Chelating Polymer Research Articles

New Colloidal Techniques for the Fabrication of Manganese Dioxide-Carbon Nanotube Electrodes of Supercapacitors

Electrochemical supercapacitors based on MnO2 electrode materials are currently attracting significant interest due to the high specific capacitance obtained using environmentally friendly aqueous electrolytes and low cost of MnO2. A complicating factor in the application and commercialization of MnO2 electrodes for electrochemical supercapacitors is low electronic and ionic conductivity of MnO2. This problem is usually addressed by the fabrication of porous nanocomposite electrodes, containing MnO2 nanoparticles and carbon nanotubes (CNT) or other conductive additives. Despite the impressive progress achieved in the fabrication of MnO2-CNT electrodes, there is a need for simple and versatile methods for the fabrication of MnO2 nanoparticles, efficient dispersion of MnO2 and CNT, and fabrication of porous electrodes. We report new strategies for the fabrication of MnO2-CNT composites, which are based on the use of new dispersing agents and new techniques for mixing of MnO2 and CNT. The electrochemical performance of the composites, prepared by different methods was compared. The results were used for the fabrication of advanced electrodes and devices. Efficient dispersing agents are of critical importance for the fabrication of MnO2 nanoparticles and formation of stable suspensions for colloidal processing. An important property of a dispersant is its adsorption on the particle surface. Therefore, there is a need in the development of charged dispersing agents with strong interfacial adhesion. New methods have been developed for the synthesis, surface modification and dispersion of MnO2 nanoparticles using advanced dispersing agents, which provide strong bidentate, polydentate or chelating bonding to the particle surface. Various dispersants were developed and compared, such as molecules from catechol, chromotropic acid, gallic acid, salicylic acid and bicinchoninic acid families. The influence of the nature of functional groups, number of aromatic rings, length of the hydrocarbon chain on the adsorption, dispersion and electrostastic charging in the suspensions was investigated. New dispersants were used for the synthesis of non-agglomerated MnO2 particles. Various aromatic and steroid dispersants were investigated for the dispersion of CNT. It was found that steroid dispersants outperform other dispersants in the dispersion of CNT. The polyaromatic molecules, containing chelating and charging functional groups can be used as co-dispersants for MnO2 and CNT. Further progress in the application of new dispersants was achieved by the development of liquid-liquid interface synthesis and extraction method, which allowed agglomerate free synthesis of MnO2 and their mixing with CNT. In this strategy, the problems related to particle agglomeration during the drying stage were avoided. As an extension of these investigations, chelating polymers were used for dispersion. The unique feature of this strategy is that chelating aromatic ligands of the monomers provide multiple adsorption sites for attachment on MnO2 and CNT and impart electrical charges for electrosteric dispersion. In another strategy, complexes of polymers and chelating agents were used for co-dispersion of MnO2 and CNT. As a result, we achieved an outstanding efficiency in dispersion. Heterocoagulation methods have been developed for the nanotechnology of MnO2 - CNT composites. The methods are based on selective strong adsorption of dispersants with specific adsorption ligands on MnO2 or CNT and heterocoagulation of the materials using electrostatic forces, related to opposite charges of individual dispersants or click chemistry methods. Proof of concept studies in aqueous and non-aqueous suspensions showed significant improvement in component dispersion and mixing. The capacitive performance of MnO2-CNT composites, prepared by different methods was compared. Ni foams were used as current collectors for the fabrication of electrodes with active mass loading of 30-50 mg cm-2 and mass ratio of active material to current collector of 0.3-0.42. The capacitive behavior of the composite electrodes was studied in Na2SO4 electrolyte using cyclic voltammetry, chronopotentiometry and impedance spectroscopy. The use of new dispersants and mixing techniques allowed for significant improvement in electrode performance. The composites, prepared in the presence of dispersants using liquid-liquid extraction and mixing methods showed the highest specific capacitance of 8 F cm-2. The liquid-liquid extraction method for the synthesis of MnO2 particles and their mixing with CNT allowed good capacitance retention at high charge-discharge rates. Significant improvement in capacitive behavior was achieved using heterocoagulation methods for the fabrication of MnO2-CNT composites. The new strategies allowed significant reduction in electrode resistance due to the use of efficient colloidal dispersion and mixing techniques. The capacitance retention of above 70% was achieved in the scan rate range of 2-100 mV s-1. The electrodes showed cyclic stability above 90% after 5000 cycles. The composite electrodes were used for the fabrication of asymmetric capacitors with voltage window of 1.6V. We report capacitances, power-energy characteristics and cyclic behavior of electrodes, prepared using different methods.

