Biosorption of Cu by Thiobacillus ferrooxidans

Current technologies for removal and recovery of both toxic and industrial interest metals usually produce wastes with high concentrations of those substances. They are an important source of environmental pollution, specially when they contain heavy metals. This is one of the most important environmental problems, and of the most difficult to solve. So far, there have been a number of studies considering the possibility of removing and recovering heavy metals from diluted solutions. These are due, principally, because of the commercial value of some metals as well as the environmental impact caused by them. The traditional methods for removing have several disadvantages when metals are present in concentrations lower than 100?mg/l. Biosorption, which uses biological materials as adsorbents, has been considered as an alternative method. In this work, several variables that affect the capacity for copper biosorption by T. ferrooxidans have been studied. Particularly, the effect of pH, chemical pretreatment, biomass concentration and temperature have been considered. Results indicate that a capacity as high as 119?mg of Cu/g of dry biomass can be obtained at a temperature of 25?°C.     

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.     

Zinc removal from model solution and wastewater by Arthrospira (Spirulina) Platensis biomass

The biosorption of zinc from model solution as well as wastewater by Arthrospira (Spirulina) platensis biomass was studied. Adsorption capacity of the biosorbent was investigated as a function of contact time between adsorbent and zinc, the initial metals and sorbent concentration, pH value, and temperature. The ability of Arthrospira biomass for zinc biosorption exhibited a maximum at the pH range 4–8. Equilibrium data fitted well with the Langmuir model as well as the Freundlich model with maximum adsorption capacity of 7.1 mg/g. The pseudo second-order model was found to correlate well with the experimental data. Different thermodynamic parameters, ΔG°, ΔH° and ΔS° were evaluated and it has been found that the sorption was feasible, spontaneous, and endothermic in nature. The process of zinc removal from industrial effluent was studied at different time of sorbat–sorbent interaction and different sorbent dosage. Maximum zinc removal (83%) was obtained at sorbent concentration 60 g/L during 1-h experiment. The results indicate that Arthrospira platensis biomass could be effectively used for zinc removal from industrial effluents.     

Biosorption Potentiality of Living Aspergillus niger Tiegh in Removing Heavy Metal from Aqueous Solution

The species of Aspergillus niger Tiegh isolated from estuarine sediments has been studied for tolerance to heavy metals such as Hg and Pb and for its capacities to uptake metals. A. niger was allowed to grow in monometal- as well as bimetal-containing media (25 mg L^?1) to determine the biosorption capacity of the organism. The effects of temperature and pH on biosorption were studied to elucidate the biosorption property and optimum growth conditions for the organism. Results revealed that 91.1% of Pb and 97.1% of Hg were removed from the monometal solutions, and there was a reduction of 96.9% of Hg and 89.3% of Pb from the bimetal solution after 92 h of fungal growth. The binding mechanism involved between metal ion and functional groups present on the cell surface of the biomass was studied using Fourier transform infrared (FTIR), which confirms the presence of amine, hydroxyl, carboxyl, and phosphate groups. The adsorption of metal ions on the biomass surface was confirmed using scanning electron microscopy–energy dispersive x-ray (SEM-EDAX) studies. The experimental study proved that A. Niger can be used as a suitable biosorption agent for removing metal ions when present in low concentration.     

Biosorption of heavy metals by distillery-derived biomass

Biomass derived from the Old Bushmill's Distillery Co. Ltd., Northern Ireland was harvested and examined for its ability to function as a biosorbent for metals such as Cu, Zn, Fe, Pb and Ag. Binding studies were carried out using biosorption isotherm analysis. Although the material had previously been shown to be capable of efficient U biosorption, its affinity for Cu, Zn, Fe was lower. However, binding studies with Pb demonstrated that it had a maximum biosorption capacity for that metal of 189?mg/g dry weight of the biomass. In addition, the biomass exhibited a maximum biosorption capacity of 59?mg/g dry weight for Ag and this compared very favourably with previously quoted values for other industrial sources of Saccharomyces cerevisiae. On the basis of the biosorption isotherm analyses carried out in this study, preference for this series of metals by the biomass was found to be Pb?>?U?>?Ag?>?Zn?≥?Fe?>?Cu.     

