Biosorption Of Heavy Metals Research Articles

Characterization of cadmium biosorption by Exiguobacterium sp. isolated from farmland soil near Cu-Pb-Zn mine

Bacteria have the ability to bind heavy metals on their cell wall. Biosorption is a passive and energy-independent mechanism to adsorb heavy metals. The efficiency of heavy metal biosorption can vary depending on several factors such as the growth phase of bacteria, solution pH, and existence of competitive heavy metals. In this study, Exiguobacterium sp. isolated from farmland soil near a mine site were used, and optimal conditions for Cd biosorption in solution were investigated. As bacterial growth progressed, Cd biosorption increased, which is attributed to changes in the structure and composition of the cell wall during bacterial growth. The biosorption process was rapid and was completed within 30min. Cadmium biosorption was highest at pH 7 due to the dissociation of hydrogen ions and the increase of negative charges with increasing pH. In the mixed metal solution of Cd, Pb, and Zn, the amount of biosorption was in the order of Pb>Cd>Zn while in a single metal solution, the order was Cd≥Pb>Zn. The maximum adsorption capacity for Cd by the isolated bacteria was 15.6mg/g biomass, which was calculated from the Langmuir isotherm model. Different adsorption efficiencies under various environmental conditions indicate that, to control metal mobility, the conditions for biosorption should be optimized before applying bacteria. The results showed that the isolated bacteria can be used to immobilize metals in metal-contaminated wastewater.

Biosorption of Heavy Metals by Low Cost Adsorbents

Biosorption of Heavy Metals by Low Cost Adsorbents

Design of a new integrated chitosan-PAMAM dendrimer biosorbent for heavy metals removing and study of its adsorption kinetics and thermodynamics

In this research, different generations of PAMAM-grafted chitosan as integrated biosorbents were successfully synthesized via step by step divergent growth approach of dendrimer. The synthesized products were utilized as adsorbents for heavy metals (Pb2+ in this study) removing from aqueous solution and their reactive Pb2+ removal potential was evaluated. The results showed that as-synthesized products with higher generations of dendrimer, have more adsorption capacity compared to products with lower generations of dendrimer and sole chitosan. Adsorption capacity of as-prepared product with generation 3 of dendrimer is 18times more than sole chitosan. Thermodynamic and kinetic studies were performed for understanding equilibrium data of the uptake capacity and kinetic rate uptake, respectively. Thermodynamic and kinetic studies showed that Langmuir isotherm model and pseudo second order kinetic model are more compatible for describing equilibrium data of the uptake capacity and kinetic rate of the Pb2+ uptake, respectively.

Kinetic studies of heavy metals biosorption by acidogenic biomass immobilized in clinoptilolite

The aim of this work was to establish the sorption equilibrium and kinetics of copper, Cu(II), and iron, Fe(II), removal by acidogenic biomass immobilized in clinoptilolite. The experimental methodology consisted of a series of batch studies in which immobilized acidogenic biomass was exposed to metallic solutions within a concentration range of: 0–300 mg/L Cu(II), 0–800 mg/L Fe(II) in single systems, and 0–1000 mg/L Cu(II)–Fe(II) in a binary system. It was found that copper and iron sorption by acidogenic biomass immobilized in clinoptilolite can be represented by the pseudo second-order type reaction. Data obtained from the equilibrium studies were adequately described by the Langmuir adsorption model. Although the predicted maximum biosorption capacity of copper increased from qmax = 28.23 mgCu(II)/gSSV in the single system to qmax = 35.46 mgCu(II)/gSSV in the binary system, it was found that co-existence of copper and iron ions decreased the actual biosorption capacity of the acidogenic biomass. The findings of this work indicate that acidogenic biomass immobilized in clinoptilolite is a promising low-cost biosorbent for the removal of copper and iron, but binary metal mixtures of copper and iron must be carefully selected to avoid low removal efficiencies during a biosorption-based wastewater treatment process.

