Maximum Chromium Removal Research Articles

Removal of chromium from synthetic wastewater using MFI zeolite membrane supported on inexpensive tubular ceramic substrate

A mordenite framework inverted (MFI) type zeolite membrane was produced on inexpensive tubular ceramic substrate through hydrothermal synthesis and applied for the removal of chromium from synthetic wastewater. The fabricated ceramic substrate and membrane was characterized by diverse standard techniques such as X-ray diffraction, field emission scanning electron microscope, porosity, water permeability and pore size measurements. The porosity of the ceramic substrate (53%) was reduced by the deposition of MFI (51%) zeolite layer. The pore size and water permeability of the membrane was evaluated as 0.272 μm and 4.43 × 10–7 m3/m2s.kPa, respectively, which are lower than that of the substrate pore size (0.309 μm) and water permeability (5.93 × 10–7 m3/m2s.kPa) values. To identify the effectiveness of the prepared membrane, the applied pressure of the filtration process and initial chromium concentration and cross flow rate were varied to study their influence on the permeate flux and percentage of removal. The maximum removal of chromium achieved was 78% under an applied pressure of 345 kPa and an initial feed concentration of 1,000 ppm. Finally, the efficiency of the membrane for chromium removal was assessed with other membranes reported in the literature.

Hexavalent Chromium Adsorption onto Fire Clay

Cr (VI) as an extremely soluble and highly toxic ion is present in effluents of industries and imposes severe health-related problems. The current study aimed to provide information on Cr (VI) adsorption potential of fire clay as an abundant, cost-effective and untried material. Batch adsorption trials of Cr (VI) were performed to investigate the effects of pH, contact time, initial metal ion concentration and the adsorbent dosage. Langmuir, Freundlich and Dubinin–Radushkevich isotherm models were used to evaluate the equilibrium data at 20°C and regression coefficients were derived. Moreover, adsorption kinetics was analyzed using the pseudo-first-order and the pseudo-second-order kinetic models. Maximum chromium removal was found at pH 2.0. A kinetic study yielded an optimum equilibrium time of 90 minutes with an adsorbent dose of 2.5 g/50 mL. Results suggested that the equilibrium adsorption described by the Freundlich model. The kinetic data of the sorption showed that the pseudo second-order equation was the more appropriate. The results of the study indicated that fire clay was not a suitable adsorbent for Cr (IV). Apart from relatively long equilibrium time, the efficiency was not satisfactory. Therefore, searching for better alternative and/or modify such adsorbent is necessary in this area.

Effect of pH on the adsorption kinetics of Cr(VI) on sodium chlorite treated coconut coir

Coconut coir is a low cost bioadsorbent containing large amount of lignin. In this research work sodium chlorite treated coconut coir (SCT CC) was used to remove Cr(VI) from industrial wastewater by implementing adsorption technique through the investigation of the adsorption kinetics at different pH values. The maximum Cr(VI) adsorption capacity of SCT-CC at pH 2.00, 3.00, 5.00 and 7.00 was 24.75, 23.92, 16.07 and 6.31 mg Cr(VI) g-1 SCT-CC respectively with the dose of 7.5 g/L. The equilibrium established within three hours resulting the maximum removal (95%) of chromium. The adsorption kinetics of Cr(VI) on SCT-CC was found to be regulated by pH of the system. Rate of adsorption was the highest at pH 2.00 and the kinetic data well-fitted with Ho's pseudo second order kinetics. Fourier transform infrared (FT-IR) spectrometry analysis indicated that the carbonyl (C=O) groups and hydroxy (O-H) groups from the lignin structure in coconut coir may be involved in the mechanism of Cr(VI) adsorption and it showed good agreement with the kinetic data to elucidate the adsorption mechanismBangladesh J. Sci. Ind. Res. 51(2), 95-100, 2016

Kinetic, isotherm and thermodynamic studies on biosorption of chromium(VI) by using activated carbon from leaves of Ficus nitida.

