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 Heavy Metal by Algae Biomass in Surface Water

Discharging wastewater containing heavy metals of Cu, Pb, Zn and Cd into water bodies can cause toxicity in plants and aquatic animals and some of them will be unable to survive except algae. Wastewater treatment method to remove heavy metal contaminants includes chemical precipitation, ion exchange, membrane, filtration, adsorption using activated carbon. However, these methods are either expensive or have other disadvantages such as high energy consumption and inefficiencies when existing heavy metals are at trace concentration. Biosorption using algae biomass can be an alternative method to eliminate heavy metals. The objective of the project is to investigate the capability of Marine Algae (MA) and Freshwater Algae (FA) bi-omass in adsorbing heavy metals of Cu, Pb, Zn and Cd from water medium using synthetic water and industrial water. MA and FA were obtained from the eastern coast of Pulau Ubin and local fish farm respectively. After being fully washed with deionised water, dried in a furnace for 105°C, they are grinded to pass 1 mm2 of siever. MA and FA were characterised using FTIR to determine their functional groups. An industrial water was collected from industrial discharge from metal fac-tories in northern side of Singapore. Effect of adsorption time, adsorbent concentra-tion, and pH were studied. The result showed that FA and MA had a higher capability in adsorbing a total metal of about 40 ppm level from an industrial water, or 4 times than synthetic water concentration, at the same adsorbent dosage of 50 mg. In con-clusion, the presence of various functional groups, hydroxyl, carboxylic and amine groups, in all MA and FA samples had enabled the algae biomass to adsorb heavy metals of Cu, Pb, Cd and Zn from synthetic and industrial water. Due to their bio-sorptive properties and fast adsorption capability, algae could be a potential method for cleaning up surface water or post-treatment of wastewater and minimise the cost of eutrophication.

Adsorption models for heavy metal biosorption

Heavy metal biosorption is an effective process for the removal and recovery of heavy metal ions.Equilibrium isotherms obtained experimentally are usually correlated empirically with commonly used adsorption models, without considering the underlying mechanisms of biosorption.Commonly used models for correlating biosorption isotherm data are briefly reviewed and the use of the adsorption models in correlating the desorption processes is analysed.A set of biosorption/desorption experiments for a marine alga derived biosorbent are carried out to test the use of the adsorption models in the desorption process.Experimental data indicate that the amount of the heavy metal ions desorbed from the biomass could not be calculated with the adsorption models.This suggests that the empirical use of adsorption models in the correlation may not be valid when the reversibility of the biosorption equlibrium in the desorption process needs to be considered.Therefore,mechanism based biosorption models are needed for better correlation of equilibrium isotherm data.

Algae-Silica Hybrid Materials for Biosorption of Heavy Metals

Algae-silica hybrid materials for biosorption purposes were prepared using sol-gel technology. The resulting biological ceramics (biocers) ought to combine the mechanical stability and porosity of the silicate matrix with the algae’s capability for the biosorption for heavy metals. The structure, mechanical properties, and sorption capability of such algae-silicate materials were investigated. Comparative equilibrium sorption ex-periments were performed batchwise with 13 different microalgae and macroalgae powders, and the corre-sponding algae biocers using waters loaded with either concentrations of nickel below 3mg/L or a mixture of different heavy metals (Cr, Ni, Cu, Pb). The algae biocers showed good mechanical stability up to an algae content of 30-50% and a total porosity of 40-60%. The silica matrix itself was involved in the sorption of metals. The metal binding capability of embedded macroalgae biomass was unaffected by immobilisation in the silica matrix. In contrast, for waters with nickel or different heavy metals, reduced sorption capability was shown by embedded microalgae.

Comparative Study on Heavy Metals Biosorption by Different Types of Bacteria

Biosorption of Cd(II), Ag(I) and Au(III) by cyanobacteria Spirulina platensis, of Au(II)—by Streptomyces spp. 19H, and of Cr(VI) and Cr(III)—by Arthrobacter species was studied by using the dialysis and atomic absorption analysis under various conditions. In particular, the impact of the following parameters on biosorption was studied: pH (for Ag, Cd, Au), living and non-living cells (for Cr), heavy metal valence (for Cr), homogenized and non-homogenized cells (for Au), Zn(II) ions (on Cr(VI)—Arthrobacter species). It was shown that biosorption efficiency of Cr(III), Cr(VI), Cd(II), Au(III) and Ag(I) ions is likely to depend on the type of bacteria used as well as on the conditions under which the uptake processes proceeded. It was shown that metal removal by microorganisms was influenced by physical-chemical parameters. The pH value of 7.0 was optimum for the removal of Ag(I) and Cd(II) by Spirulina platensis. At a low pH value of 5.5, Au (III) was by test algae more efficiently than Cd(II) and Ag(I).