Biosorption of Heavy Metals in Dumpsite Leachate by Metal-resistant Bacteria Isolated from Abule-egba Dumpsite, Lagos State, Nigeria

Biosorption of Heavy Metals in Dumpsite Leachate by Metal-resistant Bacteria Isolated from Abule-egba Dumpsite, Lagos State, Nigeria

A Study on the Potential of Moringa Leaf and Bark Extract in Bioremediation of Heavy Metals from Water Collected from Various Lakes in Bangalore

Many industrial water bodies are polluted with organic and inorganic contaminants discharged into them as effluents. Bioremediation is a waste water management technique that facilitates removal or neutralization of pollutants from a contaminated site. Many plants and their extracts have been used for bioremediation of heavy metals in the process of phytoremediation. Moringa olifera, also known as drumstick is a fast growing, drought resistant plant that belongs to the family of Moringaceae. Its fruit and leaf are consumed as diet and the bark has healing properties as recorded in ancient medicine. Moringa olifera seeds have been reported to have bioremedial property which can be enhanced on chemical modification. Data optimization studies have been performed for various heavy metals and their adsorption on to the chemically modified biosorbent. Our study aims at identifying major polluted lakes in and around Urban Bangalore and their phytoremediation using dried and chemically modified leaf and bark powders. Contaminated water samples were collected from Bellandur, Varthur and Hebbal lakes and were subjected to biosorption by the modified leaf and bark powders according to the parameters optimized for seed powders. The reduction in heavy metal content was observed by Thin Layer Chromatography (TLC) and Atomic Absorption Spectroscopy (AAS) methods. Other physico chemical parameters like turbidity, BOD, COD, DO, Nitrate and Phosphate content were examined to emphasize the bioremedial property of chemically modified Moringa olifera leaf and bark extracts. Biosorption of heavy metals was found for the bark and leaf treated water samples and also reduction in the BOD, COD, nitrate and phosphate content and turbidity were observed for both the biosorbents. These results showed the enhancement of potability of these treated water samples and their applications in a larger scale. Further recovery and reusability of the biosorbents for enhanced recovery of the pollutants has to be studied for their commercialization.

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.

Enhanced and selective adsorption of mercury ions on cassia grandis seed gum grafted with poly (methylmethacrylate) via free radical polymerization

Event Abstract Back to Event Enhanced and selective adsorption of mercury ions on cassia grandis seed gum grafted with poly (methylmethacrylate) via free radical polymerization Angela Singh1, Sneha Joshi1 and Vandana Singh1 1 University of Allahabad, Department of Chemistry, India Introduction: The present study focuses on the biosorption of heavy metals in wastewater from various industrial and domestic wastes. When discharged to water bodies, these may be harmful to both human and aquatic life as they are nondegradable and thus persistent. Therefore, it is important to remove heavy metals prior to their discharge. Mercury (Hg) is one of the most hazardous pollutants, which acquires high toxicity even at low concentrations[1]. Adsorption represents an efficient and convenient method, which can separate low amounts of substances from large volumes of solution[2]-[5]. Biodegradable materials can prove to be a better adsorbent by their surface modification[6]-[9]. In this study, Methylmethacrylate is grafted onto Cassia grandis seed gum. The graft copolymer was characterized by FTIR, SEM and XRD and has been studied as an adsorbent with good metal-chelating properties for the removal of Hg (II) from aqueous solutions. Materials and Methods: Cassia grandis seed gum(CG), Methylmethacrylate(MMA), potassium persulfate (KPS) and ascorbic acid (AA) were of analytical grade. Synthesis of Cassia grandis gum-graft-polymethylmethacrylate (CG-g-PMMA)[10],[11]: CG, MMA and AA were added to water (25ml) and thermostated at 35°C. After 30 min calculated amount of KPS was added. Graft copolymerization was allowed for 1h and the copolymer was extracted with acetone and dried. The adsorbent with different %G were obtained by variations in concentrations of MMA, AA, KPS, CG, temperature and time. (Fig1.Table (1) Hg (II) adsorption batch experiment: CG-g-PMMA with maximum %G was evaluated for Hg(II) removal from synthetic solution. The operating variables studied were pH, sorbent dosage, Hg concentration and temperature. Desorption studies[12]: The copolymers loaded with mercury were placed in the 0.05N H2SO4 and stirred at 120 rpm for 4h at 30◦C and the final Hg(II) concentration was determined. Results and Discussion: CG-g-PMMA was synthesized efficiently by thermal grafting method. The maximum %G(300%) and %E(70.69%) obtained was using [MMA]=17X10-2M, [KPS]=40X10-3, [AA]=2.3X10-2M, CG=4g/L (25 ml) for 1h. The samples were characterized using FTIR (Fig 1(1)), XRD (Fig 1(2)), SEM (Fig 1(3)). The results obtained confirm the synthesis of the graft copolymer. Optimization of Adsorption Study: Maximum sorption condition was obtained at pH=6 (Fig. 4A), Hg conc.=100mg/L (Fig.4B), Adsorbent dose=50 mg (Fig.4C) and temperature=30oC (Fig.4D). Sorption kinetics: The correlation coefficients R2 and the rate constants for CG-g- PMMA are summarized in Fig2(5)Table2.Kinetics of sorption was modeled by the first order Lagergren equation, pseudo-second-order equation and intra-particle diffusion model. Desorption studies: Adsorption desorption cycles could be repeated for six times at adsorbent dose 250mg, pH=6, 120 rpm, contact time=4h. (Fig2(6)) Adsorption thermodynamics: It was observed that Adsorption of Hg(II) onto the CG-g-PMMA was increased at higher temperature. (Table (3), (Fig2(7)). Conclusion: The optimum CG-g-PMMA was successfully synthesized and it proved to be an efficient mercury ion sorbent. The sorption by the copolymer was pH dependent and studies indicated sorption followed pseudo-second-order kinetic model.The sorbent could be successfully recycled for six consecutive cycles without much loss in its sorbing capacity. Thus, an adsorbent with good metal-chelating properties is obtained for the removal of Hg(II) from synthetic aqueous solutions. University Grant Commission ,New Delhi, India

