Bioleaching and biosorption behavior of vanadium-bearing stone coal by Bacillus mucilaginosus

The recovery of vanadium(V)from stone coal by bioleaching is a promising method.The bioleaching experiments and the biosorption experiments were carried out,aiming to explore the adsorption characteristics of Bacillus mucilaginosus(B.mucilaginosus)on the surface of vanadium-bearing stone coal,and the related mechanisms have been investigated.After bioleaching at 30℃ for 28 d,the cumulative leaching rate of V reached 60.2%.The biosorption of B.mucilaginosus on stone coal was affected by many factors.When the pH value of leaching system is 5.0,strong electrostatic attraction between bacteria and stone coal promoted biosorption.Bacteria in the logarithmic growth phase had mature and excellent biosorption properties.The initial bacterial concentration of 3.5×10^(8) CFU/mL was conducive to adhesion,with 38.9%adsorption rate and 3.6×10^(7) CFU/g adsorption quantity.The adsorption of B.mucilaginosus on the stone coal conformed to the Freundlich model and the pseudo-second-order kinetic model.Bacterial surface carried functional groups(-CH_(2),-CH_(3),-NH_(2),etc.),which were highly correlated with the adsorption behavior.In addition,biosorption changed the surface properties of stone coal,resulting in the isoelectric point(IEP)approaching the bacteria.The results could provide an effective reference for the adsorption laws of bacteria on minerals.

Taxonomy characterization and cadmium biosorption of fungus strain

The taxonomy characteriazation and cadmium （Cd） biosorption of the high Cd-resistant fungus M1 were investigated. The internal transcribed spacers （ITS） region and β-tubulin genes of the strain were amplified, sequenced and analyzed by molecular biology technology. The Cd biosorption assay was performed by shaking flask. Fourier transform infrared spectroscopy was used to analyze the mycelium. The similarity of gene sequences and phylogenetic trees show the very close relation between the strain and Paecilomyces lilacinus, and the fungus M1 was identified as P. Lilacinus. The initial pH 6 and Cd concentration about 100 mg/L are optimum. Zn and Mn have a little effect on the Cd biosorption of the strain, while Cu and Pb present obvious effects. FTIR analysis shows that the fungus adsorbs Cd by esters, anhydride, and amide. With the preferable absorption capacity, fungus M1 is considered to have good prospects in bioremediation.

Use of oilseed crops biomass for heavy metal treatment in water

The treatment of heavy metals in water is of high importance worldwide,and different treatment types have been developed.The use of plant material is becoming more and more important,and oilseed crops biomass have been investigated in terms of phytoremediation and biosorption processes.This article is a review of the literature reporting the applications in 10 different plants and evaluating the removal efficiencies for 12 metals,including the findings of 81 publications.Moringa olifera and Helianthus annuus are the most studied plants,whereas Cu(21.9%),Cd(18.5%),and Pb(19.9%)are the most studied metals.As a result,it was found that more than 90%of Pb,Cu,Cd,Fe,Zn,Ni,Cr,Sr and Mn showed removals in their experiments.At the same time,the variables most related to the efficiency of metal removal are pH,temperature,and contact time.This article includes a review of the biosorption isotherms used in the different studies.

Study on Tolerance and Biosorption of Various Microalgae Species to Arsenic

[Objective] This study aimed to select microalgae species which are capable to effectively remove arsenic contamination from water under natural conditions. [Method] Four microalgae species [Chlorella sp. （zfsaia）, Chlorella minata, Chlorella vulgaris and Selenastrum capricormulum] were used as experimental materials and cultured with six different concentrations of As （Ⅲ） （0.5, 1.0, 2.0, 5.0, 10.0, 20.0 mg/L）. Biomass, chlorophyll a content and other physiological indicators were determined to investigate the arsenic tolerance and biosorption of four microalgae species. [Result] Chlorella sp. is sensitive to arsenic toxicity, its growth was inhibited when arsenic concentration exceeded 10 mg/L, with an EC 50 of 17.32 mg/L; when the arsenic concentration was 0-20 mg/L, growth of S.c, ww1 and C.v was not affected, which showed relatively high tolerance to arsenic, with arsenic removal rates of 77.02% , 72.18% and 81.36% respectively after 24 h. [Conclusion] This study indicates that microalgae have good application prospects for processing arsenic wastewater and being indicator plants of arsenic wastewater.

