Biosorption Of Cr Research Articles

Role of NADH-dependent chromium reductases, exopolysaccharides and antioxidants by Paenibacillus thiaminolyticus PS 5 against damage induced by reactive oxygen species

ABSTRACT Cr (VI) being used in various activities of industries and its improper treatment lead to contamination of environment. Among different methods, biological is the most efficient method to control pollution from soils affected with metals. Present study was designed to assess the role of Paenibacillus thiaminolyticus PS5 for adsorption, Cr (VI) reduction and mechanism of reduction. Sorption of chromium (VI) by strain PS5 was obtained by batch equilibrium method. Cr (VI) reduction in both free and immobilised cells were evaluated by 1,5-Diphenyl Carbazide method. The formation of biofilm by Paenibacillus thiaminolyticus PS5 was observed for colour change as well as quantified spectrophotometrically. Analysis kits were used to measure the amount of eDNA, superoxide and malondialdehyde (MDA). Metal resistant strain PS5 was characterised as P. thiaminolyticus using 16S rRNA gene sequence. Maximum biosorption of Cr (VI) by strain PS5 was found at pH 6–8 and 100–400 µgCr/mL within 24 hours of incubation. Complete reduction of Cr (VI) by strain PS5 was achieved at pH 6–8 and100–300 µg/mL Cr (VI). Paenibacillus thiaminolyticus PS5 immmobilisation on sodium alginate and polyvinyl alcohol facilitated complete reduction of Cr (VI) within 18 hours due to the formation of more biofilm under metal stress conditions. Strain PS5 reduced almost all Cr (VI) into Cr (III) in supernatant, most of which was immobilised by cell debris. Experiments confirmed the reduction of Cr (VI) by cytosolic cell-free extracts which is a mechanism of detoxification. The release of exopolysaccharides and antioxidants by strain PS5 played a protective role against cell damage by Cr (VI) as Cr (VI) could not release the significant amount of eDNA, superoxide and MDA. The present study proved strain PS5 to be a super bioinoculant which has great capacity for adsorption, biotransformation and can activate cytosolic reductases, exopolysaccharides and antioxidants against oxidative damage.

Biosorption performance of date palm empty fruit bunch wastes for toxic hexavalent chromium removal

Biosorption ability of date palm empty fruit bunch (DPEFB) was examined for the removal of toxic hexavalent chromium (Cr6+) ions from synthetic wastewater. The pretreated DPEFB biosorbent was studied for its morphology and surface chemistry through Scanning electron microscopy, Energy dispersive elemental analysis and Fourier transform infrared spectroscopy. Effect of biosorption parameters such as pH, biosorbent dosage, contact time, temperature, initial feed concentration and agitation speed on the Cr6+ ions removal efficiency by DPEFB was critically evaluated. The isoelectric point for the DPEFB sorbent was observed at pH 2, above which it was dehydronated to capture the positively charged Cr6+ ions. Batch biosorption studies showed that an optimal chromium removal efficiency of 58.02% was recorded by the DPEFB biosorbent for pH 2, dosage 0.3 g, 100 rpm agitation speed, 120 min contact time, 50 mg/L initial feed concentration and 30 °C operational temperature. Thermodynamic analysis showed that the binding of Cr6+ ions on DPEFB surface was exothermic, stable and favorable at room temperature. Equilibrium behavior of chromium binding on DPEFB was more aligned to Temkin isotherm (R2 = 0.9852) highlighting the indirect interactions between Cr6+ ions and the biosorbent. Kinetic modeling revealed that the biosorption of Cr6+ ions by DPEFB obeyed pseudo-second order model than the pseudo-first order and intra-particle diffusion models. Reusability studies of the DPEFB sorbent showed that NaNO3 was an effective regenerant and the biosorbent can be efficiently reused up to three successive biosorption-desorption cycles for chromium removal. In summary, the results clearly showed that the DPEFB biowaste seems to be an efficient, economic and eco-friendly biosorbent for sustainable removal of toxic hexavalent chromium ions from domestic and industrial wastewater streams.

