Comparison of Rhizopus nigricans in a pelleted growth form with some other types of waste microbial biomass as biosorbents for metal ions

Biosorption of metal ions (Li⁺, Ag⁺, Pb²⁺, Cd²⁺, Ni²⁺, Zn²⁺, Cu²⁺, Sr²⁺, Fe²⁺, Fe³⁺ and Al³⁺) by Rhizopus nigricans biomass was studied. It was shown that metal uptake is a rapid and pH-dependent process, which ameliorates with increasing initial pH and metal concentrations. Different adsorption models: Langmuir, Freundlich, split-Langmuir and combined nonspecific-Langmuir adsorption isotherm were applied to correlate the equilibrium data. The maximum biosorption capacities for the individual metal ions were in the range from 160 to 460 mol/g dry weight. Scatchard transformation of equilibrium data revealed diverse natures of biomass metal-binding sites. The binding of metals was also discussed in terms of the hard and soft acids and bases principle. The maximum biosorption capacities and the binding constant of R. nigricans were positively correlated with the covalent index of metal ions.The following types of waste microbial biomass originating as by-products from industrial bioprocesses were tested for biosorption of metal ions: Aspergillus terreus, Saccharomyces cerevisiae, Phanerochaete chrysosporium, Micromonospora purpurea, M. inyoensis and Streptomyces clavuligerus. The determined maximum biosorption capacities were in the range from 100 to 500 mol/g dry weight. The biosorption equilibrium was also represented with Langmuir and Freundlich sorption isotherms.     

Biosorption of heavy metal ions by brown seaweeds from southern coast of Korea

Heavy metal ions (Pb²⁺, Cd²⁺, Mn²⁺, Cu²⁺, and Cr₂O₇ ^2?) were biosorbed by brown seaweeds (Hizikia fusiformis, Laminaria japonica, and Undaria pinnatifida) collected from the southern coast of South Korea. The biosorption of heavy metal ions was pH-dependent showing a minimum absorption at pH 2 and a maximum biosorption at pH 4 (Pb²⁺, Cd²⁺, Mn²⁺, and Cr₂O₇ ^2?) or pH 6 (Cu²⁺). Biosorption increased most noticeably for pH changes from 2 to 3. In the latter pH range, biosorption increased, because a higher pH decreased the electrostatic repulsion between metal ions and functional groups on the seaweed. In the pH range of 2 ～ 4, biosorption of negatively-charged chromium species (Cr₂O₇ ^?2) followed the pattern of positively-charged metal ions (Pb²⁺, Cd²⁺, Mn²⁺, and Cu²⁺). This suggests that the most prevalent chromium species were positively-charged Cr³⁺, reduced from Cr⁶⁺ in Cr₂O₇ ^?2. Whereas positively-charged heavy metal ions (Pb²⁺, Cd²⁺, Mn²⁺, and Cu²⁺) reached a plateau after the maximum level, biosorption of chromium ions decreased noticeably between pH 5 and 8. Kinetic data showed that biosorption by brown seaweed occurred rapidly during the first 10 min, and most of the heavy metals were bound to the seaweed within 30 min. Equilibrium adsorption data for a lead ion could fit well in the Langmuir and Freundlich isotherm models with regression coefficients (R ²) between 0.93 and 0.98.     

A unique metallothionein-engineered in <Emphasis Type="Italic">Escherichia coli</Emphasis> for biosorption of lead,zinc, and cadmium; absorption or adsorption?

