Biosorption Of Zinc Research Articles

Biosorption of zinc(II) ions onto powdered waste sludge (PWS): Kinetics and isotherms

Waste sludge samples obtained from a paint industry wastewater treatment plant was dried, ground and pre-treated with 1% H 2O 2 to improve the biosorption capacity. The powdered waste sludge (PWS) was sieved to different mesh sizes and used for biosorption of zinc(II) ions from aqueous solution. Kinetics of zinc biosorption onto PWS was investigated by using the PWS samples with particle size of 64 μm. The pseudo-first and -second order rate expressions were used to correlate the experimental data. The kinetic constants were determined for both models and the second order rate expression was found to be more suitable. Three different biosorption isotherms were used to correlate the equilibrium biosorption data and the isotherm constants were determined. The Langmuir isotherm was found to fit the experimental data better than the other isotherms tested. Maximum biosorption capacity was found to be 82 mg Zn g PAS −1. High biosorption capacity and low saturation constant of pre-treated PWS used for zinc ion biosorption makes the adsorbent more attractive as compared to other alternatives.

Biosorption of copper(II) and zinc(II) from aqueous solution by Pseudomonas putida CZ1

To study Pseudomonas putida CZ1, having high tolerance to copper and zinc on the removal of toxic metals from aqueous solutions, the biosorption of Cu(II) and Zn(II) by living and nonliving P. putida CZ1 were studied as functions of reaction time, initial pH of the solution and metal concentration. It was found that the optimum pH for Zn(II) removal by living and nonliving cells was 5.0, while it was 5.0 and 4.5, respectively, for Cu(II) removal. At the optimal conditions, metal ion biosorption was increased as the initial metal concentration increased. The adsorption data with respect to both metals provide an excellent fit to the Langmuir isotherm. The binding capacity of living cells is significantly higher than that of nonliving cells at tested conditions. It demonstrated that about 40–50% of the metals were actively taken up by P. putida CZ1, with the remainder being passively bound to the bacterium. Moreover, desorption efficiency of Cu(II) and Zn(II) by living cells was 72.5 and 45.6% under 0.1 M HCl and it was 95.3 and 83.8% by nonliving cells, respectively. It may be due to Cu(II) and Zn(II) uptake by the living cells enhanced by intracellular accumulation.

Biosorption of zinc (II) by Rhizopus arrhizus: equilibrium and kinetic modelling

The adsorption of zinc (II) ions on Rhizopus arrhizus , a filamentous fungus, was investigated in a batch reactor. Batch adsorption studies were carried out by varying biomass loading. A contact time of 120 min was required to reach equilibrium. Specific zinc (II) uptake decreased with increase in biomass loading and these results were analyzed in light of the Lagergren equation and the process followed a second order rate kinetics. The equilibrium data were analyzed using the Langmuir, Freundlich, Redlich- Peterson and BET adsorption isotherms. The characteristic parameters for each isotherm were determined. All the isotherms provided the best correlation for zinc (II) onto the R. arrhizus . African Journal of Biotechnology Vol. 4 (6), pp. 506-508, 2005

Investigation of zinc biosorption by brewer's yeast cells

The highest amount of zinc (= 90%) is bound after 3 hrs of contact at low initial (total) concentrations of zinc in suspension of yeast, 10-100 mg/l at 10-30?C. The equilibrium between bound and free zinc ions is established after 6 hrs of contact time, independently on the total zinc concentration in yeast milk. No bigger changes of content of zinc bound to brewer's yeast cells was determined at temperatures 10?C and 30?C. 40% of bound zinc in the equilibrium state is bound during the first 15 min of contact of zinc ions and brewer's yeast cells at all initial (total) zinc concentrations in suspension of yeast both at 10?C and 30?C. The "KEKAM" equation can be used for the description of kinetics of zinc biosorption by waste brewer's yeast cells, for the ranges of zinc concentration 10-100 mg/l at 30?C (mean correlation coefficient 0,96) and 60,0-100 mg/l at 10?C (mean correlation coefficient 0,95).