Biosorption of Cr(III) and Cr(VI) species on NaOH-modified peel of Artocarpus nobilis fruit. 1. Investigation of kinetics

Performance characteristics of peel of Artocarpus nobilis fruit can be enhanced by the treatment of the biosorbent with aqueous NaOH solutions under stirred conditions, followed by thorough washing of the treated biosorbent with water. A series of experiments performed within a wide range of solution pH demonstrates that the optimum pH for Cr(III) removal is pH 5.0, while it is 2.0 for Cr(VI) by peel of Artocarpus nobilis fruit after treatment with aqueous NaOH solutions of concentrations varied from 0.0050 to 0.15 M. Adsorption of Cr(III) and Cr(VI) from individual aqueous solutions on the above biosorbent treated with 0.010 M NaOH solution, which provides the highest extent of removal of 4.89 × 103 mg kg−1 (pH = 5) and 4.94 × 103 mg kg−1 (pH = 2), respectively, follows pseudo-first-order kinetics at the ambient temperature of 27.5 °C when the concentration of adsorbate concentration is kept relatively constant. The order of the reaction is unchanged when the solution temperature is increased up to 40.0 °C for Cr(III) although the reaction becomes pseudo-second order for Cr(VI). Further, the energy of activation for adsorption of Cr(III) is determined to be 66.82 kJ mol−1, suggesting a strong attraction between the adsorbate and the biosorbent. Application of the intraparticle diffusion model to kinetics data within the early stages of the adsorption process of Cr(III) suggests that boundary layer-retarded diffusion be valid at both solution temperatures, while no retardation be possible for Cr(VI) at the warmer temperature.

Biosorption of Cr(VI) using coconut fibers from agro-industrial waste magnetized using magnetite nanoparticles

ABSTRACT Herein, the biosorption of Cr(VI) by magnetized coconut fibres obtained from agricultural waste has been described. Magnetization was achieved by incorporating magnetite nanoparticles into the fibres by a coprecipitation reaction in alkaline media. The biosorption capacity of the fibres was evaluated by two series of experiments. In the first series, 500 mg L−1 of the biosorbent was added to a 50 mg L−1 K2Cr2O7 solution at 28 °C and stirred at 200 rpm and the pH was varied from 1 to 13 to determine the optimum pH value. The second series of experiments evaluated the sorption capacity of the fibres at the optimum pH, under the same agitation speed and temperature but with an adsorbate concentration of 100 mg L−1. The biosorbents were characterized using Fourier transform-infrared spectroscopy, inductively coupled plasma-atomic emission spectroscopy, scanning electron microscopy, dispersive X-ray fluorescence, and X-ray powder diffraction. The biosorption experiments demonstrated that the magnetization process increased the biosorption capacity of the material. Optimum biosorption occurred at pH 2, and at optimal conditions, the best adsorptive efficiency exceeded 90%, reaching a biosorption capacity of 87.38 mg g−1 for the magnetized fibre and 23.87 mg g−1 for the natural fibre, with an equilibrium time of less than 20 min.

Assessment of Cr(VI) Biosorption from Aqueous Solution by Artificial Intelligence

This work investigates the efficiency of date palm fiber as a biosorbent to the removal of Cr(VI) from aqueous solution. The effect of four main factors including, the initial pH, initial Cr(VI) concentration, biosorbent dosage, and time were assessed. The results revealed that, the maximum 89% removal of Cr(VI) at time 50 min, initial pH 3.2, initial Cr(VI) 181 ppm, and biosorbent dosage 0.8% (w/v) was obtained. The artificial neural network (ANN) model was developed to predict the Cr(VI) removal as a function of the studied variables. A number of data points were considered as test data to validate the model. The results indicated a high accuracy of the ANN modeling in estimating the target variable.

Synthesis of calcite-based bio-composite biochar for enhanced biosorption and detoxification of chromium Cr (VI) by Zhihengliuella sp. ISTPL4

The current study presents a comprehensive analysis of the potential of actinobacterium Zhihengliuella sp. ISTPL4 and different composite materials for the removal of hexavalent chromium [Cr (VI)]. Genome analysis of strain indicated the presence of several oxidoreductases which includes chromate reductase, nitrate reductase, thioredoxin, superoxide dismutase and hydrogenase are other major candidate genes. Catalytic calcite-based bio-composite material was absorbed on biochar had highest Cr removal efficiency. The main mechanism involved in Cr biosorption by this strain was explained by the Langmuir isotherm model; under equilibrium conditions the maximum adsorption was observed 49 ± 0.3 mgg−1. Kinetic studies showed that biosorption of Cr (VI) by this strain was a rate-limiting step and followed a pseudo-second-order kinetics (R2 = 0.99). SEM analysis is in line with EDX result indicating highest Cr removal by calcined biochar. MTT assay shown that the bacteria successfully convert toxic Cr (VI) to comparatively less toxic form such as Cr (III).

