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1.

Purpose

The objectives of this research are to identify the functional groups and determine corresponding pK a values of the acidic sites on dried brown algae Cystoseira barbata using FTIR and potentiometric titrations, and to investigate the biosorption ability of biomass towards divalent nickel, cadmium, and lead ions. Adsorption was studied as a function of solution pH and contact time, and experimental data were evaluated by the Langmuir isotherm model.

Methods

CaCl2 pretreatment was applied to the sorbent for enhancing the metal uptake capacity. The effect of solution pH on biosorption equilibrium was investigated in the pH range of 1.5?C5.0. Individual as well as competitive adsorption capacity of the sorbent were studied for metal cations and mixtures.

Results

The retention of the tested metal ions was mostly influenced from pH in the range of 1.5?C2.5, then stayed almost constant up to 5.0, while Ni(II) uptake showed the highest variation with pH. Potentiometric titrations were performed to find the number of strong and weak acidic groups and their acidity constants. The density of strong and weak acidic functional groups in the biomass were found to be 0.9 and 2.26?mmol/g, respectively. The FTIR spectra of the sorbent samples indicated various functionalities on the biomass surface including carboxyl, hydroxyl, and amino and sulphonate groups which are responsible for the binding of metal ions.

Conclusions

The capacity of the biomass for single metal ions (around 1?mmol/g) was increased to 1.3?mmol/g in competitive adsorption, Pb(II) showing the highest Langmuir intensity constant. Considering its extremely high abundance and low cost, C. barbata may be potentially important in metal ion removal from contaminated water and industrial effluents.  相似文献   

2.
Kaewsarn P 《Chemosphere》2002,47(10):1081-1085
Biosorption of heavy metals can be an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high uptake capacities for a number of heavy metal ions. In this paper, the adsorption properties of a pre-treated biomass of marine algae Padina sp. for copper(II) were investigated. Equilibrium isotherms and kinetics were obtained from batch adsorption experiments. The biosorption capacities were solution pH dependent and the maximum capacity obtained was 0.80 mmol/g at a solution pH of about 5. The biosorption kinetics was found to be fast, with 90% of adsorption within 15 min and equilibrium reached at 30 min. The effects of light metal ions on copper(II) uptake were studied and the presence of light metal ions did not affect copper(II) uptake significantly. Fixed-bed breakthrough curves for copper(II) removal were also obtained. This study demonstrated that the pre-treated biomass of Padina sp. could be used as an effective biosorbent for the treatment of copper(II) containing wastewater streams.  相似文献   

3.
Manganese-coated activated carbon (MCAC) and activated carbon were used in batch experiments for the removal of cadmium(II) and copper(II). Results showed that uptake of Cd(II) and Cu(II) was unaffected by increases in pH (3.0 to 8.5) or concentration (1 to 20 mg/L). Increased ionic strength (from 0.001 to 1 M NaNO3), however, significantly affected the uptake of Cd(II); adsorption of Cu(II) was not affected. Freundlich adsorption isotherm results indicated that MCAC possessed higher sorption capacity than activated carbon. Second-order rate constants were found to be 0.0386 for activated carbon and 0.0633 g/mg x min for MCAC for Cd(II) and 0.0774 for AC and 0.1223 g/mg x min for MCAC for Cu(II). Column experiments showed that maximum sorption capacity of MCAC was 39.48 mg/g for Cu(II) and 12.21 mg/g for Cd(II).  相似文献   

4.
An interactive metal-based potentiometric titration method has been developed using an ion selective electrode for studying the sorption of metal cations. The accuracy of this technique was verified by analyzing the metal sorption mechanism for the biomass of Rhizopus arrhizus fungus and diatomite, two dissimilar materials (organic and mineral, strong sorbent and weak sorbent) of a different order of cation exchange capacity. The problem of the initial electrochemical potential was addressed identifying the usefulness of a Na-sulfonic resin as a strong chelating agent applied before the beginning of sorption titration experiments so that the titration curves and the sorption uptake could be quantitatively compared. The resin stabilized the initial electrochemical potential to -405+/-5 mV corresponding to 2 micro gl(-1) of lead concentration in solution. The amounts of lead sorbed by R. arrhizus biomass and diatomite were 0.9 mmol g(-1) (C(e)=5.16 x 10(-2)mM) and 0.052 mmol g(-1) (C(e)=5.97 x 10(-2) mM), respectively. Lead sorption by the fungal biomass was pinpointed to at least two types of chemical active sites. The first type was distinguished by high reactivity and a low number of sites whereas the other was characterized by their higher number and lower reactivity.  相似文献   