Heavy metal biosorption in multi component system on dried activated sludge: investigation of adsorption mechanism by surface characterization

The dried activated sludge collected from STP- Kolkata Municipal Corporation and Tannery industry, leather complex, Kolkata were used as complex biosorbent for removal of heavy metals. The metal ion concentrations were measured using ion chromatography. The adsorption efficiency with respect to time was performed; the Zn (II) and Cd (II) showed 99% removals within 10 min while Ni (II) and Co (II) attained 98% removal at 20-24 h of contact time both in single and multi metal system. The elucidation of the mechanism of biosorption is necessary to enable the technology to be developed. Mechanism of biosorption of Ni (II), Cd (II), Co (II)and Zn (II)in multi metal removal system was studied by the characterization of the structure and surface chemistry of biomaterial using functional group modification, FT-IR, FESEM-EDX and XPS analysis. FT-IR spectra of before and after multiple metal uptake revealed that the functional groups (amino, carboxylic, hydroxyl, phosphate, sulfonyl and carbonyl) present on surface of the biomaterial were involved in the biosorption process.The wide scanning XPS spectra for dried tannery sludge after biosorption of multi metals showed peaks of Cd, Zn, Ni and Co. The deconvolution of peaks C1s spectra and N1s spectra assigned to C atoms in form of C-C, C-O, O-C-O, O-C=O and N atom in the R-NH2, R-NH3+ group. Change in the peak pattern and shift in the binding energies confirm the involvement of these functional groups.

Pb(II) biosorption by selected waste biomass

Global concerns regarding environmental issues have required the evaluation of the waste biomass as potential biosorbents of heavy metals. This paper provides a review on using aquatic weed Myriophyllum spicatum and its compost and selected agricultural wastes: corn silk, peach and apricot stones as biosorbents of lead ions. These biomasses were characterized by Scanning electron microscopy (SEM). The results of the studies on adsorbent efficiency of these bio wastes show that they apart from their wide availabilities are enriched with appreciable biosorption capacities. The paper also provides a critical view concerning future applications of this kind waste biosorbents in treatment of heavy metal contaminated water.

An engineered microorganism can simultaneously detoxify cadmium, chlorpyrifos, and γ-hexachlorocyclohexane.