BackgroundKinetics, thermodynamics and equilibrium of the removal of chromium(VI) ions from aqueous solutions by using chemically activated leaves of Ficus nitida were investigated. Adsorption runs were performed as a function of pH, mass of biosorbent, contact time, initial concentration of chromium(VI) ions and temperature.ResultsThe optimum conditions for maximum removal of chromium(VI) ion from aqueous solutions (about 99 %) were found to be 0.80 g of chemically activated leaves of F. nitida, 25 min, 50.0 mg/L of initial concentration of chromium(VI). Values of thermodynamic activation parameters proved that the biosorption process is spontaneous and endothermic. Results were analyzed by using Langmuir, Freundlich and Temkin models.ConclusionsResults of the study showed that the chemically activated leaves of F. nitida can be used as low cost, ecofriendly and effective sorbent for the removal of chromium(VI) from aqueous solutions.Graphical abstractFicus nitida is an efficient bio-sorbent used for removal of Cr(VI) ion

Biosorption of hexavalent chromium in a tannery industry wastewater using fungi species

The isolated fungi species of different kinds from chromium contaminated soil sites located in Nagalkeni, Chennai were used for reducing chromium(VI) in a tannery industry wastewater of Nagalkeni, Chennai. The experiments were conducted to know biosorption potential of isolated fungi species for removing chromium(VI) in a tannery industry wastewater against the different pH, fungi biomass and chromium(VI) concentration (dilution ratio). The results of this study indicated that the order of maximum removal of chromium(VI) by an isolated fungi species at an optimum pH of 3, fungi biomass of 4g and an initial chromium(VI) concentration of 18.125 mg/L (dilution ratio 4) is A. niger > A. flavus > A. fumigatus > A. nidulans > A. heteromorphus > A. foetidus > A. viridinutans. This study found that the maximum removal of chromium(VI) was achieved by Aspergillus niger (96.3 %) than other fungi species at chromium(VI) concentration of 18.125 mg/L in a tannery industry wastewater. The chromium removal from tannery industry wastewater was validated by checking chromium removal in an aqueous solution and by checking the removal efficiency of other parameters in a tannery industry wastewater using same isolated A. niger. Biosorption model was proposed to simulate the experimental condition for removing chromium(VI) in a tannery industry wastewater by all isolated fungi species. The R 2 and x 2 values of the proposed model predicted that the proposed biosorption model is very much useful for predicting the trend of reduction potential of chromium(VI) in a tannery industry wastewater by all isolated fungi species. This study suggested that one could select the type of fungi species, ion concentration level, selection of treatment period, quantity of biomass to be used, and pH level of the medium, to achieve the highest reduction of any toxic metals from any contaminated water, wastewater and soil environment.

Sorption of hexavalent chromium from water and water–organic solvents onto an ion exchanger Tulsion A-23(Gel)

The sorption of hexavalent chromium from water and water–organic solvents onto an ion exchange resin Tulsion A-23(Gel) is reported under various experimental conditions such as initial metal concentration, contact time, temperature, pH, and dielectric constant of the medium. The batch ion-exchange process was relatively fast and it reached equilibrium after 110 min of contact. The ion-exchange process, which is pH dependent, showed maximum removal of chromium(VI) in the pH range 7.0–9.0 for an initial chromium(VI) concentration of 0.0011 M. The equilibrium related to Tulsion A-23(Gel) ion-exchange capacity and the total amounts of the ion exchange were obtained using plots of the Langmuir and Freundlich adsorption isotherms. Various thermodynamic parameters have also been evaluated, including differential adsorption enthalpy and entropy.

Optimization of chromium(VI) biosorption using gooseberry seeds by response surface methodology

The current investigation presents the role of gooseberry ( Phyllanthus acidus ) seeds as an effective biosorbent for remediating chromium(VI)), a toxic heavy metal pollutant commonly found in effluents from tanneries and relevant industries. Biosorption was affected by pH, temperature and initial metal concentration. Furthermore, there is a need to understand the holistic effect of all variables to ascertain the best possible conditions for adsorption, therefore, these factors were considered and a total of 17 trials were run according to the Box Behnken design. Quadratic model had maximum R 2 value (0.9984) and larger F value (1109.92). From the Analysis Of Variance table and R 2 value, quadratic model was predicted to be the significant model with the best fit to the generated experimental data. The optimal parameters obtained from the contour plot for the maximum removal of chromium(VI) were initial metal concentration of 60 mg/L, pH value of 2, and temperature of 27∞C. Under these conditions, maximum removal of 92% was obtained. Thus this biosorbent substantially eliminates chromium(VI) under optimized conditions, enabling its use in larger scale.