Simultaneous and continuous biosorption of Cr and Cu (II) ions from industrial tannery effluent using almond shell in a fixed bed column

The study on performance of almond shell in the simultaneous removal of Cr ions and Cu (II) from tannery effluent was investigated in a laboratory scaled fixed bed column. The characterization of the almond shell was examined using SEM (scanning electron microscope) and FTIR (Fourier transform infrared spectroscopy). FTIR analysis of almond shell revealed the existence of hydroxyl, carbonyl and aliphatic functional groups responsible for the adsorption of the metal ions. The breakthrough curve basically was used to study the efficiency of the packed bed adsorption system with the almond shell. It was observed that the breakthrough is a function of flow rate, initial metal concentrations and the packed bed height. The column adsorption effectiveness increases with the rise in the influent concentration, bed depth and reduces with the rise in the flow rate. The column parameters analysed indicated the efficiency of the column at flow rate of 3.0 ​ml/min, bed height of 7.0 ​cm and concentrations of 67.5 ​mg/L and 7.0 ​mg/L for Cr ions and Cu (II) ions respectively. The proportional removal of Cu (II) and Cr ions at optimal values were 70.0 and 65.9% with adsorption capacities of 2.39 and 21.92 ​mg/g respectively. Column adsorption kinetics was sufficiently defined with Thomas and Yoon and Nelson models. The model parameters, such as mass transfer coefficient and kinetic parameters were determined. Comparison between experimental breakthrough curves to the breakthrough profiles determined using Thomas and Yoon-Nelson models gives prominent correlation coefficients (R2) indicating satisfactory fit for both metals.

Kinetic and thermodynamic studies on biosorption of Cr(VI) on raw and chemically modified Datura stramonium fruit.

Biosorption of Cr(VI) on sulfuric and phosphoric acid-treated Datura stramonium fruit was investigated in batch mode. The various parameters that influence the biosorption process such as Cr(VI) initial concentration, biosorbent dosage, contact time, temperature, and pH value were optimized. Both linear and non-linear regression analysis of isotherm data suggest that Langmuir isotherm model mimics the behavior of Cr(VI) ion biosorption onto Datura stramonium fruit biosorbent. The maximum Cr(VI) ions adsorption capacity of 138.074mg/g at pH 2 is achieved with phosphoric acid treated Datura stramonium (PDSF). The kinetics of adsorption process is well described by pseudo-second-order model with high R2 and low χ2 value. The estimated activation energy of < 8kJ/mol obtained for both raw and chemically modified adsorbents suggests that the adsorption occurs mainly via physisorption. Besides, thermodynamic results reveal that biosorption of Cr(VI) on both treated and untreated Datura stramonium was endothermic, spontaneous, and randomness in nature.

Biosorption of Cr (III) from Aqueous Solution Using Banana Peel Powder

O uso de cascas de banana moídas foi avaliado como biossorvente para a remoçãode resíduos de Cr (III) em eflentes aquosos. O eflente aquoso utilizado foi geradoem aulas experimentais de química analítica quantitativa no Instituto Federal do RioGrande do Sul (IFRS). Técnicas alternativas foram empregadas no presente trabalho,os ensaios combinaram duas metodologias para o tratamento deste resíduo. Oprimeiro explora a capacidade de cascas de banana como biossorvente na remoção deCr (III), enquanto o segundo emprega a complexação de Cr (III) usando EDTA, sobirradiação de microondas, para fis de quantifiação. A remoção máxima de 60% doconteúdo de Cr (III) foi alcançada em 40 minutos de tratamento, em escala de batelada.

Biosorption of Cr(VI) by immobilized waste biomass from polyglutamic acid production

Waste biomass from γ-polyglutamic acid production was used as an adsorbent to remove Cr(VI) from wastewater. Waste biomass was entrapped in sodium alginate to enhance performance. Orthogonal array design was used to optimize biosorption of Cr(VI) by immobilized waste biomass. The optimal adsorption conditions for immobilized waste biomass were as follows: pH 7.0, initial Cr(VI) concentration of 200 mg/L, 35 °C, waste biomass of 2 g/L, 60 min. Under these conditions, the absorption efficiency of Cr(VI) was 96.38 ± 0.45%. When the waste biomass was treated with 1 mol/L HCl for 1 h, the desorption rate could reach 94.42 ± 0.87%. It was shown that the adsorption kinetics followed the Freundlich adsorption model, indicating that the adsorption of Cr(VI) by bacteria was mainly based on multi-molecular layer adsorption. The absorption conditions of waste biomass were mild (pH 6.0–7.5, 20–35 °C) and easily operated. These investigations lay a foundation for reducing the pollution of γ-polyglutamic acid production, turning the biomass waste into a useful adsorbent for wastewater treatment.