5.
To develop an efficient bio-immobilization approach for the remediation of heavy metal pollution in soil, a mutant species of Bacillus subtilis (B38) was obtained by ultraviolet irradiation and selection under high concentration of cadmium (Cd) in a previous study. In the present study, to check the applicability of this mutated species to the sorption and immobilization of other metals, the sorption of four heavy metals, Cd, chromium (Cr), mercury (Hg), and lead (Pb), on living and nonliving B38 in single- and multiple-component systems under different conditions was investigated using batch experiments. Rapid metal binding occurred on both living and nonliving B38 during the beginning of the biosorption. The sorption kinetics followed the exponential equation for living biomass and the pseudo-first-order Lagergren model for nonliving biomass, with r 2 values in the range of 0.9004-0.9933. The maximum adsorptive quantity of the heavy metals on B38 changed with the solution pH, temperature, biomass dose, and ionic strength. The nonliving biomass generally showed greater or similar adsorptive capacities as compared with the living biomass and was not likely to be affected by the solution parameters. The bacterium had a stronger affinity to the cationic heavy metals than to the anionic one, and the equilibrium sorption amounts were 210.6, 332.3, and 420.9 mg/g for Cd(II), Hg(II), and Pb(II), respectively. The results of binary and ternary sorption experiments indicated that the metals with the higher sorption capacity in the single-component systems showed greater inhibitory effects on the biosorption of other metal ions in the multiple-component systems, but the sorption sites of Hg and Cd or Pb are likely to be different. The results of this study illustrated that the mutant species is a promising biosorbent for the remediation of multiple heavy metals.  相似文献   

6.
Murphy V  Hughes H  McLoughlin P 《Chemosphere》2008,70(6):1128-1134
Dried biomass of the macroalgae Fucus vesiculosus and Fucus spiralis (brown), Ulva spp. (comprising Ulva linza, Ulva compressa and Ulva intestinalis) and Ulva lactuca (green), Palmaria palmata and Polysiphonia lanosa (red) were studied in terms of their chromium biosorption performance. Metal sorption was highly pH dependent with maximum Cr(III) and Cr(VI) sorption occurring at pH 4.5 and pH 2, respectively. Extended equilibrium times were required for Cr(VI) binding over Cr(III) binding (180 and 120min, respectively) thus indicating possible disparities in binding mechanism between chromium oxidation states. The red seaweed P. palmata revealed the highest removal efficiency for both Cr(III) and Cr(VI) at low initial concentrations. However, at high initial metal concentrations F. vesiculosus had the greatest removal efficiency for Cr(III) and performed almost identically to P. lanosa in terms of Cr(VI) removal. The Langmuir Isotherm mathematically described chromium binding to the seaweeds where F. vesiculosus had the largest q(max) for Cr(III) sorption (1.21mmol g(-1)) and P. lanosa had the largest Cr(VI) uptake (0.88mmol g(-1)). P. palmata had the highest affinity for both Cr(III) and Cr(VI) binding with b values of 4.94mM(-1) and 8.64mM(-1), respectively. Fourier transform infrared analysis revealed interactions of amino, carboxyl, sulphonate and hydroxyl groups in chromium binding to Ulva spp. The remaining seaweeds showed involvement of these groups to varying degrees as well as ether group participation in the brown seaweeds and for Cr(VI) binding to the red seaweeds.  相似文献   

7.
The mechanism of accumulation of copper(II) by Pseudomonas aeruginosa was investigated. Uptake consisted of a rapid process (likely to be extracellular binding) followed by a slow phase (possibly cellular uptake). The sorption capacity of the microbe was found to be 50 mg/g, and sorption followed the Langmuir isotherm. The presence of mild mineral acids (0.1 N HCl) led to destructive desorption of 95% of sorbed metal, whereas citrate buffer (pH 4) desorbed 80% of the accumulated metal ions non-destructively. Spectroscopic and microscopic studies indicated the accumulation of metal inside the cell, though the maximum uptake was by the cell wall.  相似文献   

