Search

The aim of this study is the synthesis of nanoparticles with selective arsenic recognition capability for the removal of arsenic from water. Arsenic recognition based molecularly imprinted (As(V)-MIP) were synthesized using the molecular imprinting technique via mini-emulsion polymerization. The synthesized As(V)-MIP nanoparticles were characterized using zeta sizer, zeta potential, FTIR, Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and elemental analysis. The adsorption behavior of nanoparticles was investigated in a batch system at pH 4.0–9.0. The maximum adsorption capacity of As(V)-MIP nanoparticles was determined to be 54.29 mg As/g polymer at pH 5.0. Various parameters such as pH, concentration and adsorption time were examined to determine the optimum adsorption conditions. As(V)-MIP nanoparticle selectivity experiments were conducted in the presence of NO3−, PO43−, and SO42− anions to determine the relative selectivity coefficients (K'). The experimental data showed a good correlation with the Langmuir isotherm equation and adherence of the adsorption process to pseudo-second-order kinetics was observed. Applying As(V)-MIP nanoparticles to real water sample showed up to 95.3% As(V) removal efficiency. Reusability experiments were performed by renewal of nanoparticles using a 1 M HNO3 solution containing 0.05% thiourea. [ABSTRACT FROM AUTHOR]

In this study, we fabricated magnetic ion-imprinted polymers (IIP) for arsenic removal. Ion-imprinted method was developed by complexing N-methacryloyl-l-cysteine (MAC) monomer and As(III) and As(V) as template molecules. The utilization of the MAC-As complex was chosen to provide a rebinding of As(III) and As(V) on IIP. The template molecules were removed by using 0.01 M HNO3 containing 0.05% thiourea solution as a desorption agent. The adsorption of As(III) and As(V) was ideal in buffer solution pH 5.0 for 120 min with removal capacity. The ion-imprinted-based magnetic nanoparticles were selective for arsenic toward other analogs (NO3−, PO43-, SO42- as an anion, and AsO2−, HAsO4− as an oxi-anion). The adsorption isotherm model fitted the Langmuir model with an R2 value of 0.9935–0.9118 and the Qmax values of 91.7 mg/g for As(III)-IIP magnetic nanoparticles and 99.0 mg/g As(V)-IIP nanoparticles, respectively. Finally, IIP-based magnetic nanoparticle adsorbents have been utilized successfully for effective arsenic removal from wastewater samples. [ABSTRACT FROM AUTHOR]

In the study, magnetic poly(hydroxyethylmethacrylate-N-methacryloyl-(L)-histidine) (mPHEMAH) nanoparticles were prepared by miniemulsion polymerisation using N-methacryloyl-(L)-histidinemethylester as basic monomer. The specific surface area of the magnetic nanoparticles was found to be 1050 m2/g. Maximum Protein C adsorption capacites of the Ni(II), Cu(II) and Zn(II) ions chelated magnetic poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine) nanoparticles were calculated as 589.22, 436.33 and 388.15 mg/g nanoparticles, respectively. This work was focused on the purity of the Protein C by sodium dodecyl sulphate polyacrylamide gel electrophoresis yielding a satisfactory result of 92% purity. Thе rеusаbilitys of thе Ni(II)-mPHEMAH, Cu(II)-mPHEMAH and Zn(II)-mPHEMAH nanoparticles were аpproximаtеly 93.5%, 94% and 95% respectively. [ABSTRACT FROM AUTHOR]

The removal of heavy metal ions from aquatic media or any conditions is crucial. Silver ions turn out to be the important example of this problem on earth when these are released to the environment. In the present study, silver ions (Ag+) imprinted poly(hydroxyethyl methacrylate) (PHEMA)-based cryogels were prepared using N-methacryloyl-L-cysteine as functional monomer, to be chelated with Ag+ ions. The maximum adsorption capacity of Ag+-imprinted polymeric cryogel was found to be 49.27 mg/g from aqueous solutions. To investigate the affinity of Ag+-imprinted PHEMAC cryogel column, photographic film material from the natural silver ion source was used. The recovery results were 72.8% for the Ag+-imprinted PHEMAC cryogel and 0.62% for the non-imprinted PHEMAC cryogels. These values clearly showed the selectivity of the Ag+-imprinted PHEMAC cryogel column. The adsorption–desorption cycle was performed more 10 times with use of the same Ag+-imprinted PHEMAC cryogel for the determination of reuse. These molecularly imprinted cryogels were used in adsorption process for a long time with no significant loss. [ABSTRACT FROM AUTHOR]

