BINARY ADSORPTION OF PHENOL AND RESORCINOL ONTO GRANULAR ACTIVATED CARBON

Abstract

Adsorption of phenol and resorcinol by granular activated carbon in single and multi-component solutions was carried out at 303 K. Batch type of experiments were conducted with initial concentration range of 100-1000 mg/1 (100, 200,400, 600, 800, 1000 mg/1). In order to determine the best fit isotherm, the experimental data was analysed using six isotherm models: Langmuir, Freundlich, Redlich-Peterson, Toth, Radke-Prausnitz, Fritz Schlunder. Langmuir model gave a good fit for both the compounds. For phenol the adsorption models fitted the data in the order: Langmuir > Fritz Schlunder > Redlich-Peterson > Radke Prausnitz > Toth > Freundlich and in the order Fritz Schlunder > Toth > Redlich-Peterson > Radke Prausnitz > Langmuir >Freundlich for resorcinol. The effect of pH of solution, adsorbent dose and initial concentrations of phenol and resorcinol on adsorption behaviour was investigated. The optimum pH and adsorbent dose was found to be 5 and 4 g/L in case of phenol, 3 and 5 g/L in case of resorcinol. It was found that adsorption of phenol and resorcinol on to the activated carbon followed pseudo-second order model in both the cases. From the results it can be concluded that phenol is adsorbed more than resorcinol on to activated carbon under the present operating conditions, this can be attributed to the difference in solubility of both the compounds. Equilibrium isotherms for the binary adsorption of phenol and resorcinol on to granular activated carbon have been analysed using non-modified Langmuir model, Modified Langmuir model and Extended Freundlich model. The Extended Freundlich model fitted the binary adsorption data well with a low Average relative error (ARE =7.0 & ARE =6.46) for phenol and resorcinol respectively,