Biosorption of Cr(VI) by free and immobilized Pediastrum boryanum biomass: equilibrium, kinetic, and thermodynamic studies

15th International Symposium on Toxicity Assessment (ISTA) -- JUL 03-08, 2011 -- City Univ Hong Kong, Hong Kong, PEOPLES R CHINAWOS: 000306790200053PubMed ID: 22374187The biosorption of Cr(VI) from aqueous solution has been studied using free and immobilized Pediastrum boryanum cells in a batch system. The algal cells were immobilized in alginate and alginate-gelatin beads via entrapment, and their algal cell free counterparts were used as control systems during biosorption studies of Cr(VI). The changes in the functional groups of the biosorbents formulations were confirmed by Fourier transform infrared spectra. The effect of pH, equilibrium time, initial concentration of metal ions, and temperature on the biosorption of Cr(VI) ion was investigated. The maximum Cr(VI) biosorption capacities were found to be 17.3, 6.73, 14.0, 23.8, and 29.6 mg/g for the free algal cells, and alginate, alginate-gelatin, alginate-cells, and alginate-gelatin-cells at pH 2.0, which are corresponding to an initial Cr(VI) concentration of 400 mg/L. The biosorption of Cr(VI) on all the tested biosorbents (P. boryanum cells, alginate, alginate-gelatin, and alginate-cells, alginate-gelatin-cells) followed Langmuir adsorption isotherm model. The thermodynamic studies indicated that the biosorption process was spontaneous and endothermic in nature under studied conditions. For all the tested biosorbents, biosorption kinetic was best described by the pseudo-second-order model.PROCORE-France/Hong Kong Joint Res Scheme, Croucher Fdn, KC Wong Educ Fd

Removal of heavy mercury(II), cadmium(II) and zinc(II) metal ions by live and heat inactivated Lentinus edodes pellets

WOS: 000259850800013The live and heat inactivated forms of Lentinus edodes pellets were used for the biosorption of Hg2+, Cd2+ and Zn2+ ions. The maximum adsorption of metal ions on the live and heat inactivated pellets of fungus was observed at pH 6.0 for all the used metal ions. The effect of temperature on the biosorption capacity was negligible in the range of 15-45 degrees C. The biosorption of Hg2+, Cd2+ and Zn2+ ions on the live and heat inactivated pellets of fungus was studied in aqueous solutions in the concentration range of 25-600 mg/L. The metal biosorption capacities of the live fungal pellets Hg2+, Cd2+ and Zn2+ were 336.3 +/- 3.7, 78.6 +/- 2.6 and 33.7 +/- 1.6 mg/g, respectively, while Hg2+, Cd2+ and Zn2+ the biosorption capacities of the heat inactivated pellets were 403.0 +/- 2.9, 274.3 +/- 3.6 and 57.7 +/- 1.1 mg/g, respectively. The adsorption capacities of the heat inactivated fungus for metals were markedly increased compared to native form. For both forms the same affinity order on a molar basis were observed for single or multi-metal ions (Hg2+ > Cd2+ > Zn2+). The Langmuir and Freundlich equilibrium models represent well the experimental data. The experimental kinetic data were analyzed using the first- and second-order kinetic models and the second-order kinetic model described the biosorption kinetics accurately for each metal ions. (C) 2008 Elsevier B.V. All rights reserved.National Institute of Agrobiological Sciences [MAFF 430012]The authors wish to thanks on the behalf of National Institute of Agrobiological Sciences to Dr. Hiroshi Shinbo (Director of Genebank) for supplying the white-rot fungus Lentinus edodes (MAFF 430012)

Biosorption of Reactive Red-120 dye from aqueous solution by native and modified fungus biomass preparations of Lentinus sajor-caju

WOS: 000250640600032PubMed: 17499434The capacities and mechanisms of native and treated white-rot fungus "Lentinus sajur-caju" biomass preparations in removing of textile dye (i.e. Reactive Red-120) from aqueous solution was investigated with different parameters, such as adsorbent dosage, pH, temperature and ionic strength. In the batch system, the maximum dye uptake on all the tested fungal biomass preparations was observed at pH 3.0, and the dye uptake capacities of the biosorbents (at 800 mg/l dye concentration) were found to be 117.8, 182.9, 138.6 and 57.2 mg/g for native and heat-, acid- and base-treated dry fungal preparations, respectively. The uptake capacities order of the fungal preparations for the dye were found as heat-treated > acid-treated > native > base-treated. The Langmuir, Freundlih and Temkin adsorption models were used for the mathematical description of the biosorption equilibrium. The Freundlich and Temkin models were able to describe the biosorption equilibrium of Reactive Red-120 on the fungal biomass preparations. The dye biosorption on the fungal biomass preparations followed second-order kinetic model and equation. (c) 2007 Elsevier B.V. All rights reserved

Adsorption of Cr(VI) onto PEI immobilized acrylate-based magnetic beads: Isotherms, kinetics and thermodynamics study

