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1.
Biosorption of chromium(VI) on to cone biomass of Pinus sylvestris was studied with variation in the parameters of pH, initial metal ion concentration and agitation speed. The biosorption of Cr(VI) was increased when pH of the solution was decreased from 7.0 to 1.0. The maximum chromium biosorption occurred at 150 rpm agitation. An increase in chromium/biomass ratio caused a decrease in the biosorption efficiency. The adsorption constants were found from the Freundlich isotherm at 25 degrees C. The cone biomass, which is a readily available biosorbent, was found suitable for removing chromium from aqueous solution.  相似文献   

2.
Removal of Cr(VI) from aqueous solution by adsorption onto activated carbon   总被引:3,自引:0,他引:3  
Laboratory scale experiments were carried out to produce and characterise biofuel from tigernut (Cyperus esculentus) oil. Transesterification of tigernut oil afforded methyl and ethyl esters, which had fuel properties similar to common biofuels, hence tigernut could be utilised as an alternative renewable energy resource.  相似文献   

3.
The biosorption characteristics of Pb(II) and Cr(III) ions from aqueous solution using the lichen (Parmelina tiliaceae) biomass were investigated. Optimum biosorption conditions were determined as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of the metal ions by P. tiliaceae biomass. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The monolayer biosorption capacity of P. tiliaceae biomass for Pb(II) and Cr(III) ions was found to be 75.8 mg/g and 52.1mg/g, respectively. From the D-R isotherm model, the mean free energy was calculated as 12.7 kJ/mol for Pb(II) biosorption and 10.5 kJ/mol for Cr(III) biosorption, indicating that the biosorption of both metal ions was taken place by chemical ion-exchange. The calculated thermodynamic parameters (delta G degrees , delta H degrees and delta S degrees ) showed that the biosorption of Pb(II) and Cr(III) ions onto P. tiliaceae biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the biosorption processes of both metal ions followed well pseudo-second-order kinetics.  相似文献   

4.
5.
Biosorption of aqueous chromium(VI) by Tamarindus indica seeds   总被引:2,自引:0,他引:2  
The effectiveness of low cost agro-based materials namely, Tamarindus indica seed (TS), crushed coconut shell (CS), almond shell (AS), ground nut shell (GS) and walnut shell (WS) were evaluated for Cr(VI) removal. Batch test indicated that hexavalent chromium sorption capacity (q(e)) followed the sequence q(e)(TS) > q(e)(WS) > q(e)(AS) > q(e)(GS) > q(e)(CS). Due to high sorptive capacity, tamarind seed was selected for detailed sorption studies. Sorption kinetic data followed first order reversible kinetic fit model for all the sorbents. The equilibrium conditions were achieved within 150 min under the mixing conditions employed. Sorption equilibria exhibited better fit to Freundlich isotherms (R>0.92) than Langmuir isotherm (R approximately = 0.87). Hexavalent chromium sorption by TS decreased with increase in pH, and slightly reduced with increase in ionic strength. Cr(VI) removal by TS seems to be mainly by chemisorption. Desorption of Cr(VI) from Cr(VI) laden TS was quite less by distilled water and HCl. Whereas with NaOH, maximum desorption achieved was about 15.3%. When TS was used in downflow column mode, Cr(VI) removal was quite good but head loss increased as the run progressed and was stopped after 200 h.  相似文献   

6.
Growth-decoupled cells of Desulfovibrio vulgaris NCIMB 8303 can be used to reduce Pd(II) to cell-bound Pd(0) (Bio-Pd(0)), a bioinorganic catalyst capable of reducing hexavalent chromium to less toxic Cr(III), using formate as the electron donor. Magnetic resonance imaging showed that Bio-Pd(0), immobilized in chitosan and agar beads, is distinguishable from the surrounding gel and is evenly dispersed within the immobilization matrix. Agar-immobilized Bio-Pd(0) and 'chemical Pd(0)' were packed into continuous-flow reactors, and challenged with a solution containing 100 microM Cr(VI) (pH 7) at a flow rate of 2.4 ml h(-1). Agar-immobilized chemical Pd(0) columns lost Cr(VI) reducing ability by 160 h, whereas columns containing immobilized Bio-Pd(0) maintained 90% reduction until 680 h, after which reduction efficiency was gradually lost.  相似文献   