Thermodynamic Analysis of Heavy Metals Biosorption by Two Macroalgae

The thermodynamic process of two macroalgae, Sargassum fusiforme and Laminaria japonica, absorbing heavy metal ions Cu2+, Pb2+, Cd2+ and Ni2+, has been studied. The result indicates that the absorption isotherms of these two macroalgae clearly accord with the Landmuir adsorption model. The absorptive processes of S. fusiforme and L. japonica for Cu2+℃ are endothermal, and at 35 , the adsorption heat of these two algae is 59.5 kJ/mol and 76.8 kJ/mol respectively. Temperature could affect the algae’s adsorption capacity. Their adsorption ℃℃capacity increases with temperature ( 25 and 35 ).

Acclimatization of microalgae Arthrospira platensis for treatment of heavy metals in Yamuna River

Bioaccumulation and biosorption in microalgae are effective approaches for the removal of heavy metals(HMs)from river water.The objective of this study was to investigate the potential for use of acclimatized microalgae in the removal of HMs from the Yamuna River water as an acclimatizing medium.An active culture of Arthrospira platensis(A.platensis)was acclimatized to HMs up to a concentration of 100 mg/L.It was gradually exposed to increasing concentrations of HMs in five subsequent batches with a step increase of 20 mg/L to acclimatize live cells in the simulated Yamuna River water.The presence of high levels of HMs in the Yamuna River water caused growth inhibition.An empirical growth inhibition model was developed,and it predicted high threshold concentrations of HMs(210.7e424.5 mg/L),producing a positive specific growth rate of A.platensis.A.platensis also showed high average removal efficiencies of HMs,including 74.0%for Cu,77.0%for Cd,50.5%for Ni,76.0%for Cr,76.5%for Pb,and 63.5%for Co,from HMs-enriched Yamuna River water.The findings demonstrated that the maximum specific removal amounts of Cu,Cd,Ni,Cr,Pb,and Co were 54.0,58.0,39.0,62.8,58.9,and 45.3 mg/g,respectively.The maximum yields of the value-added products chlorophyll and phycocyanin were 2.5 mg/g(in a batch of 40 mg/L for Cd)and 1054 mg/g(in a batch of 20 mg/L for Cu),respectively.Therefore,acclimatized A.platensis was proven to be a potential microalga not only for sequestration of HMs but also for production of valuable pigments.

Biosorption of heavy metals from aqueous solution by Gracilaria corticata varcartecala and Grateloupia lithophila

Objective:To study the biosorption of heavy metals viz.,Cr(VI),Cr(III),Hg(II),Pb(II)and Cd(II)using Gracilaria corticata varcartecala(G.corticata varcartecala)and Grateloupia lithophila(G.lithophila)biomass.Methods:Batch biosorption and acid digestion methods were used.Different physical and chemical parameters were optimized for biosorption.Results:Both seaweeds absorb Hg(II)upto 99.9%and 98.2%in batch biosorption method;whereas in acid digestion method,Cr(III)absorbed upto 96.49%by G.corticata varcartecala and Pb(II)absorbed upto 93.71%by G.lithophila.FT-IR analysis was used to know the involvement of different functional groups in the biosorption process.Scanning electron microscopy was carried out to study the morphological cell surface changes due to biosorption.Conclusions:It can be concluded that G.corticata varcartecala and G.lithophila are potential algal species for effective removal of heavy metals namely Cr(VI),Cr(III),Hg(II),Pb(II)and Cd(II)from environmental sources.

Heavy Metal Adsorption Properties of Marine Algae Durvilliea Potatorum,Ecklonia Radiata and Laminaria Japonica

1 INTRODUCTIONBiosorption of heavy metals using biosorbents derived from suitable biomass is a new tech-nology for the removal and recovery of heavy metals from industrial waste waters.The ad-vantages of the biosorption technology include rapid reduction of dissolved heavy metal ionsconcentration to 10-6and 10-9levels,use of inexpensive and non-hazardous biosorbents,useof existing adsorption process equipment and therefore low operating costs,high uptake ca-pacity and specificity for selective heavy metal removals,and low interference from

Removal of Heavy Metal Ions from Wastewater by Using Biosorbents from Marine Algae-A Cost Effective New Technology

Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents derived from the biomass of a group of marine macroalgae were used for the removal and recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents have high uptake capacities and affinities for a number of heavy metal ions. The uptake capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy metal ions. The kinetics of the uptake process was fast and the process can be used in both batch and fixed-bed operations. It appears that the biosorption process by using biosorbents from marine macroalgae can be an efficient and cost effective technology for the treatment of heavy metal containing wastewater.