Camparison for biosorption modeling of heavy metals (Cr (III), Cu (II), Zn (II)) adsorption from wastewater by carrot residues

The removal of chromium (III), copper (II) and zinc (II) from aqueous solution by adsorption on carrot residues (CR) was studied. Biosorption of chromium (III), copper (II) and zinc (II) on CR were compared. It was shown that CR has high metal removal efficiency. The Freundlich and Langmuir model can describe the adsorption equilibrium of chromium (III), copper (II) and zinc (II) on CR. The Freundlich and Langmuir constants for biosorption of chromium (III), copper (II) and zinc (II) on CR were determined. The effect of solution pH on biosorption was studied.

A theoretical model for biosorption of cadmium, zinc and copper by aerobic granules based on initial conditions

AbstractBatch tests have been most commonly employed to investigate the biosorption isotherms of heavy metals. There is evidence showing that the biosorption isotherm is influenced by initial metal and biosorbent concentrations, namely Co and Xo. However, a quantitative description of the effect of initial conditions on biosorption isotherms still remained elusive. According to the thermodynamics of the biosorption process, an initial condition‐dependent isotherm equation for biosorption of heavy metals was derived and verified by experimental data. This model demonstrated that the biosorption isotherms of heavy metals by aerobic granules were a function of the Co/Xo ratio. The biosorption constant involved in the proposed model had a clearly defined physical meaning; this constant was found to be equal to the inverse of the thermodynamic equilibrium constant of the biosorption process. Copyright © 2004 Society of Chemical Industry

Cadmium(II) and zinc(II) adsorption by the aquatic moss Fontinalis antipyretica: effect of temperature, pH and water hardness

The biosorption of cadmium(II) and zinc(II) ions onto dried Fontinalis antipyretica, a widely spread aquatic moss, was studied under different values of temperature, initial pH and water hardness. The equilibrium was well described by Langmuir adsorption isotherms. Maximum biosorption capacity of cadmium was independent on temperature and averaged 28.0 mg g −1 moss, whereas for zinc, capacity increased with temperature, from 11.5 mg g −1 moss at 5°C to 14.7 mg g −1 moss at 30°C. Optimum adsorption pH value was determined as 5.0 for both metal ions. Cadmium uptake was unaffected by the presence of calcium ions, but zinc sorption was improved when water hardness increased from 101.1 to 116.3 mg CaCO 3 l −1. Inversely, as hardness increases, the competition with calcium ions strongly reduces the affinity of the biosorbent for zinc.

Heavy-metal removal from aqueous solution by fungus Mucor rouxii

Biosorption of lead, cadmium, nickel and zinc by live and dead Mucor rouxii biomass treated with NaOH was studied over a range of pH. In the case of dead biomass, low pH resulted in a decrease in the biosorption capacity. At pH 3.0 or less, the inhibition of biosorption of metal ions took place. At pH 4.0 or higher, the biosorption of metal ions increased sharply. Ho's pseudo-second-order model described the biosorption kinetics better than the Lagergren model. Live biomass had high biosorption capacity, i.e. 35.69, 11.09, 8.46 and 7.75 mg/g at pH 5.0 for Pb 2+, Ni 2+, Cd 2+ and Zn 2+, respectively. The dead biomass adsorbed metal ions in the order of Pb 2+, Zn 2+, Cd 2+ and Ni 2+, with the biosorption capability of 25.22, 16.62, 8.36 and 6.34 mg/g at pH 5.0, respectively. At pH 6.0, the capacity of the dead biomass increased to 53.75, 53.85, 20.31 and 20.49 mg/g, respectively. For bi- or multi-metal ion adsorption, biosorption capacity of individual metal ion was reduced in the presence of other metal ions, but the total biosorption capacity increased, indicating the capability of M. rouxii biomass in adsorbing multi-metal ions. In addition, M. rouxii biomasses cultured with different media exhibited the same level of capacity to bind metal ions. Metal ions adsorbed by the biomass could be eluted effectively with HNO 3, while distilled water demonstrated negligible metal elution capability. Regeneration of the biomass with NaOH regained or enhanced the biosorption capacity even after five cycles of adsorption–elution–regeneration.