Improving the High Temperature Performance of Li-Ion Batteries with Transition Metal Ion Trapping Separators - a Brief Review

One of the main performance degradation mechanisms in Li-ion batteries is initiated by the dissolution of transition metal (particularly manganese) cations from positive electrode active materials. These ions will electro-migrate to and deposit on the negative electrode surface. The deposited manganese species induce the catalytic decomposition of solvent molecules and the concurrent depletion of electrochemically active lithium, leading surface film growth, gassing, exfoliation of graphite particles, and an overall degradation of battery performance (increased cell resistance, reduced power capability, and a shortened battery life). Several measures for mitigating manganese dissolution or its consequences have been reported over the years in the literature,1,2 including elemental substitutions (doping) in the bulk of the positive electrode active material,3 surface coatings4 and the application an inorganic barrier coatings onto electrodes by atomic layer deposition,5 passivating additives in the electrolyte solution,6and the reduction of the state-of-charge swing during battery operation. Unfortunately, no single mitigation measure has proven completely successfully so far, i.e., without negatively affecting other properties of the LIB such as energy density and internal resistance. A different - and complementary - approach, that of using a separator containing manganese ion chelating agents, may avoid the previously described drawbacks.7-9 Such a separator captures the manganese ions in the inter-electrode space by means of a polymeric chelating agents with cyclic or open structures, thus preventing the migration of manganese ions to, and subsequent contamination of, the negative electrode. We will review the present status of the chelating agents approach for mitigating the consequences of Mn dissolution for battery performance and will discuss some remaining challenges.

Synthesis, characterization and sorption potentials of dialdehyde starch aminophenol Schiff’s base

Extraction of native cassava starch, its oxidation, modification and chelation of the products were achieved. Schiff’s base type Dialdehyde aminophenol was prepared by the reaction of orthoaminophenol and dialdehyde starch from periodate oxidized cassava starch. The modified starch aminophenols with different aldehyde content were tested for their adsorptive affinity for Cu(II), Cr(II) and Mn(II) ions. The modified starch was characterized by Fourier transformed infrared (FT-IR) spectroscopy, Scanning electron microscopy (SEM), elemental analysis, solubility test, Magnetic susceptibility and magnetic moment and, melting/decomposition temperature. The modified starches and the polymeric complexes have been found to have an improved physicochemical properties and the polymeric chelating ligand could be used to remove Cu(II), Cr(II)and Mn(II)ions from aqueous solution. Also the polymeric complex was found to have good cross linking ability when reacted with the metal salt. Keywords: Dialdehyde starch, Native Starch, Orthoaminophenol, Polymeric Chelating ligand, Sorption

Effect of chelating polymer as chelating agent on the PZT/PVDF pyroelectric composites

Pyroelectric composites of PZT/PVDF with 0–3 connectivity were prepared by hot-pressing technology. In the composite systems, the ethylene diamine tetraacetic acid (EDTA) was used as a chelating agent to modify the surface combination between the polymer phase and the dispersed filler phase, and its effects on the microstructure, thermal properties, volume conductivity, dielectric properties and pyroelectric properties were investigated in detail. The scanning electron microscope micrographs showed that the interaction between PZT and PVDF could be effectively improved by introducing EDTA. The FTIR spectra analysis and DSC scans indicated that with the increasing of EDTA addition, the crystallization of PVDF was enhanced gradually accompany with the emergence of a small amount of β-PVDF phase. Owing to the enhancement of chelation bonding, the thermal properties and volume conductivity were both optimized, which meant the interfacial adhesion and charge transfer became more efficient. As a result, the pyroelectric properties of the composites were significantly improved. Especially, with 0.6 wt% EDTA addition, the pyroelectric coefficient was raised to be about 30 % higher than that of the untreated composites.

