Biosorption Of Chromium Research Articles

LIGNOCELLULOSE-RICH SPENT MUSHROOM COMPOST FOR BIOSORPTION OF HEAVY METALS FROM EFFLUENT SAMPLES

"Lignocellulose-rich spent mushroom compost (SMC) has been found to contain various functional groups that can be used for biosorption. Effluent samples collected from common effluent treatment plants (CETPs), i.e. Ludhiana Electroplaters Association (L-CETP) and Punjab Small Industries and Export Corporation (PSIEC) Leather Complex, Jalandhar (J-CETP), were analyzed for different waste water quality parameters, such as Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and heavy metal profile. Chromium was the dominant heavy metal in both samples, with a concentration of 226.62 ppm in L-CETP and 1.83 ppm in J-CETP. Spent compost of different cultivated mushrooms was analysed for its use in chromium biosorption by varying physicochemical parameters. Maximum removal of Cr was obtained at an initial metal concentration (Ci) of 50 mg/L, pH 6 and temperature of 25 °C. Experimental results were well fitted to the Langmuir and Freundlich isotherms. Fourier transform infrared (FT-IR) spectra showed a shift in peaks, indicating the functional groups involved in biosorption of chromium."

Removal of Chromium(VI) from Contaminated Water Using Untreated Moringa Leaves as Biosorbent

Biosorption of chromium (Cr(VI)) is studied by using raw (chemically not modified) Moringa (Moringa Oleifera) leaf powder without any pretreatment. Cr(VI) is one of the potentially harmful heavy metals found in industrial wastewater. In the Moringa leaf powder, the presence of a significant amount of organic acids form the source for the biosorption of Cr(VI). The concentration of Cr(VI) in the feed solution is varied and different dosages of the proposed biosorbent are used to study its efficiency in the removal of Cr(VI). The concentration of Cr(VI) is varied from 1 ppm to 20 ppm while the amount of biosorbent is varied from 0.5 g to 2.5 g. The equilibrium time for adsorption of Cr(VI) is observed to vary between half an hour and 90 min. The metal removal efficiency varied from 30% to 90% which is a significant achievement compared to other conventional methods which are either energy-intensive or not cost effective. The experimental results are modeled using Langmuir, Freundlich and Redlich–Peterson isotherms. The metal removal efficiency is attributed to the chelating effect of carboxylate and hydroxyl groups present in the moringa leaves and is confirmed from the FTIR analysis. Further molecular docking simulations are performed to confirm the binding of the metal to the speculated sites within the different acids present in the moringa leaves. Untreated green moringa leaf powder used as a biosorbent in this study leads to a sustainable and cheaper option for treating wastewater containing Cr(VI).

Biosorption of Cadmium, Lead and Chromium from Aqueous Solution Using Mountain Ebony Pod

Cadmium (Cd), lead (Pb), and chromium (Cr) are among the known hazardous metals that have detrimental effects on ecosystem as well as human beings. Biosorption of Cd(II), Pb(II) and Cr(VI) from aqueous solutions by Mountain Ebony pod (ME) powder using batch technique was researched in the present study. The ME material was characterised using Fourier transform infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM). The biosorption study was investigated as a function of pH, biosorbent dosage, contact time, initial metal ion concentration, and temperature. The kinetic study showed that the biosorption of the Cd (II), Pb (II) and Cr (VI) ions followed pseudo second order kinetic model while the equilibrium data followed the Langmuir model. The maximum biosorption capacities of ME for Cd (II), Pb (II) and Cr (VI) were 68.07, 61.25 and 40.47 mg g–1, respectively. Thermodynamic parameters (ΔGo and ΔSo ) revealed that the biosorption processes for the three metal ions were feasible and spontaneous, and the randomness at the biosorbent-metal solution interface increased. The values of standard enthalpy change (ΔHo ) indicated that biosorption process for Cd (II) was endothermic whereas the processes Pb (II) and Cr (VI) removal by ME powder were exothermic. The results of the study showed that ME biosorbent could be used as an alternative, low-cost, green and eco-friendly material for removal of Cd (II), Pb (II) and Cr (VI) ions from aqueous solutions and wastewater.

Biosorption of heavy metals by dry biomass of metal tolerant bacterial biosorbents: an efficient metal clean-up strategy.