Biosorption of zinc from aqueous solutions using biosolids

The potential to remove zinc from aqueous solutions through biosorption using biosolids was investigated. Batch experimental results showed that the biosorptive capacity of dry, unground biosolids was 0.564 mM/(g dry biosolids). Pretreatment of the biosolids, including drying and grinding, affected the sorptive potential of the biomass. Kinetic experiments showed that dilute zinc solutions reached equilibrium within 5 h, whereas equilibrium was not reached until 24 h for more concentrated solutions. The biosorptive capacities were dependent on zinc solution pH, with pH 4 being optimal. Infrared spectra analysis suggested that carboxyl functional groups are responsible for zinc uptake.

Biosorption of cadmium, copper, lead and zinc by inactive biomass of Pseudomonas Putida.

The accumulation of Cd(II), Cu(II), Pb(II) and Zn(II) at mg L(-1) concentration levels by inactive freeze-dried biomass of Pseudomonas Putida has been investigated. These metals could be efficiently removed from diluted aqueous solutions. A contact time of 10 min was sufficient to reach equilibrium. The pH has a strong effect on metal biosorption and the optimal pH values were 6.0, 5.0-6.0, 6.0-6.5 and 7.0-7.5 for Cd(II), Cu(II), Pb(II) and Zn(II) respectively. Under these conditions there was 80% removal for all metals studied. The process of biosorption can be described by a Langmuir-type adsorption model. This model accounts for 98% of the data variance. The K(A) and q(max) parameters for each metal are strongly correlated (at confidence levels greater than 98%) with the metal acidity, quantified by the constant of the corresponding M(OH)(+) complex, thus confirming previous assertions by other authors.

Effect of the presence of lead on the biosorption of copper, cadmium and zinc by activated sludge

The effect of the presence of Pb on the biosorption efficiency of Cu, Cd and Zn by activated sludge was investigated. To evaluate the two-metal sorption system efficiency, simple isotherm curves had to be replaced by three-dimensional sorption isotherm surfaces. In order to describe the isotherm surfaces mathematically, three Langmuir-type models were evaluated. The isotherms indicated a competitive uptake of the different metals with Pb that was preferentially adsorbed.

Zinc biosorption from aqueous solution by a halotolerant cyanobacterium Aphanothece halophytica.

We have investigated the characteristics of zinc biosorption by Aphanothece halophytica. Zinc could be rapidly taken up from aqueous solution by the cells with an equilibrium being reached within 15 min of incubation with 100 mg L(-1) ZnCl(2). The adsorbed zinc was desorbed by treatment with 10 mM EDTA. The presence of glucose, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and N,N'-dicyclohexylcarbodiimide (DCCD) did not affect the uptake of zinc. The specific uptake of zinc increased at low cell concentration and decreased when cell concentration exceeded 0.2 g L(-1). The binding of zinc followed Langmuir isotherm kinetics with a maximum zinc binding capacity of 133 mg g(-1) and an apparent zinc binding constant of 28 mg L(-1). The presence of an equimolar concentration of Mn(2+), Mg(2+), Co(2+), K(+), or Na(+) had no effect on zinc biosorption, whereas Ca(2+), Hg(2+), and Pb(2+) showed an inhibitory effect. The biosorption of zinc was low at a pH range from 4 to 6, but increased progressively at pH 6.5 and 7.