Highly Efficient Chelating Polymers Based on Plastic Waste for Removal of Toxic Heavy Metal Pollutants

Highly Efficient Chelating Polymers Based on Plastic Waste for Removal of Toxic Heavy Metal Pollutants

Stability and Biodistribution of Thiol-Functionalized and (177)Lu-Labeled Metal Chelating Polymers Bound to Gold Nanoparticles.

We are studying a novel radiation nanomedicine approach to treatment of breast cancer using 30 nm gold nanoparticles (AuNP) modified with polyethylene glycol (PEG) metal-chelating polymers (MCP) that incorporate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelators for complexing the β-particle emitter, (177)Lu. Our objective was to compare the stability of AuNP conjugated to MCP via a single thiol [DOTA-PEG-ortho-pyridyl disulfide (OPSS)], a dithiol [DOTA-PEG-lipoic acid (LA)] or multithiol end-group [PEG-pGlu(DOTA)8-LA4] and determine the elimination and biodistribution of these (177)Lu-labeled MCP-AuNP in mice. Stability to aggregation in the presence of thiol-containing dithiothreitol (DTT), L-cysteine or glutathione was assessed and dissociation of (177)Lu-MCP from AuNP in human plasma measured. Elimination of radioactivity from the body of athymic mice and excretion into the urine and feces was measured up to 168 h post-intravenous (i.v.) injection of (177)Lu-MCP-AuNP and normal tissue uptake was determined. ICP-AES was used to quantify Au in the liver and spleen and these were compared to (177)Lu. Our results showed that PEG-pGlu(DOTA)8-LA4-AuNP were more stable to aggregation in vitro than DOTA-PEG-LA-AuNP and both forms of AuNP were more stable to thiol challenge than DOTA-PEG-OPSS-AuNP. PEG-pGlu((177)Lu-DOTA)8-LA4 was the most stable in plasma. Whole body elimination of (177)Lu was most rapid for mice injected with (177)Lu-DOTA-PEG-OPSS-AuNP. Urinary excretion accounted for >90% of eliminated (177)Lu. All (177)Lu-MCP-AuNP accumulated in the liver and spleen. Liver uptake was lowest for PEG-pGlu((177)Lu-DOTA)8-LA4-AuNP but these AuNP exhibited the greatest spleen uptake. There were differences in Au and (177)Lu in the liver for PEG-pGlu((177)Lu-DOTA)8-LA4-AuNP. These differences were not correlated with in vitro stability of the (177)Lu-MCP-AuNP. We conclude that conjugation of AuNP with PEG-pGlu((177)Lu-DOTA)8-LA4 via a multithiol functional group provided the greatest stability in vitro and lowest liver uptake in vivo and is, therefore, the most promising for constructing (177)Lu-MCP-AuNP for radiation treatment of breast cancer.

Synthesis of hyperbranched polymers towards efficient boron reclamation via a hybrid ultrafiltration process