For biomarker discovery, simultaneous removal of albumin and immunoglobulin G (IgG) become more important for both concentrating other species including potential biomarkers and getting rid of their masking effect. In this study, we have proposed a covalent and photosensitive cross-linking conjugation of the biomolecules on nanostructures for the depletion of target proteins from aqueous solution and serum. The effect of concentration, pH, temperature and ionic strength on the adsorption of twin affinity nanotraps based on Cibacron Blue F3GA and Protein A were investigated. The efficiency of albumin and IgG depletion from human serum was performed using sodium dodecylsulfate–polyacrylamide gel electrophoresis. [ABSTRACT FROM PUBLISHER]

We have synthesized PVA/PEI monolithic cryogel columns chelated with Cu2+ ions as a model adsorbent, which is capable of binding haemoglobin (Hb) from human blood. The goal of this study is to perform the depletion of Hb via a single and easy process to be useful in proteomic studies. PVA/PEI-Cu2+ cryogel columns were subjected to adsorption studies of Hb from both aqueous solution and human plasma to evaluate the extent of interaction between cryogel columns and Hb. The effects of experimental parameters, such as pH, Hb equilibrium concentration, adsorption time, temperature, and ionic strength, on Hb adsorption capacity were investigated. [ABSTRACT FROM AUTHOR]

In this study, monolithic high performance liquid chromatography (HPLC) composite columns were synthesized for immunoglobulin G (IgG) separation by boronate affinity chromatography. 4-Vinyl phenyl boronic acid (VPBA) was polymerized with 2-hydroxyethyl methacrylate (HEMA). The poly(HEMA-VPBA) monoliths were crushed into fine particles by using ball-milling. Then, the crushed particles were embedded into poly(2-hydroxyethyl methacrylate) (PHEMA) cryogels to prepare monolithic HPLC composite columns. The PHEMA cryogel was also synthesized to evaluate the efficiency of the embedding process. The monolithic HPLC composite columns were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), surface area measurements, boron content analysis, swelling studies, and flow rate-back pressure relation. The performance of IgG separation of monolithic composite columns was determined with HPLC and the parameters such as pH, IgG concentration, temperature, flow rate, and ionic strength were investigated. The maximum adsorption was observed at pH 8.0 phosphate buffer. The IgG separation from human plasma was also performed and selectivity experiments were carried out with human serum albumin (HSA) and hemoglobin (Hb) as competitors. [ABSTRACT FROM AUTHOR]

In this work, Reactive Blue 15 dye functionalized poly(HEMA) nanoparticles were synthesized for reversible adsorption of lysozyme from its aqueous solution. For this, nano-sized poly(HEMA) nanoparticles were synthesized by the surfactant free emulsion polymerization. Reactive Blue 15 dye then covalently attached to the polymeric structure. These novel dye attached poly(HEMA) nanoparticles were used for the adsorption of lysozyme. Characterization of dye attached nanoparticles was carried out by using FTIR, AFM, and elemental analysis. Incorporation of the dye onto the polymeric structure was demonstrated by FTIR and elemental analysis, while the size and the shape of the nanoparticles were shown by AFM. The incorporated amount of the dye was found to be 70.3 μmol/g nanoparticle with sulphur stoichiometry and it was found that the prepared nanoparticles were in a spherical form and were about 100 nm diameter. Lysozyme adsorption studies were carried out with different conditions (pH, lysozyme concentration, temperature, and ionic strength) and maximum lysozyme adsorption was found to be 630.7 mg/g nanoparticle at pH 7.0 in 25°C medium temperature. Adsorbed lysozyme was desorbed by 1.0 M of NaCl with 96% recovery and synthesized dye-attached nanoparticles were used 10 times without any decrease in their adsorption capacity. [ABSTRACT FROM AUTHOR]

Magnetic separation technology is a quick and easy method for sensitive and reliable detection, separation, and purification of biomolecules from any medium. Dopamine plays a crucial role for human metabolism; hence the development of selective and robust interference free methods for dopamine (DA) detection is of great importance. In the present study, we have reported an alternative method for the detection of DA which overcomes interference by coexisting compounds. We have designed a magnetically stabilized fluidized bed system (MSFB) by using fluorescein isothiocyanate (FITC) conjugated magnetic graphene oxide sheets (magGOs) as preconcentrator and diagnostic tool. In the presence of coexisting molecules, ascorbic acid (AA) and uric acid (UA), FITC-magGOs showed selectivity to DA as 39- and 34-folds, respectively. Compared with DA, a negligible amount of AA and UA were captured by FITC- magGOs non-specifically. Maximum DA adsorption capacity of FITC-magGOs was found to be 46.21 mg/g. The characteristics of the DA adsorption behavior were described by the application of the Langmuir isotherm model with monolayer adsorption more accurately. All experiments were carried out in the neutral solutions at around physiological pH. [ABSTRACT FROM AUTHOR]