Zinc Uptake by Fungal Biomass Isolated from Industrial Wastewater

In the present work, the biosorption potential of a fungal strain isolated from industrial wastewaters contaminated with zinc and other heavy metals has been investigated. Zinc biosorption studies using the fungi were conducted in an optimized media under sterile as well as nonsterile conditions using batch bioreactors. Initial pH of the media was found to be 5.6. The growth of the fungi and specific metal uptake rates were studied in the liquid media with different initial concentrations of zinc ranging from 0 to 10,000 mg/L. The growth of the fungi was not affected at lower concentrations (up to 100 mg/L) of zinc. However, a further increase in the concentration of zinc increased the lag phase duration and decreased the substrate utilization rate. The specific metal uptake by the fungi increased with an increase in initial concentrations of zinc. The effect of a sugar concentration (5–100 g/L) on the growth of the organism and the specific metal uptake by the organism were studied. These studies were carried out using an initial zinc concentration of 100 mg/L. A maximum zinc removal of 18.4 mg/g of dried biomass was observed at 20 g/L sugar concentration. Further increase in sugar concentration did not increase the specific metal uptake by the organism. The effect of pH on the growth of the organism and the specific metal uptake by the organism were also studied in the pH range 2.5–6.5. The optimum pH for the growth and the specific metal uptake was found to be in the pH range 4.5. The effect of inoculum concentration (5–20%v/v) on the growth and the metal uptake capacity of the organism was also studied. A maximum zinc removal of 77 mg/g of dried biomass was observed within 36 h at 500 mg/L of initial zinc concentration and at 20 %(v/v) inoculum concentration. The growth of the organism was also monitored in the presence of other metals such as Pb, Cu, Ni, and Cr, separately. The organism was capable of growing in each case at 100 mg/L initial concentration. Batch studies were also conducted to examine the biosorption potential of the organism adapted to minimal media. The organism was also found to be effective for the removal of zinc from an actual effluent generated by a color picture tube manufacturing industry.

Bioremoval of zinc ions by Scenedesmus obliquus and Scenedesmus quadricauda and its effect on growth and metabolism

Zinc biosorption by two green algae, Scenedesmus obliquus and Scenedesmus quadricauda, was investigated. Data show that, at concentrates between 0.5 and 8 ppm , zinc adsorption by algae increased with increasing metal ion concentration. The maximum specific adsorptive capacity of zinc ions obtained from the Langmuir adsorption isotherms was higher for S. obliquus (6.67) and lower for S. quadricauda (5.03). These S. obliquus appears to be more efficient than S. quadricauda for removing zinc ions. However, the affinity constant of zinc on the biomass of both algae were 0.19 and 0.27 indicating that S. obliquus is more tolerant to zinc phytotoxicity than S. quadricauda. Algal growth, pigment fractions, total amino acids, and the activities of some phosphatases enzyme (acid phosphatase, alkaline phosphatase, and ATPase) in the algal cells were measured in the exponential growth phase after exposure to various concentrations of zinc. Lower concentrations of zinc increased dry weight, chlorophyll a, b, carotenoids, and total amino acid contents in both algae. On the other hand, higher concentrations of zinc were inhibitory for growth and the other metabolic activities.

The release of light metals from a brown seaweed (Sargassum sp.) during zinc biosorption in a continuous system

The biosorption of zinc and calcium was investigated with a biomass of Sargassum sp., a brown seaweed, in a continuous system consisting of three serial tubular fixed-bed laboratory reactors. Results indicated that zinc was efficiently recovered by the biomass. After treatment of 9.0 liters of a mixed solution containing 130.0 mg/l zinc and 260.0 mg/l calcium, the first column of the system saturated with zinc; the remaining columns did not saturate with zinc as a result of the pre treatment performed by the first reactor. Calcium was also efficiently biosorbed by the biomass, saturating the system much faster than zinc. X-ray fluorescence spectrum indicated the presence of various elements in the structure of the Sargassum sp. biomass, especially alkaline and alkaline-earth elements. Alkaline and alkaline earth elements played a key role in the biosorption of zinc, being responsible for ion-exchange reactions performed during zinc biosorption.