Application of dried sewage sludge as phenol biosorbent

The aim of this work was to determine the potential application of dried sewage sludge as a biosorbent for removing phenol from aqueous solution. Results showed that biosorption capacity was strongly influenced by the pH of the aqueous solution with an observed maximum phenol removal at pH around 6-8. Biosorption capacity increased when initial phenol concentration was increased to 110 mg/L but beyond this concentration, biosorption capacity decreased suggesting an inhibitory effect of phenol on biomass activity. Biosorption capacity decreased from 94 to 5 mg/g when biosorbent concentration was increased from 0.5 to 10 g/L suggesting a possible competitive effect of leachable heavy metals from the sludge. The effect of Cu2+ on biosorption capacity was also observed and the results confirmed that the phenol biosorption capacity decreased when concentration of Cu2+ in the sorption medium was increased up to 15 mg/L. Desorption of phenol using distilled deionized water was less than 2% suggesting a strong biosorption by the biomass.     

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.     

Mechanism of Biosorption of Heavy Metals by Mucor rouxii

Fungi such as Aspergillus niger and Mucor rouxii are capable of removing heavy metals from aqueous solutions. The role various functional groups play in the cell wall of M. rouxii in metal biosorption of lead, cadmium, nickel and zinc was investigated in this paper. The biomass was chemically treated to modify the functional carboxyl, amino and phosphate groups. These modifications were examined by means of infrared spectroscopy. It was found that an esterification of the carboxyl groups and phosphate and a methylation of the amine groups significantly decreased the biosorption of the heavy metals studied. Thus, the carboxylate, amine and phosphate groups were recognized as important in the biosorption of metal ions by M. rouxii biomass. The role the lipids fraction play was not significant. The study showed that Na, K, Ca and Mg ions were released from the biomass after biosorption of Pb, Cd, Ni and Zn, indicating that ion exchange was a key mechanism in the biosorption of metal ions by M. rouxii biomass.     

Biosorption Performance of Multimetal Resistant Fungus Penicillium chrysogenum XJ-1 for Removal of Cu2+ and Cr6+ from Aqueous Solutions

Adsorption for heavy metals via biomaterials such as fungal biomass presents a practical remediation technique for polluted water. Among all known filamentous fungi, Penicillium chrysogenum is widespread in nature and can serve as a biosorbent for heavy metals. In the current study, the ability of P. chrysogenum XJ-1 to remove copper (Cu²⁺) and chromium (Cr⁶⁺) from water was evaluated. The maximum biosorption capacity of XJ-1 for Cu²⁺ reached 42.83 ± 0.57 mg g^?1 dry biomass at pH 5.0 after the equilibrium time of 1.5 h. The maximum biosorption capacity for Cr⁶⁺ at pH 3.0 reached 52.69 ± 1.68 mg g^?1 dry biomass after the equilibrium time of 1.5 h. The biosorption data of XJ-1 biomass were well fitted to the Freundlich isotherm model and the pseudo-second-order Lagergren kinetic model. Laundry powder-treated and HCl-treated XJ-1 biomass significantly enhanced its adsorption capacity to Cu²⁺ and Cr⁶⁺, respectively. HCl and NaOH were suitable desorbents for Cu²⁺/Cr⁶⁺ loading biomass, respectively. Fourier transform infrared spectroscopy analyses revealed that hydroxyl, amine, and sulfonyl groups on the biosorbent contributed to binding Cu²⁺ and Cr⁶⁺ and that carbonyl and carboxyl groups were also vital binding sites of Cu²⁺. Scanning electron microscopy and energy-dispersive x-ray (SEM-EDX) analyses confirmed that considerable amounts of metals were precipitated on the cell surface of XJ-1. Our results suggested that XJ-1 might be used to purify multimetal-contaminated water. This low-cost and eco-friendly biomass of XJ-1 seems to have a broad use in the restoration of metal-contaminated water.     

