VI) were investigated as a function of pH, contact time, initial concentration of Cr(VI), and temperature. It was found that the cross-linker structure and the silica morphology are the key factors controlling the sorption capacity. The adsorption process was spontaneous and endothermic and well described by pseudo-second-order kinetic and Sips isotherm models. The maximum sorption capacity of 311.2 mg Cr(VI)/g sorbent was found for the composite prepared with mesoporous silica using TEMED as cross-linker. The PSi/ANEX composite sorbents represent an excellent alternative for the removal of Cr(VI) oxyanions, being endowed with fast kinetics, equilibrium in about 60 min, and a high level of reusability in successive sorption/desorption cycles.

Removal of heavy metal ions from multi-component aqueous solutions by eco-friendly and low-cost composite sorbents with anisotropic pores.

Copper, nickel, zinc, chromium, and iron ions are the prevailing contaminants in the aqueous effluents resulting from the photo-etching industry. In this context, we investigate here the metal ion sorption performance of an ion-imprinted cryogel (IIC), consisting of low-cost materials coming from renewable resources, towards multi-component metal ion solutions. The IIC sorbent, which is based on a chitosan matrix embedding a natural zeolite, was synthesized using a straightforward strategy by coupling copper-imprinting and unidirectional ice-templating methods. As consequence, the 1D-orientation and the interconnectivity of flow-channels sustain the fast metal ion diffusion within the IIC anisotropic structure. The removal efficiency of IIC sorbent reached 50% after 30 min, and the sorption equilibrium was attained within 150 min. For assessing the successful formation of imprinted cavities with well-defined sizes controlled by the radius of copper ions used as template, selectivity studies were performed on binary, ternary, and five-component synthetic mixtures. The efficiency of IIC as sorbent was further evaluated on real-life aqueous effluents discharged from photo-etching processes; thus, an IIC dosage of 6 g L-1 was found to remove 98.89% of Cu2+, 94.56% of Fe3+, 91.67% of Ni2+, 92.24% of Zn2+, and 82.76% of Cr3+ ions from this type of industrial wastewaters.

Polysaccharides constructed hydrogels as vehicles for proteins and peptides. A review.

Macromolecular drugs, such as proteins and peptides, are lately readily available and used in the treatment of diseases including diabetes and cancer, as well as in therapies such as gene therapy, wound dressing, and tissue engineering. However, the bioavailability, the extent and the rate at which these drugs reach the target tissue are highly dependent on the carrier and on the route of administration. Among the multitude of biocompatible polymers used to design vehicles for macromolecular drugs, polysaccharides are preferred due to their mucoadhesive, antimicrobial, and anti-inflammatory properties. This review aims to give an overview on the evolution of polysaccharide-based vehicles recommended in the controlled delivery of proteins and peptides, mainly reported in the last five years. Both physically and chemically cross-linked drug delivery systems are presented such as: porous hydrogels, polyelectrolyte complexes and layer-by-layer thin films. Even if the pharmaceutical formulations for oral administration of proteins and peptides are preferred, other friendly routes are discussed in this review, such as transdermal delivery.

Influence of cross-linking in loading/release applications of polyelectrolyte multilayer assemblies. A review.

Design of polymeric matrices for loading/release purposes is of great interest in various applications, such as drug delivery systems, antimicrobial surfaces, biosensors, water purification. Compared with other strategies to fabricate materials for such applications, the Layer-by-Layer (LbL) assembly remarked itself by the countless possibilities to tailor the organic architectures at nanoscale owing to the structural diversity of "nano-bricks" suitable for assembly and easiness to control the deposition features. LbL assembled systems have been extensively used as matrices to load/release low molecular compounds such as drugs and dyes, proteins and enzymes, or DNA (RNA). In many studies, cross-linking the layers was investigated as a mean to stabilize and to induce new functionalities in the obtained architectures, as well as to tune their loading/release properties. In this review we discuss recent progress in the use of LbL constructions in loading/release of bioactive species, with a main focus on the role of cross-linking on such features. Overviews of the LbL assembly strategy describing the parameters which influence the build-up process and of the main synthetic routes used to cross-link the obtained architectures are briefly presented. The use of LbL systems (either as thin films deposited on solid surfaces or as hollow capsules) to load/release low molecular compounds and proteins/enzymes, highlighting the role of cross-linking in such processes (construction of porous architectures capable to load high molecular compounds or decreasing the assemblies permeability to delay the release of encapsulated compounds) was thoroughly discussed.