Two hyperbranched polymers, hyperbranched polyglycidol (HPG) and 2, 3-Dihydroxypropyl-hyperbranched polyethylenimine (Diol-HPEI), were synthesized and studied as polychelatogens for boron reclamation via a hybrid ultrafiltration process, with the objectives of evaluating the key factors for polymer–boron chelation and improving boron rejection efficiency. Their chemical structures were unveiled by FTIR and XPS analyses whilst molecular weights were carefully tailored in order to be fully retained by a commercial ultrafiltration (UF) membrane. The chelation capacity of the two polymers was compared under different operating conditions i.e., chelating temperature, polymer loading and pH. It appears that Diol-HPEI prominently outperforms HPG because the tertiary amine group may be more competent than the ether group in terms of their protonation capability. Eventually, a rejection of 66–91% was achieved with a Diol-HPEI polymer loading of 100g per g boron in the pH range of 6.9–9.0. Besides, the effects of interfering ions, i.e., Na+, Mg2+, Cl− and SO42- on polymer–boron interactions were examined in the Diol-HPEI/boron solution at the neutral condition. Results reveal that divalent cations may exert more negative influence on boron rejection owing to the competition between them and boron to form complexes with chelating polymers. These findings may provide useful insights in design of efficient boron-chelating polymers.

Synthesis and Characterization of Polymer Metal Chelates Derived from Poly(2,2,3,3‐tetra methyleneaminecyclopropyl)phenyl Acrylate

ABSTARCTThe new method for the synthesis of p‐(2,2,3,3‐tetracyanocyclopropyl)phenyl acrylate (P‐TCP) was applied. In this method, p‐acryloyloxybenzaldehyde was reacted with malononitrile and cyanogen bromide at 0°C in short time. Then, the P‐TCP monomer was polymerized by free‐radical polymerization to obtain a poly‐(2,2,3,3‐tetracyanocyclopropyl)phenyl acrylate with multicyanocyclopropane functionalities in the pendant group. The nitrile functions in pendant groups of the prepared polymer were reduced to primary amines using NaBH4 and NiCl2 salts at 65°C in dry ethanol for the preparation of poly(2,2,3,3‐tetra methyleneaminecyclopropyl)phenyl acrylate (PTAP) as a new polymer. The PTAP was soluble in acetone and ethylacetate. The PTAP was examined for the removal of Cu(II), Ni(II), Zn(II), and Cr(III) ions from aqueous solutions under noncompetitive and competitive conditions at various pH. The adsorption rate was high (<60 min). The complexation of selected heavy metal ions by the PTAP is strongly dependent on the pH of medium and the adsorption of all selected metal ions was more favorable at the pH 7. Also the maximum sorption of the PTAP for selected metal ions under competitive conditions belongs to Cu(II) at pH 7. The kd value is calculated for the prepared chelating polymer, and the result indicates approximately high values in the case of Cu(II) ion. The synthesized polymer and its metal chelates were characterized by FT‐IR, 1H NMR, thermogravimetric analysis, gravimetry, UV–vis spectroscopy, and atomic absorption spectrometry.

Edible Antimicrobial Coating Incorporating a Polymeric Iron Chelator and Its Application in the Preservation of Surimi Product

To explore a novel efficient method in food preservation, edible zein coating which incorporates a polymeric chelator was developed and its preservative effect on commercially manufactured fish balls was investigated. The quality indicators of the fish ball during the storage, including sensory quality, total bacterial count, total basic volatile nitrogen (TVB-N) content, thiobarbituric acid reactive substances (TBARS), and pH value were determined. It has been demonstrated that a zein film containing a polymeric chelator significantly (P 0.05), fish balls coated with antimicrobial zein maintained a relatively stable state during storage. Zein coating which incorporates a polymeric chelator extends fish ball shelf life to 19 days at 4 °C, being more efficient than zein coating lacking a polymeric chelator (13 days). Clearly, polymeric chelator-incorporated zein film could find application in the preservation of surimi products by preventing the growth of bacteria and oxidation of fat during storage.