Optimization of process parameters for the removal of chromium(VI) and nickel(II) from aqueous solutions by mixed biosorbents (custard apple seeds and Aspergillus niger) using response surface methodology

The mixture of custard apple seeds and Aspergillus niger was used as biosorbents for the removal of chromium(VI) and nickel(II) from the contaminated water. The batch biosorption process was carried out and it was influenced by the different operating parameters such as initial metal ion concentration, pH, temperature, and biomass loading. The essential process variables were optimized using response surface methodology (RSM) based on the central composite design (CCD) experiments. The ANOVA data obtained from the RSM studies were analyzed using a second-degree polynomial equation and the study of the determination of contour plots showed the interactions among the variables of the biosorption system. The optimum conditions for the removal of chromium(VI) was found to be: initial chromium(VI) concentration = 100 mg/L; pH 3.0; temperature = 36°C, and biosorbent loading = 10 g/L. At these optimized conditions, the maximum removal of chromium(VI) was found to be of 95.7%. The optimum conditions for the removal of nickel(II) was found to be: initial nickel(II) concentration = 100 mg/L; pH 5.6; temperature = 30°C, and biosorbent loading = 10 g/L. At these optimized conditions, the maximum removal of nickel(II) was found to be of 96.41%. The mixed biosorbents showed better adsorption properties towards the removal of chromium(VI) and nickel(II) ions from the aqueous solutions. These low-cost biosorption methods can be effectively adopted for the removal of metal ions from the industrial effluents.

Adsorption Studies of Chromium(VI) on Activated Carbon Derived from Mangifera indica (Mango) Seed Shell

The removal of chromium(VI) from synthetic sample by adsorption on activated carbon prepared from Mangifera indica (mango) seed shell have been carried out at room temperature 32 ± 1 °C. The removal of chromium(VI) from synthetic sample by adsorption on two types of activated carbon, physical activation and chemical activation (Calcium chloride and Sodium chloride), Impregnation Ratio’s (IR) 0.25, 0.50, 0.75 for optimum time, optimum dosages and variation of pH were studied. It is observed that contact time differs for different carbons i.e. for physically and chemically activated carbons. The contact time decreases for chemically activated carbon compared to the physically activated carbon. It was observed that as dosage increases the adsorption increased along with the increase in impregnation ratio. It was also noted that as I.R. increases the surface area of Mangifera indica shell carbon increased. These dosage data were considered in the construction of isotherms and it was found that adsorption obeys Freundlich Isotherm and does not obey Langmuir Isotherm. The maximum removal of chromium (VI) was obtained in highly acidic medium at a pH of 1.50.

Optimizing chromium (VI) adsorption onto superheated steam activated granular carbon through response surface methodology and artificial neural network

The adsorptive removal of hexavalent chromium from aqueous medium by superheated steam activated granular carbon (GAC) prepared indigenously from non‐usable coconut shell was investigated by a series of batch sorption experiments. The removal efficiency of the process is optimized using response surface methodology and artificial neural networking. The influence of five different parameters viz. pH, contact time, GAC dose, initial concentration, and temperature on percent removal was observed through the model equations developed by a 25 full factorial central composite rota table design in shake‐flask system to find optimum condition. Maximum chromium removal is observed to be 96.33% at initial concentration 100 mg/L, pH 4, GAC dose 0.8 g/L, contact time 60 min, and temperature 15°C. Second‐order regression model was developed to study analysis of variance showing the relative significance of process parameters in removal process. From the results of this study it is revealed that GAC from waste coconut shell with surface area of 989 m2/g could be a cost effective and efficient adsorbent for the removal of Cr (VI). © 2014 American Institute of Chemical Engineers Environ Prog, 34: 638–647, 2015

Removal of Chromium by Coagulation-Dissolved Air Flotation System Using Ferric Chloride and Poly Aluminum Chloride (PAC) as Coagulants

In this study, dissolved air flotation (DAF) was examined as a possible treatment method for the removal of chromium from aqueous solution and plating wastewater. Two coagulants, ferric chloride and poly aluminum chloride (PAC), were used for pretreatment of wastewater. Maximum removal of chromium was achieved for poly aluminum chloride (98 %). Artificial neural network was used for the prediction of the DAF system. The best neuron used for the prediction of chromium removal percentage of interpolated wastewater was 6 %. The mean score error and the coefficient correlation were 0.0007542 and 0.997, respectively.

Artificial Neural Network (ANN) Approach for Modeling Chromium (VI) Adsorption From Aqueous Solution Using a Borasus Flabellifer Coir Powder

An artificial neural network (ANN) model was developed to predict the removal efficiency of chromium (VI) from aqueous solution using a Borasus flabellifer coir powder as adsorbent. The effect of operational parameters such as pH, adsorbent dosage, and initial chromium (VI) concentration are studied to optimize the conditions for the maximum removal of chromium (VI) ions. The ANN model was developed using 54 experimental data points for training and 16 data points for testing by a single layer feed forward back propagation network with 18 neurons to obtain minimum mean squared error (MSE). A tansigmoid was used as transfer function for input and purelin for output layers. The high correlation coefficient (R^2_(average-ANN)=0.992) between the model and the experimental data showed that the model was able to predict the removal of chromium (VI) from aqueous solution using Borasus flabellifer coir powder efficiently. Pattern search method in genetic algorithm was applied to get optimum values of input parameters for the maximum removal of chromium (VI).

