Biomedical subjects

Adil Denizli

Publications and source records attributed to Adil Denizli.

At least 19 recordsLinked to original sources

PubMed2006

Synthesis of cholesterol imprinted polymeric particles.

The aim of this study is to prepare cholesterol-imprinted polymeric particles. N-Methacryloyl-(L)-tyrosinemethylester (MAT) was chosen as the complexing monomer. In the first step, functional monomer MAT was synthesized by the reaction of L-tyrosine methylester and methacryloyl chloride and characterized by FTIR and NMR. Then, cholesterol was complexed with MAT in different mol ratios and the cholesterol-imprinted poly(2-hydroxyethyl methacrylate-N-methacryloyl-(L)-tyrosine methylester) [MIP] particles were synthesized by bulk polymerization. After that, the template molecules (i.e., cholesterol) were removed using chloroform. MIP particles were characterized by elemental analysis, FTIR, SEM, swelling tests and surface area measurements. Cholesterol adsorption experiments were performed in a batch experimental set-up. Adsorption medium was methanol or intestinal mimicking solution. Stigmasterol and estradiol were used as competing molecules in selectivity tests. Obtained results were as follows: swelling ratio of MIP and non-imprinted (NIP) particles were 60.8% and 44.1% in water. With the increase in the amount of MAT in the polymerization medium, incorporation of MAT was increased (16.6-78.0 micromol/g). SEM photographs showed the surface roughness and porosity. Specific surface area of NIP and MIP particles were found as 19.2 and 31.5 m(2)/g, respectively. Template molecules (i.e., cholesterol) were removed from the polymer structure in the ratio of 76-84% of the initial concentration. Cholesterol adsorption increased with the increase in cholesterol concentration up to 1.5 mg/mL. MIP particles prepared using higher amounts of cholesterol exhibit significantly higher capacity to the NIP particles (i.e., control polymer). MIP particles were 3.09 and 3.60 times selective with respect to the stigmasterol and estradiol, respectively. Reusability of MIP particles was also investigated. MIP particles showed negligible loss in the cholesterol adsorption capacity after five adsorption-desorption cycles with the same adsorbent.

Adsorption↗

PubMed2006

L-histidine imprinted synthetic receptor for biochromatography applications.

We have proposed novel surface-imprinted beads for selective separation of cytochrome c (cyt c) by N-methacryloyl-(L)-histidine-copper(II) [MAH-Cu(II)] as a new metal-chelating monomer via metal coordination interactions and histidine template. We have combined molecular imprinting with the ability of histidine to chelate metal ions to create ligand exchange beads suitable for the binding of cyt c (surface histidine exposed protein). The histidine imprinted beads were produced by suspension polymerization of MAH-Cu(II)-L-histidine and ethylene glycol dimethacrylate. After polymerization, the template (L-histidine) was removed from the beads using methanolic KOH, thus getting histidine imprinted metal-chelate beads. L-Histidine imprinted metal-chelate beads can be used several times without considerable loss of cyt c adsorption capacity. The association constant (Ka) for the specific interaction between the template imprinted polymer and the template (L-histidine) itself were determined by Scatchard plots using L-histidine imprinted beads and found as 58,300 M(-1). Finally, we have used these histidine imprinted beads for cyt c and ribonuclease A (surface histidine exposed proteins) and enantiometric separation of D- and L-histidine by FPLC.

Adsorption↗

PubMed2006

Cr(III)-imprinted polymeric beads: Sorption and preconcentration studies.