Many ecosystems are currently co-contaminated with heavy metals such as cadmium (Cd(2+) ) and pesticides such as chlorpyrifos (CP) and γ-hexachlorocyclohexane (γ-HCH). A feasible approach to remediate the combined pollution of heavy metals and pesticides is the use of γ-HCH degrading bacteria endowed with CP hydrolysis and heavy metal biosorption capabilities. In this work, a recombinant microorganism capable of simultaneously detoxifying Cd(2+) , CP, and γ-HCH was constructed by display of synthetic phytochelatins (EC20) and methyl parathion hydrolase (MPH) fusion protein on the cell surface of the γ-HCH degrading Sphingobium japonicum UT26 using the truncated ice nucleation protein (INPNC) as an anchoring motif. The surface localization of INPNC-EC20-MPH was verified by cell fractionation, Western blot analysis, immunofluorescence microscopy, and proteinase accessibility experiment. Expression of EC20 on the cell surface not only improved Cd(2+) binding but also alleviated the cellular toxicity of Cd(2+) . As expected, the rates of CP and γ-HCH degradation were reduced in the presence of Cd(2+) for cells without EC20 expression. However, expression of EC20 (higher Cd(2+) accumulation) significantly restored the levels of CP and γ-HCH degradation. These results demonstrated that surface display of EC20 enhanced not only Cd(2+) accumulation but also protected the recombinant strain against the toxic effects of Cd(2+) on CP and γ-HCH degradation.

Heavy Metals Biosorption By Copper Resistant Bacteria of Acinetobacter Sp. IrC2

Heavy metal pollution is a serious problem because it cannot be degraded by natural processes and persist in soil, water, and sediment. Many indigenous microorganisms isolated from heavy metal contaminated sites had tolerance to heavy metals toxicity and could be used for bioremediation agent because of its capability to biosorb heavy metals. The aim of this research was to study the potency of copper resistant bacteria Acinetobacter sp. IrC2 as a biosorbent of heavy metals. Biosorption was determined by measuring the heavy metals concentration on growing medium by using atomic absorption spectrophotometer. The research showed that Acinetobacter sp. IrC2 was capable of growing in medium containing each of 2 mM of copper, zinc, lead, cadmium, and the mixture of those heavy metals. The addition of copper and lead in the medium changed morphological appearance of colonies to green and brown, respectively, suggesting that the survival mechanism of the isolate was by biosorbing copper or lead inside the cells. The percentage of heavy metals biosorption efficiency using live cells of Acinetobacter sp.IrC2 were up to 64.31% of copper, 24.73% of zinc, 62.79% of lead, and 11.56% of cadmium. Acinetobacter sp. IrC2 also reduced copper, lead, and cadmium concentration up to 24.30, 75.93, and 16.38%, respectively, in medium supplemented with 1 mM of the mixture of these heavy metals. The findings of this study indicated that Acinetobacter sp. IrC2 was a promising bacterium for removal of heavy metals.

Biosorption of uranium and heavy metals using some local fungi isolated from phosphatic fertilizers

A number of 26 fungal cultures were isolated from different phosphatic sources, including phosphate fertilizers and rock phosphate. The highest number and percentage of isolates were obtained from tri-phosphate fertilizer and rock phosphate samples (9 isolates with 34.6% for each sample) and then 8 isolates with 30.8% from monophosphate fertilizer. These isolates were tested for heavy metals biosorption on solid medium supplemented with different metal ions at concentration of 50ppm. Eighteen out of 26 isolates were able to grow on solid medium containing heavy metals. The selected isolates were also screened for removal of heavy metals with different concentrations (0–150ppm) in liquid medium. Among 18 fungal cultures, 5 isolates were chosen for their high capability to tolerance of high concentration of heavy metals (150ppm), and it was found that the fungal growth was promoted in the presence of U, Cr5+ Cu++ for FR1 (0.026, 0.133 and 0.128g/100ml), Cr5+ for FR7 (0.246g/100ml), Zn++, Co++ and Pb++ for FR13 (0.219, 0.371 and 0.303g/100ml), U for FR15 (0.174g/100ml) and Zn++, Co++ and Pb++ for FR16 (0. 203, 0.385 and 0.312g/100ml). These isolates FR1 & FR7, FR13, FR15 & FR16 belong to genus Aspergillus as identified by their morphological properties, respectively.