Multi-metal biosorption and bioaccumulation by Exiguobacterium sp. ZM-2

The present work deals with the biosorption performance of dried and non-growing biomasses of Exiguobacterium sp. ZM-2, isolated from soil contaminated with tannery effluents, for the removal of Cd²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ from aqueous solution. The metal concentrations studied were 25 mg/l, 50 mg/l, 100 mg/l, 150 mg/l and 200 mg/l. The effect of solution pH and contact time was also studied. The biosorption capacity was significantly altered by pH of the solution. The removal of metal ions was conspicuously rapid; most of the total sorption occurred within 30 min. The sorption data have been analyzed and fitted to the Langmuir and Freundlich isotherm models. The highest Q_max value was found for the biosorption of Cd²⁺ at 43.5 mg/g in the presence of the non-growing biomass. Recovery of metals (Cd²⁺, Zn²⁺, Cu²⁺ and Ni²⁺) was found to be better when dried biomass was used in comparison to non-growing biomass. Metal removal through bioaccumulation was determined by growing the bacterial strain in nutrient broth amended with different concentrations of metal ions. This multi-metal resistant isolate could be employed for the removal of heavy metals from spent industrial effluents before discharging them into the environment.     

Heavy metal adsorption properties of a submerged aquatic plant (Ceratophyllum demersum)

Heavy metals can be adsorbed by living or non-living biomass. Submerged aquatic plants can be used for the removal of heavy metals. In this paper, lead, zinc, and copper adsorption properties of Ceratophyllum demersum (Coontail or hornwort) were investigated and results were compared with other aquatic submerged plants. Data obtained from the initial adsorption studies indicated that C. demersum was capable of removing lead, zinc, and copper from solution. The metal biosorption was fast and equilibrium was attained within 20 min. Data obtained from further batch studies conformed well to the Langmuir Model. Maximum adsorption capacities (q(max)) onto C. demersum were 6.17 mg/g for Cu(II), 13.98 mg/g for Zn(II) and 44.8 mg/g for Pb(II). Kinetics of adsorption of zinc, lead and copper were analysed and rate constants were derived for each metal. It was found that the overall adsorption process was best described by pseudo second-order kinetics. The results showed that this submerged aquatic plant C. demersum can be successfully used for heavy metal removal under dilute metal concentration.     

Potential of Live Spirulina platensis on Biosorption of Hexavalent Chromium and Its Conversion to Trivalent Chromium

Microalga biomass has been described worldwide according their capacity to realize biosorption of toxic metals. Chromium is one of the most toxic metals that could contaminate superficial and underground water. Considering the importance of Spirulina biomass in production of supplements for humans and for animal feed we assessed the biosorption of hexavalent chromium by living Spirulina platensis and its capacity to convert hexavalent chromium to trivalent chromium, less toxic, through its metabolism during growth. The active biomass was grown in Zarrouk medium diluted to 50% with distilled water, keeping the experiments under controlled conditions of aeration, temperature of 30°C and lighting of 1,800 lux. Hexavalent chromium was added using a potassium dichromate solution in fed-batch mode with the aim of evaluate the effect of several additions contaminant in the kinetic parameters of the culture. Cell growth was affected by the presence of chromium added at the beginning of cultures, and the best growth rates were obtained at lower metal concentrations in the medium. The biomass removed until 65.2% of hexavalent chromium added to the media, being 90.4% converted into trivalent chromium in the media and 9.6% retained in the biomass as trivalent chromium (0.931 mg.g^?1).     

白腐真菌吸附铅的研究

含重金属废水的传统处理方法有化学沉淀法、离子交换法、吸附法、电解法和膜分离法等,它们虽然也能达到一定的净化效果,但因过程繁琐并易造成二次污染而不够理想,尤其是金属离子浓度较低时,往往操作费用和原材料成本相对过高。近年来采用生物吸附法去除废水中的重金属...     