WOS: 000256002000004Magnetic poly(GMA-EGDMA) beads were prepared from glycidylmetharylate (GMA) and ethyleneglycol dimethacrylate (EGDMA) in the presence of Fe3O4 nano-powder via suspension polymerization. After polymerization, the magnetic beads were coated with polyethyleneinnine (PEI). Elemental analysis of PEI immobilized beads for the free amine group content was estimated as 258.8 mu mol/g polymer. The magnetic beads were characterized by surface area measurement, electron spin resonance (ESR), and scanning electron microscopy (SEM). ESR data revealed that the beads were highly super-paramagnetic. The magnetic beads were used for the removal of Cr(VI) ions from aqueous solutions in batch mode. Adsorption equilibrium was established in about 120 min. The maximum adsorption of Cr(VI) on the magnetic beads was observed at around pH 2.0. The maximum adsorption capacity of the magnetic beads was 137.7 mg/g. The effects of adsorbent dosage, ionic strength and temperature have been also reported. (C) 2007 Elsevier B.V. All rights reserved

Enzymatic removal of phenol and p-chlorophenol in enzyme reactor: Horseradish peroxidase immobilized on magnetic beads

WOS: 000257722000021PubMed: 18207637Horseradish peroxidase was immobilized on the magnetic poly(glycidylmethacrylate-co-methylmethacrylate) (poly(GMA-MMA)), via covalent bonding and used for the treatment of phenolic wastewater in continuous systems. For this purposes, horseradish peroxidase (HRP) was covalently immobilized onto magnetic poly(GMA-MMA) beds using glutaraldehyde (GA) as a coupling agent. The maximum HRP immobilization capacity of the magnetic poly(GMA-XMA)-GA beads was 3.35 mg g(-1). The immobilized HRP retained 79% of the activity of the free HRP used for immobilization. The immobilized RRP was used for the removal of phenol and p-chlorophenol via polymerization of dissolved phenols in the presence of hydrogen peroxide (H2O2). The effect of pH and temperature on the phenol oxidation rate was investigated. The results were compared with the free HRP, which showed that the optimum pH value for the immobilized HRP is similar to that for the free HRR The optimum pH value for free and immobilized HRP was observed at pH 7.0. The optimum temperature for phenols oxidation with immobilized HRP was between 25 and 35 degrees C and the immobilized HRP has more resistance to temperature inactivation than that of the free form. Finally, the immobilized HRP was operated in a magnetically stabilized fluidized bed reactor, and phenols were successfully removed in the enzyme reactor. (C) 2007 Elsevier B.V. All rights reserved

Kinetics of mercury ions removal from synthetic aqueous solutions using by novel magnetic p(GMA-MMA-EGDMA) beads

WOS: 000247197100060PubMed: 17118552Poly(glycidylmethacrylate-methylmethacrylate), p(GMA-MMA-EGDMA), magnetic beads were prepared via suspension polymerization in the presence of ferric ions. The epoxy groups of the beads were converted into amino groups via ring opening reaction of the ammonia and, the aminated magnetic beads were used for the removal of Hg(II) ions from aqueous solution in a batch experiment and in a magnetically stabilized fluidized bed reactor (MFB). The magnetic p(GMA-MMA-EGDMA) beads were characterized with scanning electron microscope (SEM), Fr-IR and ESR spectrophotometers. The optimum removal of Hg(II) ions was observed at pH 5.5. The maximum adsorption capacity of Hg(II) ions by using the magnetic beads was 124.8 +/- 2.1 mg g(-1) beads. In the continuous MFB reactor, Hg(II) ions adsorption capacity of the magnetic beads decreased with an increase in the flow-rate. The maximum adsorption capacity of the magnetic beads in the MFB reactor was 139.4 +/- 1.4 mg g(-1). The results indicate that the magnetic beads are promising for use in MFB for removal of Hg(II) ions from aqueous solution and/or waste water treatment. (C) 2006 Elsevier B.V. All rights reserved

Preparation of poly (glycidylmethacrylate-methylmethacrylate) magnetic beads: Application in lipase immobilization

WOS: 000258892600012Magnetic bead was prepared from the monomers glycidylmethacrylate (GMA) and methylmethacrylate (MMA) via suspension copolymerization in the presence of ferric ions. The magnetic beads were characterized with scanning electron microscope (SEM), FT-IR and ESR spectrophotometers. The beads were sieved and 100-150 mu m size of fraction was used in enzyme immobilization. The specific surface area of the magnetic beads was measured by the BET method and was found to be 16.2 m(2)/g beads. The reactive character of the epoxy groups allowed the attachment of the amino groups during thermal precipitation reaction. The resulting magnetic beads were used for the covalent immobilization of Candida rugosa lipase via glutaraldehyde activation and glutaraldehyde was also acted a 5-carbon spacer arm. The maximum lipase immobilization on magnetic poly(GMA-MMA) was 23.4 mg g(-1). The activity yield of the lipase immobilized on the spacer-arm attached magnetic beads was up to 81%. Kinetic analysis shows that the dependence of lipolytic activity of both free and immobilized lipase on trybutyrin substrate concentration can be described by Michaelis-Menten model with good agreement. The estimated Michaelis constants (Km) for the free and immobilized lipase are 2.6 and 12.3 mM, respectively. The V-max values of free and immobilized enzymes were calculated as 984 and 773 U/mg enzymes, respectively. Employment of immobilization seemed to result in an increase in K-m and a decrease in V-max. Optimal operational temperature was 5 degrees C higher for immobilized enzyme than that of the free counterpart. Thermal and storage stabilities were found to he increase with immobilization. (c) 2008 Elsevier B.V. All rights reserved

