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In this study, some activated carbons were prepared from sawdust using NaOH as an impregnating agent, a full factorial plan 23 was adopted to optimize and determine the interaction effects of some preparation conditions: impregnation time, impregnation temperature, and impregnation ratio. Elimination efficiency toward Erythrosine and Methylene blue in single and binary systems was selected as an optimization measure. The results showed that both impregnation ratio and ratio-temperature interaction were the most effective effects. Activated carbon AC1 prepared in optimum conditions; a time of 2 h, an impregnation temperature of 85 °C and an impregnation ratio of (1:1); had a high specific surface area estimated at 991 m2.g−1 and a maximum elimination of dyes with efficiency more than 94%, which corresponds to 104 mg.g−1 and 72 mg.g−1 for the MB; 90 mg.g−1 and 65 mg.g−1 for the E127 in both systems. Adsorption kinetics of the two dyes by AC1 were correctly described by the pseudo-second order model. As for isotherm modeling, Langmuir model seems to be the most adequate to describe the experimental data with maximum adsorption capacities 111 mg.g−1 and 76 mg.g−1 for MB and 100 mg.g−1 and 71 mg.g−1 for E127 in single and in binary systems regularly. [ABSTRACT FROM AUTHOR]

Dyes and pigments are environmental concerns because of their nonbiodegradability and toxicity. Many methods have been employed to remove dyes from aqueous solution, and adsorption is considered superior to other techniques. Activated carbon is one of the most widely used adsorbents for this application. In this study, activated carbon was prepared from low cost and locally available cherry stones using phosphoric acid with microwave preparation. Disperse yellow 211 was used as the adsorbate because of its common use in the textile industry. The surface properties of this new adsorbent were characterized by infrared spectroscopy, Brunauer-Emmett-Teller measurements, and scanning electron microscopy. The novel activated carbon material was employed for the removal of disperse yellow 211 from aqueous solution at various contact times, pH values, and solution temperatures. The optimum pH was 11. The surface area and micropore volume of the activated carbon were 1998 m2/g and 0.937 cm3/g, respectively. Adsorption equilibrium measurements were treated with Langmuir, Freundlich, and Temkin isotherm models and model parameters were determined. Pseudo-first-order and pseudo-second-order equations were fitted to the kinetic data, and the rate constants were evaluated. The kinetics followed a pseudo-second-order equation. [ABSTRACT FROM AUTHOR]

In this paper, the characteristics and potential removal of direct yellow ARLE (DYA) dye by using coconut palm shell-based activated carbon (CPS-AC) were assessed. Both kinetic and equilibrium experimental data were obtained from a series of DYA dye sorption experiments. All the sorption experiments were performed in closed batch system under constant temperature and stirring speed, at the predetermined pH of initial solution. The kinetic mathematical models of pseudo-first order, pseudo-second order, Elovich and intra-particle diffusion model were used in order to better interpret the adsorption kinetics phenomenon. Equilibrium data were described by applying the isotherm models of Langmuir, Freundlich, Tóth, Sips and Khan. The best description of DYA sorption equilibrium data was achieved for the Langmuir isotherm model, reaching a maximum adsorption capacity of 100 mg.g-1. Finally, the DYA dye adsorption functional groups characterizations were successfully accomplished and the results elucidated the most important groups linked with CPS-AC surface where molecular interactions could occur. Hence, the quantitative evaluation of equilibrium and kinetic experiments of adsorption process have demonstrated that the CPS-AC adsorbent was a promising high effective adsorbent and its potential can be successfully used for DYA dye removal. [ABSTRACT FROM AUTHOR]