Cibacron Blue F3GA‐attached magnetic poly(2‐hydroxyethyl methacrylate) beads for human serum albumin adsorption

An affinity dye ligand, Cibacron Blue F3GA, was covalently attached onto magnetic poly(2‐hydroxyethyl methacrylate) (mPHEMA) beads for human serum albumin (HSA) adsorption from both aqueous solutions and human plasma. The mPHEMA beads, in the size range of 80 to 120 µm, were prepared by a modified suspension technique. Cibacron Blue F3GA molecules were incorporated on to the mPHEMA beads. The maximum amount of Cibacron Blue F3GA attachment was obtained as 68.3 µmol g^?1. HSA adsorption onto unmodified and Cibacron Blue F3GA‐attached mPHEMA beads was investigated batchwise. The non‐specific adsorption of HSA was very low (1.8 mg g^?1). Cibacron Blue F3GA attachment onto the beads significantly increased the HSA adsorption (94.5 mg g^?1). The maximum HSA adsorption was observed at pH 5.0. Higher HSA adsorption was observed from human plasma (138.3 mg HSA g^?1). Desorption of HSA from Cibacron Blue F3GA‐attached mPHEMA beads was obtained by using 0.1 M Tris/HCl buffer containing 0.5 M NaSCN. High desorption ratios (up to 98% of the adsorbed HSA) were observed. It was possible to re‐use Cibacron Blue F3GA‐attached mPHEMA beads without any significant decreases in their adsorption capacities. Copyright © 2004 Society of Chemical Industry     

Metal‐chelated polyamide hollow fibers for human serum albumin separation

We modified microporous polyamide hollow fibers by acid hydrolysis to amplify the reactive groups and subsequent binding of Cibacron Blue F3GA. Then, we loaded the Cibacron Blue F3GA‐attached hollow fibers with different metal ions (Cu²⁺, Ni²⁺, and Co²⁺) to form the metal chelates. We characterized the hollow fibers by scanning electron microscopy. The effect of pH and initial concentration of human serum albumin (HSA) on the adsorption of HSA to the metal‐chelated hollow fibers were examined in a batch system. Dye‐ and metal‐chelated hollow fibers had a higher HSA adsorption capacity and showed less nonspecific protein adsorption. The nonspecific adsorption of HSA onto the polyamide hollow fibers was 6.0 mg/g. Cibacron Blue F3GA immobilization onto the hollow fibers increased HSA adsorption up to 147 mg/g. Metal‐chelated hollow fibers showed further increases in the adsorption capacity. The maximum adsorption capacities of Co²⁺‐, Cu²⁺‐, and Ni²⁺‐chelated hollow fibers were 195, 226, and 289 mg/g, respectively. The recognition range of metal ions for HSA from human serum followed the order: Ni(II) > Cu(II) > Co(II). A higher HSA adsorption was observed from human serum (324 mg/g). A significant amount of the adsorbed HSA (up to 99%) was eluted for 1 h in the elution medium containing 1.0M sodium thiocyanide (NaSCN) at pH 8.0 and 25 mM ethylenediaminetetraacetic acid at pH 4.9. Repeated adsorption–desorption processes showed that these metal‐chelated polyamide hollow fibers were suitable for HSA adsorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3346–3354, 2002     

Synthesis of monodisperse nonporous crosslinked poly(glycidyl methacrylate) particles with metal affinity ligands for protein adsorption

Monodisperse nonporous crosslinked poly(glycidyl methacrylate) (PGMA) particles with immobilized metal affinity ligands were prepared for selective recovery of proteins. The PGMA particles, with an average size of 2.2 µm, were prepared by a simple dispersion polymerization of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA). The particles were characterized by scanning electron microscopy (SEM) and Fourier‐transform infrared spectroscopy (FTIR). The epoxy groups of the particles were modified with the metal chelating agent iminodiacetic acid (IDA), which forms metal–IDA chelates at the active sites. After charging with copper ions, the particles were used to recover a model protein, bovine hemoglobin (BHb), in a batchwise manner. The particles had the adsorption capacity of 218.7 mg g⁻¹ with little nonspecific adsorption. The adsorption behavior could be described with the Langmuir equation. The effect of pH on the adsorption was also studied. Regeneration of the metal‐chelated particles was easily performed with 50 mmol L⁻¹ ethylenediaminetetraacetic acid (EDTA), followed by washing with water and reloading with Cu²⁺. The particles could be very useful as an affinity separation adsorbent. Copyright © 2005 Society of Chemical Industry     

