Adsorption of Phenol in Wastewater Using Nano Grapheme Oxide-Chitosan-Bentonite Absorbent

Abstract

Background and Objectives: Contamination of surface and groundwater sources with aromatic compounds such as phenolic compounds is one of the newest environmental problems that humans encountered it today. One of the ways to remove these pollutants is the use of polymeric adsorbents. In this study, chitosan-bentonite-nano-graphene oxide nanosorbent was synthesized to investigate the phenol adsorption. Material and Methods: In this research, experimental design was performed using Design-Expert 7.0 software to investigate the effect of independent variables including nano graphene oxide, chitosan and bentonite on the dependent variable (phenol removal rate). Moreover, phenol absorption isotherm, kinetics and thermodynamics, were also examined. Results: Eventually, the optimum formulation of nano-adsorbent with specifications of 0.1 g of chitosan, 0.18 g of bentonite and 0.07 g of nano-graphene oxide was investigated. Optimal adsorption conditions were also obtained at a concentration of 100 ppm, pH=5 and 45 minutes of absorption time. Conclusion: Finally, it was found that the synthesized nanosorbent follows the Langmuir isotherm, which represents physical adsorption, and also the kinetics of the adsorption process is the diffusion between particles. As a result, it was found that the optimal application of this nano-adsrbent is in wastewaters with a temperature of less than 400 °C.