Production and characterization of modified biochar by corn cob and its ability to absorb phenol

Abstract

The adsorption performance of KOH modified biochar as adsorbent for phenol in aqueous solution was investigated. The effects of initial pH of the solution, initial concentration of phenol, contact time and temperature on the adsorption capacity of phenol were investigated. Adsorption isotherms, adsorption kinetics and thermodynamic analysis were examined. The results showed that the specific surface area of modified biochar was 487.64m2·g−1, the content of C is 72.06 wt.% and the value of H/C is 0.05, the aromatization degree of modified biochar is very high. The results showed that the maximum adsorption capacity of the modified biochar is 217.06 mg·g−1 at 298 K, which is higher than that of biochar. The adsorption process accords with the Freundlich adsorption isotherm model and pseudo-second-order kinetic equation. Thermodynamic analysis shows that adsorption is spontaneous and exothermic.