Adsorptive removal of phenol and aniline by modified bentonite: adsorption isotherm and kinetics study

In the present study, the adsorptive potential of modified bentonite in a batch system for the removal of aniline and phenol from aqueous solutions was investigated. The effect of various parameters including contact time (10–120 min), pH (2–10), adsorbent dosage (0.4–1.5 g/L) and initial concentration of aniline and phenol (50–200 mg/L) was investigated in this experimental laboratory study. Maximum removal of aniline and phenol was achieved at contact time of 30 and 45 min for aniline and phenol, respectively, and at the lowest studied initial concentration of 50 mg/L. Optimum bentonite dosage of 1 and 0.4 g/L was obtained for phenol and aniline, respectively. The adsorption process was better at the pH of 6 for aniline and pH of 4 for phenol. It was found that the equilibrium data was best followed by the Langmuir and Freundlich isotherms. Also, the pseudo-second-order kinetic model was best applicable for phenol and aniline adsorption. It was defined that bentonite not only was an inexpensive absorbent, but also a quite effective adsorbent for the removal of aniline and phenol from water and wastewater.