Experimental, Thermodynamic and Kinetic Studies for the Adsorption of Phenolic Compounds Derived from Oilfield Wastewater by the Corncob Hydrochar

The corncob hydrochar is prepared by using a stainless autoclave at 230°C for 8 h. The products are characterized by elemental analyzer, Fourier Transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects of hydrochar dosage, pH, adsorption time and phenol concentration on the adsorption performance of hydrochar are investigated by means of single-factor experimental analysis. Based on the experiments the adsorption thermodynamic and kinetics are tentatively discussed. The results show that abundant oxygen-containing functional groups are scattered on the surface of the corncob hydrochar. The adsorption kinetics of phenol on the hydrochar corresponds well with pseudo-second-order kinetic model. Thermodynamic studies indicate that Freundlich adsorption isotherm model is much better than Langmuir model in describing the adsorption of phenol on the corncob hydrochar at 25°C - 45°C. This study provides scientific basis for the development of cheap and efficient adsorbents for the removal of phenols derived from oilfield wastewater.