Enhancement of Lead(II) Biosorption by Microalgal Biomass Immobilized onto Loofa (Luffa cylindrica) Sponge

A unicellular green microalga, Chlorella sorokiniana, was immobilized on loofa (Luffa cylindrica) sponge and successfully used as a new biosorption system for the removal of lead(II) ions from aqueous solutions. The biosorption of lead(II) ions on both free and immobilized biomass of C. sorokiniana was investigated using aqueous solutions in the concentration range of 10–300 mg/L. The biosorption of lead(II) ions by C. sorokiniana biomass increased as the initial concentration of lead(II) ions increased in the medium. The maximum biosorption capacity for free and immobilized biomass of C. sorokiniana was found to be 108.04 and 123.67 mg lead(II)/g biomass, respectively. The biosorption kinetics were found to be fast, with 96 % of adsorption within the first 5 min and equilibrium reached at 15 min. The adsorption of lead(II) both by free and immobilized C. sorokiniana biomass followed the Langmuir isotherm. The biosorption capacities were detected to be dependent on the pH of the solution; and the maximum adsorption was obtained at a solution pH of about 5. The effect of light metal ions on lead(II) uptake was also studied and it was shown that the presence of light metal ions did not significantly affect lead(II) uptake. The loofa sponge‐immobilized C. sorokiniana biomass could be regenerated using 0.1 M HCl, with up to 99 % recovery. The desorbed biomass was used in five biosorption‐desorption cycles, and no noticeable loss in the biosorption capacity was observed. In addition, fixed bed breakthrough curves for lead(II) removal were presented. These studies demonstrated that loofa sponge‐immobilized biomass of C. sorokiniana could be used as an efficient biosorbent for the treatment of lead(II) containing wastewater.     

Spontaneous Cr(VI) and Cd(II) biosorption potential of native pinnae tissue of Pteris vittata L., a tropical invasive pteridophyte

Heavy metal pollution is a prevalent and critical environmental concern. Its rampancy is attributed to indiscriminate anthropogenic activities. Several technologies including biosorption have been continuously researched upon to overcome the limitations of the conventional method of treatments in removal of heavy metals. Biosorption technology involves the application of a biomass in its nonliving form. Pteris vittata L., a pteridophyte, considered as an invasive weed was investigated in the present study as a potential decontaminant of toxic metals, Cr(VI) and Cd(II). The adsorption capacity of the biosorbent for Cr(VI) and Cd(II) under equilibrium conditions was investigated. The morphology, elemental composition, functional groups, and thermal stability of the biosorbent before and after metal loading were evaluated. At 303?K and an equilibrium time of 120?min, the maximum loading of Cr(VI) on the biosorbent was estimated to be 166.7?mg/g at pH 2 and Cd(II) to be 31.3?mg/g at pH 6. Isotherm models, kinetic studies, and thermodynamic studies indicated the mechanisms, chemisorption, ion exchange and intraparticle diffusion, controlling the Cr(VI) and Cd(II) uptake, respectively. The interactive effect of multi-metal ions in binary component systems was synergistic for Cd(II) uptake. The results validate the toxic metal removal potency of the biosorbent.     

Immobilization of blue green microalgae on loofa sponge to biosorb cadmium in repeated shake flask batch and continuous flow fixed bed column reactor system

Summary An indigenous strain of blue green microalga, Synechococcus sp., isolated from wastewater, was immobilized onto loofa sponge discs and investigated as a potential biosorbent for the removal of cadmium from aqueous solutions. Immobilization has enhanced the sorption of cadmium and an increase of biosorption (21%) at equilibrium was noted as compared to free biomass. The kinetics of cadmium biosorption was extremely rapid, with (96%) of adsorption within the first 5 min and equilibrium reached at 15 min. Increasing initial pH or initial cadmium concentration resulted in an increase in cadmium uptake. The maximum biosorption capacity of free and loofa immobilized biomass of Synechococcus sp. was found to be 47.73 and 57.76 mg g⁻¹ biomass respectively. The biosorption equilibrium was well described by Langmuir adsorption isotherm model. The biosorbed cadmium was desorbed by washing the immobilized biomass with dilute HCl (0.1 M) and desorbed biomass was reused in five biosorption–desorption cycles without an apparent decrease in its metal biosorption capacity. The metal removing capacity of loofa immobilized biomass was also tested in a continuous flow fixed-bed column bioreactor and was found to be highly effective in removing cadmium from aqueous solution. The results suggested that the loofa sponge-immobilized biomass of Synechococcus sp. could be used as a biosorbent for an efficient removal of heavy metal ions from aqueous solution.     