Spectral characterization of lysozyme adsorption on dye-affinity beads

Cibacron Blue F3GA-attached magnetic poly(2-hydroxyethyl methacrylate) [mPHEMA] beads were prepared by suspension polymerization of HEMA in the presence of magnetite (Fe₃O₄) nanopowder. Average diameter size of the mPHEMA beads was 150–200 μm. The characteristic functional groups of Cibacron Blue F3GA-attached mPHEMA beads were analyzed by Fourier transform infrared spectrometer (FTIR) and Raman scattering spectrometer. The lysozyme adsorption and desorption characteristics of Cibacron Blue F3GA-attached mPHEMA beads were also investigated using FTIR and Raman spectroscopic techniques. When the Raman spectrum of lysozyme adsorbed mPHEMA is evaluated characteristic Amide-I band appears at 1657 cm⁻¹. The intensity of this band decreases in the spectrum of lysozyme desorbed mPHEMA sample. When the characteristic bands of lysozyme adsorbed and desorbed mPHEMA samples are compared, the band intensities of desorbed sample are lower than those of lysozyme adsorbed sample except for the band appearing at 656 cm⁻¹ (Tyr vC S). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Vinyl triazole carrying metal‐chelated beads for the reversible immobilization of glucoamylase

Poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [poly(EGDMA–VTAZ)] beads with an average diameter of 100–200 μm were obtained by the copolymerization of ethylene glycol dimethacrylate (EGDMA) with 1‐vinyl‐1,2,4‐triazole (VTAZ). The copolymer hydrogel bead composition was determined by elemental analysis and was found to contain 5 EGDMA monomer units for each VTAZ monomer unit. The poly(EGDMA–VTAZ) beads were characterized by swelling studies and scanning electron microscopy (SEM). The specific surface area of the poly(EGDMA–VTAZ) beads was found 65.8 m²/g. Cu²⁺ ions were chelated on the poly(EGDMA–VTAZ) beads. The Cu²⁺ loading was 82.6 μmol/g of support. Cu²⁺‐chelated poly(EGDMA–VTAZ) beads with a swelling ratio of 84% were used in the immobilization of Aspergillus niger glucoamylase in a batch system. The maximum glucoamylase adsorption capacity of the poly(EGDMA–VTAZ)–Cu²⁺ beads was 104 mg/g at pH 6.5. The adsorption isotherm of the poly(EGDMA–VTAZ)–Cu²⁺ beads fitted well with the Langmuir model. Adsorption kinetics data were tested with pseudo‐first‐ and second‐order models. The kinetic studies showed that the adsorption followed a pseudo‐second‐order reaction model. The Michaelis constant value for the immobilized glucoamylase (1.15 mg/mL) was higher than that for free glucoamylase (1.00 mg/mL). The maximum initial rate of the reaction values were 42.9 U/mg for the free enzyme and 33.3 U/mg for the immobilized enzyme. The optimum temperature for the immobilized preparation of poly(EGDMA–VTAZ)–Cu²⁺–glucoamylase was 65°C; this was 5°C higher than that of the free enzyme at 60°C. The glucoamylase adsorption capacity and adsorbed enzyme activity slightly decreased after 10 batch successive reactions; this demonstrated the usefulness of the enzyme‐loaded beads in biocatalytic applications. The storage stability was found to increase with immobilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Reversible immobilization of glycoamylase by a variety of Cu2+‐chelated membranes