Could the porous chitosan-based composite materials have a chance to a "NEW LIFE" after Cu(II) ion binding?

Currently, biosorption is considered a leading-edge environmentally-friendly method for the low-cost remediation of wastewaters contaminated with metal ions. However, the safe disposal of metal-loaded biosorbents is still a challenging issue. In this context, our major objective was to explore the possibility of "waste minimization" by reusing the metal-loaded biosorbents in further environmental applications, particularly into the oxidative catalysis of dyes. Thus, the decolourisation efficiency (DE) of Methyl Orange (MO) in aqueous solutions under ambient light using copper-imprinted chitosan-based composites in comparison to non-imprinted ones was investigated in this work. The MO degradation was established first in the absence of any co-catalyst, when a DE value of 95.3% was achieved by the ion-imprinted catalysts within 360 min of reaction, compared to only 67.4% attained by the non-imprinted ones. Under Fenton-like conditions, the apparent degradation rate constant was seventy times higher, the DE increasing within 40 min to about 98.6%, and 70.5% respectively, whereas the content of co-catalyst (H2O2) was significantly lowered compared to other reported studies. The straightforward preparation of copper-loaded composites, along with their excellent stability and high efficiency even after four consecutive reaction runs support our ion-imprinted systems as potential catalysts for dye removal by oxidative decolourisation treatments.

Development of chitosan-poly(ethyleneimine) based double network cryogels and their application as superadsorbents for phosphate.

The fabrication of novel chemically cross-linked double network cryogels (DNC), with an abundant number of amine groups, based on chitosan (CS) cross-linked with glutaraldehyde (GA), as the first network, and poly(ethyleneimine) (PEI), with a concentration up to 15% cross-linked with ethyleneglycol diglycidyl ether (EGDGE), as the second network, and their enhanced sorption capacity for phosphate ions are presented here. The phosphate sorption was fast (equilibrium in three hours) and well modeled by the pseudo-second-order kinetic model. The experimental sorption isotherms were fitted with Langmuir, Freundlich, Sips and Dubinin-Radushkevich isotherm models. The Langmuir and Sips isotherms were the best in modeling the sorption process. The maximum sorption capacity given by the Langmuir isotherm for the DNC having the highest content of GA and the highest concentration of PEI was about 343 mg phosphate/g, which placed this novel sorbent among the best sorbents for phosphate recently reported in literature.

Fabrication and characterization of composite cryobeads based on chitosan and starches-g-PAN as efficient and reusable biosorbents for removal of Cu2+, Ni2+, and Co2+ ions.

Novel composite biosorbents were developed in this work as cryobeads by dual cross-linking of a mixture of chitosan (CS) and starch coming from different botanical sources, such as potato, wheat, and rice, grafted with poly(acrylonitrile) (PAN). Glutaraldehyde and poly(ethylene glycol diglycidyl ether) were used as cross-linkers. Composite cryobeads were characterized by FTIR, SEM-EDX, and swelling kinetics. Sorption of Cu2+, Ni2+, and Co2+ onto the novel biosorbents was investigated as a function of time and the concentration of the metal ion, at the optimum pH and sorbent dose. Pseudo-second-order kinetic model and Elovich model well fitted the kinetic results, indicating chemisorption as the most probable mechanism of sorption, while the Langmuir, and Sips isotherm models described the sorption at equilibrium for all metal ions. The values of the maximum sorption capacity of Cu2+, Ni2+, and Co2+ onto the composite sorbent based on CS and rice starch-g-PAN were as follows: 100.6 mg/g, 83.25 mg/g, and 74.01 mg/g, respectively. The nitrile groups present in the biocomposites CS/starch-g-PAN constitute a source to further increase the sorption capacity by their hydrolysis. A remarkable level of reusability was found for the composite cryobeads, no decrease of the sorption capacity being observed after five consecutive sorption/desorption cycles.