Cr(VI) biosorption: Effect of temperature, particle size and bed height

The present work aimed to evaluate the effect of temperature, particle size and bed height of the chromium (VI) adsorption process using plantain peels in a continuous system. The experiment was carried out on a packed bed column, adjusting the feed temperature of the solution with a REX-C100 controller coupled to a type K thermocouple. The initial concentration of Cr (VI) was set at 100 ppm, the pH at 2 and the feed rate of 0.75 mL/s. The analyses were performed by UV-Vis spectroscopy using the colourimetric method of 1.5-diphenylcarbazide. The material was characterized by infrared spectrometry by Fourier Transforms (FTIR), from this analysis, it was determined that the OH and NH2 functional groups are the main responsible for the formation of complexes with the cations in solution. Also, it was established that only the particle size is statistically significant. According to the response surface analysis, the optimum conditions of the process were 353.15 K, a particle size of 0.819 mm and a bed height of 67.768 mm. From the thermodynamic study of the process, it is established that it is endothermic and the chemical adsorption prevails in it. The results obtained in the process modelling suggest that Dose-Response can be used reliably to scale the process.

Surface modification of nanocellulose using polypyrrole for the adsorptive removal of Congo red dye and chromium in binary mixture

In this study, nanocellulose was synthesised by acid hydrolysis of cellulose and was coupled with polypyrrole supporting matrix. The synthesised nanocellulose polypyrrole composite (NCPPY) was characterised by FESEM, XRD, FTIR, BET, TGA/DSC and NMR. These analysis showed the conversion of cellulose to nano sized crystalline structure with excellent thermal stability and higher surface area. The effect of different parameters like pH, temperature, contact time, adsorbent dosage and initial concentration of Chromium (Cr(VI)) and Congo Red (CR) were optimised in batch mode. Response Surface Methodology (RSM) has been employed as an optimization tool for the efficient removal of Cr(VI) and CR and the maximum removal efficiency was found to be 80% and 85% respectively. The Langmuir and Freundlich isotherm well fitted the equilibrium data for CR and Cr(VI) respectively. Thermodynamic data showed that the biosorption of Cr(VI) and CR on NCPPY is an endothermic, spontaneous, and entropy-driven process. The adsorption kinetic followed pseudo-second-order for Cr(VI) and intraparticle diffusion for CR. Effect of co-existing ions were checked using several common salts and heavy metals. Results indicated that NCPPY has great potential to remove Cr(VI) and CR binary mixture under simulated conditions.

Comparative assessment of raw and acid-activated preparations of novel Pongamia pinnata shells for adsorption of hexavalent chromium from simulated wastewater.

Current study deals with the comparative assessment for efficient adsorption of Cr(VI) from simulated wastewater using raw (NPP), phosphoric acid-activated (PPP) and sulphuric acid-activated (SPP) Pongamia pinnata shells. Physico-chemical alterations of the adsorbent were characterised by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), zeta-potential analysis, energy-dispersive X-ray spectroscopy (EDS) and total pore analysis using Brunauer-Emmett-Teller (BET). Parameters influencing the efficient biosorption of Cr(VI) species viz. initial pH of Cr(VI) solution, dosage of biosorbent, biosorbent-Cr(VI) contact period, initial concentration of Cr(VI) ions and reaction temperature were optimised. Various two-parameter and three-parameter isotherm models, kinetic models and thermodynamic studies were performed using equilibrium data. Langmuir adsorption capacity for NPP (raw biomass), PPP (phosphoric acid-activated biomass) and SPP (sulphuric acid-activated biomass) was found to be 96.2, 152 and 192mg/g, respectively. All the biosorbents gave best fit for pseudo-second-order model. Thermodynamic studies suggest spontaneous and endothermic interaction with increased degree of randomness. Effect of co-existing cations and anions on Cr(VI) biosorption onto the biosorbents implied that minimal competition and the biosorption capacity of the biosorbents for Cr(VI) species remained unaffected. Regeneration studies suggest that activated biosorbents can be used up to three times with continuous desorption.