Heavy metals discharge at an unrestrained rate from various industries into the environment pose serious human health problems. Considering this, the present study aimed at exploring the metal biosorbing potentials of bacterial strains recovered from polluted soils. The bacterial strains (CPSB1, BM2 and CAZ3) belonging to genera Pseudomonas, Bacillus and Azotobacter expressing multi-metal tolerance ability were identified to species level as P. aeruginosa, B. subtilis and A. chroococcum, respectively, by 16S rRNA partial gene sequence analysis. The biosorption of cadmium, chromium, copper, nickel, lead and zinc by three dead bacterial genera were studied as a function of metal concentration, variable pH of the medium and reaction (contact) time. The three bacterial strains exhibited a tremendous metal removal ability which continued even at the highest tested concentration of some metals. Later, a decline in the percentage of biosorbed metals was recorded as the metal concentration was increased with the simultaneous generation of a driving force to overcome mass transfer resistance for movement of metal ions between the solution and the surface of adsorbent. Among test bacteria, B. subtilis biosorbed a maximum of 96% chromium at 25μgmL-1 while the maximum percentage (91%) of biosorbed metals recorded at 400μg CdmL-1 was observed for P. aeruginosa. The sorption of metal ions by dead biomass of three bacterial genera at optimum conditions followed the order-(i) B. subtilis BM2: Pb > Cu > Ni > Cd > Cr, (ii) A. chroococcum CAZ3: Cr > Cd > Cu > Ni > Pb and (iii) P. aeruginosa CPSB1: Cd > Cr > Ni > Cu > Pb > Zn. It was found that the optimum pH for metal adsorption ranged between pH8 and 9 which, however, declined substantially at pH5.0 for all three bacterial strains. In general, the biosorption of Cd, Cr, Cu, Ni and Pb by B. subtilis and A. chroococcum and such metals along with Zn by P. aeruginosa occurred maximally up to 60min of bacterial growth. The adsorption data with regard to five metals provide an outstanding fit to the Langmuir and Freundlich isotherms. The biosorptive ability of three bacterial genera correlated strongly (r2 > 0.9) with each metal. The bacteria belonging to two Gram-negative genera Pseudomonas (P. aeruginosa) and Azotobacter (A. chroococcum) and one Gram-positive genus Bacillus (B. subtilis) demonstrated exceptional metal removal efficiency and, hence, provides a comprehensive understanding of metal-bacteria sorption process which in effect paves the way for detoxifying/removing metals from contaminated environment.

Reduction and Biosorption of Cr(VI) from Aqueous Solutions by Acid-Modified Guava Seeds: Kinetic and Equilibrium Studies

Abstract The use of guava seeds (GS) and acid-modified guava seeds (MGS) for the removal of Cr(VI) from aqueous solutions was investigated. Batch-type experiments were performed with Cr(VI) aqueous solutions and biosorbents to determine the kinetic and equilibrium sorption parameters. Results indicated that GS and MGS were capable of reducing and remove Cr(VI) from solutions, but the reduction was only observed at some experimental conditions. Infrared analysis showed that several functional groups were involved in the reduction, and biosorption of Cr(VI), particularly alcohol, phenolic, carboxylic, and methoxymethyl structures. The mechanisms of reduction and biosorption depended upon the type of biosorbent, pH, and temperature of the system. The pseudo-second-order kinetic model describes the kinetic sorption data, and the Langmuir-Freundlich (L-F) model describes the isotherm data in most cases. Significantly high total chromium biosorption capacities were obtained. Acid modification of guava seeds improves chromium biosorption performance.

Biosorption and speciation of chromium in aqueous medium using water hyacinth

ABSTRACT This study focuses on the speciation of chromium that occurs during biosorption of chromium in an aqueous medium using dried and powdered stems, roots and leaves of water hyacinth (Eichhornia crassipes ) as biosorbents. The effects of physico-chemical parameters like pH and biosorbent dosage on the removal of Cr(VI) and its conversion to Cr(III) were investigated through batch studies. FTIR spectroscopy plots of raw and chromium loaded biomass were compared to explore the functional groups actively involved in biosorption of chromium. Pseudo-second-order kinetic model was found to be applicable to all the parts of water hyacinth. Langmuir isotherm showed better fit for all the parts with maximum removal capacity of 13.05 mg/g, 26.74 mg/g and 39.21 mg/g for stems, roots and leaves, respectively. Structural analysis using SEM showed the presence of large specific surface area on stems, roots and leaves, thus, affirming their suitability for biosorption process. Chemical analysis using EDX confirmed uptake of chromium by all the parts of water hyacinth. The build-up of Cr(III) concentration in the solution as a result of the reduction of Cr(VI) was also studied. Reduction of Cr(VI) to Cr(III) was found to be maximum with water hyacinth leaves at an optimum dosage of 12 g/L at pH 1 within the contact time of 45 min. Overall, the biomass of E. crassipesshowed good potential at low pH for treatment of industrial effluents containing Cr(VI).