Glycoamylase (AMG) is an γ‐amylase enzyme which catalyzes the breakdown of large α(1,4)‐linked malto‐oligosaccharides to glucose. It is an extracellular enzyme and is excreted to the culture medium. In this study, AMG was immobilized on a variety of metal affinity membranes, which were prepared by chelating Cu²⁺ ions onto poly(hydroxyethyl methacrylate) (PHEMA) using N‐methacryloyl‐(L )‐histidine methyl ester (MAH), N‐methacryloyl‐(L )‐cysteine methyl ester (MAC), and N‐methacryloyl‐(L )‐phenylalanine methyl ester (MAPA) as metal‐chelating comonomers for reversible immobilization of AMG. The PHEMAH, PHEMAC, PHEMAPA membranes were synthesized by UV‐initiated photo‐polymerization and Cu²⁺ ions were chelated on the membrane surfaces. Cu²⁺‐chelated membranes were characterized by swelling tests, SEM, contact angle measurements, elemental analysis, and FTIR. AMG immobilization on the Cu²⁺‐chelated membranes was performed by using aqueous solutions of different amounts of AMG at different pH values and Cu²⁺ loadings. Durability tests concerning desorption of AMG and reusability of the Cu²⁺‐chelated membranes yielded acceptable results. It was computationally determined that AMG possesses four likely Cu²⁺/Zn²⁺ binding sites, away from the catalytic site, to which the metal‐chelated membranes can be efficiently used. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of a novel metal‐chelate affinity beads for albumin isolation from human plasma

In this study, we developed a novel approach to obtain a high protein‐adsorption capacity utilizing 2‐methacryloylamidohistidine (MAH) as a biollgand. MAH was synthesized by reacting methacryloyl chloride and histidine. Spherical beads, with an average size of 150–200 μm, were obtained by the radical suspension polymerization of MAH, ethyleneglycol dimethacrylate (EGDMA), and 2‐hydroxyethyl methacrylate (HEMA) conducted in an aqueous dispersion medium. p(EGDMA–HEMA–MAH) beads had a specific surface area of 17.6 m²/g. The synthesized MAH monomer was characterized by NMR. p(EGDMA–HEMA–MAH) beads were characterized by a swelling test, FTIR, and elemental analysis. Then, Cu(II) ions were incorporated into the beads and Cu(II) loading was found to be 0.96 mmol/g. These beads, with a swelling ratio of 65% and containing 1.6 mmol MAH/g, were used in the adsorption/desorption of human serum albumin (HSA) from both aqueous solutions and human serum. The adsorption of HSA onto p(EGDMA–HEMA–MAH) was low (8.8 mg/g). Cu(II) chelation onto the beads significantly increased the HSA adsorption (56.3 mg/g). The maximum HSA adsorption was observed at pH 8.0 Higher HSA adsorption was observed from human serum (94.6 mg HSA/g). Adsorptions of other serum proteins were obtained as 3.7 mg/g for fibrinogen and 8.5 mg/g for γ‐globulin. The total protein adsorption was determined as 107.1 mg/g. Desorption of HSA was obtained using a 0.1M Tris/HCI buffer containing 0.5M NaSCN. High desorption ratios (to 98% of the adsorbed HSA) were observed. It was possible to reuse Cu(II)‐chelated p(EGDMA–HEMA–MAH) beads without significant decreases in the adsorption capacities. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2840–2847, 2003     

Preparation of Chelating Resins Containing a Pair of Neighboring Carboxylic Acid Groups and the Adsorption Characteristics for Heavy Metal Ions

Abstract

For the functional enhancement of chelating resins containing carboxylic acids, copolymer beads were prepared by suspension polymerization of styrene (St), methyl methacrylate (MMA), and divinylbenzene (DVB) in the presence of toluene as diluent. The phenyl rings of the beads were directly chloromethylated, and the carboxylic ester groups of the beads were converted into hydroxymethyl groups by reduction followed by chlorination to give chloromethyl groups, respectively. The chelating resins containing a pair of neighboring carboxylic acid groups (NCAGs) were obtained by the alkylation of chloromethyl groups in copolymer beads with diethyl malonate in the presence of sodium hydride followed by hydrolysis using aqueous alkali solution. Accordingly, the structural effects of the resins on the adsorption of heavy metal ions were investigated. Poly(St‐co‐DVB)‐based chelating resin containing NCAGs showed adsorption abilities toward heavy metal ions like Pb²⁺, Cd²⁺, and Cu²⁺, whereas poly(MMA‐co‐DVB)‐based chelating resin containing NCAGs showed adsorption abilities toward heavy metal ions like Cu²⁺, Cd²⁺, and Co²⁺. On the other hand, poly(St‐co‐MMA‐co‐DVB)‐based chelating resin containing NCAGs showed adsorption abilities toward heavy metal ions like Pb²⁺, Cd²⁺, Hg²⁺, Co²⁺, and Cu²⁺: a synergistic effect on the adsorption of heavy metal ions like Pb²⁺, Cd²⁺, Hg²⁺, and Co²⁺ was observed. The adsorption ability of poly(St‐co‐MMA‐co‐DVB)‐based chelating resin among three kinds of chelating resins was relatively good.     

