改性玉米芯生物炭对废水中铜和氨氮的吸附

Adsorption characters of Cu^(2+) and NH_4^+-N in wastewater by modified corncob biochar

用KMnO_4改性玉米芯生物炭,并用改性生物炭吸附水中的Cu^(2+)和氨氮。结果表明:改性后,生物炭中的—OH基团数量增多且其表面有新生态MnO_2生成,吸附能力增强;生物炭吸附Cu^(2+)、氨氮的最佳pH为7;共存Na^+不影响生物炭对Cu^(2+)的吸附,但显著影响对氨氮的吸附。生物炭对Cu^(2+)、氨氮的吸附分别遵循准二级、一级动力学模型。Freundlich模型能更好地模拟生物炭对Cu^(2+)的吸附行为,Langmuir模型能更好地模拟生物炭对氨氮的吸附行为。

The corncob biochar has been modified by KMnO4,and the modified biochar has been used for adsorbing Cu2＋and NH4＋-N in wastewater. The results show that after the modification,the number of the hydroxyl groups is increased and the fresh MnO2 is formed on the surface of biochar,which significantly enhances the adsorption capacity of biochar. The optimal p H value for modified biochar adsorbing Cu2＋and NH4＋-N is 7. The coexisting Na＋has no influences on the adsorption capacity of biochar for Cu2＋,but has significantly influences on the adsorption for NH4＋-N.The adsorption of biochar forCu2＋and NH4＋-N complies with the pseudo-second order kinetic model and the first order kinetic model,respectively. Freundlich model can simulate the adsorption behavior of biochar for Cu2＋better.and the Langmuir isotherm model can simulate the adsorption behavior of biochar for NH4＋-N better.