Waste Musa acuminata residue as a potential biosorbent for the removal of hexavalent chromium from synthetic wastewater

The present study is undertaken to evaluate the feasibility use of Musa acuminata bract as (MAB) biosorbent towards the removal of hexavalent chromium from synthetic wastewater. Chromium is a potential pollutant to all forms of life and therefore efficient way of treatment is necessary even towards lower chromium concentration removal. The objectives of the present research include optimizing parameters influencing biosorption of hexavalent chromium, pH, dosage of the MAB, influent Cr(VI) concentration, and time. The MAB was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) analysis, to examine the surface functional group and structural assessments of the MAB. Optimum pH for the effective biosorption was found to be 2.0, and the biosorption capacity was found to be 36.84 mg/g with 87.55% of Cr(VI) removal. Further experiments were carried out at the optimized pH for other parameters influence on the Cr(VI) biosorption. Langmuir isotherm shows better fit than the rest of the models because of the higher R2 value. The data were analyzed using pseudo-first-order, pseudo-second-order, intra-particle diffusion, and Elovich models. Higher degree of coefficient of determination was obtained for the pseudo-second-order kinetic model. The results of the present study suggested that MAB could be used beneficially in treating industrial effluents containing hexavalent chromium through further research study of column biosorption.

Biosorption of chromium and nickel from aqueous solution using pine cones, eucalyptus bark, and moringa pods: a comparative study

AbstractLow-cost local plants (eucalyptus bark, moringa pods, pine cones) have been successfully used to remove heavy metals from simulated wastewater. Two types of heavy metals were chosen to study the removal capacity, nickel (Ni) and chrome (Cr), with a concentration of 400, 600, 900 ppm. The results show that moringa pods have the best removal capacity for heavy metals with percentages of 90–99% for both metals, Ni and Cr, for the eucalyptus bark the removal capacity percentages reach 50–98%, while for the pine cones revealed a lower removing capacity with percentages of 40–99%, indicating that this is the lowest removal capacity. The data has been best fitted to the Langmuir adsorption model for all plants, while the Freundlich adsorption model could not fit the obtained results at the experimental conditions. The kinetic study has revealed that the first-order kinetic model successfully describes the kinetics of Ni adsorption, while the second-order describes the kinetics of Cr adsorption. The removal of heavy metals (Ni, Cr) was obtained when moringa was used; its highest removal efficiency was reached within 20 minutes. On the other hand, other plants (eucalyptus bark, pine cone) removal efficiency was attained in more than two hours. The removal is remarkable even at a high concentration of heavy metals, especially with the moringa plant.

Innovative low-cost biosorption process of Cr6+ by Pseudomonas alcaliphila NEWG-2

Chromium is one of the heavy metal pollutants that causing risky health issues when discharged into the aquatic ecosystems. The current investigation focused on the bioremoval of Cr6+ depending on the bacterial sorption process by using Pseudomonas sp. NEWG-2 which was identified on the basis of morphological, cultural characteristics, 16S rRNA sequencing and phylogenetic analysis as Pseudomonas alcaliphila strain NEWG-2. It is clear from the FCCD experiments that the bacterium can grow normally and remove 96.60% of 200 mg/l of Cr6+ using yeast extract (5.6 g/l), glucose (4.9 g/l), pH (7) for 48 h incubation period. SEM and EDS analyses proved that the Cr6+ was biosorbed by P. alcaliphila NEWG-2. FTIR spectra indicated that the phenolic, carbonyl ester, acetyl, carboxylate, alkanes and carbonyl were the main groups involved in the chromium biosorption. Of the equilibrium isotherms models, the Langmuir model was more obedient, with a maximum uptake (qmax) of 10 mg/g (bacterial-alginate beads), than the Freundlich one. The findings reveal the efficiency of P. alcaliphila NEWG-2 in Cr6+ biosorption, with feasibility in the treatment of chromium-contaminated water as a green-technology tool. Interestingly, to the best of our knowledge, this is the first report on Cr6+ biosorption process by P. alcaliphila.