The purpose of this study is to prepare a novel molecular imprinted adsorbent to Cr(III) analysis with high selectivity. Initially, chromium (III)-methacryloylhistidine (MAH/Cr(III)) complex monomer was synthesized and then Cr(III) ion imprinted ethyleneglycoldimethacrylate-methacryloylhistidine (poly(EDMA-MAH/Cr(III))) was polymerized. Cr(III) ions were removed from the Cr(III)-imprinting polymer. Selective cavity for the chromium (III) ions was obtained in the (poly(EDMA-MAH/Cr(III))) beads. These Cr(III)-imprinted beads were used in the sorption-desorption process. The effect of initial concentration of metal, the sorption rate and the pH of the medium on sorption capacity of Cr(III)-imprinting sorbents were studied. Sorption equilibrium time was achieved in about 30min. The maximum sorption of Cr(III) ions onto imprinted beads was about 69.28mg/g. Sorption studies of Co(II), Ni(II), Cr(III) and Cr(VI) ions were also investigated using Cr(III)-imprinting polymers. The obtained results show that selectively adsorbed amount of Cr(III) ion on Cr(III)-imprinting polymers is higher than all other studied ions. When the beads were used repeatedly, their adsorption capacity was showed feasibility.

Adsorption↗

PubMed2006

Removal of phenol and chlorophenols from water with reusable dye-affinity hollow fibers.

Reactive Green HE 4BD carrying polyamide hollow fibers were investigated as dye-affinity adsorbents for removal of chlorophenols (i.e., phenol, o-chlorophenol, p-chlorophenol and 2,4,6-trichlorophenol). Adsorption rates of chlorophenols were very high. Equilibrium was achieved in about 30 min. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption process could be the rate-limiting step in the adsorption process. The maximum adsorption values of chlorophenols onto the Reactive Green HE 4BD carrying hollow fibers were 145.9 micromol/g for phenol, 179.2 micromol/g for 2,4,6-trichlorophenol, 194.5 micromol/g for p-chlorophenol and 202.8 micromol/g for o-chlorophenol. The affinity order was as follows: o-chlorophenol>p-chlorophenol>2,4,6-trichlorophenol>phenol. The adsorption capacity of chlorophenols decreased with increasing pH. Desorption of chlorophenols was achieved using methanol solution (30%, v/v). The Reactive Green HE 4BD-carrying hollow fibers are suitable for repeated use for more than 10 cycles without noticeable loss of adsorption capacity.

Adsorption↗

PubMed2006

Immunoglobulin G depletion from human serum with metal-chelated beads under magnetic field.

Magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-(L)-histidine methyl ester) [mag-poly(EGDMA-MAH) beads, 50-100 microm in diameter, were produced by suspension polymerization for affinity depletion of immunoglobulin G (IgG) from human serum. Cu2+ ions were complexed directly via MAH groups (Cu2+ loading: 4.1 micromol/g). IgG depletion studies were performed by magnetically stabilized fluidized bed column. Acetate, Tris-HCl, MES and phosphate buffers all allow adsorption of similar quantities of IgG (27.3-45.6 mg/g). MOPS and HEPES allow higher adsorption quantities (79.6 mg/g and 74.1mg/g, respectively). Maximum adsorption capacities in MOPS buffer were 46.8 mg/g for mag-poly(EGDMA-MAH) and 102.1mg/g for Cu2+ chelated mag-poly(EGDMA-MAH) beads. The adsorption capacity decreased drastically from 102.1mg/g to 30.7 mg/g with the increase of the flow rate from 0.2 ml/min to 3.5 ml/min. The elution studies were performed by 1.0M NaCl. The elution results demonstrated that the adsorption of IgG to the adsorbent was reversible. To test the efficiency of IgG depletion from human serum, proteins in the serum and eluted portion were analyzed by two-dimensional gel electrophoresis. The depletion efficiency for IgG was above 99.4%. Eluted proteins include mainly IgG, and a small number of non-albumin proteins such as apo-lipoprotein A1, sero-transferrin, haptoglobulin and alpha1-antitrypsin. When anti-HSA-sepharose adsorbent is used together with our metal-chelated mag-beads, IgG and HSA can be depleted in a single step.

Chelating Agents↗

PubMed2006

Ion-imprinted beads for molecular recognition based mercury removal from human serum.

