Kinetics, equilibrium, and isotherm of the adsorption of cyanide by MDFSD

Abstract

Adsorption of cyanide out of aqueous media by moderate density fiberboard saw dust (MDFSD) was investigated using a batch system under controlled conditions. The kinetic data were followed more closely to the pseudo-first-order model. The adsorption rate and the related parameters, such as the MDFSD relative quantity, cyanide initial concentration, pH, temperature, and ionic strength were studied. The saturation equilibrium was also studied as a function of the related parameters (MDFSD quantity, initial concentration, pH and temperature). The adsorption isotherm was established and compared to other isotherms of activated carbon, TDRP and polyurethane foam. Linearized Langmuir, Freundlich and Frumkin models were applied to estimate the adsorption constants.It was estimated through this study that the adsorption rate is positively affected by increasing MDFSD’s relative quantity, adsorbent concentration, acidity and temperature. The adsorption equilibrium was shifted toward higher adsorption capacity by the substrate concentration, temperature and acidity. The adsorption data fit to Freundlich, Langmuir and Frumkin models, but attained a better correlation with the order of models as Langmuir>Frumkin>Freundlich. Activation thermodynamic parameters of adsorption, the adsorption thermodynamic parameters, and Freundlich, Langmuir and Frumkin constants were obtained.