The present study introduced and evaluated modification of E. coli BL21 (DE3) to improve its biosorption capacity by the transfer of the Corynebacterium glutamicum metallothionein gene (C.gMT). The C.gMT sequence was extracted and cloned in pET28a vector and the ligation product was transferred into E. coli BL21 (DE3). It has been also submitted to the GenBank database (accession number KJ638906.1). The performance of the recombinant bacterium was evaluated at different metal ions concentrations, contact times, pH values, and co-ions. The results show that recombinant BL21 (DE3) was able to uptake Pb⁺², and Zn⁺² at greater percentages than could BL21 (DE3). The optimum pH for the removal of each heavy metal was different. As contact time increased, Pb⁺² and Zn⁺² biosorption by the recombinant bacterium increased, while the biosorption of Cd⁺² remained at a nearly steady rate for contact times of more than 1 h. Increasing the concentrations of Pb⁺² and Zn⁺² in solution increased biosorption of these metals by the recombinant BL21 (DE3) over that of Cd⁺². It could be hypothesized that Pb⁺² and Zn⁺² removal by C.gMT-engineered BL21 (DE3) occurred mainly via intracellular biosorption (absorption) and that Cd⁺² was mainly taken up through cell surface biosorption (adsorption).     

Effects of different growth forms of Mucor indicus on cultivation on dilute-acid lignocellulosic hydrolyzate, inhibitor tolerance, and cell wall composition

The dimorphic fungus Mucor indicus was grown in different forms classified as purely filamentous, mostly filamentous, mostly yeast-like and purely yeast-like, and the relationship between morphology and metabolite production, inhibitor tolerance and the cell wall composition was investigated. Low concentrations of spores in the inoculum with subsequent aeration promoted filamentous growth, whereas higher spore concentrations and anaerobic conditions promoted yeast-like growth. Ethanol was the main metabolite with glycerol next under all conditions tested. The yields of ethanol from glucose were between 0.39 and 0.42 g g⁻¹ with productivities of 3.2–5.0 g l⁻¹ h⁻¹. The ethanol productivity of mostly filamentous cells was increased from 3.9 to 5.0 g l⁻¹ h⁻¹ by the presence of oxygen, whereas aeration of purely yeast-like cells showed no such effect. All growth forms were able to tolerate 4.6 g l⁻¹ furfural and 10 g l⁻¹ acetic acid and assimilate the sugars, although with different consumption rates. The cell wall content of the fungus measured as alkali insoluble materials (AIM) of the purely yeast-like cells was 26% of the biomass, compared to 8% of the pure filaments. However, the chitosan concentration of the filaments was 29% of the AIM, compared to 6% of the yeast-like cells.     

POTENTIAL USE OF LEAF BIOMASS,ARAUCARIA HETEROPHYLLA FOR REMOVAL OF Pb+2

The present investigation attempt to analyze the biosorption behavior of novel biosorbent, Araucaria heterophylla (green plant) biomass, for removal of Pb⁺² from solution as the function of initial metal ion concentration, pH, temperature, sorbent dosage and biomass particle size. The maximum biosorption was found to be 95.12% at pH 5 and biosorption capacity (q_e) of Cd⁺² is 9.643 mg/g. The Langmuir and Freundlich equilibrium adsorption isotherms were studied and observed that Freundlich model is best fit than the Langmuir model with correlation coefficient of 0.9927. Kinetic studies indicated that the biosorption process of Cd⁺² followed well pseudo second order model with R² 0.999. The process is exothermic and, spontaneous. The chemical functional groups –OH, CH₂ stretching vibrations, C?O of alcohol, C?O of amide, P?O stretching vibrations, –CH, were involved in the process. The XRD pattern of the A. heterophylla was found to be mostly amorphous in nature. The SEM studies showed Pb⁺² biosorption on selective grains of the biosorbent. It was concluded that A. heterophylla leaf powder can be used as an effective, low cost, and environmentally friendly biosorbent for the removal of Pb⁺² from aqueous solution.     

Biosorption of Pb<Superscript>2+</Superscript> and Zn<Superscript>2+</Superscript> by Non-Living Biomass of <Emphasis Type="Italic">Spirulina</Emphasis> sp.