Spectacular Selectivity in the Capture of Methyl Orange by Composite Anion Exchangers with the Organic Part Hosted by DAISOGEL Microspheres.

There is a paramount need in finding sorbents endowed with selectivity in sorption of certain dyes from their mixture with other dyes from the same family. In this context, novel composite anion exchangers (CANEXs) were fabricated here by an innovative approach using silica DAISOGEL as the host for an anion exchanger (ANEX) bearing vinylbenzyl N, N-diethyl 2-hydroxyethyl ammonium moieties. Information about the outer surface versus in-pore generation of ANEX as a function of silica morphology was acquired by scanning electron microscopy. It was demonstrated that the CANEX microspheres were able to selectively capture methyl orange (MO) in binary mixtures with either methylene blue (MB) as the cationic dye or Chicago Sky Blue 6B (CSB) as the competing azo dye. The adsorption kinetics of MO and CSB were well-fitted by a pseudo-second-order model, indicating that chemisorption controlled the sorption process. Isotherms of "H" type characterized the sorption of MO, whereas "L" type isotherms described the sorption of CSB. Langmuir and Sips isotherms were the most suitable models to describe the sorption process at equilibrium. Even if only about 10 wt % of the CANEX sorbents was involved in the sorption process, the maximum sorption capacity was 180.25 mg MO/g composite and 153.86 mg CSB/g sorbent. Moreover, the CANEX sorbents exhibited a spectacular preference for MO molecules in competition with CSB at pH 5.5. Selectivity coefficient for MO in the mixture with either MB or CSB was 370 and 38.4, respectively. Removal efficiency of MO remained up to 100% after 10 consecutive sorption/desorption cycles.

Chitosan-based ion-imprinted cryo-composites with excellent selectivity for copper ions.

An original strategy is proposed here to design chitosan-based ion-imprinted cryo-composites (II-CCs) with pre-organized recognition sites and tailored porous structure by combining ion-imprinting and ice-templating techniques. The cryo-composites showed a tube-like porous morphology with interconnected parallel micro-channels, the distance between the channel walls being around 15 µm. Both the entrapment of a natural zeolite and the presence of carboxylate groups, generated by partial hydrolysis of amide moieties, led to II-CCs with controlled swelling ratios (25-40 g/g, depending on pH) and enhanced overall chelating efficiency (260 mg Cu2+/g composite). To point out the importance of introducing Cu2+ recognition sites, sorption experiments using mixtures of Cu2+ and other competing ions (Co2+, Ni2+, Zn2+ or/and Pb2+) were also carried out. The higher values of selectivity coefficients obtained for the II-CCs compared to those of non-imprinted ones highlight the remarkable potential of our sorbents for decontamination of wastewaters and recycling of Cu2+ ions.

Poly(N,N-dimethylamino)ethyl methacrylate/sodium alginate multilayers and their interaction with proteins/enzymes.

The aim of the present work is to construct and investigate the properties of novel polyelectrolyte multilayers consisting of poly(N,N-dimethylamino)ethyl methacrylate (PDMAEMA) and sodium alginate (SA). The influence of PDMAEMA's pH dependent ionization degree on the charge balance, thickness and roughness of the multilayer films was assessed by potentiometric titrations, dye sorption and atomic force microscopy. Moreover, the cross-linking of PDMAEMA/SA films with a dihalogenated aromatic derivative with high reactivity (α,α'-dichloro-p-xylene) by means of Menshutkin reaction and the stability of the multilayer architecture to repeated treatments with NaOH are demonstrated. Also, the interaction of the obtained films with various proteins/enzymes (pepsin, bovine serum albumin, haemoglobin and lysozyme) is investigated. It was found that biomolecules with the isoelectric point in the acidic region of pH were adsorbed in a higher amount than the biomolecules with the isoelectric point in the basic region of pH.