Background & Objectives: Chlorophenols, commonly found in most industrial waste products are persistent compounds in the environment. The purpose of this study was to investigate performance of modified Na-MMT nanoclay using cationic surfactant tetradecyltrimethyl ammonium bromide in the removal of 4-chlorophenol from aqueous solutions. Methods: This study was implemented under laboratory scale and in a batch flow adsorption reactor. The influence of various parameters such as modification in different pH conditions, initial pH of solution, loading rates of the surfactant, adsorbate concentration, 4-chlorophenol concentration, contact time were evaluated, the raw and modified nanoclay structure was investigated using XRD and FTIR spectrum.The experimental data were evaluated with the Langmuir and Freundlich isotherm models and pseudo-first-order and pseudo-second-order adsorption kinetic. Results: The results showed that removal of 4-chlorophenol increased by increasing the pH of solution from 3 to 11, as the maximum absorption of 4-chlorophenol was achieved at initial solution pH of 11 and for modified nanoclay in acidic conditions pH was4.5.Onthese conditions and after 120 min, the removal efficiency was obtained by 94.5%.Removal efficiency of 4-chlorophenol increased from 69.25% to 94.5% as surfactant loading increased from 0.25 to 2 CEC of the nanoclay, while increased loading surfactant from 3 to 4decreasedremoval efficiency. With increasing concentrations of 4-chlorophenol and adsorbent dose the removal efficiency, respectively, decreased and increased. Absorption of 4-chlorophenol on cationic modified nanoclay was consistent with Langmuir model and pseudo-second-order kinetics. Maximum absorption capacity (qm) was obtained 25.77 mg/g FTIR analysis revealed that the modification was successfully achieved due to the bands at 2919, 2851 and 1469 cm−1. After modification, XRD results showed that basal spacing value increase from 17 Ao to 24 Ao Conclusion: Cationic surfactant-modified nanoclay with tetradecyltrimethyl ammonium bromide by changing the properties of the adsorbent from hydrophilic to hydrophobic leads to increased efficiency of the absorbent in the absorption of 4-chlorophenol in aqueous environments.