A comparative study of sorption of chromium (III) onto chitin and chitosan

Heavy metals have always been the most hazardous components in the wastewater of industries like electroplating, automobiles, mining facilities and fertilizer manufacturers. Treatment of heavy metal laden wastewater requires expensive operational and maintenance systems. Food processing industries create a huge amount of shell waste which is sold to poultry farms in powdered form but the quantity thus used is still not comparable to the left over waste. The shell contains chitin which acts as an adsorbent for the heavy metals and can be used to treat heavy metal wastewater. The paper presents a study on the use of chitin and its processed product, chitosan, to remove chromium. Shake flask experiment was conducted to compare the adsorptive capacity of chitin and chitosan for chromium removal from simulated solution and isotherm studies were carried out. The studies showed that the chitosan was a better adsorbent than chitin. Both chitin and chitosan gave best adsorption results at pH 3. Chitin exhibited maximum chromium removal of 49.98 % in 20 min, whereas chitosan showed 50 % removal efficiency at a contact time of 20 min showing higher adsorptive capacity for chromium than chitin. The Langmiur and Freundlich isotherm studies showed very good adsorption capacity and monolayer interaction according to the regression coefficient 0.973 for chitosan and 0.915 for chitin. The regression coefficient for Freundlich isotherm was 0.894 and 0.831 for chitosan and chitin, respectively.

Portuguese

The inappropriate disposal of effluents containing toxic metals in high concentrations is a serious problem for the environment, and hexavalent chromium has received attention due to its high toxicity. The biosorption is a technology characterized as an alternative to remove these compounds from wastewater, due to lower material cost and lower operating costs of biosorbents. The aim of this work was to evaluate the removal of hexavalent chromium of effluent by biosorption using agroindustrial wastes fermented with fungi of the genus Aspergillus. The maximum hexavalent chromium removal was of 58%, using 2% biosorbent produced by solid state fermentation of soybean and rice husk using Aspergillus O-8 strain. The biomass was submitted to heat treatment for sterilization and the initial concentration of hexavalent chromium in the medium was 120 mg/L. This result can be optimized through the study of reaction conditions such as pH and agitation. Keywords: biosorption, rice husk, hexavalent chromium, fungi, soybean.

Heavy Metal Removal Efficiency of Paper Mulberry Biochar and Commercially Available Silica Powder from Simulated Industrial Wastewater

Paper mulberry bio-char produced was characterized and evaluated for heavy metals removal from simulated industrial wastewater in compare to silica powder. The batch adsorption study was conducted under different conditions like, the effects of solution pH, contact time and temperature. The paper mulberry bio-char (PMB) was more effective and exhibited a higher adsorption potential for cadmium, copper, chromium, lead and zinc than commercially available silica powder. Experiments conducted with an initial metal concentration of 50 mg/l at pH 2, 4, 8, 12. Maximum removal of cadmium, copper, chromium, lead and zinc by PMB was higher than silica powder. Contact time of 2, 3, 4 h showed maximum removal of cadmium, copper, chromium, lead and zinc removal for PMB and was found higher than that of silica powder. The thermodynamic parameters such as G°, H° and S° were calculated for predicting the nature of sorption. The results showed that plant-residue bio-char can act as effective alternative sorbent instead of silica powder for the removal of heavy metal ions from industrial wastewater.

Biological reduction and removal of Cr(VI) with microbial consortia collected from local water treatment plant

Application of microbes in water treatment is a well-established technique. A few microbes are tolerant to toxic heavy metals. Cr(VI) tolerant microbes have practical importance of detoxifying Cr(VI) to Cr(III). The water treatment plant situated at Indian Institute of Technology Guwahati (IITG), India, employs both physical and biological processes to treat domestic wastewater. The microbial consortia collected from this plant is employed to investigate Cr(VI) reduction to Cr(III) and removal behaviour from model effluent. The results reveal that microbial consortia efficiently grow at wide pH range from 4 to 10. Microbial growth is inhibited even with addition of 5 mg L –1 Cr(VI) to the nutrient media over the entire pH range. Reduction efficiency of Cr(VI) to Cr(III) increases with decreasing solution pH, while total chromium removal is higher at elevated pH. Maximum chromium removal is achieved at initial pH of 6. Higher pH may result in Cr(III) precipitation. Therefore, chromium removal is possibly the combined effect of precipitation as well as bioaccumulation.