Removal of heavy metals (Pb²⁺, Zn²⁺) from aqueous solution by dried biomass of Spirulina sp. was investigated. Spirulina rapidly adsorbed appreciable amount of lead and zinc from the aqueous solutions within 15 min of initial contact with the metal solution and exhibited high sequestration of lead and zinc at low equilibrium concentrations. The specific adsorption of both Pb²⁺ and Zn²⁺ increased at low concentration and decreased when biomass concentration exceeded 0.1 g l⁻¹. The binding of lead followed Freundlich model of kinetics where as zinc supported Langmuir isotherm for adsorption with their r ² values of 0.9659 and 0.8723 respectively. The adsorption was strongly pH dependent as the maximum lead biosorption occurred at pH 4 and 10 whereas Zn²⁺ adsorption was at pH 8 and 10.     

Biosorption of copper(II) from aqueous solutions by green alga <Emphasis Type="Italic">Cladophora fascicularis</Emphasis>

Biosorption is an effective means of removal of heavy metals from wastewater. In this work the biosorption behavior of Cladophora fascicularis was investigated as a function of pH, amount of biosorbent, initial Cu²⁺ concentration, temperature, and co-existing ions. Adsorption equilibria were well described by Langmuir isotherm models. The enthalpy change for the biosorption process was found to be 6.86 kJ mol⁻¹ by use of the Langmuir constant b. The biosorption process was found to be rapid in the first 30 min. The presence of co-existing cations such as Na⁺, K⁺, Mg²⁺, and Ca²⁺ and anions such as chloride, nitrate, sulfate, and acetate did not significantly affect uptake of Cu²⁺ whereas EDTA substantially affected adsorption of the metal. When experiments were performed with different desorbents the results indicated that EDTA was an efficient desorbent for the recovery of Cu²⁺ from biomass. IR spectral analysis suggested amido or hydroxy, C=O, and C–O could combine strongly with Cu²⁺.     

Zn2+ biosorption by Oscillatoria anguistissima

Oscillatoria anguistissima showed a very high capacity for Zn²⁺ biosorption (641 mg g⁻¹ dry biomass at a residual concentration of 129·2 ppm) from solution and was comparable to the commmercial ion-exchange resin IRA-400C. Zn²⁺ biosorption was rapid, pH dependent and temperature independent phenomenon. Zn²⁺ adsorption followed both Langmuir and Freundlich models. The specific uptake (mg g⁻¹ dry biomass) of metal decreased with increase in biomass concentration. Pretreatment of biomass did not significantly affect the biosorption capacity of O. anguistissima. The biosorption of zinc by O. anguistissima was an ion-exchange phenomenon as a large concentration of magnesium ions were released during zinc adsorption. The zinc bound to the biomass could be effectively stripped using EDTA (10 mM) and the biomass was effectively used for multiple sorption–desorption cycles with in-between charging of the biomass with tap water washings. The native biomass could also efficiently remove zinc from effluents obtained from Indian mining industries.     

The application of a micro-algal/bacterial biofilter for the detoxification of copper and cadmium metal wastes

In the present study the potential of a biofilter containing a mixture of dried micro-algal/bacterial biomass for removing heavy metals (Cu²⁺, Cd²⁺) from dilute electroplating waste was tested. The biomass was produced in an artificial stream using the effluent of a municipal waste water treatment plant as a nutrient source, with the additional benefit of reducing phosphorus and nitrogen loadings. Baseline batch experiments determined that optimum adsorption for both metals (80–100%) were achieved with the deionized-H₂O conditioned biomass at initial pH 4.0. Other biosorption variables (contact time, initial metal concentration) were also tested. Biosorption data were fitted successfully by the Langmuir model and results showed a high affinity of the used biomass for both metals (q_max 18–31 mg metal/g.d.w). Flow-through column experiments containing Ca-alginate/biomass beads showed that metal adsorption depends also on flow-rate and volume of treated waste. Desorption of both metals with weak acids was very successful (95–100%) but the regeneration of the columns was not achieved due to the destabilization of beads.     

