Comparison of Modified Canola and Azolla Efficiencies in Phenol Adsorption from Aqueous Solutions: An Adsorption Isotherm and Kinetics Study

Background: The presence of phenol in water and wastewater, due to its toxic threat to human life and environment, is a major concern. The purpose of this study was to investigate the rate of phenol adsorption by modified Azolla and Canola. Methods: This study was conducted at laboratory scale. In this study the effect of various parameters on adsorption performance was investigated and isotherms and kenitics adsorption were determined. In order to measure the specific surface area of absorbents the BET isotherm technique was carried out. The concentration of phenol in samples was measured by HPLC instrument. Results: Removal efficiency increased with increase of adsorbent dose and contact time and decrease of the initial concentration of phenol. Optimal phenol removal was obtained at pH =3, adsorbent dose of 10 g/L and contact time of 90 and 120 min for Azolla and Canola biomass respectively. Coefficients showed that the best isotherms for Azolla and Canola adsorbents are Langmuier and Freundlich respectively. The reaction rate for both adsorbents agrees with the pseudo-second order kenitics model. Based on the Langmuier model, the maximum adsorption capacities were calculated to be 11.2 and 9.4 mg/g for Azolla and Canola biomasses respectively. Conclusion: According to the obtained results, Azolla and Canola biomass can be used as efficient and cost-effective adsorbents for treatment of industrial effluents. Keywords: Azolla, Canola, Phenol, Adsorption isotherm, Wastewater treatmen