Comparative Study of Removal of Cadmium (II) and Chromium (III) Ions from Aqueous Solution Using Low-Cost Biosorbent

Abstract This study aims to evaluate the ability of abundant low-cost garden grass to remove cadmium and chromium ions from aqueous solutions. Batch biosorption studies were carried out to examine the biosorption capacity, pH value, temperature, agitation speed, and metal ions concentration. The biosorption process revealed that the garden grass was an effective biosorbent of cadmium and chromium. The maximum chromium and cadmium removal rate was 90 and 80% at pH 4, respectively. FTIR spectroscopy analysis showed that the hydroxyl, amine, and carboxyl groups were the major groups responsible for the biosorption process. The maximum biosorption capacity was 18.19 and 19.4 mg/g for cadmium and chromium, respectively. The biosorption isotherm data fitted well the Langmuir model. Kinetic data were adequately fitted by the pseudo-second-order kinetic model.

Process optimization for Cr(VI) removal by Mangifera Indica seed powder: a response surface methodology approach

In this study, Mangifera Indica (mango) seed kernel powder was used as an adsorbent for chromium(VI) removal. The interactive effects between the process variables such as pH, temperature, adsorbent concentration, chromium concentration, and stirring speed (RPM) on chromium(VI) removal have been studied. In order to optimize the process, the experiments were designed using central composite design under response surface methodology by MINITAB 16.0 software. Based on the study, the optimum conditions for maximum removal of chromium(VI) from synthetic solution were obtained as: pH 1, temperature 27.5°C, adsorbent concentration 3.5 g/L, chromium concentration 100 ppm, and RPM 75. The statistical analysis of the data shows that experiments are statistically significant with a regression coefficient (R2) value of 0.95.

Artificial Neural Network and Response Surface Methodology Approach for Modeling and Optimization of Chromium (VI) Adsorption from Waste Water using Ragi Husk Powder

An artificial neural network (ANN) and response surface methodology models were developed to predict the removal efficiency of chromium (VI) from waste water using Ragi husk powder as adsorbent. Both of the models were used to study the effect of operational parameters such as pH, adsorbent dosage and initial chromium (VI) concentration and to optimize the conditions for the maximum chromium (VI) adsorption. The ANN model for the adsorption of chromium (VI) was developed by a single-layer feed-forward back-propagation network with 14 neurons in the hidden layer to obtain minimum mean squared error. A tansigmoid was used as transfer function for input and purelin for output layers. The response surface methodology model was developed using Box–Behnken design technique. The high correlation coefficient (R2 = 0.996 in ANN and 0.993 in response surface methodology models) between the predicted data and the experimental data showed that both of the models were capable of envisaging the chromium (VI) removal. The pattern search method in a genetic algorithm was applied to obtain optimum values of input parameters for the maximum removal of chromium (VI) for the ANN model. A comparison of the models for the optimization of input parameters is also discussed.

Use of activated dry flowers (ADF) of Alstonia Scholaris for chromium (Vl) removal: equilibrium, kinetics and thermodynamics studies

In this study, a natural adsorbent (activated dry flowers (ADF)) was prepared from plant-derived waste biomass by chemical activation and employed for chromium (VI) removal from aqueous medium using experimental batch technique. Experiments were carried out as function of adsorbent dosage, pH, and contact time. The maximum chromium (Vl) removal was observed at initial pH 3 (~94 % removal). The equilibrium data was fitted well to Langmuir isotherm. The adsorption capacity of ADF was found to be 4.40 (mg chromium (Vl)/g) which was comparable to the adsorption capacity of some other adsorbents documented. Among various kinetic models applied, pseudo second-order model was found to explain the kinetics of chromium (VI) adsorption most effectively (R (2) >0.99). Thermodynamic parameters such as ΔG, ΔS, and ΔH shows that adsorption process was spontaneous and endothermic at all the concentration ranges studied. Desorption of chromium (Vl) with 2 N NaOH was effective (~71 %) and, hence, there exists the possibility of recycling the ADF. The major advantages of using ADF as an adsorbent are due to its effectiveness in reducing the concentration of chromium (Vl) to very low levels. It requires little processing and is reversible as well as eco-friendly in contrast to traditional methods.