Biosorption of benzidine based textile dyes "Direct Blue 1 and Direct Red 128" using native and heat-treated biomass of Trametes versicolor

WOS: 000246465800018PubMed: 17010509The capacities and mechanisms of native and heat-treated white rot fungus "Trametes versicolor" biomass in removing of two different benzidine based dyes (i.e., Direct Blue 1, DB-1 and Direct Red 128, DR-128) from aqueous solution was investigated with different parameters, such as molecular weight of dye, adsorbent dosage, pH, temperature and ionic strength. In the batch system, the biosorption equilibrium time for both dyes was about 6 h. The maximum biosorption was observed at pH 6.0 for DB-1 and at pH 3.0 for DR-128 on the native and heat-treated fungal biomass. The biosorption capacities of the native and heat-treated fungal biomass (at 800 mg/L dye concentration) were found to be 101.1 and 152.3 mg/g for DB-1 and these were 189.7 and 225.4 mg dye/g biomass for DR-128, respectively. The Freundlih and Temkin adsorption isotherm models were used for the mathematical description of the biosorption equilibrium. The Freundlich and Temkin models were able to describe the biosorption equilibrium of DB-1 and DR-128 on the native and heat-treated fungal preparations. The Freundlich model also showed that the small molecular weight dye (i.e., DR-128) had a higher affinity of adsorption that than of the higher molecular weight dye (i.e., DB-1). The dye biosorption on the fungal biomass preparations followed the second order kinetics model. (C) 2006 Elsevier B.V. All rights reserved

Cytochrome c adsorption on glutamic acid ligand immobilized magnetic poly(methylmethacrylate-co-glycidylmethacrylate) beads

WOS: 000245072500008This work presents data on cytochrome c adsorption onto glutamic acid immobilized magnetic poly(methylmethacrylate-coglycidylmethacrylate), mp(GMA-MMA) beads which were synthesized from glycidylmethacrylate (GMA) and methylmethacrylate (MMA) in the presence of a cross-linker (i.e., ethyleneglycol dimethacrylate; EGDMA) via suspension polymerization. The epoxy groups of the mp(GMA-MMA) beads were converted into amino groups after reaction with ammonia and the aminated magnetic beads was activated with glutaric dialdhyde. It was then glutamic acid as an amino acid ligand covalently immobilized on the activated beads. The affinity mp(GMA-MMA)-A-GA beads were used in cytochrome c (Cytc) adsorption studies under defined pH, ionic strength or temperature conditions in a batch system using plain mp(GMA-MMA)-A beads as a control system. The maximum adsorption capacity of the mp(GMA-MMA)-A-GA affinity beads was found to be 140.3 mg g(-1) beads and the affinity constant (K-d), evaluated by the Langmuir model, was 5.42 x 10(-6) M. Adsorption capacity of the mp(GMA-MMA)-A-GA were decreased to Cytc by increasing the ionic strength adjusted with NaCl. Adsorption kinetic of Cytc onto magnetic affinity beads was analyzed with first-order and second-order kinetic equations. The first-order equation fitted well with the experimental data. (c) 2006 Elsevier B.V. All rights reserved

Studies of adsorption of alkaline trypsin by poly(methacrylic acid) brushes on chitosan membranes

WOS: 000253287600059Poly(methacrylic acid)-grafted chitosan membranes (chito an-g-poly(MAA)) were prepared in two sequential steps: in the first step, chitosan membranes were prepared by phase-inversion technique and then epichlorohydrin was used as crosslinking agent to increase its chemical stability in acidic media; in the second step, the graft copolymerization of methacrylic acid onto the chitosan membranes was initiated by ammonium persulfate (APS) under nitrogen atmosphere. The chitosan-g-poly(MAA) membranes were first used as an ion-exchange support for adsorption of trypsin from aqueous solution. The influence of pH, equilibrium time, ionic strength, and initial trypsin concentration on the adsorption capacity of the chitosan-g-poly(MAA) membranes have been investigated in a batch system. Maximum trypsin adsorption onto chitosan-gpoly(MAA) membrane was found to be 92.86 mg mL(-1) at pH 7.0. The experimental equilibrium data obtained for trypsin adsorption onto chitosan-g-poly(MAA) membranes fitted well to the Langmuir isotherm model. The adsorption data was analyzed using the first- and second-order kinetic models, and the experimental data was well described by the second-order equation. More than 97% of the adsorbed trypsin was desorbed using glutamic acid solution (0.5M, pH 4.0). In addition, the chitosan-gpoly(MAA) membrane prepared in this work showed promising potential for various biotechnological applications. (C) 2007 Wiley Periodicals, Inc