Adsorption and desorption properties of the chelating membranes prepared from the PE films

The chelating membranes for adsorption of metal ions were prepared by the photografting of glycidyl methacrylate (GMA) onto a polyethylene (PE) film and the subsequent modification of the resultant GMA‐grafted PE (PE‐g‐PGMA) films with disodium iminodiacetate in an aqueous solution of 55% DMSO at 80°C. The adsorption and desorption properties of the iminodiacetate (IDA) group‐appended PE‐g‐PGMA (IDA‐(PE‐g‐PGMA)) films to Cu²⁺ ions were investigated as functions of the grafted amount, pH value, Cu²⁺ ion concentration, and temperature. The amount of adsorbed Cu²⁺ ions increased with an increase in the pH value in the range of 1.0–5.0. The time required to reach the equilibrium adsorption decreased with an increase in the temperature, although the degree of adsorption stayed almost constant. The amount of Cu²⁺ ions desorbed from the (IDA‐(PE‐g‐PGMA)) films increased and the time required to reach the equilibrium desorption decreased with an increase in the HCl concentration. About 100% of Cu²⁺ ions were desorbed in the aqueous HCl solutions of more than 0.5M. The amounts of adsorbed and desorbed Cu²⁺ ions were almost the same in each cyclic process of adsorption in a CuCl₂ buffer at pH 5.0 and desorption in an aqueous 1.0M HCl solution. These results indicate that the IDA‐(PE‐g‐PGMA) films can be applied to a repeatedly generative chelating membrane for adsorption and desorption of metal ions. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:1895–1902, 2006     

Alanine containing porous beads for mercury removal from artificial solutions

N‐methacryloyl‐(L )‐alanine (MALA) was synthesized by using methacryloyl chloride and alanine as a metal‐complexing ligand or comonomer. Spherical beads with an average diameter of 150–200 μm were obtained by suspension polymerization of MALA and 2‐hydroxyethyl methacrylate (HEMA) conducted in an aqueous dispersion medium. Poly(HEMA–MALA) beads were characterized by SEM, swelling studies, surface area measurement, and elemental analysis. Poly(HEMA–MALA) beads have a specific surface area of 68.5 m²/g. Poly(HEMA–MALA) beads with a swelling ratio of 63%, and containing 247 μmol MALA/g were used in the removal of Hg²⁺ from aqueous solutions. Adsorption equilibrium was achieved in about 60 min. The adsorption of Hg²⁺ ions onto PHEMA beads was negligible (0.3 mg/g). The MALA incorporation into the polymer structure significantly increased the mercury adsorption capacity (168 mg/g). Adsorption capacity of MALA containing beads increased significantly with pH. The adsorption of Hg²⁺ ions increased with increasing pH and reached a plateau value at around pH 5.0. Competitive heavy metal adsorption from aqueous solutions containing Cd²⁺, Cu²⁺, Pb²⁺, and Hg²⁺ was also investigated. The adsorption capacities are 44.5 mg/g for Hg²⁺, 6.4 mg/g for Cd²⁺, 2.9 mg/g for Pb²⁺, and 2.0 mg/g for Cu²⁺ ions. These results may be considered as an indication of higher specificity of the poly(HEMA–MALA) beads for the Hg²⁺ comparing to other ions. Consecutive adsorption and elution operations showed the feasibility of repeated use for poly(HEMA–MALA) chelating beads. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1222–1228, 2006     

Formation of thermosensitive copolymer beads having phosphinic acid groups and adsorption ability for metal ions