A supermacroporous cryogel was prepared to obtain an efficient and cost effective purification of IgG from human plasma. N-methacryloyl-(L)-histidine methyl ester (MAH) was chosen as the pseudospecific ligand and/or comonomer. Poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine methylester) [PHEMAH] cryogel was produced by free radical polymerization initiated by N,N,N′,N′-tetramethylene diamine (TEMED) and ammonium persulfate (APS) pair in an ice bath. PHEMAH cryogel had a specific surface area of 38.6 m2/g. PHEMAH cryogel was characterized by swelling studies, scanning electron microscopy and elemental analysis. PHEMAH cryogel containing 113.7 µmol MAH/g was used in the purification of IgG from human plasma. Compared with the poly(hydroxyethyl methacrylate) (PHEMA) cryogel (0.4 mg/g), the IgG adsorption capacity of the PHEMAH cryogel (24.7 mg/g) was improved significantly due to the MAH incorporation into the polymeric matrix. The maximum amount of IgG adsorption from aqueous solution in phosphate buffer was observed at pH 7.4. The IgG adsorption amount from human plasma was 97.3 mg/g with a purity of 94.6%. It was observed that IgG could be repeatedly adsorbed and eluted with PHEMAH cryogel without significant loss in the adsorption capacity. [ABSTRACT FROM PUBLISHER]

Brewer's yeast (bottom yeast, Saccharomyces cerevisiae subsp. uvarum) cells were magnetically modified using water-based magnetic fluid stabilized perchloric acid. The magnetically modified yeast cells were characterized by scanning electron microscopy (SEM). Cu2+ biosorption properties of magnetically modified yeast cells from synthetic solutions were utilized in a continuous magnetic system. The Cu2+ ion-binding capacity decreased drastically with the increase of the flow rate. The maximum Cu2+ biosorption capacity was obtained to be 1.2 mmol/g at 25°C. Biosorption of Cu2+ increased with increasing pH and then reached almost a plateau value around pH 4.0. The yeast biomass can be easily regenerated by 0.1 M HNO3 with higher effectiveness. Biosorption of heavy metal ions from artificial wastewater was also studied. The biosorption capacities are 0.92 mmol/g for Cu2+, 0.52 mmol/g for Hg2+, and 0.28 mmol/g for Ni2+. Magnetically-modified yeast cells exhibits the following metal ion-affinity sequence: Cu2+ > Hg2+ > Ni2+. [ABSTRACT FROM AUTHOR]

We have studied a new method for the preparation of Th(IV)-imprinted chitosan-phthalate particles, which can considerably enhance the adsorption capacity and selectivity of thorium ions. In this study, chitosan-phthalate was used as the complexing monomer, Th(IV) as template, epichlorohydrin as crosslinking agent. Initially, chitosan was modified with phthalic anhydrides and complex formation occured between carboxylic acid functional groups and Th(IV) ions. Secondly, particles were crosslinked with epichlorohydrin. After the removal of Th(IV) ions, thorium solid phase extraction (SPE) on the Th(IV) ion-imprinted particles from aqueous solutions containing their different amounts, selectivity study of thorium versus other interfering metal ions mixture which are Fe3+, La3+, and Mn2+ and distribution and selectivity coefficients were reported here. A comparison of the selectivity coefficient of Th(IV)-imprinted chitosan-phthalate particles with the selectivity coefficient of non-imprinted polymers showed that the imprinted matrix for Th(IV)/Fe(III), Th(IV)/La(III) and Th(IV)/Mn(II) was 8.35, 8.75 and 10.81 times greater than non-imprinted matrix, respectively. [ABSTRACT FROM AUTHOR]

