Adsorption of 2,4,6-trichlorophenol from aqueous solutions by a surfactant-modified zeolitic tuff: batch and continuous studies

In the present study, a clinoptilolite-rich tuff was modified with hexadecyl trimethyl ammonium chloride and was used for the removal of 2,4,6-trichlorophenol (TCP) from aqueous solutions. Kinetic and isotherm of TCP adsorption were studied in a batch system, and the continuous adsorption experiments were performed as a function of initial TCP concentration in a packed bed column. Kinetic experiments indicated that the TCP adsorption by the surfactant-modified zeolite (SMZ) was rapid and reached to equilibrium in 30min for all TCP concentrations. The pseudo-second-order rate equation best described the kinetic of TCP adsorption onto the SMZ (R-2>0.99). Isotherm experiments were conducted in an initial TCP concentration range of 25-200mg/L, and the isotherm data were found to be in the best fitness with the Langmuir model (R-2>0.99). According to the Langmuir model, the maximum adsorption capacity (q(m)) of TCP was obtained to be 12.9mg/g. In the packed bed column, by increasing the influent TCP concentration from 100 to 200mg/L, the adsorption capacity at complete exhaustion point drastically increased from 14.7 to 35.5mg/L. The breakthrough curves were predicted with the suitable fitness by both the Thomas and Yoon-Nelson models (R-2>0.93).