8.
Lead (II) has been as one of the most toxic heavy metals because it is associated with many health hazards. Therefore, people are increasingly interested in discovering new methods for effectively and economically scavenging lead (II) from the aquatic system. Recent studies demonstrate biosorption is a promising technology for the treatment of pollutant streams. To apply these techniques, suitable adsorbents with high efficiency and low cost are demanded. The waste biomass of Bacillus gibsonii S-2 biosorbent was used as low-cost biosorbent to remove metallic cations lead (II) from aqueous solution. To optimize the maximum removal efficiency, the effect of pH and temperature on the adsorption process was studied. The isotherm models, kinetic models and thermodynamic parameters were analysed to describe the adsorptive behaviour of B. gibsonii S-2 biosorbent. The mechanisms of lead (II) biosorption were also analysed by FTIR and EDX. The results showed that the optimum pH values for the biosorption at three different temperatures, i.e. 20, 30 and 40 °C, were determined as 4. The equilibrium data were well fitted to Langmuir model, with the maximum lead (II) uptake capacities of 333.3 mg?g?1. The kinetics for lead (II) biosorption followed the pseudo-second-order kinetic equation. The thermodynamic data showed that the biosorption process were endothermic (?G?<?0), spontaneous (?H?>?0) and irreversible (?S?>?0). The mechanism of lead (II) biosorption by the waste biomass of B. gibsonii S-2 biosorbent could be a combination of ion exchange and complexation with the functional groups present on the biosorbent surface. The application of the waste biomass of B. gibsonii S-2 for lead (II) adsorption, characterized with higher lead (II) sorption capacity and lower cost, may find potential application in industrial wastewater treatment.  相似文献   

9.
In this study, the adsorption properties of a pre-treated biomass from marine alga Padina sp., a biomass collected from Surin Island, Thailand, for removal of cadmium(II) ions from aqueous solutions was investigated. Batch and column experiments were conducted to determine the adsorption properties of the modified biomass. At a pH of 5, the maximum removal capacity of the biomass is 0.53 mmol/g. The kinetics of cadmium(II) adsorption were fast with 90% of adsorption taking place within 35 min. This study demonstrated that the pre-treated biomass of Padina sp. could be used as an efficient biosorbent for the treatment of cadmium(II)-bearing wastewater streams.  相似文献   

10.
This study examines the possibility of using Spirulina (Arthrospira) platensis TISTR 8217 to remove low concentrations of cadmium (less than 100 mg/l) from wastewater. The cyanobacteria were exposed to six different cadmium concentrations for 96 h, and the growth rate was determined using an optical density at 560 nm. The inhibiting concentration (IC50) was estimated using probit analysis. The IC50 at 24, 48, 72, and 96 h were 13.15, 16.68, 17.28, and 18.35 mg/l Cd, respectively. Cellular damage was studied under a light microscope and a transmission electron microscope. Swollen cells and fragmented filaments were observed. Cell injury increased with increasing concentrations of cadmium. Ultrastructural changes were observed in the algae exposed to cadmium concentrations both close to IC50 (14.68 mg/l) and at IC50 (18.35 mg/l). The alterations induced by cadmium were disintegration and disorganization of thylakoid membranes, presence of large intrathylakoidal space, increase of polyphosphate bodies, and cell lysis. In addition, the cadmium adsorption by algal cells was studied. Environmental factors were found to have an effect on biosorption. The uptake of cadmium was not affected by the temperature of the solution, but the sorption was pH dependent. The optimum pH for biosorption of algal cells was 7. The cadmium uptake process was rapid, with 78% of metal sorption completed within 5 min. The sorption data fit well to the Langmuir isotherm. The maximum adsorption capacity for S. platensis was 98.04 mg Cd per g biomass.  相似文献   