Biosorption of Copper(II) by Live and Dried Biomass of the White Rot Fungi Phanerochaete chrysosporium and Funalia trogii

Biosorption is an innovative and alternative technology to remove heavy metal pollutants from aqueous solution using live, inactive and dead biomasses such as algae, bacteria and fungi. In this study, live and dried biomass of Phanerochaete chrysosporium and Funalia trogii was applied as heavy metal adsorbent material. Biosorption of copper(II) cations in aqueous solution by live and dried biomass of Phanerochaete chrysosporium and Funalia trogii was investigated to study the effects of initial heavy metal concentration, pH, temperature, contact time, agitation rate and amount of fungus. Copper(II) was taken up quickly by fungal biomass (live or dried) during the first 15 min and the most important factor which affected the copper adsorption by live and dried biomass was the pH value. An initial pH of around 5.0 allowed for an optimum adsorption performance. Live biomass of two white rot fungi showed a high copper adsorption capacity compared with dried biomass. Copper(II) uptake was found to be independent of temperature in the range of 20–45 °C. The initial metal ion concentration (10–300 mg/L) significantly influenced the biosorption capacity of these fungi. The results indicate that a biosorption as high as 40–60 % by live and dried biomass can be obtained under optimum conditions.     

Biosorption of Chromium,Cadmium, and Cobalt from Aqueous Solution by Immobilized Living Cells of Chryseomonas luteola TEM 05

Abstract

In this work, the potential use of the immobilized cells of Chryseomonas luteola TEM 05 for the removal of Cr⁺⁶, Cd⁺² and Co⁺² ions from aqueous solutions was investigated. The living cells of C. luteola TEM 05 were firstly entrapped both in carrageenan and chitosan coated carrageenan gels and then used in biosoption of the metal ions in batch reactors at pH 6.0, 25°C, in 100 mg L^?1 of each metal solution. Besides this, a process of competitive biosorption of these metal ions was also described and compared to single metal ion adsorption in solution. According to the immobilization results, the replacement of KCl by KCl-chitosan as gelling agent improved the mechanical strength and thermal stability of the gel. In addition, the C. luteola TEM 05 immobilized carrageenan-chitosan gel system was quite more efficient for the fast adsorption of metal ions from aqueous solution than the carrageenan gels without biomass.     

Toxic metal biosorption by macrocolonies of cyanobacterium <Emphasis Type="Italic">Nostoc sphaeroides</Emphasis> Kützing

The cyanobacterium Nostoc sphaeroides Kützing is expected to be effective in toxic metal adsorption as it produces abundant exopolysaccharides with functional groups. Therefore, the adsorption properties of Cu²⁺, Cd²⁺, Cr³⁺, Pb²⁺, Ni²⁺, and Mn²⁺ on fresh macrocolonies and algal powder of N. sphaeroides were compared at pH 5 and 25 °C. The adsorption capacity of fresh biomass for Pb²⁺ and of algal powder for Pb²⁺ and Cr³⁺ were highest in single metal solutions. Compared to the fresh biomass, the metal adsorption capacities of algal powder were similar for Ni²⁺, Cd²⁺, and Pb²⁺ and slightly greater for Cr³⁺, but they were markedly smaller for Mn²⁺ and Cu²⁺. Coexisting ions (in tap water or in multiple solutions) significantly decreased the metal adsorption capacity, except for Cr³⁺ in tap water. The Pb²⁺ and Cr³⁺ adsorption dynamic process fitted the pseudo-second-order model well, showing fast adsorption at the first stage in 10 and 20 min, respectively. Higher pH in acidic ranges favored the adsorption greatly. The Langmuir isotherm model was suitable for explaining the adsorption, and the maximum adsorption capacities were 116.28 and 22.37 mg g^?1 for Pb²⁺ and Cr³⁺, respectively. The adsorption process was endothermic, confirmed by the significantly higher adsorption capability at higher temperature. Hydroxyl, amino, and carboxyl groups were the main functional groups based on Fourier transform infrared spectroscopy analysis, and they bind to metal ions via ion exchange. The results suggest that fresh macrocolonies of N. sphaeroides can be used as an effective biosorbent for metal ion removal, especially for Pb²⁺ and Cr³⁺.     