<p>Chromium (VI) biosorption using novel biosorbents from <em>Calotropis gigantea</em></p>

Biosorption of heavy metals using plant based materials contributes a significant role in reducing environmental pollution. Here, we investigated removal of hexavalent chromium metal [Cr (VI)] from an aqueous solution by alkali treated novel biosorbent prepared from Calotropis gigantea (L.) Dryand. ex W.T. Aiton leaves and flower. Batch studies were conducted to examine the process parameters. The effect of pH, biomass dosage, initial metal ion concentration, contact time was evaluated keeping temperature and agitation speed constant. As much as 70% removal of Cr (VI) was observed with a leaf biomass dosage of 4 g/L at pH 2.0 and initial metal ion concentration of 1.0 ppm. data obtained from the experiment were used to calculate the equilibrium data with two variable isothermal models. Freundlich and Temkin isotherm models suited the process for leaves and petals, respectively. Pseudo second order reaction suited in the kinetic study. The data obtained from the study suggests that biosorbents derived from C. gigantea has effective chromium biosorption capability. The results indicate that C. gigantea could be used as an efficient, cost effective and environmental friendly biosorbent for the treatment of chromium contaminated water bodies

Determination of Kinetic Parameters in the Biosorption of Chromium (VI) in Aqueous Solution

he contamination of aquatic bodies by heavy metals is a growing environmental problem, making more critical the study and development of new technologies and materials that can be used for the removal of this type of pollutants. Thus, adsorption arises using residual materials as a sustainable alternative for the solution to this problem. In the present study, the use of plantain peels in the adsorption of Cr (VI) in a batch system is proposed, establishing the kinetics of the process at different temperature conditions, particle size and amount of adsorbent. The fit of the data was done using the theoretical models of pseudo-first-order, pseudo-second-order and Elovich. From the data, it is established that the pseudo-second-order and Elovich models show a better adjustment, so that the adsorption in the material occurs on two adsorption sites and that such process is related to chemical adsorption. The maximum adsorption capacity of Cr (VI) was found at a condition of 0.0306 g, 0.6775 mm and 55°C at a time of 420 min establishing the efficient use of plantain peels for the removal of the ion metallic in the studio.

Biosorption of chromium (VI) from textile waste water using luffa cylindrica activated carbon

AbstractLuffa cylindrica was applied as a low‐cost adsorbent for removing chromium (VI) from textile industry effluent in this study. The adsorbent was characterized using scanning electron micrograph (SEM). A batch mode experiment was conducted to study the effect of pH, contact time, and adsorbent dosage on the adsorptive potential of the prepared luffa cylindrica activated carbon. The characterization results from SEM indicate that the adsorbents' potential was fully exploited in this study. A significance test conducted using ANOVA indicated that contact time and adsorbent dosage had the most effect on the adsorptive removal of Cr (VI). The optimum removal efficiency was 99.90% at pH 8.0, 99.8% at 60 min of contact time, and 99.82% at an adsorbent dosage of 1.0 g. The experimental results were analyzed using the Langmuir and Freundlich adsorption isotherm models, and the Freundlich isotherm provided a better correlation for Cr (VI) adsorption. The kinetic data by the pseudo‐first‐order kinetic model gave a better fit than the pseudo‐second‐order kinetic model.

Kinetics and equilibrium studies on biosorption of hexavalent chromium from leather tanning wastewater by Sargassum tenerrimum from Chabahar-Bay Iran

The traditional leather tanning is one of the oldest technologies which produces effluents containing different pollutants, including Cr(VI) oxyanions. In this lab-scale study, batch experiments were conducted to measure Cr(VI) removal capacity of Sargassum tenerrimum. The efficacy of biosorption was optimized considering variables including pH, temperature, initial chromium concentration, as well as biomass particle size and dosage. Surface characteristics of S. tenerrimum and its changes after Cr(VI) adsorption were investigated by BET/BJH, SEM-EDX and FT-IR techniques. Desorption studies were carried out to investigate the capability of multiple uses of the algal biomass, with the results showing a high performance of five successive sorption/desorption cycles. The maximum biosorption was obtained with the biomass particle size of 0.6 mm at 25 °C at pH 2. The Langmuir isotherm model was recognized as the most correlated model of biosorption where the maximum biosorption capacity (qmax) was obtained to be 37.7 mg/g dry biomass. The batch experiments were repeated using real tannery wastewater under the optimized conditions and the biosorbent could remove about 88% of Cr(VI) from the real wastewater.