Biosorption characteristics of unicellular green alga Chlorella sorokiniana immobilized in loofa sponge for removal of Cr(Ⅲ)

Loofa sponge （LS） immobilized biomass of Chlorella sorokiniana （LSIBCS）, isolated from industrial wastewater, was investigated as a new biosorbent for the removal of Cr（Ⅲ） from aqueous solution. A comparison of the biosorption of Cr（Ⅲ） by LSIBCS and free biomass of C. sorokiniana （FBCS） from 10-300 mg Cr（Ⅲ）/L aqueous solutions showed an increase in uptake of 17.79% when the microalgal biomass was immobilized onto loofa sponge. Maximum biosorption capacity for LSIBCS and FBCS was found to be 69.26 and 58.80 mg Cr（Ⅲ）/g biosorbent, respectively, whereas the amount of Cr（Ⅲ） ions adsorbed onto naked LS was 4.97 mg/g. The kinetics of Cr（Ⅲ） biosorption was extremely rapid and equilibrium was established in about 15 and 20 min by LSIBCS and FBCS, respectively. The biosorption equilibrium was well defined by Langmuir adsorption isotherm model. The biosorption kinetics followed the pseudo-second order kinetic model. The biosorption was found to be pH dependent and the maximum sorption occurred at the solution pH 4.0. Desorption studies showed that 98% of the adsorbed Cr（Ⅲ） could be desorbed with 0.1 mol/L HNO3, while other desorbing agents were less effective in the order： EDTA 〉 H2SO4 〉 CH3COOH 〉 HCl. The regenerated LSIBCS retained 92.68% of the initial Cr（Ⅲ） binding capacity up to five cycles of reuse in continuous flow-fixed bed columns. The study revealed that LSIBCS could be used as an effective biosorbent for the removal of Cr（Ⅲ） from wastewater.

Biosorption of cadmium(II) and lead(II) ions from aqueous solutions onto dried activated sludge

The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions（Cd（Ⅱ） and Pb（Ⅱ）） followed the pseudo-second-order rate expression. The equilibrium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd（Ⅱ） and Pb（Ⅱ） biosorption onto dried activated sludge was their binding with amide I group.

Biosorption of Cu(Ⅱ) on extracellular polymers from Bacillus sp.F19

Biosorption can be an effective process for the removal of heavy metals from aqueous solutions.The adsorption of Cu(Ⅱ) from aqueous solution on the extracellular polymers (EPS) from Bacillus sp.(named MBFF19) with respect to pH,incubation time,concentration of initial Cu(Ⅱ),and biosorbent dose was studied.Biosorption of Cu(Ⅱ) is highly pH dependent.The maximum uptake of Cu(Ⅱ) (89.62 mg/g) was obtained at pH 4.8.Biosorption equilibrium was established in approximately 10 min.The correlation coeffcient of mor...

Immobilization study of biosorption of heavy metal ions onto activated sludge

Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10\_100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH≤5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. The adsorption rate of immobilized pre-treated activated sludge(PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40℃. Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS.