The aim of this study is to prepare ion-imprinted polymers which can be used for the selective removal of mercury ions [Hg(2+)] from human serum. N-Methacryloyl-(L)-cysteine (MAC) was chosen as the complexing monomer. In the first step, Hg(2+) was complexed with MAC and the Hg(2+)-imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-(l)-cysteine) (MIP) beads were synthesized by suspension polymerization. After that, the template ions (i.e., Hg(2+)) were removed using thiourea (0.5%, v/v) in 0.05 M HCl. The specific surface area of the MIP beads was found to be 59.04 m(2)/g with a size range of 63-140 micro m in diameter and the swelling ratio was 91.5%. According to the elemental analysis results, the MIP beads contained 87.0 micro mol MAC/g polymer. The maximum adsorption capacity was 0.45 mg Hg(2+)/g beads. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. The relative selectivity coefficients of MIP beads for Hg(2+)/Cd(2+), Hg(2+)/Zn(2+) were 14.7 and 21.5 times greater than the non-imprinted (NIP) matrix, respectively. The MIP beads could be used many times without decreasing in their adsorption capacities significantly.

Cations, Divalent↗

PubMed2006

Affinity separation of immunoglobulin G subclasses on dye attached poly(hydroxypropyl methacrylate) beads.

Poly(hydroxypropyl methacrylate) [poly(HPMA)] gel beads with an average size of 150-200 micro m were prepared by suspension polymerization of hydroxypropyl methacrylate (HPMA). The poly(HPMA) gel beads were characterized by swelling studies, surface area measurements, scanning electron microscopy (SEM) and elemental analysis. Poly(HPMA) gel beads had a specific surface area of 88.6 m(2)/g. The dye Reactive Green HE 4BD was chemically attached to yield dye-poly(HPMA) gel beads at an average concentration of 44.3 micro mol dye/g bead with a swelling ratio of 75%. These dye attached gel beads were used in the separation of immunoglobulin-G (IgG) through adsorption-elution studies. The non-specific adsorption of IgG on the poly(HPMA) gel beads was 0.5 mg/g. The attachment of Reactive Green HE 4BD significantly increased the adsorption of IgG up to 71 mg/g. The Langmuir adsorption model was found to be applicable in interpretation of data pertaining to the adsorption studies of IgG with Reactive Green HE 4BD attached to the poly(HPMA) gel beads. The adsorption of IgG was found to be optimal at pH 7.0. The adsorption of IgG was observed to decrease by about 76% as the NaCl concentration was increased from 0.001 to 0.1 M. The IgG adsorption capacity of the dye attached poly(HPMA) gel beads was determined for a commercially available IgG solution to be 4.2 mg/g for IgG(1), 64.5 mg/g for IgG(2), 7.1 mg/g for IgG(3) and 10.8 mg/g for IgG(4). The Reactive Green HE 4BD attached poly(HPMA) gel beads have a significant adsorption capacity for IgG(2). The quantity of adsorbed IgG(2) is three times higher than the quantity of the other subclasses, IgG(1), IgG(3) and IgG(4). A similar adsorption behaviour was observed when the albumin free human plasma was used. The quantity of adsorbed IgG(2) is higher than the quantity of the other subclasses, IgG(1), IgG(3) and IgG(4). Adsorption capacities for albumin free human plasma were obtained as 6.4 mg/g for IgG(1), 67.8 mg/g for IgG(2), 5.2 mg/g for IgG(3) and 8.6 mg/g for IgG(4). Significant amount of the adsorbed IgG (up to 95%) was eluted in 1h in the elution medium containing 2.0 M NaCl. Repeated adsorption/elution processes showed that these dye attached gel beads are suitable for IgG adsorption.

Adsorption↗

PubMed2006

Synthesis of tentacle-type magnetic beads as immobilized metal-chelate affinity support for cytochrome c adsorption.