Hydrophilic thermosensitive copolymer beads having phosphinic acid groups were prepared by suspension copolymerization of acryloyloxypropyl n‐octylphosphinic acid (APPO), N‐isopropyl acrylamide (NIPAAm), and tetraethyleneglycol dimethacrylate (4G). The thermosensitivity and the adsorption ability of the copolymer beads for metal ions beads were studied. The APPO‐NIPAAm‐4G copolymer beads were obtained in a good yield by suspension copolymerization of monomers (APPO, NIPAAm, and 4G) dissolved in chloroform, in a saturated Na₂SO₄ aqueous solution in the presence of surfactant and MgCO₃. The APPO‐NIPAAm‐4G copolymer beads had higher adsorption ability for lanthanide metal ions (Eu³⁺, Sm³⁺, Nd³⁺, or La³⁺) than for main transition metal ions (Cu²⁺, Ni²⁺, or Co²⁺). Furthermore, it was also found that the APPO‐NIPAAm‐4G copolymer beads had selective adsorption ability between lanthanide metal ions, and the order of adsorption ability for lanthanide metal ions was as follows: Eu³⁺ > Sm³⁺ > Nd³⁺ > La³⁺. The selective adsorption for these metal ions from their mixed solutions was performed by both a batch method and a column method. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 449–460, 2006     

Porous dye affinity beads for albumin separation from human plasma

Porous polymeric beads were obtained by the suspension polymerization of 2‐hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA). Poly(HEMA–EGDMA) beads were characterized by surfacearea measurements, swelling studies, FTIR, scanning electron microscopy (SEM), and elemental analysis. Poly (HEMA–EGDMA) beads had a specific surface area of 56 m²/g. SEM observations showed that the poly(HEMA–EGDMA) beads abounded macropores. Poly(HEMA–EGDMA) beads with a swelling ratio of 55%, and containing different amounts of Reactive Red 120 (9.2–39.8 μmol/g) were used in the adsorption/desorption of human serum albumin (HSA) from aqueous solutions and human plasma. The nonspecific adsorption of HSA was very low (0.2 mg/g). The maximum HSA adsorption amount from aqueous solution in phosphate buffer was 60.1 mg/g at pH 5.0. Higher HSA adsorption value was obtained from human plasma (up to 95.7 mg/g) with a purity of 88%. The equilibrium monolayer adsorption amount, Q_max was determined as 172.4 mg/g. The dimensionless separation factor (R_L) value shows that the adsorption behavior of HSA onto the Reactive Red 120 attached poly(HEMA–EGDMA) beads was favorable (0 < R_L < 1). Desorption of HSA from Reactive Red 120 attached poly (HEMA–EGDMA) beads was performed using 0.1M Tris/HCl buffer containing 0.5M NaCl. It was observed that HSA could be repeatedly adsorbed and desorbed with Reactive Red 120‐attached poly(HEMA–EGDMA) beads without significant loss in the adsorption amount. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Hydrophilic PVA-co-PE nanofiber membrane functionalized with iminodiacetic acid by solid-phase synthesis for heavy metal ions removal

A novel hydrophilic poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofiber membrane for heavy metal ions removal was fabricated by the solid phase synthesis of iminodiacetic acid (IDA) on nanofiber membrane surfaces. The hydrophilic PVA-co-PE nanofiber membranes were activated with cyanuric chloride. The IDA was then covalently linked to the activated PVA-co-PE nanofiber membranes. The chemical structures of activated and functionalized PVA-co-PE nanofiber membranes were confirmed with FTIR–ATR. The morphology of PVA-co-PE nanofiber membranes were characterized with SEM. The increase in the amount of IDA on functionalized PVA-co-PE nanofiber membranes significantly improved the adsorption amount of Cu²⁺. The IDA functionalized PVA-co-PE nanofiber membranes demonstrated excellent adsorption capability of Cu²⁺, Co²⁺, Zn²⁺ and Ni²⁺. The adsorption of above heavy metal ions could be repeatedly regenerated by desorbing the ions adsorbed on nanofiber membranes. The novel IDA functionalized PVA-co-PE nanofiber membranes have great potential in the application of industry and drinking water treatment.     