11.
Natural clinoptilolite can be used as an ion exchanger for removal of heavy metals and treatment of environmental pollution because of its desirable characteristics of high ion exchange selectivity and resistance to different media. In this work, the potential of natural clinoptilolite from G?rdes mines (West Anatolia, Turkey) for the uptake of lead(II), nickel(II), copper(II), and zinc(II), from their single and mixed ion solutions, was evaluated using the batch method. The mineralogical and chemical properties of the sorption material were carried out by X-ray diffraction, X-ray fluoremetry, scanning electron microscopy, and wet analysis. Contact time, initial solution pH, solid-to-liquid ratio, and initial metal cation concentration were determined as single ion sorption parameters. The silicon/aluminum ratio and the theoretical and equivalent exchange capacities, both in single and mixed solutions, were established. Corresponding adsorption constants and distribution coefficients have been found.  相似文献   

12.
In this paper, we investigate the effect of different biomass pretreatments on metal ion uptake by various biosorbents. Heat-treated as well as caustic-treated and ground biomass of Saccharomyces pastorianus was used to remove copper, lead and cadmium from various solutions. Untreated yeast was used as the control sample. The effect of yeast modification on sorption capacity depended on the different types of heavy metal ions and whether they were in single- or multi-component solutions. The highest uptake of copper and lead from a single-metal solution was obtained from heat-treated cells. Ground biomass was the most efficient at cadmium removal. However, the sorption capacity of the modified biomass did not improve when metal ions were removed from multi-component solutions. Indeed, the results in this paper show that optimizing metal removal from single-cation solutions can lead to decreased sorption capacity in multi-component solutions. Therefore, while adjusting the procedure of biomass modification, not only the nature of the metal ion being sorbed but also the chemical composition of the metal ion solution should be taken into account.  相似文献   

13.
Iqbal M  Edyvean RG 《Chemosphere》2005,61(4):510-518
The potential of loofa sponge discs to immobilize fungal biomass of Phanerochaete chrysosporium (a known biosorbent) was investigated as a low cost biosorbent for the removal of Cd(II) ions from aqueous solution. A comparison of the biosorption of Cd(II) by immobilized and free fungal biomass from 10 to 500 mg l(-1) aqueous solutions showed an increase in uptake of over 19% when the biomass is immobilized (maximum biosorption capacity of 89 and 74 mg Cd(II) g(-1) biomass for immobilized and free biomass respectively at a solution pH of 6). Equilibrium was established within 1h and biosorption was well defined by the Langmuir isotherm model. The immobilized biomass could be regenerated using 50 mM HCl, with up to 99% metal recovery and reused in ten biosorption-desorption cycles without significant loss of capacity. This study suggests that such an immobilized biosorbent system has the potential to be used in the industrial removal/recovery of cadmium and other pollutant metal ions from aqueous solution.  相似文献   

14.
In recent years, increasing awareness of the environmental impact of heavy metals has prompted a demand for monitoring and decontaminating industrial wastes prior to discharging into natural water bodies. This paper describes the preparation and electrochemical application of carbon paste electrode modified with nanocellulosic fibers for the determination of cadmium and lead in water samples using anodic stripping voltammetry. First, cadmium and lead were adsorbed on the carbon paste electrode surface at open circuit potential, followed by anodic stripping voltammetric scan from -1 to 0 V. Different factors affecting sensitivity and precision of the electrode, including accumulating solvent, pH of the accumulating solvent, accumulation time, supporting electrolyte, and scan rate were investigated. The proposed method was also applied to the determination of Cd (II) and Pb (II) in the presence of other interfering metal ions and cetyl trimethyl ammonium bromide, sodium dodecyl sulfate, and Triton X-100 as a representative of cationic, anionic, and neutral surfactants. Linear calibration curves were obtained in the concentration ranges of 150–650 μg?L?1 and 80–300 μg?L?1, respectively, for cadmium and lead at an accumulated time of 10 min with limits of detection 88 and 33 μg?L?1. Optimized working conditions are defined as acetate buffer of pH?5 as accumulating solvent, hydrochloric acid as supporting electrolyte, and scan rate 50 mV/s. This technique does not use mercury and therefore has a positive environmental benefit. The method is reasonably sensitive and selective and has been successfully applied to the determination of trace amounts of Cd (II) and Pb (II) in water samples.  相似文献   