Magnetic poly(2-hydroxyethylmethacrylate) (mPHEMA) beads with an average diameter of 100-140 microm were produced by suspension polymerization in the presence of magnetite particles (i.e. Fe3O4). Specific surface area and average pore size of the magnetic beads was found to be 50 m2/g and 819 nm, respectively. Ester groups in the mPHEMA structure were converted to imine groups by reacting with poly(ethyleneimine) (PEI) in the presence of NaH. Amino (-NH2) content of PEI-attached mPHEMA beads was determined as 102 mg PEI/g. Then, Cu2+ ions were chelated on the magnetic beads in the range of 20-793 micromol Cu2+/g. Cytochrome c (cyt c) adsorption was performed on the metal chelating beads from aqueous solutions containing different amounts of cyt c at different pHs, Cu2+ loadings and temperatures. Cyt c adsorption on the mPHEMA/PEI beads was 4.6 mg/g. Cu2+ chelation increased the cyt c adsorption significantly (40.1 mg/g). Adsorption capacity increased with Cu2+ loading and then reached a saturation value. Cyt c adsorption decreased with increasing temperature. Cyt c molecules could be reversibly adsorbed and eluted ten times with the magnetic adsorbents without noticeable loss in their cyt c adsorption capacity. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium capacity and correlation coefficients. Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. In the last part of this article, cyt c adsorption experiments were performed in a magnetically stabilized fluidized bed (MSFB) system at optimum conditions determined from the batch experiments. The adsorption capacity decreased significantly from 46.8 to 15.4 mg/g polymer with the increase of the flow-rate from 0.5 to 4.0 ml/min. The resulting magnetic chelator beads possessed excellent long-term storage stability.

Adsorption↗

PubMed2006

Monosize poly(glycidyl methacrylate) beads for dye-affinity purification of lysozyme.

Cibacron Blue F3GA was covalently attached onto monosize poly(glycidyl methacrylate) [poly(GMA)] beads for purification of lysozyme from chicken egg white. Monosize poly(GMA) beads, 1.6 microm in diameter, were produced by a dispersion polymerization technique. The content of epoxy groups on the surface of the poly(GMA) sample determined by the HCl-pyridine method (3.8 mmol/g). Cibacron Blue F3GA loading was 1.73 mmol/g. The monosize beads were characterized by elemental analysis, FTIR and SEM. Adsorption studies were performed under different conditions in a batch system (i.e., medium pH, protein concentration, temperature and ionic strength). Maximum lysozyme adsorption amount of poly(GMA) and poly(GMA)-Cibacron Blue F3GA beads were 1.6 and 591.7 mg/g, respectively. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium adsorption capacity and correlation coefficients. Results suggest that chemisorption processes could be the rate-limiting step in the adsorption process. It was observed that after 10 adsorption-elution cycle, poly(GMA)-Cibacron Blue F3GA beads can be used without significant loss in lysozyme adsorption capacity. Purification of lysozyme from egg-white was also investigated. Purification of lysozyme was monitored by determining the lysozyme activity using Micrococcus lysodeikticus as substrate. The purity of the eluted lysozyme was analyzed by SDS-PAGE and found to be 88% with recovery about 79%. The specific activity of the eluted lysozyme was high as 43,600 U/mg.

Adsorption↗

PubMed2006

Efficient removal of albumin from human serum by monosize dye-affinity beads.

Cibacron Blue F3GA was covalently attached onto monosize poly(glycidyl methacrylate) [poly(GMA)] beads for removal of human serum albumin (HSA) from human serum. Monosize poly(GMA) beads, 1.6 microm in diameter, were produced by dispersion polymerization. Cibacron Blue F3GA loading was 1.73 mol/g. HSA adsorption experiments were performed by stirred-batch adsorption. The non-specific adsorption of HSA was low (0.8 mg/g polymer). Dye attachment onto the monosize beads significantly increased the HSA adsorption (189.8 mg/g). The maximum HSA adsorption was observed at pH 5.0. With an increase of the aqueous phase concentration of sodium chloride, the adsorption capacity decreased drastically. The equilibrium adsorption of HSA significantly decreased with increasing temperature. The elution studies were performed by adding 0.1 M Tris/HCl buffer containing 0.5 M NaSCN to the HSA solutions in which adsorption equilibria had been reached. The elution results demonstrated that the adsorption of HSA to the adsorbent was reversible. The depletion efficiencies for HSA were above 87% for all studied concentrations. To test the efficiency of HSA removal from human serum, proteins in the serum and eluted portion were analyzed by two-dimensional gel electrophoresis. Eluted proteins include mainly albumin, and a small number of nonalbumin proteins such as apo-lipoprotein A1, sero-transferrin, haptoglobulin and alpha1-antitrypsin were bound by the dye-affinity beads. IgA was not identified in eluted fraction.