Molecular recognition based separation systems have received much attention because of their high selectivity for target molecules. Molecular imprinting has been recognized as a promising technique for the development of affinity adsorbents. Molecularly imprinted polymers (MIP) are easy to prepare, stable, inexpensive, and capable of molecular recognition. Cadmium is a carcinogenic and mutagenic element. The limit value of cadmium in blood should be no higher than 50 pg/L when exposure to cadmium is unavoidable in industry. There is no specific treatment available for acute or chronic metal poisoning. Besides supportive therapy and hemodialysis, metal poisoning is often treated with commercially available chelating agents including EDTA and dimercaprol. However, there is histopathological evidence for increased toxicity in animals when these agents are utilized. The aim of this study is to prepare superporous ion-imprinted polymer monolith which can be used for the selective removal of Cd2+ ions from Cd2+ -overdosed human plasma. N-methacryloly-(L)-cysteinemethylester (MAC) was chosen as the complexing monomer. In the first step, MAC synthesized by using methacryloyl chloride and cysteine. Cd2+ was complexed with MAC monomer and the Cd2+-imprinted poly(HEMA-MAC) monoliths were synthesized by bulk polymerization. After that, Cd 2+ ions were removed by 0.1 M thiourea and 0.1 M HNO3 solutions, respectively. Cd2+-imprinted poly(HEMA-MAC) monoliths had a specific surface area of 226.8 m²/g and the swelling ratio was determined to be 76%. According to the elemental analysis results, monoliths contain approximately 58.3 μmol/g of MAC. The maximum adsorption capacity for Cd2+ ions was 26.6 μmol/g of the dry weight of monolith. The adsorption capacity decreased significantly from 23.25 μmol/g to 3.08 μmol/g polymer with the increase of the flow-rate from 1 mL/min to 4 mL/min. The Cd2+-imprinted poly(HEMA-MAC) monolith could be used many times without decreasing their adsorption capacities significantly. [ABSTRACT FROM AUTHOR]

Comonomer and/or metal-chelating ligand N-methacryloyl-(L)-histidine-methylester(MAH) was synthesized by using methacryloyl chloride and L-histidine methyl ester. Spherical beads with an average diameter of 75–125 µm were produced by suspension polymerization of 2-hydroxyethyl methacrylate(HEMA) and MAH carried out in an aqueous dispersion medium. Poly(HEMA-MAH) beads had a specific surface area of 18.3 m2/g. Elemental analysis of MAH for nitrogen was estimated as 895 µmol/g of polymer. Then the beads were loaded with different metal ions(i.e. Zn2+, Cu2+, Ni2+) to form the metal chelate. The effect of pH, concentration of lysozyme, and metal type on the adsorption of lysozyme to the metal-chelated beads was examined in a batch reactor. Purification of lysozyme from egg-white was also investigated. Maximum lysozyme adsorption capacity of poly(HEMA-MAH) beads was found to be 8.7 mg/g at pH 7.0 in phosphate buffer. Lysozyme adsorption capacity of Zn2+, Cu2+, and Ni2+-chelated beads was higher than that of non-chelated beads. The maximum capacities of Ni2+, Zn2+, or Cu2+-chelated beads were 11.5, 12.6, and 37.1 mg/g, respectively. A significant amount of the adsorbed lysozyme(up to 97%) was eluted in 1 h in the elution medium containing 25 mM EDTA at pH 4.9. Repeated adsorption-desorption process showed that this novel metal chelated beads are suitable for lysozyme adsorption. Purification of lysozyme was monitored by determining the lysozyme activity using Micrococcus lysodeikticus as substrate. The purity of the desorbed lysozyme was about 80% with recovery about 75%. [ABSTRACT FROM AUTHOR]

This manuscript describes a method for the selective removal of phenolic compounds from aqueous medium by imprinted polymers, which is the noncovalent approach based on both hydrogen bonding and hydrophobic interaction. These imprinted polymers were prepared by both bulk polymerization(IP1) and suspension polymerization(IP2) of methacryloylantipyrine(MAAP) in the presence of azobisisobutyronitrile(AIBN) as an initiator and cross-linking EGDMA and was imprinted with 4-nitrophenol. The effect of polymerization technique(bulk and suspension) on the adsorption and selectivity of phenolics was investigated. The maximum adsorption capacities of these IP1 and IP2 polymers were 25.9 and 27.6 mg/g for 4-nitrophenol, respectively. It was observed that the 4-nitrophenol binding capacity decreased with increasing pH. The selectivity experiments showed that the polymer prepared via suspension polymerization has high-binding ability for 4-nitrophenol to other phenolics compared to the polymer prepared via bulk polymerization. [ABSTRACT FROM AUTHOR]