7.
Growth-decoupled cells of Desulfovibrio vulgaris NCIMB 8303 can be used to reduce Pd(II) to cell-bound Pd(0) (Bio-Pd0), a bioinorganic catalyst capable of reducing hexavalent chromium to less toxic Cr(III), using formate as the electron donor. Magnetic resonance imaging showed that Bio-Pd0, immobilized in chitosan and agar beads, is distinguishable from the surrounding gel and is evenly dispersed within the immobilization matrix. Agar-immobilized Bio-Pd0 and `chemical Pd0' were packed into continuous-flow reactors, and challenged with a solution containing 100 m Cr(VI) (pH 7) at a flow rate of 2.4 ml h–1. Agar-immobilized chemical Pd0 columns lost Cr(VI) reducing ability by 160 h, whereas columns containing immobilized Bio-Pd0 maintained 90% reduction until 680 h, after which reduction efficiency was gradually lost.  相似文献   

8.
Biosorption of mercury from aqueous solution by Ulva lactuca biomass   总被引:4,自引:0,他引:4  
The mercury biosorption onto non-living protonated biomass of Ulva lactuca, as an alternative method for mercury removal from aqueous solutions, was investigated. Batch equilibrium tests showed that at pH 3.5, 5.5 and 7 the maxima of mercury uptake values, according to Langmuir adsorption isotherm, were 27.24, 84.74 and 149.25 mg/g, respectively. The ability of Ulva lactuca biomass to adsorb mercury in fixed-bed column, was investigated as well. The influence of column bed height, flow rate and effluent initial concentration of metal was studied. The adsorbed metal ions were easily desorbed from the algal biomass with 0.3 N H2SO4 solution. After acid desorption and regeneration with distilled water, the biomass could be reused for other biosorption assays with similar performances.  相似文献   

9.
Biosorption of cadmium (II) ions from aqueous solution onto immobilized cells of Pycnoporus sanguineus (P. sanguineus) was investigated in a batch system. Equilibrium and kinetic studies were conducted by considering the effect of pH, initial cadmium (II) concentration, biomass loading and temperature. Results showed that the uptake of cadmium (II) ions increased with the increase of initial cadmium (II) concentration, pH and temperature. Langmuir, Freundlich and Redlich-Peterson isotherm models were used to analyze the equilibrium data at different temperatures. Langmuir isotherm model described the experimental data well followed by Redlich-Peterson and Freundlich isotherm models. Biosorption kinetics data were fitted using pseudo-first, pseudo-second-order and intraparticle diffusion. It was found that the kinetics data fitted well the pseudo-second-order followed by intraparticle diffusion. Thermodynamic parameters such as standard Gibbs free energy (Delta G0), standard enthalpy (Delta H0) and standard entropy (Delta S0) were evaluated. The result showed that biosorption of cadmium (II) ions onto immobilized cells of P. sanguineus was spontaneous and endothermic nature.  相似文献   

10.
Aside from its excellent mechanical properties, spider silk (SS) would offer an active surface for heavy metal interaction due to its rich protein structure. The present study describes the potential use of natural (SS) as a sorbent of heavy metals from aqueous solutions. Single and multi-species biosorption experiments of heavy metals by natural SS were conducted using batch and column experiments. The biosorption kinetics, in general, was found to follow the second-order rate expression, and the experimental equilibrium biosorption data fitted reasonably well to Freundlich isotherm. From the Freundlich isotherm, the biosorption capacities of Cu(II) and Pb(II) ions onto SS were found as 0.20 and 0.007 mmol g?1, respectively. The results showed a decrease in the extent of metal ion uptake with lowering the pH.  相似文献   

11.
Batch removal of chromium(VI) from aqueous solution by Turkish brown coals   总被引:1,自引:0,他引:1  
The ability of using low-rank Turkish brown coals (Ilgın: BC1, Beyşehir: BC2, and Ermenek: BC3) to remove Cr(VI) from aqueous solutions was studied as a function of contact time, solution pH, temperature, concentration of metal solutions and amount of adsorbent. Their sorption properties were compared with the activated carbon from Chemviron (AQ-30). Adsorption of Cr(VI) uptake is in all cases pH-dependent showing a maximum at equilibrium pH values between 2.0 and 3.2, depending on the biomaterial, that correspond to initial pH values of 2.3 units for BC1, 3.0 units for BC2 and 3.2 units for BC3 and AQ-30. Batch equilibrium tests showed that the Cr(VI) removal was fitted with Freundlich isotherm and the adsorption reached equilibrium in 80 min. It was proceeding effectively into a short acid pH interval (2.0–3.2) where processes of Cr(VI) sorption are maximized. It was observed that the maximum adsorption capacity of 11.2 mM of Cr(VI)/g for Ilgın (BC1), 12.4 mM of Cr(VI)/g for Beyşehir (BC2), 7.4 mM of Cr(VI)/g for Ermenek (BC3) and 6.8 mM of Cr(VI)/g for activated carbon (AQ-30) was achieved at pH of 3.0. The rise in temperature caused a slight decrease in the value of the equilibrium constant (Kc) for the sorption of Cr(VI) ion. The Cr(VI) sorption capacities of Beyşehir and Ilgın brown coals were the same. Ermenek brown coals and activated carbon (AQ-30) showed a similar sorption capacity.  相似文献   