Humans↗

PubMed2006

Methacryloylamidoglutamic acid having porous magnetic beads as a stationary phase in metal chelate affinity chromatography.

We have prepared a novel magnetic metal-chelate adsorbent utilizing methacryloylamidoglutamic acid (MAGA) as a metal-chelating ligand. MAGA was synthesized by using methacryloyl chloride and L-glutamic acid dihydrochloride. Magnetic beads with an average diameter of 50-100 microm were produced by suspension polymerization of 2-hydroxyethyl methacrylate (HEMA) and MAGA in the presence of Fe3O4 particles carried out in an aqueous dispersion medium. Magnetic beads were charged with the Cu2+ ions directly via MAGA for the adsorption of cytochrome c (cyt c) from aqueous solutions. The maximum cyt c adsorption capacity of the Cu2+-chelated beads (0.86 mmol/g Cu2+ loading) was found to be 37 mg/g at pH 8.0 in phosphate buffer. Cyt c adsorption on the poly(HEMA-MAGA) beads was 15.4 mg/g. Cu2+ charging increased the cyt c adsorption significantly (37 mg/g). Cyt c adsorption decreased with increasing temperature. Cyt c molecules could be adsorbed and desorbed five times with these adsorbents without noticeable loss in their cyt c adsorption capacity. The resulting magnetic chelator beads posses excellent long term storage stability.

Animals↗

PubMed2006

Bilirubin removal performance of immobilized albumin in a magnetically stabilized fluidized bed.

Human serum albumin (HSA)-immobilised magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) particles were investigated as an adsorbent for selective bilirubin removal from human plasma in a magnetically stabilized fluidized bed system. mPHEMA particles were prepared by suspension polymerization in the presence of Fe3O4 particles. mPHEMA particles were characterized by scanning electron microscopy (SEM), surface area and pore size measurements. The mPHEMA beads have a spherical shape and porous structure. The specific surface area of the mPHEMA particles was found to be 50 m2/g with a size range of 80-120 microm in diameter and the swelling ratio was 45%. Then, HSA was covalently coupled to the cyanogen bromide (CNBr)-activated mPHEMA particles. The amount of coupled HSA was arranged by changing the activation degree of particles (i.e., CNBr concentration). In vitro bilirubin removal was investigated from hyperbilirubinemic human plasma on the mPHEMA particles containing different amounts of immobilised HSA (between 11 and 100 mg/g). The non-specific bilirubin adsorption on the bare mPHEMA particles was 0.47 mg/g. Higher bilirubin adsorption capacities, up to 88.3 mg/g, were obtained with the HSA-immobilised magnetic particles. Bilirubin capacity decreased significantly from 75.0 mg/g to 40.0 mg/g polymer with the increase of the flow-velocity from 0.5 ml/min to 4.0 ml/min. Bilirubin adsorption increased with increasing temperature. Adsorption behavior of bilirubin could be modelled using the Langmuir isotherm.

Adsorption↗

PubMed2005

Pathogenic antibody removal using magnetically stabilized fluidized bed.