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 Cadmium Ions by Unmodified, Microwave and Ultrasound Modified Brewery and Pure Strain Yeast Biomass

The present study investigates the biosorption of cadmium ions from aqueous solution onto unmodified, ultrasound and microwave treated cells of Saccharomyces cerevisiae. FTIR analysis was conducted to characterize the biosorbent. Equilibrium and kinetic studies of unmodified RBW (residual brewery waste) cell yeast and DSM 1333 (pure strain) were conducted by considering the effect of initial cadmium ions concentration. Results showed that the ultrasound and microwave treatments decrease the heavy metal uptake compared with the unmodified biomass. Langmuir and Freundlich isotherm models on both unmodified yeast cell types were used to analyze the equilibrium data. It was found that the Langmuir isotherm and pseudo-second-order kinetics models describe better the cadmium ions removal process.

Biosorption behaviors of Cu^(2+),Zn^(2+),Cd^(2+) and mixture by waste activated sludge

Biosorption of heavy metal ions,such as Cu2+,Cd2+ and Zn2+,was carried out using waste activated sludge from municipal sewage treatment plant as adsorption material,and the effects of parameters,such as pH value,temperature,reaction time and sorption duration,were studied in detail.The results indicate that the removal rates of Cu2+,Zn2+ and Cd2+ with low concentration are 96.47%,80% and 90%,respectively,adsorbed by waste activated sludge.Little effect of dosage of activated sludge on the adsorption of Cu2+ and more effects on the adsorption of Zn2+and Cd2+ are observed.Little effect of temperature is observed,while pH value and adsorption time exert important influence on the sorption process.The adsorption behaviors of heavy metal ions all have parabolic relationships with pH value.The optimum pH value is between 6 and 10,and the optimum adsorption time is 1 h.In single heavy metal ion system,the sorption processes of Cu2+,Zn2+ and Cd2+ are in accordance with Freundlich model,which indicates that it is suitable for the treatment of these three heavy metal ions using intermittent operation.In addition,the sorption capacity of the sludge for Cu2+ is preferential to the other two ions.

Biosorption of Ni²⁺and Cd²⁺from Aqueous Solutions Using NaOH-Treated Biomass of <i>Eupenicillium ludwigii</i>: Equilibrium and Mechanistic Studies

The removal of Ni2+ and Cd2+ ions by Eupenicillium ludwigii biomass was studied in a batch system. The optimum pH for the biosorption was 6 for Ni2+ and 5 for Cd2+. Temperature changes in the range from 15oC to 40oC affected the biosorption capacity, and the nature of the reaction was found to be endothermic for both metal ions. HCl was the best desorbing agent for the desorption of both metals. Chemical modifications of the biomass demonstrated that carboxyl and amine groups played an important role in Ni2+ and Cd2+ biosorption. Ion exchange mechanism was also suggested in the biosorption process.

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 Cr(Ⅳ),Cr(Ⅲ),Pb(Ⅱ) and Cd(Ⅱ) from Aqueous Solutions by Sargassum wightii and Caulerpa racemosa Algal Biomass

Heavy metal pollution is one of the most important environmental problems today.Biosorption is an innovative tech-nology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemi-cal pathways of uptake.Even though several physical and chemical methods are available for removal of heavy metals,currently many biological materials such as bacteria,algae,yeasts and fungi have been widely used due to their good performance,low cost and large quantity of availability.The aim of the present study is to explore the biosorption of toxic heavy metals,Cr(VI),Cr(III),Pb(II) and Cd(II) by algal biomass obtained from algae Sargassum wightii(brown) and Caulerpa racemosa(green).Biosorption of algal biomass was found to be biomass concentration-and pH-dependent,while the maximal biosorption was found at pH 5.0 and with the metal concentration of 100 mg L-1.S.wightii showed the maximal metal biosorption at the biomass concentration of 25 g L-1,followed by C.racemosa with the maximal biosorption at 30 g L-1.S.wightii showed 78% biosorption of Cr(VI),Cr(III),Pb(II) and Cd(II) ions.C.racemosa exhibited 85% biosorption of Cd(II) and Cr(VI),and 50% biosorption of Cr(III) and Pb(II).The results of our study suggest that seaweed biomass can be used efficiently

Biosorption of Ni^(2+) and Fe^(3+) by Fungal Cell Wall Sacchrides

This paper reports on the adsorption characteristic of heavy metal ions (Ni^2+and Fe^3+) using a novel biosorbent, prepared from cell walls of Rhizopus oryzae. The optimum operating conditions are investigated in both single ion system and binary system.