Optimization using central composite design (CCD) of response surface methodology (RSM) for biosorption of hexavalent chromium from aqueous media

In this study, unmodified biosorbent was obtained from Arachis hypogea husk and applied to remove hexavalent chromium [Cr(VI)] from aqueous media through batch technique. The independent variables (contact time, pH of the solution and initial Cr(VI) concentration) influencing the adsorption process were optimized by central composite design (CCD) found in response surface methodology of the Design-Expert software 12.0.0 at a fixed temperature of 30 ± 0.5 °C. Furthermore, equilibrium sorption isotherms and kinetics studies were also investigated. The ANOVA component of the CCD indicated that all the process independent variables investigated had significant impacts on the sorption capacity of Cr(VI) by Arachis hypogea husk. The obtained experimental data showed that at the optimized 120 min contact time, 8.0 pH of the aqueous solution and 50 mg/L initial Cr(VI) concentration resulted in an optimum adsorption capacity of 2.355 mg/g. Equilibrium sorption isotherm and kinetic studies showed that Redlich–Peterson adsorption isotherm and pseudo-second-order kinetic models fitted well to the equilibrium data. The unmodified adsorbent from Arachis hypogea husk was found to be efficient for Cr(VI) decontamination from the aqueous media.

Biosorption of Chromium and Nickel from Aqueous Solution by Chicken Feather

Background & Aims of the StudyHeavy metals and its compounds are toxic pollutants that have priority in the studies due to their potential harm to human health.Materials and MethodsThis study evaluated the potential of a chicken feather for the removal of nickel and chromium from aqueous solutions. The chicken feather was prepared from aviculture for nickel and chromium removal from aqueous solutions. The effects of pH, contact time, adsorbent dosage, and initial metal concentration on Ni and Cr removal were also evaluated in this study. Freundlich and Langmuir isotherm models were used to characterize the biosorption of the mentioned metals onto the chicken feather.ResultsBased on the findings, the maximum removal of metals was found in a contact time of 3 h, 1 g/L of adsorbent, pH 5 (for Ni) and 6 (for Cr), and concentration of 1 mg/l of metals. According to the Langmuir isotherms, the maximum biosorption capacities (qm) of Cr and Ni were 22.3 and 119.05 mg/g, respectively.ConclusionThe results showed that chicken feathers can absorb chromium and nickel at low concentrations. However, the ability and possibility of the use of the chicken feather are limited for the treatment of contaminated wastewater at high concentrations.

Biosorption of hexavalent chromium from aqueous solution by polyethyleneimine-modified ultrasonic-assisted acid hydrochar from Sargassum horneri.

In this study, an efficient route to synthesizing polyethyleneimine-modified ultrasonic-assisted acid hydrochar (PEI-USAH) is developed and reported. Ultrasonic irradiation technique was used as surface modification method to shorten the crosslinking reaction for hydrochar and polyethyleneimine (PEI). The PEI-USAH showed an excellent adsorption capacity for Cr(VI) from aqueous solution. The physicochemical properties of this PEI-modified adsorbent were comparatively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller analysis and CNHS analysis. The effects of contact time, initial pH, and biosorbent dose on adsorption capacities were investigated. The batch adsorption experiments showed that PEI-USAH possessed the maximum adsorption capacities of 94.38 mg/g and 330.84 mg/g for initial Cr(VI) concentration of 100 mg/L and 500 mg/L, respectively. Furthermore, this adsorption process could be fitted to Langmuir adsorption and described by the pseudo second order kinetic model. Based on the above findings, PEI-USAH could be used as a potential adsorbent for removal of Cr(VI) from wastewater.