Magnetic poly(2-hydroxyethyl methacrylate) (mPHEMA) beads were used in the removal of anti-dsDNA antibodies from systemic lupus erythematosus (SLE) patient plasma in a magnetically stabilized fluidized bed. mPHEMA beads, in the size range of 80-120 microm, were produced by suspension technique. Then, DNA was immobilized onto mPHEMA beads by carbodiimide activation. Magnetic beads were contacted with blood in in vitro systems. Loss of blood cells and clotting times were followed. mPHEMA beads were characterized by scanning electron microscopy (SEM). Important results obtained in this study are as follows: the mPHEMA beads have a spherical shape and porous structure. Loss of cells in the blood contacting with mPHEMA/DNA was negligible. The anti-dsDNA adsorption capacity decreased significantly with the increase of the flow-rate. With increasing anti-dsDNA antibody concentration, the amount of antibody adsorbed per unit mass increased, then reached saturation. Maximum anti-dsDNA antibody adsorption capacity was found to be 97.8 mg/g. Pathogenic antibody molecules could be repeatedly adsorbed and desorbed with these magnetic beads without noticeable loss in their antibody adsorption capacity. Because of the good blood-compatibility, mPHEMA is hopeful for the treatment of SLE by magnetically stabilized fluidized bed systems in the future.

Antibodies, Antinuclear↗

PubMed2005

Magnetic dye affinity beads for the adsorption of beta-casein.

Casein is well known as a good protein emulsifier and beta-casein is the major component of casein and commercial sodium caseinate. Dye affinity adsorption is increasingly used for protein separation. beta-Casein adsorption onto Reactive Red 120 attached magnetic poly(2-hydroxyethyl methacrylate) (m-PHEMA) beads was investigated in this work. m-PHEMA beads (80-120 microm in diameter) were produced by dispersion polymerization. The dichlorotriazine dye Reactive Red 120 was attached covalently as a ligand. The dye attached beads, having a swelling ratio of 55% (w/w) and carrying different amounts of Reactive Red 120 (9.2 micromol . g(-1)-39.8 micromol . g(-1)), were used in beta-casein adsorption studies. The effects of the initial concentration, pH, ionic strength and temperature on the adsorption efficiency of dye attached beads were studied in a batch reactor. The non-specific adsorption on the m-PHEMA beads was 1.4 mg . g(-1). Reactive Red 120 attachment significantly increased the beta-casein adsorption up to 37.3 mg . g(-1). More than 95.4% of the adsorbed beta-casein was desorbed in 1 h in a desorption medium containing 1.0 M KSCN at pH 8.0. We concluded that Reactive Red 120 attached m-PHEMA beads can be applied for beta-casein adsorption without significant losses in the adsorption capacities.

Caseins↗

PubMed2005

Molecularly imprinted ligand-exchange recognition assay of glucose by quartz crystal microbalance.

Molecular imprinted polymers (MIP) as a recognition element for sensors are increasingly of interest and MIP-quartz crystal microbalance (QCM) have started to appear in the literature. In this study, we have combined quartz crystal microbalance with MIP to prepare a sensor using the ability of glucose to chelate of copper (II) ion of methacrylamidohistidine (MAH) monomer to create ligand exchange (LE) assembled monolayer which is suitable for glucose determination. The study includes the measurement of binding interaction of molecularly imprinted QCM sensor via ligand interaction, investigation of the pH effect on frequency shift and recognition selectivity studies of glucose-imprinted polymer with respect to methyl-alpha-d-glucopyranoside and sucrose. Bmax (number of binding sites) and K(D) (dissociation constant of the metal-chelate copolymer) were also calculated using Scathard plot and the detection limit was found as 0.07 mM. MIP showed higher glucose-binding affinity than a well-known glucose binding protein, conconavalin A.

Copper↗

PubMed2005

Immunoadsorption of cholesterol on protein A oriented beads.