Production of lactic acid with loofa sponge immobilized Rhizopus oryzae RBU2-10

Lactic acid production by Rhizopus oryzae RBU2-10 immobilized in loofa sponge was evaluated. Shape and texture of loofa sponge, which was obtained from the mature dried fruit of Luffa cylindrica, remained intact after its treatment with buffers of varying pH and following its repeated autoclaving for up to four cycles (121 degrees C, 20 min per cycle). The medium having four pieces of loofa sponge (1.008 cm(3)) per 100 ml medium and inoculated with 3 x1 0(6) spores ml(-1) resulted maximum production (80.75 g l(-1)) of lactic acid in 48 h of fermentation. Repeated batch fermentation for lactic acid production could be carried out for 10 cycles. Remarkably higher levels of productivity (1.66-1.84 g l(-1)h(-1)) was obtained during first five cycles of fermentation with a maximum productivity (1.84 g l(-1)h(-1)) obtained during third cycle of fermentation.     

L-Lactic acid production from raw cassava starch in a circulating loop bioreactor with cells immobilized in loofa (Luffa cylindrica)

l-Lactic acid was produced from raw cassava starch, by simultaneous enzyme production, starch saccharification and fermentation in a circulating loop bioreactor with Aspergillus awamori and Lactococcus lactis spp. lactis immobilized in loofa sponge. A. awamori was immobilized directly in cylindrical loofa sponge while the L. lactis was immobilized in a loofa sponge alginate gel cube. In the loofa sponge alginate gel cube, the sponge serves as skeletal support for the gel with the cells. The alginate gel formed a hard outer layer covering the soft porous gel inside. By controlling the rate and frequency of broth circulation between the riser and downcomer columns, the riser could be maintained under aerobic condition while the downcomer was under anaerobic condition. Repeated fed-batch l-lactic acid production was performed for more than 400 h and the average lactic acid yield and productivity from raw cassava starch were 0.76 g lactic acid g^–1 starch and 1.6 g lactic acid l^–1 h^–1, respectively.     

Cadmium removal in a biosorption column

New biosorbent material derived from a ubiquitous brown marine alga Ascophyllum nodosum has been examined in packed-bed flow-through sorption columns. It effectively removed 10 mg/L of cadmium down to 1.5 ppb levels in the effluent, representing 99.985% removal. The experimental methodology used was based on the early Bohart and Adams sorption model, resulting in quantitative determination of the characteristic process parameters which can be used for performance comparison and process design. An average metal loading of the biosorbent (N(0)) determined was 30 mg Cd/g, corresponding closely to that observed for the batch equilibrium metal concentration of 10 mg Cd/L. The critical bed depth (D(min)) for the potable water effluent quality standard (0.005 mgg Cd/L) varied with the column feed flow rate (2.4 to 9.6 L/h . cm(2)) from 20 to 50 cm. The sorption column mass transfer and dispersion coefficients were determined, which are also required for solving the sorption model equations. (c) 1994 John Wiley & Sons, Inc.     

Microalgal-luffa sponge immobilized disc: a new efficient biosorbent for the removal of Ni(II) from aqueous solution

AIMS: The aim was to develop a new, efficient and cost-effective biosorbent for the removal of heavy metals from aqueous solution. METHODS AND RESULTS: A new biosorbent was developed by immobilizing a unicellular green microalga Chlorella sorokiniana within luffa sponge discs and used for the removal of metal ions from aqueous solution. Microalgal-luffa sponge immobilized discs (MLIDs) removed Ni(II) very rapidly, with 97% of equilibrium loading being reached in 5 min. MLIDs were tested for their potential to remove Ni(II) from aqueous solution in fixed-bed column bioreactor. The regenerated MLIDs retained 92.9% of the initial binding capacity for Ni(II) up to five cycles of reuse. CONCLUSIONS: In this study for the first time, C. sorokiniana biomass immobilized within luffa sponge disc was successfully used as a metal biosorbent for the removal of Ni(II). It appears that MLIDs can be used as an effective biosorbent for efficient removal of Ni(II) or other metals from aqueous solution. SIGNIFICANCE AND IMPACT OF THE STUDY: MLIDs biosorption system was shown to have good biosorption properties with respect to Ni(II). Efficient metal removal ability of MLIDs, low cost and simplicity of the technique used for the preparation of MILDs could provide an attractive strategy for developing high-affinity biosorption system for heavy metal removal.     