In this study, human serum albumin (HSA) adsorption properties of reactive green HE-4BD-attached monodisperse poly(styrene-2-hydroxyethyl methacrylate) [poly(St-HEMA)] microspheres were investigated. Poly(St-HEMA) microspheres with an uniform size of 4.0 µm in diameter were produced by the dispersion copolymerization of St and HEMA in an ethanol–water medium. Reactive green HE-4BD was covalently attached onto the poly(St-HEMA) microspheres via a nucleophilic substitution reaction between the hydroxyl groups of HEMA and triazinyl chloro groups of dye with the equilibrium coupling capacity of 45.8 µmol dye (g polymer)−1. The poly(St-HEMA) monodisperse microspheres were characterized by scanning electron microscopy. The effect of concentration of HSA, medium pH, and ionic strength on the adsorption efficiency of dye-attached microspheres were studied in a batch system. The nonspecific adsorption of HSA on the poly(St-HEMA) microspheres was 2.1 mg g−1. Reactive green HE-4BD attachment significantly increased the HSA adsorption up to 221 mg g−1. The langmuir adsorption model was found to be applicable in interpreting HSA adsorption by reactive green HE-4BD attached microspheres. Significant amount of the adsorbed HSA (up to 92%) was eluted in 1 hr in the elution medium containing 1.0-M NaCl. To determine the effects of adsorption conditions on possible conformational changes of HSA structure, fluorescence spectrophotometry was employed. We resulted that poly(St-HEMA) dye-affinity microspheres can be applied for HSA adsorption without causing any significant conformational changes. Repeated adsorption/elution processes showed that these dye-attached monodisperse microspheres are suitable for HSA adsorption. [ABSTRACT FROM AUTHOR]

Describes the use of an ion-imprinting polymer prepared with methacryloylamidoglutamic acid for selective separation of uranyl ions from gaseous solutions. Synthesis of 2-methacryloylamidoglutamic acid monomer; Preparation of uranyl-imprinted polymeric microbeads; Adsorption of uranium.

The potential use of the fungus Penicillium purpurogenum to remove cadmium, lead, mercury, and arsenic ions from aqueous solutions was evaluated. Biosorption of heavy metal ions reached equilibrium in 4 h. Heavy metal ions binding by Penicillium purpurogenum was clearly pH dependent. Heavy metal loading capacity increased with increasing pH under acidic conditions, presumably as a function of heavy metal speciation and due to the H+ competition at the same binding sites. The adsorption of heavy metal ions reached a plateau value at around pH 5.0. The maximum adsorption capacities of heavy metal ions onto the fungal biomass under noncompetitive conditions were 35.6 mg/g for As(III), 70.4 mg/g for Hg(II), 110.4 mg/g for Cd(II) and 252.8 mg/g for Pb(II). Their adsorption behavior can be described at least approximately with the Langmuir equation. The competitive adsorption capacities of the heavy metal ions were 3.4 mg/g for As(III), 15.8 mg/g for Hg(II), 13.1 mg/g for Cd(II), and 41.8 mg/g for Pb(II) at 50 mmol/L initial concentration of metal ions. The same affinity order on a molar basis was observed under noncompetitive and competitive adsorption conditions, which was as follows: Pb(II)>Cd(II)>Hg(II)>As(III). The equilibrium loading capacity of Pb(II) was greater than that of other metal ions. This fungal biomass showed a preference for binding Pb(II) over Cd(II), Hg(II), and As(III). Elution of heavy metal ions was performed using 0.5 M HCl. The fungus Penicillium purpurogenum could be used for ten cycles for biosorption. [ABSTRACT FROM AUTHOR]

Poly(hydroxyethyl methacrylate) (PHEMA) beads (in the size range of 150–200 μm) with good mechanical properties were prepared and crosslinked with ethylene glycol dimethacrylate (EGDMA) to increase their chemical stability. Because of their hydroxyl groups, they can serve as affinity adsorbent and can be employed for medical applications. Cibacron Blue F3GA was succesfully immobilized onto the beads. The maximum dye attachment was 16.5 μmol/g. Then, metallopeptide-ligand cysteinylhexapeptide (CysHP) was incorporated onto these beads and they were used for removal of cadmium ions [Cd(II)] from human plasma in a packed-bed column. The maximum amount of CysHP attached was 3.2 mg/g. Non specific Cd(II) adsorption from human plasma on the PHEMA beads was 0.32 mg/g. The adsorption capacity of the beads decreased from 11.8 to 3.7 mg/g with the raise of the flow-rate from 1.0 to 5.0 ml/min. It has been found that the CysHP loading has a great effect on the capacity of beads for adsorbing Cd(II) ions from human plasma. This suggests that these modified beads could be used for removal of Cd(II) ions from human plasma. [ABSTRACT FROM AUTHOR]