NMR Determination of the Relative Binding Affinity of Crown Ethers for Manganese Cations in Aprotic Nonaqueous Lithium Electrolyte Solutions

Polymeric chelating agents placed in the interelectrode space of a Li-ion battery (LIB) have been suggested as a means of sequestering Mn cations dissolved from positive electrodes of LIBs to prevent their migration to, and deposition onto, negative electrodes and thus mitigate the associated degradation of LIB performance and life. In order to select the most effective chelating agent and optimize its polymeric form, it is desirable to determine the binding affinity of various chelating agents for manganese cations. The present study evaluates the relative binding affinity of crown ethers for manganese cations in a lithium-containing environment through the detection of the 7Li nucleus chemical shift. Results are presented for the relative binding affinities of 15-crown-5 and 1-aza-15-crown-5 ethers for Mn2+ and Mn3+. Significant differences in relative binding affinity were discovered with particular crown ether–manganese oxidation state combinations. Additionally, a substantial decrease in binding affi...

Study on adsorption property of uranium based on novel magnetic chelating polymer

Study on adsorption property of uranium based on novel magnetic chelating polymer

Assessing the effects of model Maillard compound intake on iron, copper and zinc retention and tissue delivery in adult rats.

The behaviour of dietary Maillard reaction compounds (MRP) as metal chelating polymers can alter mineral absorption and/or retention. Our aim in this study was to analyse the long-term effects of the consumption of model MRP from glucose-lysine heated for 90 min at 150 °C (GL) on iron, copper and zinc whole-body retention and tissue delivery. For 88 days, weaning rats were fed a Control diet or one containing 3% GL, until reaching the adult stage. During the experimental period a mineral balance was conducted to investigate the mineral retention. At day 88, the animals were sacrificed, blood was drawn for haemoglobin determination and some organs were removed. Copper and zinc balances were unaffected (Cu: 450 vs. 375 μg; Zn: 6.7 vs. 6.2 mg for Control and GL groups, respectively) and no change was observed in whole-body delivery. Iron retention, too, was unaltered (11.2 mg for Control and GL groups) but due to the tendency toward decreased body weight in the GL group (248 vs. 233 g for the Control and GL groups), whole-body iron concentration was 13% higher in the GL group than in the Control group. Absorbed iron accumulated particularly in the liver (144 vs. 190 μg g(-1) for the Control and GL groups), thus reducing haemoglobin levels. The long-term intake of MRP induced iron accumulation in the body but this did not result in enhanced iron functionality, since the haemoglobin concentration declined. Taking into account the findings of our research group's studies of young and adult rats, we now corroborate the hypothesis that the negative effect of GL MRP consumption on iron functionality takes place regardless of the animals' stage of life.

Synthesis and dyes adsorption properties of calix[4]crown-grafted chitosan chelating polymer

By the Schiff-base condensation of formacyl calix[4]crown(2) with raw chitosan, a novel calix[4]crown-grafted chitosan chelating polymer(3) was conveniently prepared in good yield. The structure of polymer 3 was confirmed by elemental analysis, infrared(IR) spectrometry and X-ray diffraction(XRD) analysis. The elemental analysis suggests that the grafting degree of calixcrown unit was 22% on the amino groups of chitosan. The morphological characteristic of polymer 3 was studied by scanning electron microscopy(SEM). Polymer 3 possessed loose porous and smooth morphology of surface. The dyes adsorption abilities of polymer 3 for a series of organic dyes[Orange I(OI), Neutral red(NR), Victoria blue B(VB) and Brilliant green(BG)] were studied by solid-liquid adsorption experiments. The adsorption percentages increased from 45%―60%(raw chitosan for dyes) to 75%―90%(polymer 3 for dyes). The highest adsorption percentage reached 89% for VB. The saturated adsorption capacities for OI, NR, VB and BG were as high as 622, 564, 854 and 781 mg/g, respectively. The adsorption abilities kept stable at 70%―90% in the scope of pH=5―9. The adsorption abilities for anionic dye(OI) decreased gradually with the increase of pH and the opposite trend was observed for cationic dyes(NR, BG, VB). The adsorption percentages were 70%―90% after five times’ cycles for adsorption.