Biosorption of Pb^（2＋） with Modified Soybean Hulls as Absorbent

Using soybean hull residue after the soluble dietary fiber being removed during the soybean processing industry as crude material,a novel absorbent,modified soybean hulls,is prepared.Its adsorption behavior for Pb2＋ is studied.The adsorbent has a large and efficient adsorption capacity for Pb2＋,up to 20% of the mass of dry ad-sorbent.Its maximum adsorption capacity for Pb2＋ reaches 217 mg·g-1 at initial Pb2＋ concentration of 2000 mg·L-1,which is twice that of yeast absorbent and threefold greater than that of chitosan absorbent.The adsorption ability is sensitive to pH value in the solution and the optimal pH for adsorption of Pb2＋ is 7.0.In the presence of other metal ions （Ca2＋,Mg2＋ and Na＋） in the solution,their effect on the adsorption capacity for Pb2＋ is not obvious.After 5 cy-cles of adsorption,80% adsorption capacity of Pb2＋ is maintained.Compared with various available commercial resins,the modified soybean hulls are a plentiful,inexpensive and effective medium for the capture of dissolved Pb2＋ from waste streams.

Biosorption of zinc(Ⅱ) from aqueous solution by dried activated sludge

The biosorption potential of dried activated sludge as a biosorbent for zinc（Ⅱ） removal from aqueous solution was investigated.The effects of initial pH,contact time,initial zinc ion concentration,and adsorbent dosage on the biosorption processes were determined,and the equilibrium data were modeled by the Langmuir and Freundlich isotherms.The Langmuir isotherm model （R 2=0.999） was proved to fit the equilibrium data much better than the Freundlich isotherm model （R 2=0.918）.The monolayer adsorption capacity of dried activated sludge for zinc（Ⅱ） was found to be 17.86 mg/g at pH of 5 and 25°C.The kinetic data were tested using pseudo firstand second-order models.The results suggested that the pseudo second-order model （R 2 〉 0.999） was better for the description of the adsorption behavior of zinc（Ⅱ） onto the dried activated sludge.Fourier transform infrared spectral analysis showed that the dominant mechanism of zinc（Ⅱ） biosorption onto the dried activated sludge was the binding between amide groups and zinc ions.

Surface reaction of Bacillus cereus biomass and its biosorption for lead and copper ions

In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared （FTIR） analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sitesthree pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu（Ⅱ） and Pb（Ⅱ） ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm.

Biosorption of Cu^(2+) and Zn^(2+) by raw and autoclaved Rocella phycopsis

The behavior of Cu2＋ and Zn2＋ biosorption onto raw and modified Roccella phycopsis from aqueous solutions was studied. Modification process was applied by autoclavation at 121°C for 30 min. The effcts of pH, initial metal concentration and biosorbent dosage were investigated. The maximum Cu2＋ biosorption was achieved at pH 5.0 and the maximum biosorption capacities of 31.5 and 37.8 mg/g were recorded for raw and modified biosorbent, respectively. In the case of Zn2＋ biosorption, maximum biosorption capacities were obtained at pH 4.0 as 29.1 and 35.3 mg/g for raw and modified biosorbent, respectively. Biosorption of Zn2＋ and Cu2＋ on all form of R. phycopsis increased much quickly with increasing initial metal concentrations from 10 to 100 mg/L. After modification process, probable changes in the surface polarity of raw and modified R. phycopsis were investigated by contact angle measurements. As expected, R. phycopsis has a polar surface and shows a highest contact angle with water, while after autoclavation water contact angle of R. phycopsis was significantly decreased from 47.5° to 34.4°.

Copper biosorption on immobilized seaweed biomass:Column breakthrough characteristics

The biosorption of copper by the brown seaweed Sargassum baccularia, immobilized onto polyvinyl alcohol （PVA） gel beads, was investigated with fixed-bed experiments. Laboratory-scale column tests were performed to determine breakthrough curves with varying flow rates and feed concentrations. A theoretical fixed-bed model, known as the Bohart-Adams equation, was evaluated in simulating the experimental breakthrough curves. The Bohart-Adams model qualitatively predicted the breakthrough trends. PVA- immobilized seaweed biomass beads were amenable to efficient regeneration with aqueous solution containing the chelating agent ethylenediaminetetraacetic acid （EDTA）. The biosorbent retained most of its original uptake capacity over three cycles of use. The excellent reusability of the biosorbent could lead to the development of a viable metal remediation technology.