12.
The performance of a new biosorbent system, consisting of a fungal biomass immobilized within an orange peel cellulose absorbent matrix, for the removal of Zn(2+) heavy metal ions from an aqueous solution was tested. The amount of Zn(II) ion sorption by the beads was as follows; orange peel cellulose with Phanerochaete chrysosporium immobilized Ca-alginate beads (OPCFCA) (168.61 mg/g) > orange peel cellulose immobilized Ca-alginate beads (OPCCA) (147.06 mg/g) > P. chrysosporium (F) (125.0 mg/g) > orange peel cellulose (OPC) (108.70 mg/g) > plain Ca-alginate bead (PCA) (98.26 mg/g). The Zn(2+) concentration was 100 to 1000 mg/L. The widely used Langmuir and Freundlich isotherm models were utilized to describe the biosorption equilibrium process. The isotherm parameters were estimated using linear and non-linear regression analysis. The Box-Behnken model was found to be in close agreement with the experimental values, as indicated by the correlation coefficient value of 0.9999.  相似文献   

13.
Summary A tropical white-rot basidiomycete, BDT-14 (DSM 15396) was investigated for its chromium (VI) biosorption potential from an aqueous solution. Pre-treatment of fungal biomass with acid resulted in 100% metal adsorption compared to only 26.64% adsorption without any pre-treatment. Chromium adsorption was a rapid process at early exposure resulting in 60% chromium removal within the first 2 h of exposure. An increase in biomass showed an increase in the total metal ions adsorption but a decrease in specific uptake of metal ions. The concentrations of chromium had a pronounced effect on the rate of adsorption. The adsorption efficiency was 100% when the initial Cr (VI) concentration was 100 mg l−1 with 1,000 mg biomass. Only 47.5% adsorption was observed with 500 mg l−1 Cr (VI) concentration. The adsorption data fit well with the Langmuir and Freundlich isotherm models. Comprehensive characterization of parameters indicates BDT−14 biomass as a promising material for Cr (VI) adsorption.  相似文献   

14.
Biosorption of phenol from an aqueous solution by Aspergillus niger biomass   总被引:6,自引:0,他引:6  
Intra-particle diffusion of sulfuric acid into sugarcane bagasse, corn stover, rice straw and yellow poplar was investigated to determine the effective diffusivity of sulfuric acid within the porous biomass structure. Diffusion experiments were conducted over 25-75 degrees C for two different biomass sizes using dynamic diffusion test cells. Diffusivities of sulfuric acid in agricultural residues were significantly higher than those of hard wood. Diffusivity data for each biomass were fitted into the Arrhenius equation for extrapolation to higher temperatures. The diffusivity data were subsequently incorporated into a theoretical model to determine acid profile within the biomass matrix. The modeling results indicate that intra-particle diffusion of acid influences the rate of dilute-acid pretreatment if unground biomass feedstock is used under normal pretreatment conditions. A criterion was set up to determine the critical biomass size at which the intra-particle acid diffusion becomes a rate-influencing factor for a given pretreatment condition.  相似文献   

15.
Aspergillus fumigatus removed uranium(VI) very rapidly and reached equilibrium within 1 h of contact of biomass with the aqueous metal solution. Biosorption data fitted to Langmuir model of isotherm and a maximum loading capacity of 423 mg U g–1 dry wt was obtained. Distribution coefficient as high as 10,000 (mg U g–1)/(mg U ml–1) at a residual metal ion concentration of 19 mg l–1 indicates its usefulness in removal of uranium(VI) from dilute waste streams. Optimum biosorption was seen at pH 5.0 and was independent of temperature (5–50°C ). Initial metal ion concentration significantly influenced uptake capacity which brought down % (w/w) uranium(VI) removal from 90 at 200 mg U l–1 to 35 at 1000 mg U l–1. Presence of 0.84 mmol Fe2+, Fe3+, Ca2+ and Zn2+ had no effect on uranium(VI) biosorption unlike Al3+ (0.84 mM) which was inhibitory.  相似文献   