Integrating photobiological hydrogen production with dye-metal bioremoval from simulated textile wastewater

The study reports production of hydrogen in photobioreactors with free (PBR_Fr) and immobilized (PBR_Imm) Nostoc biomass at enhanced and sustained rates. Before running the photobioreactors, effects of different immobilization matrices and cyanobacterial dose on hydrogen production were studied in batch mode. As hydrogen production in the PBRs declined spent biomass from the photobioreactors were collected and utilized further for column biosorption of highly toxic dyes (Reactive Red 198 + Crystal Violet) and metals (hexavalent chromium and bivalent cobalt) from simulated textile wastewater. Breakthrough time, adsorption capacity and exhaustion time of the biosorption column were studied. The photobioreactors with free and immobilized cyanobacterium produced hydrogen at average rates of 101 and 151 μmol/h/mg Chl a, respectively over 15 days, while the adsorption capacity of the spent biomass was up to 1.4 and 0.23 mg/g for metals and 15 and 1.75 mg/g for the dyes, respectively in continuous column mode.     

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.     

Biosorption of lead, cadmium, and zinc by Citrobacter strain MCM B-181: characterization studies

The biosorption process for removal of lead, cadmium, and zinc by Citrobacter strain MCM B-181, a laboratory isolate, was characterized. Effects of environmental factors and growth conditions on metal uptake capacity were studied. Pretreatment of biomass with chemical agents increased cadmium sorption efficiency; however, there was no significant enhancement in lead and zinc sorption capacity. Metal sorption by Citrobacter strain MCM B-181 was found to be influenced by the pH of the solution, initial metal concentration, biomass concentration, and type of growth medium. The metal sorption process was not affected by the age of the culture or change in temperature. Equilibrium metal sorption was found to fit the Langmuir adsorption model. Kinetic studies showed that metal uptake by Citrobacter strain MCM B-181 was a fast process, requiring <20 min to achieve >90% adsorption efficiency. The presence of cations reduced lead, zinc, and cadmium sorption to the extent of 11. 8%, 84.3%, and 33.4%, respectively. When biomass was exposed to multimetal solutions, metals were adsorbed in the order Co2+ < Ni2+ < Cd2+ < Cu2+ < Zn2+ < Pb2+. Among various anions tested, only phosphate and citrate were found to hamper metal sorption capacity of cells. Biosorbent beads prepared by immobilizing the Citrobacter biomass in polysulfone matrix exhibited high metal loading capacities. A new mathematical model used for batch kinetic studies was found to be highly useful in prediction of experimentally obtained metal concentration profiles as a function of time. Metal desorption studies indicated that Citrobacter beads could, in principle, be regenerated and reused in adsorption-desorption cycles. In an expanded scale trial, biosorbent beads were found to be useful in removal/recovery of metals such as lead from industrial wastewaters.     

The effect of pulse voltage and capacitance on biosorption of uranium by biomass derived from whiskey distillery spent wash

Biosorption of uranium by residual biomass from The Old Bushmill's Distillery Co. Ltd., Bushmills, Co. Antrim, Northern Ireland, following exposure to short and intense electric pulses has been examined. The biomass was prepared from the distillery spent wash and consisted of non-viable yeast and bacterial cells. As shown previously, untreated biomass had a maximum biosorption capacity of 170?mg uranium/g dry weight biomass. When biosorption reactions were placed between two electrodes and exposed to electric pulses with field strengths ranging from 1.25–3.25?kV/cm at a capacitance of 25?μF, biosorption increased from 170?mg of uranium to 275?mg uranium/g dry weight biomass. The data were obtained from biosorption isotherm analyses and taken as the degree of biosorption at residual uranium concentrations of 3?mM. In addition, when the capacitance of the electric pulses increased from 0.25?μF to 25?μF at a fixed pulse field strength the degree of biosorption increased from 210?mg uranium to 240?mg uranium/g dry weight biomass. The results suggest that application of short and intense electric pulses to biosorption reactions may play an important role in enhancing microbial biosorption of toxic metals/radionuclides from waste water streams.     