15.
Potentiometric titrations and lead sorption tests were conducted using muscovite, clinochlore, hematite, goethite, quartz, and a mixture of these same minerals. Mechanistic models were developed to represent and interpret these data. The aim was isolating the specific contribution of each mineral in proton and lead binding. Acid-base properties of each single mineral as well as their mixture were represented by discrete models, which consider the dissociation of n monoprotic sites (n-site/n-K(H) models). A one-site/one-K(H) model (logK(H1) = 10.69) was chosen for quartz (dissociation of SiOH edge hydroxyl groups). Goethite and hematite (FeOH groups) were represented by the same one-site/one-K(H) model (logK(H1) = 10.35). Three-site/three-K(H) models were used for muscovite (logK(H1) = 4.18; logK(H2) = 6.65; logK(H3) = 9.67) and clinochlore (logK(H1) = 3.84; logK(H2) = 6.57; logK(H3) = 9.71) assuming that SiOH and AlOH of the aluminosilicate matrix dissociate in the acid-neutral pH range while SiOH groups of quartz inclusions dissociate in the basic range. Similarly, the mixture of these minerals was represented by a three-site/three-K(H) model (logK(H1) = 3.39; logK(H2) = 6.72; logK(H3) = 10.82). According to crossed comparisons with single minerals, the first two sites of the mixture were associated with the aluminosilicate matrix (SiOH and AlOH respectively) and the third site with iron oxides (FeOH) and quartz groups. Additivity of proton binding in the mixture was demonstrated by simulating the mixture's titration curve. A unified model for the entire set of titration curves (single minerals and mixture) was also developed introducing a three-peak distribution function for proton affinity constants. Experimental data for lead sorption onto the mixture and individual minerals in 3-5 pH range denoted the competition between protons and metallic ions. The entire set of lead isotherms (individual mineral and mixture data) was represented adequately by a unified model taking into account both monodentate and bidentate complexes with the three active sites (additivity of lead binding). Experimental data of metal distribution in solid and liquid phases were successfully simulated by implementing the protonation and the surface complexation constants into the database of a dedicated software for chemical equilibria.  相似文献   

16.
Luo F  Liu Y  Li X  Xuan Z  Ma J 《Chemosphere》2006,64(7):1122-1127
In this paper, marine brown algae Laminaria japonica was chemically-modified by crosslinking with epichlorohydrin (EC(1), EC(2)), or oxidizing by potassium permanganate (PC), or only washed by distilled water (DW). They were used for equilibrium sorption uptake studies with lead. As can be seen from the experimental results that biosorption equilibriums were rapidly established in about 2h. The lead adsorption was strictly pH dependent, and maximum removal of lead on biosorbents were observed at pH 5.3. The effects solid/liquid ratio on lead biosorption was also investigated. The maximum lead uptakes were 1.67 mmol g(-1), 1.62 mmol g(-1), 1.54 mmol g(-1) and 1.21 mmol g(-1), respectively for EC(1), EC(2), PC and DW. The order of maximum lead uptakes for different pretreated and raw alga was EC(1)>EC(2)>PC>DW. A comparison of different isotherm models revealed that the combination of Langmuir and Freundlich (L-F) isotherm model fitted the experimental data best.  相似文献   

17.
Palygorskite as a feasible amendment to stabilize heavy metal polluted soils   总被引:19,自引:0,他引:19  
The sorption behaviour of palygorskite has been studied with respect to lead, copper, zinc and cadmium in order to consider its application to remediate soils polluted with these metals. The Langmuir model was found to describe well the sorption processes offering maximum sorption values of 37.2 mg/g for lead, 17.4 mg/g for copper, 7.11 mg/g for zinc and 5.83 mg/g for cadmium at pH 5-6. In addition the effect of palygorskite amendment in a highly polluted mining soil has been studied by means batch extractions and leaching column studies. The soluble metal concentrations as well as the readily-extractable metal concentrations were substantially decreased at any concentration of palygorskite applied to soil (1, 2, 4%), although the highest decrease is obtained at the 4% dose. The column studies also showed a high reduction in the metal leaching (50% for lead, 59% for copper, 52% for zinc and 66% for cadmium) when a palygorskite dose of 4% was applied.  相似文献   