Comparison of low-pressure reverse osmosis filtration and polyelectrolyte-enhanced ultrafiltration for the removal of Co and Sr from nuclear plant wastewater

Abstract Volume reduction and the concentration of long-lived radioactive species are critical issues for the management of liquid low-level radioactive waste. This study investigated and compared the performances of low-pressure reverse osmosis (LPRO) and polyelectrolyte-enhanced ultrafiltration (PEUF) for the removal of target metals (Co and Sr) from simulated low-level radioactive waste. The effects of dosage and types of chelating polymers, such as polyacrylic acid (PAA) and polyethylenimine (PEI), were evaluated at acidic and neutral pH levels. The metal removal efficiencies by precipitation at acidic pH (4.5) and neutral pH (6.5) were marginal. The addition of PAA to LPRO had no effect on metal removal, but had a negative impact on membrane permeability, particularly at acidic pH levels. The LPRO itself already achieved sufficient metal rejection; therefore, the addition of PAA only caused fouling. In contrast, the PAA dosage and solution pH governed the metal rejection in PEUF. Deprotonated PAA molecules bound to metal ions, but the distribution of PAA species had no significant impact on flux decline. The PEUF with PEI exhibited almost no pH dependency in metal removal, but showed metal-specific removal behaviors. The PEUF with PAA achieved metal removal as high as LPRO, with relatively high water permeability.

Film deposition mechanisms and properties of optically active chelating polymer and composites

Poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) exhibits a number of unique physical properties. An electrophoretic deposition (EPD) method has been utilized for the deposition of PAZO films, which exhibited photoinduced birefringence. The advantages of EPD, deposition mechanism and kinetics of deposition are discussed. PAZO exhibits unique adsorption properties, which are related to its chemical structure. The salicylate ligands of PAZO monomers with strong chelating properties provide numerous adsorption sites for PAZO adsorption on inorganic materials. It was found that PAZO can function as a charging, dispersing and film forming agent for EPD of a wide array of materials, such as TiO2 (anatase and rutile), micron size platelets and submicrometre particles of Al2O3, zirconia, MnO2, MgAl2O4, aluminium hydroxide, SiC, Pd metal, carbon nanotubes and polypyrrole nanofibers. The feasibility of incorporation of other polymers and organic dyes into the PAZO films has been demonstrated. PAZO showed superior performance compared to other dispersing agents for the EPD method, overcoming their limitations. Another major finding of this study was the possibility of EPD of composites, using PAZO as a co-dispersant for different materials. Testing results showed that composites can be used for optical, energy storage, corrosion protection and other applications.

Abstract 1813: Tumor and normal tissue localization of trastuzumab-modified with a metal chelating polymer for auger electron radioimmunotherapy in HER2-positive xenografts

