Two-Parameter Isotherms Of Methyl Orange Sorption By Pinecone Derived Activated Carbon

The adsorption of a mono azo dye methyl-orange (MeO) onto granular pinecone derived activated carbon (GPAC), from aqueous solutions, was studied in a batch system. Seven two-parameter isotherm models Langmuir, Freundlich, Dubinin-Radushkevic, Temkin, Halsey, Jovanovic and Hurkins-Jura were used to fit the experimental data. The results revealed that the adsorption isotherm models fitted the data in the order of Jovanovic (X2=1.374) > Langmuir > Dubinin-Radushkevic > Temkin > Freundlich > Halsey > Hurkins-Jura isotherms. Adsorption isotherms modeling showed that the interaction of dye with activated carbon surface is localized monolayer adsorption. A comparison of kinetic models was evaluated for the pseudo-second order, Elovich and Lagergren kinetic models. Lagergren first order model was found to agree well with the experimental data (X2=9.231). In order to determine the best-fit isotherm and kinetic models, two error analysis methods of Residual Mean Square Error and Chi-square statistic (X2) were used to evaluate the data

Prediction of optimum adsorption isotherm: Comparison of chi-square and Log-likelihood statistics

A comparison of chi-square (X2) and Log-likelihood (G2) statistics of 19 adsorption isotherm models-seven two-parameter models (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Jovanovic, Harkins-Jura and Halsey) and 12 three-parameter models (Koble-Corrigan, Langmuir-Freundlich, Tóth, Redlich-Peterson, Radke-Prausnitz (three models), Fritz-Schlunder, Jossens, Khan, UNILAN, Vieth-Sladek) have been applied to the experiment of two dyes (Acid Blue 113, Acid Black 1) sorption onto Granular PineCone derived Activated Carbon (GPAC) and three dyes (Acid Blue 80, Acid Red 114, Acid Yellow 117) sorption onto Granular Activated Carbon type Filtrasorb 400 (GAC F400). The study has focused on the assessment of the adequacy and goodness of the fitted models, using two well-known--X2 and G2--statistics. The results showed that G2 could be better than X2 statistic when the number of model parameters is three. © 2012 Desalination Publications. All rights reserved

Removal Of Divalent Nickel From Aqueous Solutions By Adsorption Onto Modified Holly Sawdust: Equilibrium And Kinetics

The removal of divalent nickel from aqueous solutions on modified holly sawdust was studied at varying contact times, pH, initial divalent nickel concentrations and adsorbent dose. Results showed the removal efficiency by increasing of pH increased and decreased with initial nickel divalent concentration. By increasing pH from 2 to 12 (equilibrium time= 240 min, adsorbent dose= 0.6g/100 mL, divalent nickel concentrations= 60 mg/L), the removal efficiency increased from 17.47 % to 81.76 %. Also removal efficiency was decreased from 98 % to 19.3 % by increasing of initial divalent nickel concentrations from 20 mg/l to 100 mg/L. Also the results showed the removal efficiency was increased by increasing of adsorbent dose and contact time. By increasing of adsorbent dose from 0.2 g/100CC to 1 g/100CC, the removal efficiency increased from 32.78% to 99.98%. The removal efficiency increased from 34.7% to 83.67% by increasing of contact time from 5 min to 240 min. Experimental equilibrium and kinetics data were fitted by Langmuir and Freundlich isotherms and pseudo-first-order and pseudo-second-order kinetics models, respectively. The results show that the equilibrium data follow Langmuir isotherm and the kinetic data follow pseudo-second-order model. The obtained maximum adsorption capacity was 22.47 mg/g at a pH 7. The results show that the modified holly sawdust can be used for the treatment of aqueous solutions containing nickel as a low cost adsorbent

Removal of Nitrate by Zero Valent Iron in the Presence of H2O2

Background & Aims: Nitrate is the oxidation state of nitrogen compounds, which is founded in water resources that contaminated by municipal, industrial and agricultural waste water. If nitrate leek in to ground water resources, it can cause health problems. Material and Methods: Removal of nitrate from ground water by iron powder in the presence of H2O2 was investigated. Experiments have been done by use of 250 ml of water samples containing 100 mg/L nitrate in various condition. Various parameters such as pH (3, 5, 7, 9), iron dosage (10, 15, 20, 30 g/L), initial H2O2 concentration (5, 10, 15, 20 ml/L) and contact time (10-120 min). Results: Obtained results shows the removal of nitrate was increased by pH reduction, increment of iron mass and contact time. In addition, nitrate reduction was increased by increment of initial H2O2 concentration up to 15 ml/L. High removal was observed at pH=3, iron mass=30 g/L, contact time equal 120 min and H2O2 concentration=15 ml/L. At above condition, upon 98% of nitrate was removed. Conclusion: In summary, this method is simple, low cost and effective for removal of nitrate from ground water and industrial activity