摘要：Cornstalk biomass was utilized to prepare biochar as an adsorbent substrate. In order to significantly improve adsorption capability of the cornstalk biochar, a cationic surfactant hexadecylpyridinium bromide (CPB) was immobilized onto the cornstalk biochar, generating CPB-modified cornstalk biochar. CPBmodified cornstalk biochar performed slightly better than CPB-modified wheat straw biochar during adsorptive removal of an azo dye Orange II (ORII). It was observed that the adsorption capability of the raw cornstalk biochar for ORII was improved by as much as 183.5% after modification by CPB. The adsorption kinetics of the raw cornstalk biochar and the CPB-modified cornstalk biochar were compared and investigated at neutral solution pH. The experimental points were simulated by both pseudo-firstorder and pseudo-second-order models using linear and non-linear fitting methods. Both linear and nonlinear simulation results indicated that the pseudo-second-order kinetic model was more suitable to describe the adsorption kinetics, which demonstrates that the adsorption process might be chemisorption. Additionally, the calculated qe value from non-linear pseudo-second-order model for the CPB-modified cornstalk biochar is 44.29 mg/g, which is much close to the experimental value of 44.20 mg/g.
