Two functionalized biochar composites (ZF@CBC and SZF@CBC) were fabricated and applied for capturing Pb(II) and Cd(II) from wastewater. SZF@CBC were achieved by loading Zn/Fe nanoparticles (NPs) and coating starch onto corn cobs biochar (CBC) surface, while ZF@CBC was realized by loading Zn/Fe NPs onto CBC surface. The characterization analysis (SEM-EDS, XRD and FTIR) revealed that Zn/Fe NPs and starch were successfully introduced onto CBC surface. The adsorption data of Pb(II) and Cd(II) by ZF@CBC and SZF@CBC conformed to the model of pseudo second order kinetic and Langmuir isothermal and the capture Pb(II) and Cd(II) was a chemisorption process. The maximum sorption capacities of SZF@CBC for Pb(II) and Cd(II) reached 199.98 mg/g and 183.93 mg/g, which were 3.37 and 3.84 times high as that of CBC, respectively. Due to the presence of plentiful exposed adsorption sites (–OH, –COOH, Zn-O and Fe-O) on SZF@CBC surface, which endowed it to accelerate Pb(II) and Cd(II) adsorption. In addition, complexation, electrostatic attraction, ion exchange and physical adsorption took part in the adsorption process. Besides, SZF@CBC still exhibited very good removal capacity for Pb(II) and Cd(II) even in the coexistence of multiple interfering ions and maintained stable adsorption capacity after five consecutive cycles. Therefore, SZF@CBC could be used as an excellent adsorbent for decontaminating Pb(II) and Cd(II) from wastewater with multiple pollutants, and also could be used in resource utilization of biomass waste, which possessed potential applications prospects.

制备了两种功能化生物炭复合材料（ZF@CBC 和 SZF@CBC）并用于捕获废水中的 Pb(II) 和 Cd(II)。SZF@CBC是通过在玉米芯生物炭(CBC)表面负载Zn/Fe纳米粒子(NPs)并涂覆淀粉来实现的，而ZF@CBC是通过在CBC表面负载Zn/Fe NPs来实现的。表征分析（SEM-EDS、XRD 和 FTIR）表明 Zn/Fe 纳米颗粒和淀粉成功引入到 CBC 表面。ZF@CBC和SZF@CBC对Pb(II)和Cd(II)的吸附数据符合准二级动力学模型和Langmuir等温模型，捕获Pb(II)和Cd(II)是一个化学吸附过程。SZF@CBC对Pb(II)和Cd(II)的最大吸附容量分别达到199.98 mg/g和183.93 mg/g，分别是CBC的3.37和3.84倍。由于SZF@CBC表面存在大量暴露的吸附位点（–OH、–COOH、Zn-O和Fe-O），这使其能够加速Pb(II)和Cd(II)的吸附。此外，络合、静电吸引、离子交换和物理吸附也参与了吸附过程。此外，即使在多种干扰离子共存的情况下，SZF@CBC仍表现出很好的Pb(II)和Cd(II)去除能力，并在连续五个循环后保持稳定的吸附能力。因此，SZF@CBC可作为一种优良的吸附剂用于净化多种污染物废水中的Pb(II)和Cd(II)，也可用于生物质废弃物的资源化利用，具有潜在的应用前景。