Antibody purification from human plasma by metal‐chelated affinity membranes

The aim of this study is to investigate in detail the feasibility of poly(2‐hydroxyethyl methacrylate‐N‐methacryloyl‐(L )‐histidine methyl ester), PHEMAH membranes for purification of immunoglobulin G (IgG) from human plasma. PHEMAH membranes were prepared by photo‐polymerization technique. Then, Zn²⁺, Ni²⁺, Co²⁺, and Cu²⁺ ions were chelated directly on the PHEMAH membranes. Elemental analysis assay was performed to determine the nitrogen content and polymerized MAH was calculated as 168.5 μmol/g. The nonspecific IgG adsorption onto the plain PHEMA membranes was negligible (about 0.25 mg/mL). A remarkable increase in the IgG adsorption capacities were achieved from human plasma with PHEMAH membranes (up to 68.4 mg/mL). Further increase was observed with the metal‐chelated PHEMAH membranes (up to 118 mg/mL). The metal‐chelate affinity membranes allowed the one‐step separation of IgG from human plasma. The binding range of metal ions for surface histidines from human plasma followed the order: Cu²⁺ > Ni²⁺ > Zn²⁺ > Co²⁺. Adsorbed IgG was eluted using 250 mM EDTA with a purity of 94.1%. IgG molecules could be repeatedly adsorbed and eluted with the metal‐chelated PHEMAH membranes without noticeable loss in their IgG adsorption capacity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Removal of heavy‐metal ions by magnetic beads containing triazole chelating groups

The aim of this study was to prepare magnetic beads that could be used for the removal of heavy‐metal ions from synthetic solutions. Magnetic poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [m‐poly(EGDMA–VTAZ)] beads were produced by suspension polymerization in the presence of a magnetite Fe₃O₄ nanopowder. The specific surface area of the m‐poly(EGDMA–VTAZ) beads was 74.8 m²/g with a diameter range of 150–200 μm, and the swelling ratio was 84%. The average Fe₃O₄ content of the resulting m‐poly(EGDMA–VTAZ) beads was 14.8%. The maximum binding capacities of the m‐poly(EGDMA–VTAZ) beads from aquous solution were 284.3 mg/g for Hg²⁺, 193.8 mg/g for Pb²⁺, 151.5 mg/g for Cu²⁺, 128.1 mg/g for Cd²⁺, and 99.4 mg/g for Zn²⁺. The affinity order on a mass basis was Hg²⁺ > Pb²⁺ > Cu²⁺ > Cd²⁺> Zn²⁺. The binding capacities from synthetic waste water were 178.1 mg/g for Hg²⁺, 132.4 mg/g for Pb²⁺, 83.5 mg/g for Cu²⁺, 54.1 mg/g for Cd²⁺, and 32.4 mg/g for Zn²⁺. The magnetic beads could be regenerated (up to ca. 97%) by a treatment with 0.1M HNO₃. These features make m‐poly(EGDMA–VTAZ) beads potential supports for heavy‐metal removal under a magnetic field. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Dithiocarbamate functionalized Al(OH)3‐polyacrylamide adsorbent for rapid and efficient removal of Cu(II) and Pb(II)

Heavy metal ions such as Cu²⁺ and Pb²⁺ impose a significant risk to the environment and human health due to their high toxicity and non‐degradable characteristics. Herein, Al(OH)₃‐polyacrylamide chemically modified with dithiocarbamates (Al‐PAM‐DTCs) was synthesized using formaldehyde, diethylenetriamine, carbon disulfide, and sodium hydroxide for rapid and efficient removal of Cu²⁺ and Pb²⁺. The synthesized adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, scanning electron microscopy–energy dispersive X‐ray spectroscopy analysis, and transmission electron microscope measurements. Al‐PAM‐DTCs showed rapid removal of Cu²⁺ (<30 min) and Pb²⁺ (<15 min) with high adsorption capacities of 416.959 mg/g and 892.505 mg/g for Cu²⁺ and Pb²⁺ respectively. Al‐PAM‐DTCs also had high capacities in removing suspended solids and metal ions simultaneously in turbid bauxite suspensions. FTIR, thermodynamic study, and elemental mapping were used to determine the adsorption mechanism. The rapid, convenient, and effective adsorption of Cu²⁺ and Pb²⁺ indicated that Al‐PAM‐DTCs has great potential for practical applications in purification of other heavy metal ions from aquatic systems. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45431.     