Abstract Purpose We have been investigating a potential radioimmunotherapeutic (RIT) agent using the anti-HER2 monoclonal antibody trastuzumab to address the issue of primary and acquired resistances in HER2-positive Breast cancer (BC). Trastuzumab was conjugated to a metal chelating polymer (MCP) with multiple DTPA units for labeling with the Auger electron emitter Indium-111 (111In) [trastuzumab-MCP-111In]. We aim to increase the amount of radioactivity delivered and enhance the therapeutic effect towards trastuzumab sensitive and resistant tumors. High specific activity (SA) (5.5 MBq/μg) trastuzumab-Hy-MCP-111In was more cytotoxic at killing HER2-positive BC cells sensitive and resistant than low SA (0.37MBq/μg) radioimmunoconjugates (RICs) in vitro. The current study aimed to investigate the tumor localization properties of this new RIT in mice with HER-2 positive BC xenografts. Methods Hydrazide MCP with polyglutamide backbone, 20 or 30 DTPA units, and without or with PEG chains [Hy-(PEG)-MCP-111In] were site-specifically linked to periodate-oxidized carbohydrates on the Fc domain of trastuzumab. Tumor and normal tissue distribution were assessed in CD-1 athymic mice bearing BT-474 (1×106 HER2 receptors/cell) or trastuzumab resistant TrR1 (5×105 HER2 receptors/cell) xenografts. Mice were injected intravenously with trastuzumab-Hy-(PEG)-MCP-111In (10μg; 3-4 MBq/μg), or trastuzumab-Hy-(PEG)-MCP-111In (1μg; 3-5 MBq/μg) without or with non-labeled non specific anti-CD20 rituximab (9μg). Controls consisted of mice injected with MCPs only and trastuzumab-NH-Bn-DTPA-111In. Results Trastuzumab-Hy-(PEG)-MCP-111In exhibited a HER2-mediated uptake in BT-474 tumors. Both RICs (10μg) had a higher tumor uptake (0.8±0.4 and 1.3±0.3%ID/g) than the non-targeted Hy-(PEG)-MCP-111In (0.2±0.04 and 0.3±0.1%ID/g) (p = 0.0104; p<0.0001). Tumor uptake was also HER2-density dependent with about a 3-fold decrease (0.4±0.1%ID/g) in TrR1-bearing mice for trastuzumab-Hy-PEG-MCP-111In. Kidneys were found to be the major normal organ accumulation in both formulations. Nevertheless, pegylation of the MCP caused a 4-fold decrease in kidneys uptake (6.9±2.5 to 1.6±0.1% ID/g; p = 0.0018). At low mass (1μg) and high SA, addition of non-labeled rituximab improved the tumor uptake of trastumab-Hy-MCP-111In by 2 fold (0.3±0.1 to 0.6±0.1%ID/g), but no change in tumor uptake was seen for trastuzumab-Hy-PEG-MCP-111In. Nonetheless, BT-474 tumor uptake of trastuzumab-Hy-(PEG)-MCP-111In was lower than the one obtained with trastuzumab-NH-Bn-DTPA-111In (13.3±3.4%ID/g). Conclusion Our results suggest that trastuzumab-Hy-(PEG)-MCP-111In could target HER2-positive xenografts sensitive and resistant to trastuzumab. Further modifications on the MCP are needed to improve the tumor uptake for Auger electron radioimmunotherapy. Citation Format: Ghislaine Ngo Ndjock Mbong, Yijie Lu, Conrad Chan, Zhongli Cai, Mitchell A. Winnik, Raymond Reilly. Tumor and normal tissue localization of trastuzumab-modified with a metal chelating polymer for auger electron radioimmunotherapy in HER2-positive xenografts. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1813. doi:10.1158/1538-7445.AM2015-1813

Equilibrium, kinetics, and thermodynamics of Pd(II) adsorption onto poly(m‐aminobenzoic acid) chelating polymer

ABSTRACTThis study describes the equilibrium, kinetics, and thermodynamics of the palladium(II) (Pd(II)) adsorption onto poly(m‐aminobenzoic acid) (p‐mABA) chelating polymer. The p‐mABA was synthesized by the oxidation reaction of m‐aminobenzoic acid monomer with ammonium peroxydisulfate (APS). The synthesized p‐mABA chelating polymer was characterized by FTIR spectroscopy, gel permeation chromatography (GPC), thermal analysis, potentiometric titration, and scanning electron microscopy (SEM) analysis methods. The effects of the acidity, temperature, and initial Pd(II) concentration on the adsorption were examined by using batch adsorption technique. The optimum acidity for the Pd(II) adsorption was determined as pH 2. In the equilibrium studies, it was found that the Pd(II) adsorption capacity of the polymer was to be 24.21 mg/g and the adsorption data fitted better to the Langmuir isotherm than the Freundlich isotherm. The kinetics of the adsorption fitted to pseudo‐second‐order kinetic model. In the thermodynamic evaluation of the adsorption, the ΔG° values were calculated as −16.98 and −22.26 kJ/mol at 25–55°C temperatures. The enthalpy (ΔH°), entropy (ΔS°), and the activation energy (Ea) were found as 35.40 kJ/mol, 176.05 J/mol K, and 61.71 kJ/mol, respectively. The adsorption of Pd(II) ions onto p‐mABA was a spontaneous, endothermic, and chemical adsorption process which is governed by both ionic interaction and chelating mechanisms. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42533.