Comparative diversity and heavy metal biosorption of myxomycetes from forest patches on ultramafic and volcanic soils

Ultramafic and volcanic soils are exploited for industrial activities such as mining due to their high metal content, thus it is important that species in these areas are documented before irreversible environmental damage sets in. In this study, aerial and ground leaf litter, dead vines and twigs from six forest patches on volcanic and ultramafic soils in the provinces of Bataan, Pangasinan and Zambales in the Philippines were cultured in moist chambers (MC) and assessed for myxomycete diversity. From the 77% positive MC for myxomycetes, a total of 40 species from 14 genera were identified. Despite the higher heavy metal content, forest patches on ultramafic soils had greater species diversity as compared to volcanic soils. In this study, 10 species were abundant in both forest patches, namely Arcyria cinerea, Diachea leucopodia, Diderma effusum, D. hemisphaericum, Didymium ochroideum, Perichaena chrysosperma, P. corticalis, P. depressa, P. dictyonema and Physarum melleum. Selected myxomycetes tested for Cr and Mn content had equal or higher heavy metal levels than that of their leaf substrate. The study hypothesised that the presence of Mn7+ in fruiting bodies of myxomycetes was due to the phagocytosis of food bacteria inhabiting the substrates on the forest soil laden with heavy metal.

Biosorption of cadmium and chromium from water by endophytic Kocuria rhizophila: equilibrium and kinetic studies

Heavy metal removal from water is an important issue of environmental concern. This study demonstrates the application of endophytic bacterium Kocuria rhizophila (gene bank No: KF875448) isolated from hyperaccumulator Oxalis corniculata for the adsorption of Cd(II) and Cr(III) from aqueous solution. Minimum inhibitory concentration of Cd and Cr for the selected strain was found to be 6 and 8 mM, respectively. The effects of certain parameters like pH, contact time, and initial metal concentration on biosorption were assessed at a temperature of 35 ± 2°C. The optimum pH values for Cd and Cr biosorption were found to be 8 and 4, respectively. Maximum biosorption for both the metals was obtained after 60 min. Biosorption equilibrium was described by Langmuir and Freundlich isotherms. The Langmuir model showed maximum adsorption capacity (Qmax) for Cd and Cr as 9.07 and 14.4 mg g−1, respectively. Kinetic data indicated that biosorption of the selected heavy metals on K. rhizophila follows pseudo-second-order rate equation. FTIR analysis showed that functional groups like OH, C=O, C=N, N–H, CH2, PO2, C–O, C–O–C and C–H on K. rhizophila surface might be responsible for heavy metals biosorption. Results suggested that K. rhizophila has potential for the removal of metal ions from aqueous solution. Therefore, current research presents novelty in terms of evaluating endophytic K. rhizophila as a biosorbent for Cd and Cr.

Biosorption for lead (II) ions from aqueous solutions by the biomass of Spyridia filamentosa algal species found in Indian Ocean

Biosorption of heavy metals is an efficient cost effective method for removal of heavy metal ions from industrial wastewater. Studies have shown that algal species biomasses have high uptake of heavy metal ions. In this research, an adsorption property of Spyridia filamentosa algal species was studied on the basis of equilibrium isotherms and kinetics from batch experiments. It was found that biosorption capacities were pH dependent. The maximum adsorption capacity was found to be at 0.86 mmol/g at pH of 5. It was observed that biosorption kinetics was first within the first 30 minutes before equilibrium was obtained. The effect of light metal ions was found not to significantly affect uptake of lead (II) ions. It was as well found that Spyridia filamentosa biomass could purify 2.1, 1.1, 0.7 and 0.5 liters when the feed concentrations were 0.5, 1.0, 2.0 and 4.0 mM, respectively of lead (II) before breakthrough was reached. This study illustrated that that biomass of Spyridia filamentosa is a good biosorbent for treatment of lead (II) contained in industrial wastewater.