Biosorption of Basic Blue 7 by fungal cells immobilized on the green-type biomatrix of Phragmites australis spongy tissue

Biosorption is an effective alternative method for the control of water pollution caused by different pollutants such as synthetic dyes and metals. A new and efficient biomass system was developed from the passively immobilized fungal cells. The spongy tissue of Phragmites australis was considered as the carrier for the immobilization of Neurospora sitophila cells employed for the biosorption of Basic Blue 7. This plant tissue was used for the first time as a carrier for fungal cells. The biosorption was examined through batch- and continuous-mode operations. The biosorption process conformed well to the Langmuir model. Maximum monolayer biosorption capacity of the biosorbent was recorded as 154.756 mg g^?1. Kinetic findings showed a very good compliance with the pseudo-second-order model. The negative values of ΔG° indicated a spontaneous nature of the biosorption process and a positive value of ΔH° (14.69 kJ mol^?1) concluded favorable decolorization at high temperature. The scanning electron microscopy analysis showed that a porous, rippled, and rough surface of biomass system was covered with BB7 molecular cloud. IR results revealed that functional groups like –OH, –NH, and C?O participated to the decolorization. Breakthrough and exhausted points were found as 360 and 570 minutes, respectively. The biomass system was successfully applied to the treatment of real wastewater.     

Cunninghamella echinulata a new biosorbent of metal ions from polluted water in Egypt

Thirty-two fungal species were isolated from a polluted watercourse near the Talkha fertilizer plant, Mansoura Province, Egypt. Aspergillus niger, A. flavus, Cunninghamella echinulata and Trichoderma koningii were isolated frequently. On the basis of its frequency, Cunninghamella echinulata was chosen for biosorption studies. Free and immobilized biomass of C. echinulata sequestered ions in this decreasing sequence is: Pb >Cu >Zn. The effects of biomass concentration, pH and time of contact were investigated. The level of ion uptake rose with increasing biomass. The maximum uptake for lead (45 mg/g), copper (20 mg/g) and zinc (18.8 mg/g) occurred at 200 mg/L biomass. The uptake rose with increasing pH up to 4 in the case of Pb and 5 in the case of Cu and Zn. Maximum uptake for all metals was achieved after 15 min. Ion uptake followed the Langmuir adsorption model, permitting the calculation of maximum uptake and affinity coefficients. Treatment of C. echinulata biomass with NaOH improved biosorbent capacity, as did immobilization with alginate. Immobilized biomass could be regenerated readily by treatment with dilute HCl. The biomass-alginate complex efficiently removed Pb, Zn and Cu from polluted water samples. Therefore,Cunninghamella echinulata could be employed either in free or immobilized form as a biosorbent of metal ions in waste water.     

Biosorption of uranium by cross-linked and alginate immobilized residual biomass from distillery spent wash

Residual biomass from a whiskey distillery was examined for its ability to function as a biosorbent for uranium. Biomass recovered and lyophilised exhibited a maximum biosorption capacity of 165–170?mg uranium/g dry weight biomass at 15?°C. With a view towards the development of continuous or semi-continuous flow biosorption processes it was decided to immobilize the material by (1) cross-linking with formaldehyde and (2) introducing that material into alginate matrices. Cross-linking the recovered biomass resulted in the formation of a biosorbent preparation with a maximum biosorption capacity of 185–190?mg/g dry weight biomass at 15?°C. Following immobilization of biomass in alginate matrices it was found that the total amount of uranium bound to the matrix did not change with increasing amounts of biomass immobilized. It was found however, that the proportion of uranium bound to the biomass within the alginate-biomass matrix increased with increasing biomass concentration. Further analysis of these preparations demonstrated that the alginate-biomass matrix had a maximum biosorption capacity of 220?mg uranium/g dry weight of the matrix, even at low concentrations of biomass.