Synthesis and characterization of salep sulfate and its utilization in preparation of heavy metal ion adsorbent

A multicomponent polysaccharide obtained from dried tubers of certain natural terrestrial orchids was chemically modified by sulfonation using chlorosulfonic acid–dimethylformamide (HClSO_3–DMF) complex as a reagent. For a structural characterization of salep sulfate ¹H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, and Thermogravimetric analysis (TGA) curves were recorded. The sulfate content of modified salep was determined using elemental analysis. This modified biopolymer was used to prepare a new environment‐friendly heavy metal ion adsorbent, salep sulfate‐graft‐polyacrylic acid hydrogel (SS‐g‐PAA). Swelling rate and equilibrium water absorbency in various pH and saline solutions were investigated to study the effect of salep sulfate on swelling behavior of the hydrogel. In addition, the effect of sulfate content on heavy metal ion adsorption from aqueous solution was investigated. The results show that SS‐g‐PAA can effectively remove heavy metal ions (Co²⁺, Zn²⁺, Cu²⁺) from aqueous solution and swelling behavior of the hydrogels highly dependent on the amount of sulfate group on corresponding modified polysaccharide. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3001–3008, 2013     

Preparation of amidoximated bacterial cellulose and its adsorption mechanism for Cu2+ and Pb2+

Amidoximated bacterial cellulose (Am‐BC) was prepared through successive polymer analogous reactions of bacterial cellulose with acrylonitrile in an alkaline medium followed by reaction with aqueous hydroxylamine. It was used as an adsorbent to remove Cu²⁺ and Pb²⁺ from aqueous solutions. The adsorption behaviors of Cu²⁺ and Pb²⁺ onto Am‐BC were observed to be pH‐dependent. The maximum adsorption capacity of 84 and 67 mg g^–1 was observed, respectively, for Cu²⁺ and Pb²⁺ at pH 5. Scanning electronic microscopy (SEM) indicated that the microporous network structure of Am‐BC was maintained even after the modifacation. The adsorption mechanisms for Cu²⁺ and Pb²⁺ onto Am‐BC were investigated by fourier transform infrared spectroscopy (FTIR), ζ potential measurement and X‐ray photoelectron spectroscopy (XPS). The results revealed that the mechanism for the adsorption of Cu²⁺ onto Am‐BC could be mainly described as between metal ions and nitrogen atom in the amidoxime groups or oxygen atom in the hydroxyl groups. However, in the adsorption process for Pb²⁺, precipitation played the important role along with electrostatic interactions, although chelation action also existed in the process accounted for the adsorption process. The regeneration of Am‐BC was studied by treatment with a strong complexing agent, ethylenediaminetetracetic acid (EDTA). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thiourea modified hyper‐crosslinked polystyrene resin for heavy metal ions removal from aqueous solutions

A hyper‐crosslinked resin chemically modified with thiourea (TM‐HPS) was synthesized, characterized, and evaluated for the removal of heavy metal ions (Pb²⁺, Cd²⁺, and Cu²⁺) from aqueous solutions. The structural characterization results showed that a few thiourea groups were grafted on the surface of the resin with a big BET surface area and a large number of narrow micropores. Various experimental conditions such as pH, contact time, temperature, and initial metal concentration of the three heavy metal ions onto TM‐HPS were investigated systematically. The results indicated that the prepared resin was effective for the removal of the heavy metal ions from aqueous solutions. The isotherm data could be better fitted by Langmuir model, yielding maximum adsorption capacities of 689.65, 432.90, and 290.69 mg/g for Pd²⁺, Cd²⁺, and Cu²⁺, respectively. And the adsorption kinetics of the three metal ions followed the pseudo‐second‐order equation. FTIR and XPS analysis of TM‐HPS before and after adsorption further revealed that the adsorption mechanism could be a synergistic effect between functional groups and metal ions and electrostatic attraction, which may provide a new insight into the design of highly effective adsorbents and their potential technological applications for the removal of heavy metal ions from aqueous solutions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45568.     

Adsorption for metal ions of chitosan coated cotton fiber

A kind of adsorbent for metal ions, cotton fiber coated by high loading of chitosan (SCCH) was prepared. Its structure was characterized by elemental analysis, scanning electronic microscopy (SEM), Fourier transform infrared spectrum (FTIR), and wide‐angle X‐ray diffraction (WAXD). The adsorption properties of SCCH for Cu²⁺, Ni²⁺, Pb²⁺, Cd²⁺, such as saturated adsorption capacities, static kinetics, and isotherm were investigated. The adsorption for Ni²⁺, Pb²⁺, and Cd²⁺ was controlled by liquid film diffusion, but by particle diffusion for Cu²⁺. The adsorption process for Cu²⁺, Ni²⁺, Cd²⁺ could be described with Langmuir or Freundlich equation, but only with Freundlich equation for Pb²⁺. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008