Adsorption of Atrazine from Aqueous Solution onto Peanut Shell Activated Carbon: Kinetics and Isotherms Studies

In this study, the activated carbon (AC) was prepared from phosphoric acid activation of peanut shell and used as adsorbent for atrazine removal from aqueous solutions. The prepared AC was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. The effect of parameters such as solution pH, contact time, adsorbent dosage and concentration of atrazine solution were studied on adsorption process. The results of characteristics study shown that the surface of AC was porous with numerous functional groups. The kinetic results revealed that the adsorption process was well described by the pseudo-second-order model than the pseudo-first-order model. The intraparticle diffusion model involved in the adsorption process by multi steps. The equilibrium data were in the best agreement with the Langmuir model than the Freundlich and the Temkin models. The maximum adsorption capacities calculated according to the Langmuir isotherm were 66.66, 52.63 and 48.08 mg g-1 at 30°C and at pH 5, 7 and 9 respectively. The results of this study pointed out that the activated carbon prepared from the peanut shell has strong adsorption potential toward the atrazine herbicide, hence, it could be used for efficient adsorption of pesticide residues and other hazardous pollutants from wastewater.