The biosorption of heavy metals from aqueous solution by Spirogyra and Cladophora filamentous macroalgae

The aim of this research was to develop a low cost adsorbent for wastewater treatment. The prime objective of this study was to search for suitable freshwater filamentous algae that have a high heavy metal ion removal capability. This study evaluated the biosorption capacity from aqueous solutions of the green algae species, Spirogyra and Cladophora, for lead (Pb(II)) and copper (Cu(II)). In comparing the analysis of the Langmuir and Freundlich isotherm models, the adsorption of Pb(II) and Cu(II) by these two types of biosorbents showed a better fit with the Langmuir isotherm model. In the adsorption of heavy metal ions by these two types of biosorbents, chemical and physical adsorption of particle surfaces was perhaps more significant than diffusion and adsorption between particles. Continuous adsorption-desorption experiments discovered that both types of biomass were excellent biosorbents with potential for further development.     

Using pretreated chestnut endothelium to adsorb lead and cadmium ions from water

The nature chestnut endothelium, as waster source from chestnut (Castaneamollissima) has pigment effecting the process of adsorbing heavy metalions, and the decolorized endothelium has low adsorption capacity. In order to raise the adsorption capacity of heavy metal ions, the discolor endothelium was pretreated by acidic formaldehyde, cis-butenedioic acid and irradiation. Thermodynamic and kinetics model was fitted to the adsorption of Pb (II) and Cd(II) ions onto modified chestnut endothelium by cis-butenedioic acid. Three independent variables including pH, adsorption time and contact temperature were selected as affecting factors to Response Surface. The modified experiment results showed adsorption rate of Pb(II) and Cd(II) ions on the chestnut endothelium modified by 0.5?mol/L cis-butenedioic acid was higher than other modified methods. Thermodynamic and kinetics model was fitted with Langmuir and Pseudo-second-order kinetic model, respectively. 59.23?°C of the adsorption temperature, the 5.72?h of adsorption time and the 6.16 of pH are the optimized conditions of the adsorption rate of Pb²⁺ on modified chestnut endothelium. 55.93?°C of the adsorption temperature, the 4.43?h of adsorption time and the 6.06 of pH are the optimized adsorption conditions of Cd²⁺. Under the optimized condition, the experiment value of the adsorption of Pb²⁺ and Cd²⁺ was 99.76% and 98.90%, respectively, which are close to the predicted value. The FTIR indicated that CO, OH and CH involved in the adsorption process of Pb²⁺ and Cd²⁺.     

Equilibrium and kinetic studies on biosorption potential of charophyte biomass to remove heavy metals from synthetic metal solution and municipal wastewater

The risk of heavy metal contamination in domestic water causes serious health and environmental problems. Biosorption has been considered as an efficient and alternative way for treatment of heavy metal–contaminated wastewater. The potentials of dried charophytes, Chara aculeolata and Nitella opaca, to biosorb lead (Pb), cadmium (Cd), and zinc (Zn) from synthetic solutions and municipal wastewater were investigated. The efficiency of metal removal was studied under varied conditions in different sorbent dosages, pH, and contact times. Biosorption isotherm and kinetics were used to clarify heavy metal preference and biosorption mechanism. C. aculeolata and N. opaca performed well in the biosorption of all three metal ions, with preference towards Pb, followed by Cd and Zn, in the single-metal solutions. Pb adsorption onto algal biomass followed first-order rate kinetics (N. opaca) and intraparticle diffusion (C. aculeolata and N. opaca). These results indicated physical adsorption process between Pb ions and both algal biomasses. Cd and Zn biosorption kinetics fitted the second-order rate model, indicating chemical adsorption between metal ions and both algae. The experimental data of three-metal biosorption fitted well to Langmuir isotherm model, suggesting that the metal ion adsorption occurred in a monolayer pattern on a homogeneous surface. C. aculeolata exhibited slightly higher maximum uptake of Pb, Cd, and Zn (105.3 mgPb/g, 23.0 mgCd/g, 15.2 mgZn/g) than did N. opaca (104.2 mgPb/g, 20.5 mgCd/g, 13.4 mgZn/g). In multi-metal solutions, antagonistic effect by metal competition was observed. The ability of charophytes to remove Pb and Zn was high in real municipal water (81–100%). Thus, the charophytic biomass may be considered for the treatment of metal contamination in municipal wastewater.     