Biosorption of Cd (Ⅱ) and Pb (Ⅱ) Ions by Aqueous Solutions of Novel Alkalophillic Streptomyces VITSVK5 spp. Biomass

Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Bio-sorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution.The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species.The biosorption property of Streptomyces VITSVK5 spp.was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb).Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L-1,cadmium 3.1±0.3μg L-1,zinc 8.4±2.6μg L-1 and copper 0.3±0.1μg L-1,whereas mercury was well below the detection limit.The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated.The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively.The biosorbent dosage was optimized as 3 g L-1 for both the trace metals.Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (–COOH),hydroxyl (–CHOH) and amine (–NH2) groups of biomass with the metal ions.This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp.The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

Biosorption of cadmium(Ⅱ) from aqueous solutions by industrial fungus Rhizopus cohnii

An important filamentous industrial fungus,Rhizopus cohnii(R.cohnii),was used as an efficient biosorbent for removing cadmium from wastewater.The sorption conditions,such as pH,the dose of biomass and the initial concentration of cadmium were examined.Two kinds of adsorption models were applied to simulate the biosorption data.The uptake of cadmium was higher in weak acid condition than in strong acid condition.Nearly no sorption of cadmium occurred when the pH value was lower than 2.0. Biosorption isothermal data could be well simulated by both Langmuir and Freundlich models.Langmuir simulation of the biosorption showed that the maximum uptake of cadmium was 40.5 mg/g(0.36 mmol/g)in the optimal conditions,which was higher than many other adsorbents,including biosorbents and activated carbon.In addition,the reusability results showed that after five times of sorption and desorption process,the sorption capacity of R.cohnii could still maintain nearly 80%,confirming its practical application in cadmium treatment.Fourier transform infrared spectrum revealed that carboxyl,amino and hydroxyl groups on biosorbent R.cohnii surface were responsible for the biosorption of cadmium.

Biosorption Behavior and Mechanism of Lead(II) from Aqueous Solution by Aerobic Granules(AG) and Bacterial Alginate(BA)

Lead(Pb) and its compounds are common pollutants in industrial wastewaters.To develop appropriate Pb 2+ treatment technologies,aerobic granules(AG) and bacterial alginates(BA) were studied as alternative biosorbents to remove Pb 2+ from aqueous solutions.The biosorption mechanism of AG and BA were further analyzed to determine which functional groups in AG and BA are active in Pb 2+ biosorption.In this paper,the Pb 2+ biosorption behavior of AG and BA was respectively investigated in batch experiments from the perspectives of the initial pH,contact time,and initial Pb 2+ concentration.The results showed that biosorption of Pb 2+ by AG and BA occurred within 60min at the initial Pb 2+ concentrations(0 150 mg L-1).The actual saturated Pb 2+ biosorption capability of AG was 101.97 mg g-1(dry weight of aerobic granular biomass).When the initial pH was 5,the biosorption capability of AG and BA was highest at the initial Pb 2+ concentrations(0 20mg L-1).During the process of Pb 2+ biosorption,K +,Ca 2+,and Mg 2+ were released.The Ion Chromatography(IC) and Fourier Transform Infrared Spectroscopy(FTIR) further highlighted the main role of ion exchange between Ca 2+ and Pb 2+ and sequestration of Pb 2+ with carboxyl(-COO) of AG and BA.This analogical analysis verifies that BA is responsible for biosorption of Pb 2+ by AG.At the same optimal pH,AG cultivated with different carbon source has different Pb 2+ biosorption capacity.The Pb 2+ biosorption by AG with sodium acetate as the sole carbon source is higher than AG with glucose as carbon source.