Production of Fungal Biomass Immobilized Loofa Sponge (FBILS)-discs for the Removal of Heavy Metal Ions and Chlorinated Compounds from Aqueous Solution

A white rot basidiomycete, Phanerochaete chrysosporium, was immobilized on loofa sponge (FBILS) discs. It removed ca. 37 and 71 mg Cd (II) g⁻¹ from 50 and 200 mg l⁻¹ aqueous solutions and up to 89% of 4-chloroanisole from a 10 mg l⁻¹ aqueous solution. FBILS are physically strong and chemically recalcitrant, resisting temperature, mechanical agitation, and variations in pH without alteration to shape, structure or texture.     

Loofa sponge as a scaffold for the culture of human hepatocyte cell line

Loofa sponge was investigated as a three-dimensional scaffold for stationary and perfusion culture of human hepatoblastoma cell line C3A/HepG2. In stationary culture, C3A/HepG2 cells in loofa cubes showed higher alpha-fetoprotein and albumin secretion rates than those in polyurethane foam (PU). To use loofa cylinders in a packed-bed reactor, immobilization of C3A/HepG2 cells by recirculating medium at 26 mL/min (superficial velocity = 51.7 cm/min) resulted in a cell loading density of 5.15 x 10(7) cells/cm(3)-loofa. This cell loading density is higher than values reported in the literature for packed-bed reactor intended for bioartificial liver. During 9 days of perfusion culture in the reactor, immobilized C3A/HepG2 showed steady synthesis of albumin with an average synthesis rate at 42.2 microg/10(6) cells/day. These experimental results and observations by SEM suggested that loofa sponge is a suitable scaffold for high-density culture of human hepatocyte cell line and the immobilized cells could express high levels of liver-specific functions.     

Comparison of the Heavy Metal Biosorption Capacity of Active,Heat‐Inactivated and NaOH‐Treated Phanerochaete chrysosporium Biosorbents

Three different kinds of Phanerochaete chrysosporium (NaOH‐treated, heat‐inactivated and active) biosorbent were used for the removal of Cd(II) and Hg(II) ions from aquatic systems. The biosorption of Cd(II) and Hg(II) ions on three different forms of Phanerochaete chrysosporium was studied in aqueous solutions in the concentration range of 50–700 mg/L. Maximum biosorption capacities of NaOH‐treated, heat‐inactivated and active Phanerochaete chrysosporium biomass were found to be 148.37 mg/g, 78.68 mg/g and 68.56 mg/g for Cd(II) as well as 224.67 mg/g, 122.37 mg/g and 88.26 mg/g for Hg(II), respectively. For Cd(II) and Hg(II) ions, the order of affinity of the biosorbents was arranged as NaOH‐treated > heat‐inactivated > active. The order of the amount of metal ions adsorbed was established as Hg(II) > Cd(II) on a weight basis, and as Cd(II) > Hg(II) on a molar basis. Biosorption equilibriums were established in about 60 min. The effect of the pH was also investigated, and maximum rates of biosorption of metal ions on the three different forms of Phanerochaete chrysosporium were observed at pH 6.0. The reusability experiments and synthetic wastewater studies were carried out with the most effective form, i.e., the NaOH‐treated Phanerochaete chrysosporium biomass. It was observed that the biosorbent could be regenerated using 10 mM HCl solution, with a recovery of up to 98%, and it could be reused in five biosorption‐desorption cycles without any considerable loss in biosorption capacity. The alkali‐treated Phanerochaete chrysosporium removed 73% of Cd(II) and 81% of Hg(II) ions from synthetic wastewater.     

Biosorption of copper(II) and cobalt(II) from aqueous solutions by crab shell particles

Biosorption of each of the heavy metals, copper(II) and cobalt(II) by crab shell was investigated in this study. The biosorption capacities of crab shell for copper and cobalt were studied at different particle sizes (0.456-1.117 mm), biosorbent dosages (1-10 g/l), initial metal concentrations (500-2000 mg/l) and solution pH values (3.5-6) in batch mode. At optimum particle size (0.767 mm), biosorbent dosage (5 g/l) and initial solution pH (pH 6); crab shell recorded maximum copper and cobalt uptakes of 243.9 and 322.6 mg/g, respectively, according to Langmuir model. The kinetic data obtained at different initial metal concentrations indicated that biosorption rate was fast and most of the process was completed within 2h, followed by slow attainment of equilibrium. Pseudo-second order model fitted the data well with very high correlation coefficients (>0.998). The presence of light and heavy metal ions influenced the copper and cobalt uptake potential of crab shell. Among several eluting agents, EDTA (pH 3.5, in HCl) performed well and also caused low biosorbent damage. The biosorbent was successfully regenerated and reused for five cycles.     