Arthrospira (Spirulina) platensis: An effective biosorbent for nutrients

Arthrospira (Spirulina) platensis was tested for biosorption properties. Preliminary experiments concerning biosorption kinetics were performed on Cr(III) ions. Equilibrium of biosorption was tested for Cr(III), Mn(II) and Mg(II) ions, since these elements are crucial for animals with metabolic disorders. In our study, Spirulina was proposed as a feed additive for animals suffering from diseases characterized by insulin dysregulation, abnormal adipose distribution and a high risk for laminitis. Maximum biosorption capacity of A. platensis, determined from Langmuir equation, was 45.2 for Cr(III), 44.3 for Mn(II) and 42.0 mg/g for Mg(II) ions. Biosorption of Mg(II) ions by microalga has never been studied so far. Finally, the raw and enriched microalgal biomass was examined by ICP-OES to determine its multielamental analysis before and after biosorption, FTIR to indicate functional groups that participated in biosorption and SEM-EDX to illustrate the binding of metal ions on the surface of algal biomass. ICP-OES showed that the content of elements significantly increased in the enriched A. platensis. FTIR spectroscopy evidenced that biosorption of metal ions was mainly due to carboxylate groups present on the microalgal cell wall. SEM analysis clearly showed that biosorption occurred. Arthrospira platensis turned out to be a good biosorbent of metal ions.     

Removal of Chromium(VI) Ions from Synthetic Solutions by the Fungus Penicillium purpurogenum

The ability of Penicillium purpurogenum to bind high amounts of chromium(VI) from aqueous solutions is demonstrated. Cr(VI) adsorption capacity increases with time during the first four hours and then leveled off toward the equilibrium adsorption capacity. Biosorption of Cr(VI) ions reached equilibrium in four hours. Binding of Cr(VI) ions with Penicillium purpurogenum biomass was clearly pH dependent. Cr(VI) loading capacity increased with increasing pH. The adsorption of Cr(VI) ions reached a plateau value at a pH of approx. 6.0. The maximum capacity of adsorption of Cr(VI) ions onto the fungal biomass was 36.5 mg/g. Adsorption behavior of Cr(VI) ions can be approximately described with the Langmuir equation. When applying the Langmuir model, the maximum adsorption capacity (Q_max) and the Langmuir constant were found to be 40 mg/g and 3.9 × 10^–3 mg/L. Elution of Cr(VI) ions was performed by means of 0.5 M HCl. It was possible to use the biomass of Penicillium purpurogenum for six cycles for biosorption.     

pH effects on the removal of Cu2+, Cd2+ and Pb2+ from aqueous solution by waste brewery biomass

