Background Removal of pentachlorophenol (PCP) from wastewater containing chlorophenols, due to its toxicity, mutagenic and carcinogenic properties, has been attracted much interests of researchers. Methods In this research, K10 montmorillonite was modified by silane and imidazole (Im) for increasing the removal percentage of PCP from aqueous solutions. It was characterized by FTIR, XRF, FESEM, EDS, and BET techniques. The influence of different parameters such as initial concentration, contact time, adsorbent dosage, pH, temperature and agitating speed was investigated. Results The maximum removal percentage (95%) were obtained for PCP at pH = 4. The isotherm experimental data for pentachlorophenol was best fitted using the Langmuir model and the kinetic studies were better described by the pseudo-second-order kinetic model. The thermodynamic study indicated that the adsorption of PCP by the adsorbent was feasible, spontaneous and exothermic. Conclusion In this study, the modified montmorillonite by silane and imidazole is appropriate and low cost adsorbent for increasing of the removal percentage of PCP from aqueous solutions.
