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

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

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

Removal of Cd(II), Hg(II), and MID ions from aqueous solution using p(HEMA/Chitosan) membranes

WOS: 000248609900023An interpenetration network (IPN) was synthesized from 2-hydroxyethyl methacrylate (HEMA) and chitosan, p(HEMA/chitosan) via UV-initiated photo-polymerization. The selectivity to different heavy metal ions viz Cd(II), Pb(II), and Hg(II) to the IPN membrane has been investigated from aqueous solution using bare pHEMA membrane as a control system. Removal efficiency of metal ions from aqueous solution using the IPN membranes increased with increasing chitosan content and initial metal ions concentrations, and the equilibrium time was reached within 60 min. Adsorption of all the tested heavy metal ions on the IPN membranes was found to be pH dependent and maximum adsorption was obtained at pH 5.0. The maximum adsorption capacities of the IPN membrane for Cd(II), Pb(II), and Hg(II) were 0.063, 0.179, and 0.197 mmol/g membrane, respectively. The adsorption of the Cd(II), Hg(II), and Pb(II) metal ions on the bare pHEMA membrane was not significant. When the heavy metal ions were in competition, the amounts of adsorbed metal ions were found to be 0.035 mmol/g for Cd(II), 0.074 mmol/g for Hg(II), and 0.153 mmol/g for Pb(II), the IPN membrane is significantly selective for Pb(II) ions. The stability constants of IPN membrane-metal ions complexes were calculated by the method of Ruzic. The results obtained from the kinetics and isotherm studies showed that the experimental data for the removal of heavy metal ions were well described with the second-order kinetic equations and the Langmuir isotherm model. (c) 2007 Wiley Periodicals, Inc

Biosorption of Reactive Blue 4 dye by native and treated fungus Phanerocheate chrysosporium: Batch and continuous flow system studies

WOS: 000241310000055PubMed: 16765512The native and treated fungal biomass of Phanerocheate chrysosporium was used for the biosorption of a textile dye (i.e., Reactive Blue 4). In the batch system, the biosorption equilibrium time was about 4 h and the maximum dye uptake on all the tested fungal biomass preparations was observed at pH 3.0. The dye uptake capacities of the biosorbents at 600 mg L-1 dye concentration were found to be 132.5, 156.9, 147.6 and 81.1 mg g(-1) for native and heat-, acid- and base-treated dry fungal preparations, respectively. The dye uptake capacity order of the fungal preparations was found as heat-treated > acid-treated > native > base-treated. The Langmuir, Freundlich 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 Blue 4 on native and treated fungal preparations. The dye biosorption on the fungal biomass preparations followed Ritchie kinetic model. Biosorption of the dye from aqueous solution was also investigated in a continuous flow system. The maximum biosorption capacity of the heat-treated fungal biomass P chrysosporium was 211.6 mg (g dry biomass)(-1) at an initial dye concentration of 600 mg L-1 and at a flow rate of 20 mL h(-1). (c) 2006 Elsevier B.V. All rights reserved

Studies on accumulation of uranium by fungus Lentinus sajor-caju

WOS: 000239230900027PubMed: 16431018The untreated, heat- and alkali-treated Lentinus sajor-caju mycelia were used for the recovery of uranium from aqueous solutions. The effect of pH, temperature, initial concentration of UO22+, ions and contact time parameters were investigated in a batch system. The particles sizes of the fungal mycelia were ranging from 100 to 200 mu m. Biosorption equilibriums were established in about 30 min and the correlation regression coefficients show that the adsorption process can be well defined by the Freundlich equation. The alkali treated form had a high biosorption capacity (378 mg/g) than those of the untreated (268 mg/g) and heat-treated fungal mycelia (342 mg/g). Optimum biosorption was observed at pH 4.5 for all the tested fungal preparations and was independent of temperature (5-35 degrees C). In addition, the polarity and surface energy of the fungal biomass film preparations were determined by contact angle measurement. The fungal biomass could be regenerated using 10 mM sodium carbonate, with up to 93% recovery. The biosorbents were used in six biosorption-desorption cycles and no considerable loss in the biosorption capacity was observed. (c) 2005 Elsevier B.V. All rights reserved

Immunoglobulin G adsorption behavior of L-histidine ligand attached and Lewis metal ions chelated affinity membranes

WOS: 000240521800011Immobilized metal affinity membranes were prepared by chelating Cu(II) and Fe(III) ions on poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA) membranes using L-histidine as a chelating ligand. To achieve this goal, the poly(HEMA-GMA) membrane was prepared via UV initiated photopolymerization. A spacer-arm (i.e., 1,6-diaminohexane) was introduced through the epoxy groups of the membrane (poly(HEMA-GMA)-SA). A chelating ligand (i.e., L-histidine amino acid) was covalently attached on the poly(HEMA-GMA) and/or poly(HEMAGMA)-SA using glutaric dialdehyde as a coupling agent, poly(HEMA-GMA)-H and poly(HEMA-GMA)-SAH membranes, respectively. Then, Cu(II) and Fe(III) ions were chelated through poly(HEMA-GMA)-SAH membrane. The binding characteristics of human immunoglobulin G (IgG) to IMAC membranes and the selectivity of Cu(II) and Fe(III) ions to the IgG have been investigated from aqueous solution using L-histidine attached membrane (poly(HEMA-GMA)-SAH) as a control system. The experimental data was analyzed using two adsorption kinetic models, the pseudo-first-order and the pseudo-second-order, to determine the best-fit equation for the adsorption of IgG onto L-histidine incorporated and/or different metals ion immobilized affinity membranes. The first-order equation in the affinity membrane systems is the most appropriate equation to predict the adsorption capacity for all the tested adsorbents. Moreover, the effect of spacer-arm on the adsorption capacity was evaluated using poly(HEMA-GMA)-H membrane as a control system. The IgG binding order on the affinity membranes was poly(HEMA-GMA)-SAHCu(II) > poly(HEMA-GMA)-SAH-Fe(III) > poly(HEMA-GMA)-SAH > poly(HEMA-GMA)-H. Finally, the polarities and the surface free energies of the affinity membranes were determined by contact angle studies. (c) 2006 Elsevier B.V. All rights reserved