An industrial strain of Saccharomyces cerevisiae collected from the waste of a brewing industry was used to remove lead, cadmium and copper from aqueous solutions (1?mm). Metal removal efficiency by using either biomass suspension directly diluted into the metal solutions or biomass previously incubated and washed in distilled water was compared. In all experiments with unwashed biomass a shift in the medium pH from 4.5 to a final value in the 7.0–8.0 range occurred. This pH increase was responsible for a metal precipitation effect associated to the metal biosorption. A very different pH profile was observed when washed biomass was used leading to different removal profiles for Cd²⁺ and Pb²⁺ and a similar one for Cu²⁺. In the absence of biomass, medium components and/or the excreted intracellular products proved to interfere in the metal removal and to be responsible for 80% Pb²⁺ precipitation, in the pH 4.5–5.0 range. To initial metal solution pH, leading to the lowest residual ion concentrations, after 96?h of contact with unwashed biomass and in the absence of pH adjustment, was 4.5–5.0. Continuous or stepwise adjustment of medium pH to this range during the process was unfavourable for metal removal, being the continuous adjustment the worst procedure. In this case, Cd²⁺ was not biosorbed and Cu²⁺ removal decreased from 76 to 33%. However, Pb²⁺ was always extensively removed (89%) and only slightly affected by pH control. The global results suggest different removal mechanisms for each cation. Cu²⁺ was removed by both metal sorption and precipitation, due to the pH shift that occurred during the process, while Cd²⁺ removal showed to be completely dependent of this pH shift. Pb²⁺ was totally and quickly removed, by precipitation, in the presence of the biomass suspension and at pH 4.5. Moreover, the biosorbent changes occurring during the process played an important role in the metal removal when non-viable microbial biomass is used.     

Copper biosorption in an aerobic bioreactor

Abstract

This study evaluates the biosorption of copper by aerobic biomass that was selected from surface waters of the San Pedro River in Sonora, Mexico. Using a batch system, 73% biosorption of copper was obtained in 75 minutes. Continuous biosorption assays were carried out for 133 days in an ascending flow aerobic reactor packed with zeolite (AFAR-PZ) that was inoculated with a bacterial consortium. Strains were grown until 1g L^?1 of biomass was obtained. Tests using continuous biosorption were performed as follows: (i) the addition of 50 mg Cu²⁺ L^?1 without recirculation of biomass; (ii) the addition of 20 mg Cu²⁺ L^?1without recirculation of biomass; and (iii) the biomass were recirculated with the addition of 20 mg Cu²⁺ L^?1 to pH 3 to 4. The fourth and fifth assays varied pH between 4 and 5, with 20 mg Cu²⁺ L^?1and the biomass recirculated. Biosorption capacity of the first and second assays was 96% on the first day of experimentation. During the third trial 97% of biosorption was obtained during 6 days and the process was improved by varying the pH. Copper biosorption equilibrium was investigated under the same operating conditions. Langmuir adsorption isotherms were used to fit experimental data. The biosorption capacity of aerobic biomass was 3.08 mmol g^?1. It was demonstrated that this biomass is capable of biosorbing copper and this method has potential for the treatment of industrial effluents contaminated with heavy metals.     

Biosorption of Cr (VI) with Trichoderma viride immobilized fungal biomass and cell free Ca-alginate beads

Ability of Cr (VI) biosorption with immobilized Trichoderma viride biomass and cell free Ca-alginate beads was studied in the present study. Biosorption efficiency in the powdered fungal biomass entrapped in polymeric matric of calcium alginate compared with cell free calcium alginate beads. Effect of pH, initial metal ion concentration, time and biomass dose on the Cr (VI) removal by immobilized and cell free Ca-alginate beads were also determined. Biosorption of Cr (VI) was pH dependent and the maximum adsorption was observed at pH 2.0. The adsorption equilibrium was reached in 90 min. The maximum adsorption capacity of 16.075 mgg(-1) was observed at dose 0.2 mg in 100 ml of Cr (VI) solution. The high value of kinetics rate constant Kad (3.73 x 10(-2)) with immobilized fungal biomass and (3.75 x 10(-2)) with cell free Ca- alginate beads showed that the sorption of Cr (VI) ions on immobilized biomass and cell free Ca-alginate beads followed pseudo first order kinetics. The experimental results were fitted satisfactory to the Langmuir and Freundlich isotherm models. The hydroxyl (-OH) and amino (-NH) functional groups were responsible in biosorption of Cr (VI) with fungal biomass spp. Trichoderma viride analysed using Fourier Transform Infrared (FTIR) Spectrometer.