玉米秸秆生物炭对溶液体系中不同重金属离子的吸附特性

Adsorption of different heavy metal ions in solution system by corn stalk-based biochar

为探究在废水处理中针对不同重金属吸附特征选择合适的生物炭修复方案,以玉米秸秆为原料,在300和500℃下热裂解得到2种生物炭,通过试验模拟研究生物炭在单组分溶液体系和多种重金属离子的混合溶液体系中,对不同重金属离子的吸附能力,并用等温吸附模型对试验结果进行拟合。研究结果表明:1)对于同种重金属而言,500℃下得到的生物炭的吸附能力更强;2)对于同种吸附材料,单组分与多种重金属离子的混合溶液中对重金属离子饱和吸附量的顺序均为:Ni ^(2+)<Zn^(2+)<Cd^(2+)<Pb^(2+)<Cu^(2+);3)但在多种重金属离子的混合溶液体系中金属离子浓度较高条件下,离子之间的相互作用影响生物炭吸附能力;同时Cu^(2+)和Pb^(2+)2种离子具有较高的吸附量,竞争力更强。

The adsorption ability of different heavy metal ions by corn stalk-based biochars of 300 and 500 ℃,respectively was investigated in solution system with single and multiple ions.The experimental data were fitted by isothermal adsorption model.The results showed that 500 ℃ biochar has higher adsorption capacity than that of 300 ℃biochar.For the same biochar,the order of the saturated adsorption capacity of biochar in single ion solution is Ni 2＋〈Zn2＋〈Cd2＋〈Pb2＋〈Cu2＋.However,under the condition of high concentration of metal ions in heterogeneous solution system,the interaction between ions has a great influence on the adsorption capacity of biochar.Meanwhile,both biochars show higher adsorption capacity to Cu2＋and Pb2＋.In conclusion,these results provide references for choosing suitable biochar remediation schemes for different heavy metal adsorption characteristics in practical applications such as wastewater treatment.