Anti-low density lipoprotein antibody (anti-LDL) molecules were attached covalently and oriented through Protein A onto poly(2-hydroxyethyl methacrylate-ethylene glycol dimethacrylate) [poly(HEMA-EGDMA)] beads in order to remove cholesterol specifically from hypercholesterolemic human plasma. Poly(HEMA-EGDMA) beads were produced by suspension polymerization. Blood compatibility tests were performed. All the clotting times were increased when compared with control plasma. Loss of platelets and leukocytes was very low. The maximum anti-LDL attachment was 11.6 mg . g(-1) in the case of random immobilization and 28.3 mg . g(-1) in the case of oriented immobilization. In the latter case, Protein A loading was 8.3 mg . g(-1) at pH 7.5 (borate buffer, 0.15 M NaCl). There was low non-specific cholesterol adsorption onto the poly(HEMA-EGDMA) beads, about 0.83 mg . g(-1). Random and oriented anti-LDL attached beads adsorbed 8.2 mg and 11.7 mg cholesterol per g of bead from hypercholesterolemic human plasma, respectively. Up to 96% of the adsorbed cholesterol was desorbed. The binding-elution cycle was repeated 6 times using the same beads. There was no significant loss of binding capacity.

Adsorption↗

PubMed2005

Removal of chlorophenols from aquatic systems using the dried and dead fungus Pleurotus sajor caju.

In this study, the potential use of the fungus Pleurotus sajor caju to remove phenols (i.e., phenol, o-chlorophenol, p-chlorophenol and 2,4,6-trichlorophenol) from aqueous solutions was evaluated. Biosorption of phenol or chlorophenols reached equilibrium in 4 h. The maximum adsorptions of phenol and chlorophenols onto the Pleurotus sajor caju were 0.95 mmol/g for phenol, 1.24 mmol/g for o-chlorophenol, 1.47 mmol/g for p-chlorophenol and 1.89 mmol/g for 2,4,6-trichlorophenol. The affinity order was as follows: 2,4,6-trichlorophenol> p-chlorophenol> o-chlorophenol>phenol. Phenol and chlorophenols bindings onto Pleurotus sajor caju were clearly pH dependent. The adsorption of phenol and chlorophenols increased with increasing pH. Desorption was achieved using methanol solution (30%, v/v). Pleurotus sajor caju biomass is suitable for reuse for more than five cycles without noticeable loss of adsorption capacity.

Adsorption↗

PubMed2005

Removal and pre-concentration of phenolic species onto beta-cyclodextrin modified poly(hydroxyethylmethacrylate-ethyleneglycoldimethacrylate) microbeads.

Poly(Hydroxyethylmethacrylate-Ethyleneglycoldimethacrylate), poly(HEMA-EGDMA), microbeads with 150-200 microm in size, was prepared by suspension polymerization. Beta-cyclodextrin was modified onto the polymeric microbeads using glutaraldahyde activation in an acidic medium at pH=2.5. FT-IR and TGA were used for the characterization of modified polymers and the determination of the nature of the interaction between phenolic compounds and the modified polymeric microbeads. Plain and beta-cyclodextrin modified microbeads were used in adsorption-desorption studies of phenolic species in single solution. Adsorption capacities of the phenolic species onto the plain microbeads were found to be 28.2, 17.0, 14.3, 9.8, and 1.92 mg/g polymer for o-chloro phenol, p-nitro phenol, p-chloro phenol, o-nitro phenol, and phenol, respectively. However, for beta-cyclodextrin modified microbeads, adsorption capacity of phenolic species was determined as 274, 365, 128, 182, and 87 mg/g for phenol, o-nitro phenol, p-nitro phenol, o-chloro phenol, and p-chloro phenol, respectively. Desorption ratio for the phenolic species was more than 90%, except for o-nitro phenol. Detection limits of the phenolic species were improved at least 500-fold for UV-Vis spectrophotometric detection, after the pre-concentration of all phenolic species used in this study. Adsorption time for the phenolic species onto beta-cyclodextrin-modified poly(HEMA-EGDMA) microbeads was found to be reasonable short (10-60 min) and suitable for the applications. Also, synthesized microbeads were useful for the repeated use for the removal and pre-concentration of phenolic species.

Adsorption↗