Uptake of cadmium ions in white-rot fungus Trametes versicolor: effect of cd (II) ions on the activity of laccase

The effects of cadmium Cd (II) ions on the physiology and biological activity of Trametes versicolor, a strain belonging to white-rotting Basidiomycetes, were examined. Cd (II) ions were added to 10-day-old cultures grown on a liquid medium, or at the time of inoculation. Our experiments showed that T. versicolor is a good cadmium biosorbent from aqueous solution, this strain removing almost all the Cd (ll) ions over the first 2h of incubation by what appears to be a rapid, energy-independent surface binding phenomenon, at the rate of approximately 2mg Cd per g mycelial dry weight. An additional slower and energy-dependent transport mechanism was also present, taking in approximately 0.3mg Cd (II) perg dry weight. It is also shown that these Cd (II) ions significantly stimulate the activity of extracellular laccase when added to 10-day-old cultures.     

Biosorptive removal of cadmium from contaminated groundwater and industrial effluents

The cadmium removing capacity of a biosorbent Calotropis procera, a perennial wild plant, is reported here. The biomass was found to possess high uptake capacity of Cd(II). Adsorption was pH dependent and the maximum removal was obtained at two different pH i.e. pH 5.0 and 8.0. Maximum biosorption capacity in batch and column mode was found to be 40 and 50.5 mg/g. The adsorption equilibrium (> or =90% removal) was attained within 5 min irrespective of the cadmium ion concentration. Interfering ions viz. Zn(II), As(III), Fe(II), Ni(II) interfered only when their concentration was higher than the equimolar ratio. The Freundlich isotherm best explained the adsorption, yet the monolayer adsorption was also noted at lower concentrations of Cd(II). The FTIR analysis indicates the involvement of hydroxyl (-OH), alkanes (-CH), nitrite (-NO(2)), and carboxyl group (-COO) chelates in metal binding. The complete desorption of the cadmium was achieved by 0.1M H(2)SO(4) and 0.1M HCl. The C. procera based Cd(II) removal technology appears feasible.     

Removal of cadmium(II) ion from aqueous system by dry biomass, immobilized live and heat-inactivated Oscillatoria sp. H1 isolated from freshwater (Mogan Lake)

Oscillatoria sp. H1 (Cyanobacteria, microalgae) isolated from Mogan Lake was used for the removal of cadmium ions from aqueous solutions as its dry biomass, alive and heat-inactivated immobilized form on Ca-alginate. Particularly, the effect of physicochemical parameters like pH, initial concentration and contact time were investigated. The sorption of Cd(II) ions on the sorbent used was examined for the cadmium concentrations within the range of 25-250 mg/L. The biosorption of Cd(II) increased as the initial concentration of Cd(II) ions increased in the medium up to 100 mg/L. Maximum biosorption capacities for plain alginate beads, dry biomass, immobilized live Oscillatoria sp. H1 and immobilized heat-inactivated Oscillatoria sp. H1 were 21.2, 30.1, 32.2 and 27.5 mg/g, respectively. Biosorption equilibrium was established in about 1 h for the biosorption processes. The biosorption was well described by Langmuir and Freundlich adsorption isotherms. Maximum adsorption was observed at pH 6.0. The alginate-algae beads could be regenerated using 50 mL of 0.1 mol/L HCl solution with about 85% recovery.     

Utilization of an exopolysaccharide produced by Chryseomonas luteola TEM05 in alginate beads for adsorption of cadmium and cobalt ions

Cadmium and cobalt adsorption from aqueous solution onto calcium alginate, sodium alginate with an extracellular polysaccharide (EPS) produced by the activated sludge bacterium Chryseomonas luteola TEM05 and immobilized C. luteola TEM05 was studied. In addition, solutions containing both of these ions were prepared and partial competitive adsorption of these mixtures was investigated. Metal adsorption onto gel beads was carried out at pH 6.0 and 25 degrees C. The maximum adsorption capacities determined by fitting Langmuir isotherms to the data for calcium alginate, calcium alginate+EPS, calcium alginate + C. luteola TEM05 and calcium alginate + EPS + C. luteola TEM05 were 45.87, 55.25, 49.26, 51.81 mg g(-1) for Co(II) and 52.91, 64.10, 62.5, 61.73 mg g(-1) for Cd(II), respectively. The biosorption capacity of the carrier for both metal ions together in competition was lower than those obtained when each was present alone.     