In this study, we synthesized a novel adsorbent to obtain high protein-adsorption capacity utilizing 2-methacrylamidoalanine (MAAL) containing membrane. Amino acid-ligand MAAL was synthesized by using methacrylochloride and alanine. Then, poly(2-hydroxyethylmethacrylate-co-2-methacrylamidoalanine) [p(HEMA-co-MAAL)] membranes were prepared by UV-initiated photopolymerization of HEMA and MAAL in the presence of an initiator (azobisisobutyronitrile, AIBN). Synthesized MAAL was characterized by nuclear magnetic resonance spectroscopy. p(HEMA-co-MAAL) membranes were characterized by swelling studies, porosimeter, scanning electron microscopy, Fourier transform-infra red spectroscopy, and elemental analysis. These membranes have macropores in the size range 5–10 μm. Different metal ions including Zn(II), Ni(II), Co(II), and Cu(II) were chelated on these membranes. p(HEMA-co-MAAL) were used in the adsorption of human serum albumin (HSA) from aqueous media containing different amounts of albumin (0.1–5.0 mg L-1) and at different pH values (4.0–8.0). The maximum HSA adsorption was observed at pH 5.0. The nonspecific adsorption of HSA on the pHEMA membranes was negligible 0.9 μg cm-2. MAAL incorporation significantly increased the HSA adsorption (1.76 mg cm-2). The HSA adsorption capacities of the metal-incorporated membranes were greater than that of the p(HEMA-co-MAAL) membranes under the same conditions. Higher HSA adsorption capacity was observed from the human plasma (2.88 mg HSA cm-2). [ABSTRACT FROM AUTHOR]

Bioaffinity adsorption has a unique and powerful role as a support tool in the removal of toxic substances from human plasma. Synthetic hollow-fiber membranes have advantages as support matrices in comparison to conventional hemoperfusion columns because they are not compressible and they eliminate internal diffusion limitations. In this study, Cibacron Blue F3GA was covalently attached onto commercially available microporous polyamide hollow-fiber membranes for bilirubin removal from hyperbilirubinemic human plasma. Different amounts of Cibacron Blue F3GA were attached on the polyamide hollow-fibers by changing the dye-attachment conditions, i.e., initial dye concentration, addition of sodium carbonate, and sodium chloride. The maximum amount of Cibacron Blue F3GA attachment was obtained at 42.5 μmol g-1 when the hollow fibers were treated with 3 M HCl for 30 min before performing the dye attachment. The nonspecific bilirubin adsorption on the unmodified polyamide hollow-fiber membranes was 0.65 mg g-1 from human plasma. Higher bilirubin adsorption capacities, of up to 39.7 mg g-1, were obtained with the Cibacron Blue F3GA-attached polyamide hollow-fiber membranes. Further increase in bilirubin adsorption was obtained as 48.9 mg g-1. Bilirubin molecules interacted with these adsorbents directly. Contribution of albumin adsorption on the bilirubin adsorption was much pronounced. Bilirubin adsorption increased with increasing temperature and maximum adsorption was observed at 37°C. [ABSTRACT FROM AUTHOR]

The pseudo-biospecific affinity ligand l-histidine immobilized poly(2-hydroxyethylmethacrylate) (PHEMA) in spherical form (100–150 μm in diameter) was used for the affinity chromatographic separation of human-immunoglobulin-G (HIgG) from aqueous solutions and human plasma. The PHEMA adsorbents were prepared by a radical suspension polymerization technique. Reactive aminoacid-ligand l-histidine was then immobilized by covalent binding onto these adsorbents. Elemental analysis of immobilized l-histidine for nitrogen was estimated as 62.3 mg l-histidine/g of PHEMA. The maximum HIgG adsorption on the l-histidine immobilized PHEMA adsorbents was observed at pH 7.4. The non-specific HIgG adsorption onto the plain PHEMA adsorbents was very low (about 0.167 mg/g). Higher adsorption values (up to 3.5 mg/g) were obtained when the l-histidine immobilized PHEMA adsorbents were used from aqueous solutions. Much higher amounts of HIgG were adsorbed from human plasma (up to 44.8 mg/g). Adsorption capacities of other blood proteins were obtained as 2.2 mg/g for fibrinogen and 2.8 mg/g for albumin. The total protein adsorption was determined as 52.1 mg/g. The affinity microbeads allowed the one-step separation of HIgG from human plasma. The HIgG molecules could be repeatedly adsorbed and desorbed with these l-histidine-immobilized PHEMA adsorbents without noticeable loss in their HIgG adsorption capacity. [ABSTRACT FROM AUTHOR]