Bioremoval of heavy metals and nutrients from sewage plant by Anabaena oryzae and Cyanosarcina fontana

ABSTRACTThe present study demonstrated the growth of two species of cyanobacteria on wastewater isolated from sewage plant in Aswan, Egypt. We evaluated their efficiency for eliminating nitrogen, phosphorus, chemical oxygen demand (COD) and heavy metals (Fe2+, Pb2+, Cu2+, and Mn2+). The growth of Cyanosarcina fontana has supported wastewater as a growth medium than Anabaena oryzae compared to standard medium. The nutrients concentration such as COD, NO3–N and PO4–P were decreased by the growth of A. oryzae and C. fontana in the wastewater after primary settling and centrate. However, the reduction of COD was less efficient than the other nutrients. The reduction percentage of COD, NO3–N and PO4–P reached 39.3, 84.1 and 90.7% as well as 54.6, 83.1, and 89.8%, in cultures of A. oryzae and C. fontana grown in the wastewater after primary settling, respectively. The reduction amounted to 10.1, 76.8, and 63.0% by A. oryzae and 43.2, 62.1, and 74.8% by C. fontana, grown in the centrate, respectively. Cyanobacteria species have the ability to accumulate the heavy metals from the wastewater to level far than the exceeding metal level in the water. Whereas, the heavy metals biosorption performance of C. fontana was higher in accumulating Fe2+ (93.95%), Pb2+ (81.21%), Cu2+ (63.9%), and Mn2+ (48.49%) compared to A. oryzae. The biosorption ability is dependent on the nature of the adsorbent studied and the type of wastewater treated. Therefore, removal of heavy metals and nutrients by the tested algae is strongly recommended as a powerful technique for the removal of pollutants from wastewater.

Application of orange peel waste in the production of solid biofuels and biosorbents

This work aimed to study the potential use of pyrolyzed orange peels as solid biofuels and biosorption of heavy metals. The dry biomass and the biofuel showed moderate levels of carbon (44–62%), high levels of oxygen (30–47%), lower levels of hydrogen (3–6%), nitrogen (1–2.6%), sulfur (0.4–0.8%) and ash with a maximum of 7.8%. The activation energy was calculated using Kissinger method, involving a 3 step process: volatilization of water, biomass degradation and volatilization of the degradation products. The calorific value obtained was 19.3MJ/kg. The studies of metal biosorption based on the Langmuir model obtained the best possible data fits. The results obtained in this work indicated that the potential use of waste orange peel as a biosorbent and as a solid biofuel are feasible, this product could be used in industrial processes, favoring the world economy.

Multicomponent isotherm for biosorption of Zn(II), CO(II) and Cd(II) from ternary mixture onto pretreated dried Aspergillus niger biomass

In the present study, multicomponent competitive biosorption of heavy metal from aqueous solution onto pretreated dried Aspergillus niger in batch system was investigated. The adsorption data were fitted to the multicomponent Langmuir, Freundlich, Temkin and Sips equations. We used the genetic algorithm of biosorption in ternary mixture to evaluate the potential effects of each metal in the removal of other metals. In order to take both mechanisms of the cell-surface binding and intra-particle diffusion into account, an alternative model was investigated by combining the pseudo-second-order kinetics model and the intra-particle diffusion model. A model describing the process of biosorption by a single-stage batch design was developed and verified based on the Temkin isotherm model. Fundamentally, the outlook from these observations of the experiments that the pretreated dried biomass is a suitable absorbent for the removal of significant amounts of the heavy metal from the effluents of industrial wastewater is promising.

Characterization of a multi-metal binding biosorbent: Chemical modification and desorption studies

This work attends to preparation and characterization of a novel multi-metal binding biosorbent after chemical modification and desorption studies. Biomass is a combination of tea waste, maple leaves and mandarin peels with a certain proportion to adsorb cadmium, copper, lead and zinc ions from aqueous solutions. The mechanism involved in metal removal was investigated by SEM, SEM/EDS and FTIR. SEM/EDS showed the presence of different chemicals and adsorbed heavy metal ions on the surface of biosorbent. FTIR of both unmodified and modified biosorbents revealed the important role of carboxylate groups in heavy metal biosorption. Desorption using different eluents and 0.1M HCl showed the best desorption performance. The effectiveness of regeneration step by 1M CaCl2 on five successive cycles of sorption and desorption displays this multi-metal binding biosorbent (MMBB) can effectively be utilized as an adsorbent to remove heavy metal ions from aqueous solutions in five cycles of sorption/desorption/regeneration.