Comparative biosorption of chromium (VI) using chemically modified date pits (CM-DP) and olive stone (CM-OS): Kinetics, isotherms and influence of co-existing ions

Chemically modified date pit (CM-DP) and olive stone (CM-OS) were studied for their biosorption capacity for hexavalent chromium (Cr(VI)) removal in the aqueous phase. The effect of changing the process conditions, such as the initial Cr (VI) concentration, pH, biosorbent dosage, ionic strength, presence of other ions and temperature were investigated. It showed that at pH = 2, biosorbent dosage >4 g/L and a low ionic strength, both biosorbents showed best biosorption capacity of the Cr(VI) removal. Various isotherm models were applied to fit the experimental data and the Freundlich isotherm model was the best fitting isotherm model for the biosorption experimental data of both biosorbents. The maximum biosorption capacities of CM-DP and CM-OS were found to be 82.63 and 53.31 mg/g respectively, which is comparable to other materials. In the kinetic study, the pseudo second order model can best describe the biosorption process of both biosorbents and the intraparticle diffusion was not the rate-limiting step indicating the contribution of film diffusion in the Cr(VI) removal processes.

Hexavalent chromium removal and total chromium biosorption from aqueous solution by Quercus crassipes acorn shell in a continuous up-flow fixed-bed column: Influencing parameters, kinetics, and mechanism.

Continuous fixed-bed column studies were carried out, utilizing acorn shell from Quercus crassipes Humb. & Bonpl. (QCS), in order to remove total chromium and Cr(VI) from aqueous solution. Effects of various fixed-bed column parameters such as influent solution pH, influent flow rate, QCS bed height, and influent Cr(VI) concentration were investigated. Results from the fixed-bed column experiments demonstrate that total chromium biosorption and Cr(VI) removal by QCS depend strongly on the pH of influent solution. The highest capacities for Cr(VI) removal and total chromium biosorption are about 181.56 and 110.35 mg g-1 and are achieved at influent solution pH of 1.0 and 2.0, respectively. Besides this, total chromium biosorption capacities increased from 104.25 to 116.14 mg g-1, 109.07 to 117.44 mg g-1, and 85.02 to 129.87 mg g-1, as bed height, inlet flow rate, and influent Cr(VI) concentration increased from 1.7 to 6.5 cm, 0.25 to 1 mL min-1, and 50 to 400 mg L-1, respectively. The dose–response model defines the entire breakthrough curve for total chromium biosorption onto QCS, under all experimental conditions. X-ray photoelectron spectroscopy (XPS) and biosorption kinetic studies revealed that QCS is able to remove toxic Cr(VI) from acidic liquid solution by means of a complex mechanism that involves the binding of Cr(VI) oxyanions to positively charged groups present at the QCS surface, after which the Cr(VI) species are reduced to Cr(III) by adjacent electron donor groups, and the generated Cr(III) ions then become partially bound to the QCS biomass and partially released into the liquid phase. Results show that QCS can be employed as an easily accessible, abundant, eco-friendly, and inexpensive biosorbent for the removal of total chromium and Cr(VI) from Cr(VI) solutions, in continuous operation.

Assessment of biosorbents for chromium removal from aqueous media

In the present work, the potential of biosorbents such as leaves and saw dust of neem tree (Azadirachta indica), different parts (stems, roots and leaves) of water hyacinth (Eichhornia crassipes), sewage sludge and brewery byproducts was investigated for removal of chromium from aqueous media. The most conducive operating conditions such as pH, biosorbent dosage and equilibrium time were examined through batch studies. Maximum removal of chromium and highest reduction of Cr (VI) to Cr (III) was seen with neem leaves. Fourier transform infrared spectra of the biosorbents were recorded at the optimized conditions to identify the functional groups responsible for biosorption of chromium. The suitability of the biosorbents was tested by fitting the equilibrium data with Langmuir and Freundlich isotherms. Langmuir isotherm showed better fit for neem leaves and all the parts of water hyacinth while Freundlich isotherm showed better fit for neem saw dust, sewage sludge and brewery byproducts. Overall, the results showed that sorption-coupled reduction mechanism is manifested by all the biosorbents which make them suitable for treatment of chromium from industrial wastewaters of low pH.

Kinetic and Equilibrium Study on Biosorption of Chromium using Tamarind Fruit Shell

The Tamarindus indica, a plant based waste material was investigated for biosorption of chromium from industrial waste water. The various parameters were evaluated to know the effects on biosorption. The experiments were conducted in batch process. The maximum contact time obtained was 50 min, dosage 1.2gm, metal on concentration 1mg/l and pH 5. The data estimated more suitable to Langmuir model than Freundlich model. The kinetic data well correlated to second order. The thermodynamic parameters were also evaluated. The results revealed that tamarind fruit shell powder (Tamarindus indica) was favourable for biosorption of chromium from waste water. The maximum removal of chromium was 82%.