Removal of heavy metal ions from aqueous solutions containing low-to-moderate levels of contamination using Turkish Beypazari low-rank coal was investigated. Carboxylic acid and phenolic hydroxyl functional groups on the coal surface were the adsorption sites for heavy metal ions via the ion-exchange mechanism. The equilibrium pH of the coal-solution mixture was the principal factor controlling the extent of removal of Cd(II) and Hg(II) from aqueous solutions. The optimum pH was 4.0, and the adsorption reached equilibrium in 30 minutes. The maximum adsorption capacities of the metal ions from their single solutions were 1.55 mg for Hg(II) and 1.42 mg for Cd(II) per g of coal. Based on a weight uptake by coal, Hg(II) was found to have a greater affinity for the adsorption sites than does Cd(II). The same behavior was observed during competitive adsorption, that is, adsorption from binary solutions. The adsorption phenomena followed a typical Langmuir isotherm. The maximum adsorption capacities (qm) were calculated as 2.03 mg/g and 1.70 mg/g for Hg(II) and Cd(II), respectively. The Kd values were 8.2 mg/L for Cd(II) and 9.8 mg/L for Hg(II). The use of low-rank coal was considerably effective in removing Hg(II) and Cd(II) from aqueous solutions. High amounts of adsorbed metal ions could be desorbed (up to 90%) with 25 mmol/L EDTA. Low-rank Turkish coals are suitable for use in more than 10 cycles without experiencing significant loss of adsorption capacity. [ABSTRACT FROM AUTHOR]

Polyethylene glycol methacrylate (PEG-MA) gel beads carrying Cibacron Blue F3GA (42.6 μmol/g polymer) were prepared for the removal of Pb(II), Cu(II), and Cd(II) from aqueous solutions that contained different amounts of these ions (10–100 mg/L) and at different pH values (2.0–7.0). Adsorption rates were high, and adsorption equilibria were reached within 20 minutes. Adsorption of these metal ions on the unmodified PEG-MA gel beads was zero. The maximum adsorptions of heavy metal ions onto the Cibacron Blue F3GA–attached microbeads from single solutions were 23.3 mg/g (112.4 μmol/g) for Pb(II), 12.4 mg/g (110.3 μmol/g) for Cd(II), and 7.0 mg/g (110.2 μmol/g) for Cu(II). When the heavy metal ions competed (in the case of the adsorption from their mixture) the amounts of adsorption were 14.96 mg/g (72.2 μmol/g) for Pb(II), 0.72 mg/g (11.3 μmol/g) for Cu(II), and 1.10 mg/g (9.8 μmol/g) for Cd(II). Under competitive conditions, the system showed high selectivity for Pb(II) ions. The formation constants of Cibacron Blue F3GA–metal ion complexes were investigated through the application of the Ruǽić method. The calculated values of formation constants were 8.5 × 105 L/mol1 for Pb(II) dye, 2.5 × 105 L/mol for Cu(II) dye, and 8.2 × 104 L/mol for the Cd(II) dye complex. PEG-MA gel beads carrying Cibacron Blue F3GA can be regenerated through washing with a solution of nitric acid (0.1 mol/L). The maximum regeneration value was as high as 98.5%. These PEG-MA gel beads are suitable for more than 3 adsorption-desorption cycles without experiencing considerable loss of adsorption capacity. [ABSTRACT FROM AUTHOR]