Biosorption characteristics of Aspergillus flavus biomass for removal of Pb(II) and Cu(II) ions from an aqueous solution

The Pb(II) and Cu(II) biosorption characteristics of Aspergillus flavus fungal biomass were examined as a function of initial pH, contact time and initial metal ion concentration. Heat inactivated (killed) biomass was used in the determination of optimum conditions before investigating the performance of pretreated biosorbent. The maximum biosorption values were found to be 13.46 +/- 0.99 mg/g for Pb(II) and 10.82 +/- 1.46 mg/g for Cu(II) at pH 5.0 +/- 0.1 with an equilibrium time of 2 h. Detergent, sodium hydroxide and dimethyl sulfoxide pretreatments enhanced the biosorption capacity of biomass in comparison with the heat inactivated biomass. The biosorption data obtained under the optimum conditions were well described by the Freundlich isotherm model. Competitive biosorption of Pb(II) and Cu(II) ions was also investigated to determine the selectivity of the biomass. The results indicated that A. flavus is a suitable biosorbent for the removal of Pb(II) and Cu(II) ions from aqueous solution.     

Biosorption of Cd, Zn and Cu by Sargassum sp. waste biomass

Biosorption is becoming an important component in the integrated approach to the treatment of aqueous effluents. The economics of biomass technical applications are improved by using waste biomass instead of purposely-produced biomass. Biomass derived from an alginate extraction industry - Sargassum sp. - was examined for its ability to function as a biosorbent for metals such as cadmium, zinc and copper. For use in column applications, biomass should be immobilized. To the algae reinforcement, the biomass was embedded in polyethleneimine (PEI), followed by glutaraldehyde crosslinking. Equilibrium Zn and Cu isotherms were analysed using the immobilization ratio that showed the best Cd performance. Either Freundlich or Langmuir models can describe the passive biosorption equilibrium of cadmium, zinc and cooper. The preference for this series of metals by the biomass was found to be Cd > Zn > Cu, with maximum uptake values of 157.8, 118.5 and 77.4 mg/g dry weight biomass for Cd, Zn and Cu. respectively. The metal binding capacity by non-living biomass is an important quality for industrial use.     

Biosorption of cadmium by biomass of marine algae

Biomass of nonliving, dried brown marine algae Sargassum natans, Fucus vesiculosus, and Ascophyllum nodosum demonstrated high equilibrium uptake of cadmium from aqueous solutions. The metal uptake of cadmium from aqueous solutions. The metal uptake by these materials was quantitatively evaluated using sorption isotherms. Biomass of A. nodosum accumulated the highest amount of cadmium exceeding 100 mg Cd(2+)/g (at the residual concentration of 100 mg Cd/L and pH 3.5), outperforming a commercial ion exchange resin DUOLITE GT-73. A new biosorbent material based on A. nodosum biomass was obtained by reinforcing the algal biomass by formaldehyde cross-linking. The prepared sorbent possessed good mechanical properties, chemical stability of the cell wall polysaccharides and low swelling volume. Desorption of deposited cadmium with 0.1-0.5M HCI resulted in no changes of the biosorbent metal uptake capacity through five subsequent adsorption/desorption cycles. There was no damage to the biosorbent which retained its macroscopic appearance and performance in repeated metal uptake/elution cycles. (c) 1993 Wiley & Sons, Inc.     

Experimental and theoretical approaches for Cd(II) biosorption from aqueous solution using Oryza sativa biomass

Biomass of Oryza sativa (OS) was tested for the removal of Cd(II) ions from synthetic and real wastewater samples. Batch experiments were conducted to investigate the effects of operating parameters on Cd(II) biosorption. Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy were used to examine the surface characteristics of the Cd(II)-loaded biomass. The maximum removal efficiency of Cd(II) was 89.4% at optimum pH 6.0, biosorbent dose 10.0 g L^?1, initial Cd(II) 50 mg L^?1, and biosorbent particle size 0.5 mm. The applicability of Langmuir and Freundlich isotherms to the sorbent system implied the existence of both monolayer and heterogeneous surface conditions. Kinetic studies revealed that the adsorption process of Cd(II) followed the pseudo-second-order model (r2: 0.99). On the theoretical side, an adaptive neuro-fuzzy inference system (ANFIS) was applied to select the operating parameter that mostly influences the Cd(II) biosorption process. Results from ANFIS indicated that pH was the most influential parameter affecting Cd(II) removal efficiency, indicating that the biomass of OS was strongly pH sensitive. Finally, the biomass was confirmed to adsorb Cd(II) from real wastewater samples with removal efficiency close to 100%. However, feasibility studies of such systems on a large-scale application remain to be investigated.