Quantitative effects of surface oxidation on biochar derived from long-root Eichhornia Crassipes plants as Cd2+ adsorbent

Quantitative effects of surface oxidation on Cd 2+ adsorption performance of biochar derived from long-root Eichhornia Crassipes plants were systematically investigated. It was revealed that oxidation degree was positively related with the intensity of surface functional groups and harmless for the structural stability, while biochar yield would decline sharply resulting from for over-oxidization. Correspondingly, the Cd 2+ adsorption capacity exhibited an uptrend with the increasing oxidation on account of the abundant adsorption sites. Moreover, Cd 2+ adsorption on the biochar with different oxidation degrees were also investigated comprehensively, indicating adsorption performances in a similar trend highly sensitive to solution pH and ionic strength . In addition, the adsorption isotherms were found to manifest the saturated adsorption capacity for Cd 2+ increased from 0.333 mol/g to 0.487 mmol/g at 30 °C by strengthening oxidation. All synthesized biochar could keep consistent adsorption performance in multiple adsorption-desorption cycles.