The abilities of various sorbent materials for heavy metal removal have been reported in the literature. We have developed a novel approach to obtain high metal-sorption capacity utilizing a membrane containing 2-methacrylamidophenylalanine. Metal-complexing ligand 2-methacrylamidophenylalanine (MAPA) was synthesized through the use methacrylo chloride and phenylalanine. Then, poly(2-hydroxyethylmethacrylate-co-2-methacrylamidophenylalanine) (p(HEMA-co-MAPA)) membranes were prepared by UV-initiated photopolymerization of HEMA and MAPA in the presence of the initiator azobisisobutyronitrile. MAPA monomer was characterized by nuclear magnetic resonance spectroscopy. p(HEMA-co-MAPA) membranes were characterized by swelling studies, scanning electron microscopy, Fourier transform infrared spectroscopy, and elemental analysis. These membranes have large pores; the micropore dimensions are approximately 5–10 μm. p(HEMA-co-MAPA) affinity membranes with a swelling ratio of 133.2% and containing 18.9 mmol MAPA/m2 were used in the removal of the heavy-metal ions of copper, nickel, and mercury from aqueous media containing different amounts of these ions (5–600 mg/L) and at different pH values (2.0–7.0). The maximum adsorption capacities of heavy metal ions onto the MAPA-containing membranes under noncompetitive conditions were 23.8 mmol/m2 for Cu(II), 29.1 mmol/m2 for Ni(II), and 50.3 mmol/m2 for Hg(II). The affinity order was Hg(II) > Ni(II) > Cu(II).The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at approximately pH 5.0. Adsorption of heavy metal ions from artificial wastewater was also studied. The adsorption capacities were 11.9 mmol/m2 for Cu(II), 7.33 mmol/m2 for Ni(II), and 9.79 mmol/m2 for Hg(II). Desorption of heavy metal ions was performed using 0.1 M HNO3. The p(HEMA-co-MAPA) membranes are suitable for more than five cycles without noticeable loss of capacity. [ABSTRACT FROM AUTHOR]

The triazine dye Cibacron Blue F3GA was covalently immobilized as an affinity ligand onto microporous poly(2-hydroxyethyl methacrylate) (pHEMA) membranes. Three different metal ions [i. e., Fe(III), Zn(II), or Cu(II)] were then chelated with the immobilized Cibacron Blue F3GA molecules. Lysozyme adsorption onto these affinity adsorbents from aqueous solutions containing different amounts of lysozyme at different pH was investigated in a batch system. Lysozyme adsorption capacity of all of the metal-dye-immobilized membranes was greater than that of the dye-immobilized membranes. The nonspecific adsorption of the protein on the pHEMA membranes was negligible. The adsorption phenomena appeared to follow a typical Langmuir isotherm. The maximum capacity (qm) of the Fe(III)–Zn(II),–or Cu(II)–dye chelated membranes for lysozyme adsorption (384, 326, and 306 μg/cm2) was greater than that of the dye-immobilized membrane (224 μg lysozyme/cm2), respectively. The dissociation constant (kd) values were found to be 2.51 × 10-7 M with dye-immobilized membrane, and 2.32 ×10-7×10-7and 2.40 ×10-7 M with the Fe(III)–Zn(II),–and Cu(II)–dye-chelated membranes, respectively. More than 95% of the adsorbed lysozyme was desorbed in 60 min in the desorption medium containing 0.5 M KSCN at pH 8.0. [ABSTRACT FROM AUTHOR]

pHEMA membranes carrying 25.6 mmol Procion Blue MX-3G/m2 were used for removal of heavy metal ions (i.e., copper, arsenic, cadmium, and mercury) from aqueous media containing different amounts of these ions (0.1–4.5 mmol/L) and at different pH values (2.0–8.0). The maximum adsorption capacities of heavy metal ions onto Procion Blue MX-3G-attached membranes under noncompetitive conditions were 5.6 mmol/m2 for Cu(II), 19.6 mmol/m2 for As(III), 46.2 mmol/m2 for Cd(II), and 119.6 mmol/m2 for Hg(II). The competitive adsorption capacities of the heavy metal ions were 6.9 mmol/m2 for Cu(II), 21.2 mmol/m2 for As(III), 33.9 mmol/m2 for Cd(II), and 52.5 mmol/m2 for Hg(II). The same affinity order was observed under noncompetitive and competitive adsorption: Hg(II) > Cd(II) > As(III) > Cu(II). The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at around pH 6.0. Adsorption of heavy metal ions from artificial wastewater was also studied. The adsorption capacities are 3.5 mmol/m2 for Cu(II), 10.2 mmol/m2 for As(III), 24.7 mmol/m2 for Cd(II), and 37.3 mmol/m2 for Hg(II). Desorption of heavy metal ions was performed using 0.1 M HNO3. Procion Blue MX-3G-attached membranes are suitable for repeated use of more than 5 cycles without noticeable loss of capacity. [ABSTRACT FROM AUTHOR]