16.
Chromium(VI) was removed from aqueous solution using sulfuric- and phosphoric-acid-activated Strychnine tree fruit shells (SSTFS and PSTFS) as biosorbents. Effects of various parameters such as adsorbent dose (0.02–0.1 g/L), temperature (303–333 K), agitation speed, solution pH (2–9), contact time, and initial Cr(VI) concentration (50–250 mg/L) were studied for a batch adsorption system. The optimum pH range for Cr(VI) adsorption was determined as 2. Equilibrium adsorption data were analyzed with isotherm models and the Langmuir and Freundlich models got best fitted values for SSTFS (R2 value – 0.994) and PSTFS (R2 value – 0.996), respectively. The maximum adsorption capacities of SSTFS and PSTFS were 100 and 142.85 mg/g, respectively. The biosorption process was well explained by pseudo-second-order kinetic model with higher R2 value (SSTFS – 0.996, PSTFS – 0.990) for both biosorbents. Characterization of biosorbents was done using Fourier transform infrared spectroscopy, scanning electron microscopy, elemental analysis, energy-dispersive X-ray analysis, and thermogravimetric analysis. Thermodynamic studies revealed the spontaneous, endothermic, and randomness in nature of the Cr(VI) adsorption process. Different concentrations of NaOH solutions were used to perform the desorption studies. The results demonstrated that both SSTFS and PSTFS can be used as an effective and low-cost biosorbent for removal of Cr(VI) from aqueous solutions.  相似文献   

17.
Journal of Applied Phycology - In this study, the dried biomass of Synechocystis sp. PCC 6803 was used as biosorbent for removing Fe(III)) ions from aqueous solution. The effects of exposure time,...  相似文献   

18.
In this work, the brown alga Fucus serratus (FS) used as a low cost sorbent has been studied for the biosorption of copper(II) ions in batch reactors. Firstly, the characterization of the surface functional groups was performed with two methods: a qualitatively analysis with the study of FT-IR spectrum and a quantitatively determination with potentiometric titrations. From this latter, a total proton exchange capacity of 3.15 mmolg(-1) was extrapolated from the FS previously protonated. This value was similar to the total acidity of 3.56 mmolg(-1) deduced from the Gran method. Using the single extrapolation method, three kinds of acidic functional groups with three intrinsic pK(a) were determined at 3.5, 8.2 and 9.6. The point of zero net proton charge (PZNPC) was found close to pH 6.3. Secondly, the biosorption of copper ions was studied. The equilibrium time was about 350 min and the adsorption equilibrium data were well described by the Langmuir's equation. The maximum adsorption capacity has been extrapolated to 1.60 mmolg(-1). The release of calcium and magnesium ions was also measured in relation to the copper biosorption. Finally, the efficiency of this biosorbent in natural tap water for the removal of copper was also investigated. All these observations indicate that the copper biosorption on FS is mainly based on ion exchange mechanism and this biomass could be then a suitable sorbent for the removal of heavy metals from wastewaters.  相似文献   

19.
The present study investigated the kinetics, equilibrium and thermodynamics of chromium (Cr) ion biosorption from Cr(VI) aqueous solutions by Cupressus lusitanica bark (CLB). CLB total Cr biosorption capacity strongly depended on operating variables such as initial Cr(VI) concentration and contact time: as these variables rose, total Cr biosorption capacity increased significantly. Total Cr biosorption rate also increased with rising solution temperature. The pseudo-second-order model described the total Cr biosorption kinetic data best. Langmuir´s model fitted the experimental equilibrium biosorption data of total Cr best and predicted a maximum total Cr biosorption capacity of 305.4 mg g-1. Total Cr biosorption by CLB is an endothermic and non-spontaneous process as indicated by the thermodynamic parameters. Results from the present kinetic, equilibrium and thermodynamic studies suggest that CLB biosorbs Cr ions from Cr(VI) aqueous solutions predominantly by a chemical sorption phenomenon. Low cost, availability, renewable nature, and effective total Cr biosorption make CLB a highly attractive and efficient method to remediate Cr(VI)-contaminated water and wastewater.  相似文献   

20.
The aim of this study was to investigate the potential to remove chromium (Cr) from aqueous solutions using the fruiting body of Auricularia polytricha. Batch experiments were conducted under various conditions, and different models were used to characterize the biosorption process. Results showed that, for both fresh and dried fruiting bodies of A. polytricha, removal efficiencies of Cr(VI) and total Cr reached maximum values at pH values of 1 and 2, respectively. The process of Cr(VI) removal by A. polytricha included the sorption process as well as the reduction of Cr(VI) to Cr(III). Spectra of X-ray photoelectron spectroscopy of the biosorbent revealed that most of the Cr loaded on the biomass surface was in the trivalent form. The Freundlich model fitted the isotherm process better than the Langmuir model in the concentration range examined. The pseudo-second-order model well described the adsorption process of Cr onto the biomass. The biosorption capacity of Cr(VI) by fruiting bodies was much higher than that by most of other biosorbents reported. The results suggest that the fruiting bodies of A. polytricha should be a promising biomaterial for Cr removal from water contaminated by the heavy metal.  相似文献   

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