Studies relating to an electrochemically assisted coagulation for the removal of chromium from water using zinc anode

2011 ◽  
Vol 11 (2) ◽  
pp. 142-150 ◽  
Author(s):  
S. Vasudevan ◽  
J. Lakshmi
Keyword(s):  
Adsorption Kinetics ◽  
Current Density ◽  
Second Order ◽  
Rate Equations ◽  
Zinc Anode ◽  
Effects Of Ph ◽  
Equilibrium Data ◽  
Density Concentration ◽  
Chromium Adsorption ◽  
Kinetics And Isotherms

In this work, an electrochemically assisted coagulation for the removal of chromium from water has been studied using zinc as anode and galvanized iron as cathode. The effects of pH, current density, concentration of chromium, temperature, adsorption kinetics and isotherms on the removal of chromium were investigated. The results showed that the optimum removal efficiency of 96.5% was achieved at a current density of 0.2 A/dm2, at a pH of 7.0. First- and second-order rate equations, Elovich and intraparticle diffusion models were applied to study adsorption kinetics. The adsorption process follows second-order kinetics model with good correlation. An equilibrium isotherm was measured experimentally and the results were analyzed by the Langmuir, Freundlich and Dubinin-Redushkevich model using linearized correlation co-efficient. The Langmuir adsorption isotherm was found to fit the equilibrium data for chromium adsorption. Temperature studies showed that the adsorption was endothermic and spontaneous in nature.

scholarly journals Removal of Methylene Blue in aqueous solutions by Electrocoagulation process: Adsorption, Kinetics, studies

2018 ◽  
Vol 9 (4) ◽  
pp. 311-316 ◽  
Author(s):  
Alain Stéphane Assémian ◽  
Konan Edmond Kouassi ◽  
Kopoin Adouby ◽  
Patrick Drogui ◽  
David Boa
Keyword(s):  
Methylene Blue ◽  
Energy Consumption ◽  
Adsorption Kinetics ◽  
Current Density ◽  
Goodness Of Fit ◽  
Specific Energy Consumption ◽  
Second Order ◽  
Rate Equations ◽  
Order Kinetic ◽  
Electrocoagulation Process

The purpose of this study is to understand the mechanism driving the removal of methylene blue through electrocoagulation process. Experiments were carried out using iron as anode and cathode in a batch electrochemical cell operated in a monopolar configuration. The effects of operating parameters (initial pH, current density, initial dye concentration and energy consumption) on the removal of methylene blue from solution were investigated. The results showed that the optimum removal efficiency of 93.2% was achieved for a current density of 9.66 mA/cm2, optimal pH of 8±0.01 with a specific energy consumption of 7.451 kWh/m3. Afterwards, first and second-order rate equations were successively applied to study adsorption kinetics models. On top of usual correlation coefficients (r2), statistical test Chi-square (χ2) were applied to evaluate goodness of fit and consequently find out the best kinetic model. Results showed that MB adsorption process onto iron hydroxides formed in aqueous solution during electrocoagulation treatment followed a second-order kinetic.

scholarly journals Comparison of adsorptions by rice hull and Lewatit TP 214 of platinum in chloride solution

2013 ◽  
Vol 78 (6) ◽  
pp. 811-826 ◽  
Author(s):  
M.H. Morcali ◽  
B. Zeytuncu ◽  
O. Yucel
Keyword(s):  
Waste Product ◽  
Second Order ◽  
Attenuated Total Reflection ◽  
Rate Equations ◽  
Rice Hull ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
Biomass Waste ◽  
Equilibrium Data ◽  
Pseudo Second Order

Rice hull, a biomass waste product, and Lewatit TP 214, a thiosemicarbazide sorbent, were investigated as adsorbents for the adsorption of platinum (IV) ions from synthetically prepared dilute chloroplatinic acid solutions. The rice hull was characterized by Attenuated Total Reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The effects of the different adsorption parameters, sorbent dosage, contact time, temperature and pH of solution on adsorption percentage were studied in detail on a batch sorption. The adsorption equilibrium data were best fitted with the Langmuir isotherm model. The maximum monolayer adsorption capacities, Qmax, at 25?C were found to be 42.02 and 33.22 mg g-1 for the rice hull and Lewatit TP 214, respectively. Thermodynamic calculations using the measured ?H?, ?S? and ?G? values indicate that the adsorption process was spontaneous and exothermic. The pseudo-first-order and pseudo-second-order rate equations were investigated; the adsorption of platinum ions for both sorbents was found to be described by the pseudo-second-order kinetic model. The kinetic rate, k2, using 30 mg sorbent at 25?C was found to be 0.0289 and 0.0039 g min-1 mg-1 for the rice hull and Lewatit TP 214, respectively. The results indicated that the rice hull can be effectively used for the removal of platinum from aqueous solution.