Biosorption of Cu(Ⅱ) and Pb(Ⅱ) by Auricularia polytricha

For searching biological material for heavy metal removal of waste-water, using macrofungus Auricularia polytricha as biosorbent for Cu^2＋ and Pb^2＋ removal was investigated. After shaking and biosorbing Cu^2＋ and Pb^2＋ in solution by biosorbents, the filtrates were tested by AAS and the adsorbed quantity of Cu^2＋ and Pb^2＋ was calculated. The biosorbents were effective in removal of Cu^2＋ and Pb^2＋ on the biosorbents that showed a high- est value around pH 5-6. The biosorption rate of Cu^2＋ and Pb^2＋ on A. polytricha biomass decreased with increasing the initial concentration of Cu^2＋ and Pb^2＋ in the medium. The biosorption of Cu^2＋ and Pb^2＋ on the biomasses follows pseudo-second order kinetics. The determined maximum biosorption capacities presented by the fungus biomass were 3.34 and 13.03 mg·g^-1 dry weight for Cu^2＋ and Pb^2＋, respectively by the biosorption equilibrium with Langmuir adsorption isotherm. According to the whole data analysis in each experiment of studying Cu^2＋ and Pb^2＋ biosorption including condition factors and adsorption isotherm, the adsorbed capacity of Pb^2＋ by A. polytricha biomass was bigger than Cu^2＋. The biosorption by A. polytricha was most effective when pH 5-6. The biosorbents are suitable for low Cu^2＋ and Pb^2＋ concentration waste-water, especially for Pb^2＋ removal.

Biosorption Characteristics of Ectomycorrhizal Fungal Mycelium for Anthracene

Objective To investigate the potential of Gomphidius viscidus,a kind of ectomycorrhizal fungi,for phytoremediation of anthracene in soil.Methods Absorptioe changes of micro-habitat were studied in detail.Conclusion Ectomycorrhizal plants have a strong potential for remediation of polycyclic aromatic hydrocarn characteristics of both active and inactivated mycelia.Results A high calculated adsorption capacity of 1 886.79 mg/g and 1 515.15 mg/g at 25 ℃,pH 6.0 for active and inactivated mycelia respectively,was obtained based on Langmuir model.The ANT biosorption was more ideally characterized by the Langmuir model than by the Freundlich model.The biosorption of anthracene to biomass was extremely fast and could be modeled with pseudo-second order adsorption kinetics.Moreover,ectomycorrhizal mycelia demonstrated a strong ability to adjust the physiological process to get adapted to the change of micro-habitat.

Improvement of chromium biosorption through protoplast electrofusion between Candida tropicalis and Candida lipolytica

Protoplasts from Candida tropicalis and Candida lipolytica were fused under an optimized electrofusion （electrical pulse strength 6 kV/cm, pulse duration time 40μs and pulse times 5） and then regenerated on YEPD media for achieving new genotypes with higher chromium loading capacity. A target fusant RHJ-004 was screened out by its chromium resistance and chromium-sorbing capacity tests for further research. The comparative study of applicability shows that the fusant has better performance than its parent strains in respect of solution pH, biomass concentration and chromium loading capacity. Especially for treating low concentration Cr（VI） （〈20 mg/L）, above 80% chromium is sequestered from the aqueous phase at pH 1-9. Atomic force microscopy （AFM） visualizes the distribution of chromium on the binding sites of the cells, suggesting that the altered surface structure and intracellular constitutes of the fusant associate with its increased biosorption capacity. The rapid biosorption processes of chromium foUow the Langmuir model well.

Biosorption and desorption of Cd^(2+) from wastewater by dehydrated shreds of Cladophora fascicularis

The adsorption and desorption of algae Cladophora fascicularis and their relation with initial Cd2+ concentration, initial pH, and co-existing ions were studied. Adsorption equilibrium and biosorption kinetics were established from batch experiments. The adsorption equilibrium was adequately described by the Langmuir isotherm, and biosorption kinetics was in pseudo-second order model. The experiment on co-existing ions showed that the biosorption capacity of biomass decreased with an increasing concentration of competing ions. Desorption experiments indicated that EDTA was efficient desorbent for recovery from Cd2+. With high capacities of metal biosorption and desorption, the biomass of Cladophora fascicularis is promising as a cost-effective biosorbent for the removal of Cd2+ from wastewater.