The release of light metals from a brown seaweed (Sargassum sp.) during zinc biosorption in a continuous system

The release of light metals from a brown seaweed (Sargassum sp.) during zinc biosorption in a continuous system

Calcium interference with continuous biosorption of zinc by Sargassum sp. (Phaeophyceae) in tubular laboratory reactors

The zinc biosorptive capacity of the brown seaweed Sargassum sp. (Phaeophyceae) was studied in the presence or absence of competing calcium ions, using a continuous system with tubular fixed-bed reactors. In order to detect the effect of calcium on zinc biosorption, a 130 mg/l zinc solution was used, and calcium was added at 50–340 mg/l. The potential zinc biosorptive capacity of the biomass was markedly influenced by the presence of ionic calcium. Zinc sorption decreased with increasing calcium concentrations, as expressed by zinc uptake rates. Calcium was effectively recovered only during the initial stages of the process, as expressed by the decrease in its uptake rates. Calcium uptake rates were also much higher than zinc uptake rates, indicating that calcium was preferentially recovered when compared to zinc.

Continuous biosorption of Cu and Zn by immobilized waste biomass Sargassum sp.

Biosorption of copper and zinc by the residual biomass of the alga Sargassum sp. was investigated in a mini packed-bed column. The biomass was immobilized in a polymeric matrix to improve its physicochemical properties for continuous biosorption of heavy metals from aqueous solutions. Adsorption breakthrough curves obtained at different flow rates indicated that an increase in flow rate decreased the volume treated until the breakthrough point as well as the service time of the bed and the dynamic capacity of the column. At the lowest flow rate of 1.0 ml/min per cm 2 it was possible to treat 446 and 414 bed volumes of copper and zinc up to their respective breakthrough points. At this flow rate, the dynamic capacity of the column was 11.9 mg Cu/g and 21.0 mg Zn/g.

Investigation of kinetics of zinc biosorption by Saccharomyces cerevisiae cells.

The highest amount of zinc (approximately 90%) is bound after 3 h of contact at low initial (total) concentrations of zinc in yeast broth, 2.0-16.0 g/l at 10-30 degrees C. The equilibrium between bound and free zinc ions is established after 6 h of contact time, independently on total zinc concentration in yeast milk. No bigger changes of content of zinc bound to yeast cells was determined at 10 degrees C and 30 degrees C. 40% of bound zinc in the equilibrium state is bound during the first 15 min of contact of zinc ions and yeast cells at all initial (total) zinc concentrations in yeast milk both at 10 degrees C and 30 degrees C. The KEKAM (Kolmogorov-Erofeev-Kozeeva-Avrami-Mampel) equation can be used for the description of kinetics of zinc biosorption by yeast cells, for the ranges of zinc concentration of 2.0-16.0 g/l at 30 degrees C (mean correlation coefficient 0.96) and 10.0-16.0 g/l at 10 degrees C (mean correlation coefficient 0.95).

Studies on biosorption of zinc(II) and copper(II) on Desulfovibrio desulfuricans

The objectives of these studies are to determine the equilibrium concentration and kinetics of metal sorption on sulfate-reducing bacteria (SRB) isolates. Adsorption establishes the net reversible cellular metal uptake and is related to SRB metal toxicity and the effects of environmental factors. Results from biosorption equilibria and kinetics of copper(II) and zinc(II) ions on Desulfovibrio desulfuricans and the effects of adsorption of these metals on SRB are discussed. Adsorption studies were conducted using stationary phase cells with equilibrium uptake at 24 h and pHs in the range of 4–7. Equilibrium adsorption in milligram of metal/g dry cell for copper(II) of 2.03 (pH 4.0) and 16.7 (pH 5.0) and zinc(II) of 6.40 (pH 5.5), 13.8 (pH 6.0), 39.2 (pH 6.2) and 49.6 (pH 6.6) was measured experimentally. Negligible biosorption of copper and zinc was found below pH 4.0, with metal sorption increasing within a limited range of pH mainly due to the neutral and/or deprotonated state of binding ligands on cell walls. Competition of metal ions during biosorption was investigated by conducting sorption experiments with Zn(II) using potassium phosphate buffer (KP) and deionized/distilled water. Zn(II) sorption capacity was lower in KP buffer than deionized water due to competition from potassium ions. Scanning Electron Microscope micrographs indicated that metal biosorption on SRB may be related to the production of extracellular polymeric substance (e.g., polysaccharide).