Development of an analytical method for the extraction and determination of trace metals using fungus (Mucor pusillus, Lindt., 1886) immobilised sepiolite powder biocomposite in various samples by ICP-AES

ABSTRACT In this study, an extraction procedure based on biosorption of Co(II), Cr(III), Mn(II), Ni(II) and Zn(II) using biocomposite of fungus (Mucor pusillis, Lindt., 1886) immobilised sepiolite powder has been developed preconcentration. For the quantitative recovery of the analytes, different parameters pH, amount of solid-phase, flow rate of the sample solution and eluent type were optimised. The interference of foreign ions on the recovery of the analytes was also investigated. Elution was carried out with 2 mL of 5% HNO3, 100 mg sorbent dosage. The recoveries of Co(II), Cr(III), Mn(II), Ni(II) and Zn(II) by Mucor pusillis (Lindt., 1886) immobilised on sepiolite powder were obtained 100 ± 2%, 98 ± 2% 96 ± 2%, 99 ± 2%, 98 ± 3% at 95% confidence level, respectively, for spiked environmental samples. The analytical detection limits were calculated 1.2, 1.3, 1.4, 0.6 and 0.2 ng/mL for Co(II), Cr(III), Mn(II), Ni(II) and Zn(II) preconcentration, respectively. Standard reference materials of biological samples were used to validate the data. Method was applied on the real environmental samples including tap water, river water and vegetable samples to determine the concentration of the analytes. Determinations were carried out using ICP-AES.

Linearized Forms of Langmuir Equations and Its Effect on the Prediction of Biosorption of Cr (VI) on Neem Leaf Powder

In order to understand the biosorption mechanism of Cr (VI) on to Neem leaf powder (NLP), the experimental data needs to be fitted onto a linearized form of isotherm equations. The Langmuir isotherm has five different linearized equations, and each form is generating a different constant for adsorption equilibrium based on KL and qmax. The effect of linearized forms of Langmuir isotherms (LL) is studied in this work. KL, qmax was calculated using five different linearized forms of Langmuir isotherm and compared. R2 values of these LL varied drastically between 0.577 to 0.974. From the calculated KL and qmax, qe was predicted and plotted. When these predicted values and experimental values were compared, LL4 was found to be the best suited linearized form despite not having the highest correlation coefficient. The LL2 and LL4 having highest correlation coefficient showed high overshoot for predicted values over experimental values.

Feasibility Of Metal Biosorption using Gulmohar (Delonix Regia) Tree Leaves Power: Effect Of Biosorption Structure On Adsorption Isotherms And Kinetics

In this work, biosorption process was commited for expulsion of metals using Gulmohar tree leaf powder since Gulmohar tree leaf powder (GTLP) is a efficient biosorbent for treating Cr(VI) ions. The optimum values observed for efficient removal of Cr(VI) ions were pH-2, concentration for Cr(VI) biosorption by GTLP- 20 ppm and biosorbent dosage-0.1 g. The symmetry was attained at 75 min of acquaintance time. Experimental values were depicted with Freundlich and Langmuir models. Sorption equilibrium exhibited good robust to Langmuir model (R2 = 0.991).

Bioreduction and biosorption of Cr(VI) by a novel Bacillus sp. CRB-B1 strain

This study reported an efficient novel chromium reducing bacteria (Bacillus sp. CRB-B1) and investigated its removal mechanism. Bacillus sp. CRB-B1 could effectively reduce high level Cr(VI), under a wide range of shaking velocity (125–200 rpm), temperature (33–41 °C), pH (6–9). The co-existing ions Cd2+ and NO3- inhibited its Cr(VI) reduction capacity, while Cu2+ enhanced the reduction efficiency. In addition, Bacillus sp. CRB-B1 could reduce Cr(VI) using glucose and fructose as an electron donor. Micro-characterization analysis confirmed the Cr(VI) reduction and adsorption ability of Bacillus sp. CRB-B1. Cells degeneration result indicated that Cr(VI) removal was mainly bioreduction rather than biosorption. The cell-free suspension had a Cr(VI) removal rate of 68.5.%, which was significantly higher than that of cell-free extracts and cell debris, indicating Cr(VI) reduction mainly occurs extracellularly, and possibly mediated by extracellular reductase. The reduced Cr was mainly distributed in the extracellular suspension, and a small amount was accumulated in the cells. In conclusion, Bacillus sp. CRB-B1 was a highly efficient Cr(VI) reducing bacteria, which has potential in the remediation of Cr(VI)-containing water and soil.

