A natural kaolin/γ-Fe2O3 composite as an efficient nano-adsorbent for removal of phenol from aqueous solutions

Phenol and its derivatives are among the most important environmental pollutants in wastewaters. Consequently, removal of these pollutants from wastewaters using non-toxic materials and eco-friendly technologies has been of considerable interests. In this study, a composite of natural kaolin and gamma-Fe2O3 nano particles was made via a facile co-precipitation method. The employed characterization techniques showed that the synthesized composite consisted of halloysite nanotubes that were partially covered with gamma-Fe2O3 nano particles. Further investigations revealed that the composite has a mesoporous structure with a BET surface area of 28 m(2) g(-1) that results in efficient removal of phenol from aqueous solutions. The effect of different experimental parameters (such as solution temperature, solution pH, contact time, and initial phenol concentration) on the performance of the composite toward the removal of phenol was then investigated. The results demonstrated that the removal of 30 mg L-1 phenol from an aqueous solution containing 20 g L-1 of the composite is achieved after 4 h. The experimental data correlated well with the Freundlich isotherm model and suggested that the removal of phenol from aqueous solution follows the pseudo-first-order kinetics.