18.
Heavy metal pollution is a common environmental problem all over the world. The purpose of the research is to examine the applicability of bagasse fly ash (BFA)—an agricultural waste of sugar industry used for the synthesis of zeolitic material. The zeolitic material are used for the uptake of Pb(II) and Cd(II) heavy metal. Bagasse fly ash is used as a native material for the synthesis of zeolitic materials by conventional hydrothermal treatment without (conventional zeolitic bagasse fly ash (CZBFA)) and with electrolyte (conventional zeolitic bagasse fly ash in electrolyte media (ECZBFA)) media. Heavy metal ions Pb(II) and Cd(II) were successfully seized from aqueous media using these synthesized zeolitic materials. In this study, the zeolitic materials were well characterized by different instrumental methods such as Brunauer–Emmett–Teller, XRF, Fourier transform infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopic microphotographs. The presence of analcime, phillipsite, and zeolite P in adsorbents confirms successful conversion of native BFA into zeolitic materials. Seizure modeling of Pb(II) and Cd(II) was achieved by batch sorption experiments, isotherms, and kinetic studies. These data were used to compare and evaluate the zeolitic materials as potential sorbents for the uptake of heavy metal ions from an aqueous media. The Langmuir isotherm correlation coefficient parameters best fit the equilibrium data which indicate the physical sorption. Pseudo-second-order and intra-particle diffusion model matches best which indicates that the rate of sorption was controlled by film diffusion. The column studies were performed for the practical function of sorbents, and breakthrough curves were obtained, which revealed higher sorption capacity as compared to batch method. Synthesized zeolitic material (CZBFA and ECZBFA), a low-cost sorbent, was proven as potential sorbent for the uptake of Pb(II) and Cd(II) heavy metal ions.  相似文献   

19.
The biosorption of lead(II) ions in both simulated and real wastewater by spent mushroom Tricholoma lobayense, was studied in this work. The results show a biomass with a high potential for removing lead ions from wastewater. The optimum pH for the adsorption is 4, and the adsorption process is fast. The best sorbent mass of the biomaterial is 5 g/L with an initial lead(II) concentration of 1 mmol/L. The process follows the Langmuir isotherm model, and the biosorption capacity of lead ions reaches to 210 mg/g, which is higher than many biosorbents previously studied. The mechanism of biosorption may be mainly attributed to ion exchange. The FT-IR study identifies the functional groups responsible for this process. A scanning electron microscope showed a significant change of the sorbent surface after the biosorption process. The energy dispersive elemental analysis also confirmed the adsorption of lead(II) ions.  相似文献   

20.
Sugarcane bagasse and hydroponic lettuce roots were used as biosorbents for Cu(II), Fe(II), Zn(II), and Mn(II) removal from monoelemental solutions in aqueous medium, at pH 5.5, using batch procedures. These biomasses were studied in natura (lettuce roots, NLR, and sugarcane bagasse, NSB) and modified with HNO3 (lettuce roots, MLR, and sugarcane bagasse, MSB). Langmuir, Freundlich, and Dubinin-Radushkevich non-linear isotherm models were used to evaluate the data from the metal ion adsorption assessment. The maximum adsorption capacities (qmax) in monoelemental solution, calculated using the Langmuir isothermal model for Cu(II), Fe(II), Zn(II), and Mn(II), were respectively 24.61, 2.64, 23.04, and 5.92 mg/g for NLR; 2.29, 16.89, 1.97, and 2.88 mg/g for MLR; 0.81, 0.06, 0.83, and 0.46 mg/g for NSB; and 1.35, 2.89, 20.76, and 1.56 mg/g for MSB. The Freundlich n parameter indicated that the adsorption process was favorable for Cu(II) uptake by NLR; Fe(II) retention by MLR and MSB; and Zn(II) sorption by NSB, MLR, and NSB and favorable for all biomasses in the accumulation of Mn(II). The Dubinin-Radushkevich isotherm was applied to estimate the energy (E) and type of adsorption process involved, which was found to be a physical one between analytes and adsorbents. Organic groups such as O–H, C–O–C, CH, and C=O were found in the characterization of the biomass by FTIR. In the determination of the biomass surface charges by using blue methylene and red amaranth dyes, there was a predominance of negative charges.  相似文献   

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