Simultaneous Biosorption of Chromium (III) and Chromium (VI): Application of Multiple Response Optimizations

This work aims, optimization of simultaneous biosorption of Cr(III) and Cr(VI) onto Gelidilla acerosa, a marine macro algae using multiple response optimization combined with central composite design of design of experiments. The three important physicochemical parameters of biosorption such as initial pH, initial concentration of metal solution and biosorbent dosage were optimized. The most favorable condition for simultaneous removal of Cr(III) and Cr(VI) were: pH 2.8, initial concentration 20 mg l-1 and biosorbent dosage 0.05g with maximum overall desirability of 1.0. Surface morphological features of biosorbent were studied using FTIR. The nature of biosorption was analyzed by fitting the equilibrium data to various adsorption isotherms and found that both Langmuir and Freundlich model were best fitted with R2: 0.99 for both chromium species. The maximum biosorption capacities predicted from Langmuir model were 285.71 mg g-1 for Cr(III) and 270.27 mg g-1 for Cr(VI). The pseudo-second order kinetic model was found to be proper approach to demonstrate biosorption kinetics indicating chemisorption with film diffusion as the rate controlling mechanism. The results demonstrated that multiple response optimization combined with central composite design using desirability function was best approach for optimization of simultaneous biosorption of Cr(III) and Cr(VI) from aqueous medium.

Chromium tolerance and accumulation in Aspergillus flavus isolated from tannery effluent

Cr(VI) tolerance in Aspergillus flavus, strain SFL, isolated from tannery effluent was measured and compared with a reference strain of A. flavus, A1120. On solid medium, SFL had a high level of Cr(VI) tolerance (1,600 mg/L), which was 16 times that of A1120 and greater than most previously analyzed fungal strains. When in 100 mg/L of Cr(VI), SFL completely depleted Cr(VI) within 72 h while A1120 depleted 85% of Cr(VI). SFL was more effective in reducing extracellular Cr(VI) than A1120. While A1120 showed greater biosorption of Cr(VI) than SFL, intracellular accumulation was approximately 50% greater in SFL and was more energy-dependent than A1120. Cr(VI) modified the external surface of the hyphae. Cr speciation detected the presence of only Cr(III), corresponding to Cr(OH)3 , which precipitated on the hyphal surface. Cr(VI) bound to the functional groups carboxyl, amine, and hydroxyl in both SFL and A1120. Transmission electron microscopy energy-dispersive X-ray detected Cr on the fungal wall and within membrane-bound organelles of the cytoplasm. In conclusion, the greater tolerance of SFL to Cr(VI) relative to A1120 is due to more effective energy-dependant uptake of Cr(VI) into the cell and increased capacity of SFL to store Cr in intracellular vacuoles compared with A1120.

Calcium alginate entrapped Eupatorium adenophorum Sprengel stems powder for chromium(VI) biosorption in aqueous mediums.

A novel biosorbent, Eupatorium adenophorum Sprengel-alginate beads was used for chromium(VI) biosorption from aqueous solutions. Biosorption process was optimized at pH 2.0, biomass concentration 1.0 g/L, contact time 60 min, and temperature 30 oC respectively. Maximum uptake capacity of Cr(VI) was calculated at 28.011 mg/g. It was found that the overall biosorption process was best described by pseudo second-order kinetics with high correlation coefficient values. Intraparticle diffusion model suggested that Cr(VI) biosorption may proceed within multiple steps. Data obtained from the batch studies confirmed well to the Langmuir, Temkin, and Hill-der Boer isotherm models. Scatchard plot analysis further supported the mono-layer biosorption of Cr(VI) ions on Eupatorium adenophorum Sprengel-alginate beads as described by Langmuir isotherm model. Numerical values of E obtained from Dubinin-Radushkevich isotherm model identified the physisorption as predominant mechanism for Cr(VI) biosorption. The negative values of ΔGo confirmed the spontaneous and feasibility nature, whereas positive value of ΔHo showed the endothermic nature of biosorption process. Positive value of ΔSo indicated an increase in the randomness at the solid/solution interface during the biosorption process. The endothermic nature of Cr(VI) biosorption was also described by Temkin isotherm model. The results indicated that Cr(VI) biosorption was not significantly affected by the presence of co-ions at lower concentrations. Desorption of Cr(VI) ions from metal-loaded Eupatorium adenophorum-alginate beads was observed at 92.091% with 0.5 M HNO3 solution in solid to liquid ratio of 1.0 g/L.