Reactive red 120 retention through ultrafiltration enhanced by synthetic and natural polyelectrolytes

Two cationic chelating polymers, namely synthetic polyethylenimine (PEI), and biopolymer chitosan were employed in the present study to bring about the retention of anionic reactive red 120 (RR 120) from its aqueous solutions by way of polymer enhanced ultrafiltration (PEUF). The effects of process parameters, namely, cross-flow rate, transmembrane pressure, time, polyelectrolyte loading, and ionic strength on dye retention and permeation flux were examined. PEI enhanced ultrafiltration achieved dye retentions as high as 99.9%, and significant permeation fluxes around 148L/m2h. However, in case of chitosan, relatively low retention (88%), and flux (120L/m2h) levels were observed. A careful comparison of the changes induced in the UV–vis spectra of RR 120 by PEI and chitosan indicated a predominant electrostatic interaction between PEI and RR 120, as opposed to the relatively weak and sterically as well as chemically hindered interaction between chitosan and the dye ion. The respective binding constants of PEI-RR 120, and PEI–chitosan complexes, in addition to the relatively more pronounced permeation flux decline witnessed in the presence of chitosan, clearly advocated the use of PEI, rather than chitosan, as the most appropriate complexing agent in the present context.

Immobilization of carboxymethylated polyethylenimine-metal-ion complexes in porous membranes to selectively capture his-tagged protein.

Membrane adsorbers rapidly capture tagged proteins because flow through membrane pores efficiently conveys proteins to binding sites. Effective adsorbers, however, require membrane pores coated with thin films that bind multilayers of proteins. This work employs adsorption of polyelectrolytes that chelate metal ions to create functionalized membranes that selectively capture polyhistidine-tagged (His-tagged) proteins with binding capacities equal to those of high-binding commercial beads. Adsorption of functional polyelectrolytes is simpler than previous membrane-modification strategies such as growth of polymer brushes or derivatization of adsorbed layers with chelating moieties. Sequential adsorption of protonated poly(allylamine) (PAH) and carboxymethylated branched polyethylenimine (CMPEI) leads to membranes that bind Ni(2+) and capture ∼60 mg of His-tagged ubiquitin per mL of membrane. Moreover, these membranes enable isolation of His-tagged protein from cell lysates in <15 min. The backbone amine groups in CMPEI likely increase swelling in water to double protein binding compared to films composed of PAH and the chelating polymer poly[(N,N-dicarboxymethyl)allylamine] (PDCMAA), which has a hydrocarbon backbone. Metal leaching from PAH/CMPEI- and PAH/PDCMAA-modified membranes is similar to that from GE Hitrap FF columns. Eluates with 0.5 M imidazole contain <10 ppm of Ni(2+).

Hexavalent Chromium Removal and Reduction to Cr (III) by Polystyrene Tris(2-aminoethyl)amine

A commercially available chelating polymer, polystyrene tris(2-aminoethyl)amine, was used for the removal of chromium from aqueous solution. The influence of pH, contact time, adsorbent dosage and initial Cr (VI) concentration on adsorption was studied. The optimum pH for the removal of Cr (VI) was at pH 5, while optimum contact time and adsorbent dosage were 120 minutes and 10 g/L, respectively. Total chromium and Cr (VI) concentrations were analyzed by ICP-MS and UV-Visible. Adsorption isotherms using Langmuir and Freundlich isotherm models revealed that the data fitted Langmuir isotherm model better than Freundlich with a maximum adsorption capacity of 312.27 mg/g. FTIR spectroscopy, Scanning electron microscopy (SEM) and Energy Dispersive Spectrometry (EDS) analyses were performed on the adsorbent before and after binding Cr (VI). All analyses confirmed the complexation of Cr (VI) to the adsorbent. Desorption experiments using KCl solution indicated 89.3% release of chromium, rendering this method of high potential for adsorbent regeneration.