Adsorption behavior and mechanism of 2,4,6-trichlorophenol on nut shell activated carbon

Abstract

The adsorbable organic halides (AOX) produced during chlorine dioxide bleaching are highly toxic and difficult to degrade. Currently, AOX generation is mainly reduced by controlling conditions during bleaching. Studies on AOX removal in the natural environment are rarely reported. In this study, the adsorption of 2,4,6-trichlorophenol (2,4,6-TCP) on nut shell activated carbon was investigated. The effects of activated carbon dosage, adsorption time, and temperature on the removal of 2,4,6-TCP were examined. The optimal adsorption conditions was activated carbon dosage 0.20 g × L-1, adsorption time 130 min, and temperature 25 °C. The removal efficiency of 2,4,6-TCP was 91.5%. The adsorption kinetics and isothermal adsorption were studied, and a thermodynamic equation was established. The adsorption was more consistent with a pseudo-second-order kinetic model and Freundlich adsorption isotherm model. Thermodynamic studies showed that the adsorption of 2,4,6-TCP on activated carbon was a spontaneous exothermic process. These findings provide a new method for AOX removal in natural environments.