Theoretical prediction of gas adsorption kinetics based on equilibrium data

2012 ◽  
Vol 90 (10) ◽  
pp. 828-835 ◽  
Author(s):  
Krzysztof Nieszporek ◽  
Tomasz Banach
Keyword(s):  
Theoretical Model ◽  
Theoretical Prediction ◽  
Intermolecular Interactions ◽  
Adsorption Kinetics ◽  
Gas Adsorption ◽  
Rate Equations ◽  
Equilibrium Isotherm ◽  
Energetic Heterogeneity ◽  
Equilibrium Data ◽  
Adsorption Systems

Based on the equilibrium adsorption isotherms, new expressions describing the rate of adsorption were developed. The theoretical model takes into account the influence of diffusional effects on the rate of adsorption. Other nonideal effects such as surface energetic heterogeneity or intermolecular interactions can be taken into account by using the adequate equilibrium isotherm. The accuracy of the presented rate equations was verified using real adsorption systems.

Equilibrium and Kinetic Modeling on Biosorption of Reactive Red 2 Using Tamarindus indica Fruit Hulls

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
S. Renganathan ◽  
M. Seenuvasan ◽  
S. Selvaraj ◽  
P. Gautam ◽  
M. Velan
Keyword(s):  
Second Order ◽  
Isotherm Model ◽  
Rate Equations ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Tamarindus Indica ◽  
Order Rate ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Reactive Red 2

Biosorption of Reactive Red 2 dye, from an aqueous solution was evaluated using Tamarindus indica fruit hulls in a batch system. The influence of pH (1-6), temperature (20-30°C) and initial dye concentration (20 to 120 mg/L) on the biosorption process was studied. Maximum biosorption was observed at initial pH of 2.0, temperature of 30°C and at the initial dye concentration of 120 mg/L. Equilibrium data were analysed for Langmuir, Freundlich and generalized isotherm model. The equilibrium data were found to fit very well with Freundlich isotherm model when compared to all other isotherm models studied in the present investigation. Batch biosorption kinetics was studied with different initial dye concentrations and rate of biosorption was determined using pseudo first and pseudo second order rate equations. From the result it was observed that pseudo second order rate expression fit the experimental data well for Reactive Red 2 when compared to a pseudo first order kinetic model.

Evaluation of the possible use of a Bulgarian clinoptilolite for removing strontium from water media

Clay Minerals ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 55-64 ◽  
Author(s):  
N. Lihareva ◽  
O. Petrov ◽  
Y. Tzvetanova ◽  
M. Kadiyski ◽  
V.A. Nikashina
Keyword(s):  
Second Order ◽  
Isotherm Models ◽  
Sorption Data ◽  
Water Media ◽  
Effects Of Ph ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Na Ions ◽  
Natural Clinoptilolite

AbstractThe sorption of Sr2+ ions by natural clinoptilolite was investigated using the batch method. The effects of pH, contact time and strontium concentrations were tested and the optimal conditions for sorption were determined. The process was very fast initially and equilibrium was reached within 24 h. Kinetic sorption data were fitted to pseudo-first-order, pseudo-second-order and intra-particle diffusion models. The simple pseudo-second-order rate model provides good agreement with the experimental data for Sr2+ uptake. The respective rate constants, k2, calculated at different initial Sr2+ concentrations, were obtained. The equilibrium data were analysed by applying the Langmuir, Freundlich and Dubinin–Raduchkevich isotherm models. The Langmuir model describes the observed Sr2+ uptake most accurately and the value of the monolayer sorption capacity is 32.81 mg Sr2+/g. The effect of Na+ ions and the effectiveness of uptake from low saline groundwater simulated solutions were also studied and discussed.

Cellulose/Biochar Cryogels: A Study of Adsorption Kinetics and Isotherms

Langmuir ◽  
2021 ◽  
Author(s):  
Lídia Kunz Lazzari ◽  
Daniele Perondi ◽  
Ademir José Zattera ◽  
Ruth Marlene Campomanes Santana
Keyword(s):  
Adsorption Kinetics ◽  
Kinetics And Isotherms

Studies of Chromium Removal from Tannery Effluents by Dead Streptomyces Rimosus

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar
Keyword(s):  
Fractional Power ◽  
Kinetic Studies ◽  
Second Order ◽  
Order Kinetic ◽  
Streptomyces Rimosus ◽  
Tannery Effluents ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ph Range

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.

Electrochemical Treatment of Simulated Dye Wastewater

2012 ◽  
Vol 441 ◽  
pp. 555-558
Author(s):  
Feng Tao Chen ◽  
San Chuan Yu ◽  
Xing Qiong Mu ◽  
Shi Shen Zhang
Keyword(s):  
Current Density ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Dye Wastewater ◽  
Electrolysis Time ◽  
Electrochemical Degradation ◽  
Mild Conditions ◽  
Thermal Decomposition Method ◽  
Initial Ph ◽  
Effects Of Ph

The Ti/SnO2-Sb2O3/PbO2 electrodes were prepared by thermal decomposition method and its application in the electrochemical degradation of a heteropolyaromatic dye, Methylene blue (MB), contained in simulated dye wastewater were investigated under mild conditions. The effects of pH, current density and electrolysis time on de-colorization efficiency were also studied. Chemical oxygen demand (COD) was selected as another parameter to evaluate the efficiency of this degradation method on treatment of MB wastewater. The results revealed that when initial pH was 6.0, current density was 50 mA·cm2, electrolysis time was 60 min, Na2SO4 as electrolyte and its concentration was 3.0 g·dm3, the de-colorization and COD removal efficiency can reach 89.9% and 71.7%, respectively.

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