Abstract Highly porous carbon material is one of the most widely used sorbents in removing Cr and Pb from polluted water. Moreover, heavy metal ions of Pb(II) and Cr(III) have become the global health and environmental concerns. A novel nanoporous Zn/Co/C derived from ZIF-8/ZIF-67 core-shell was reported in the present study. The prepared sorbent was used for dispersive solid phase extraction of Cr(III) and Pb(II) ions. The extracted ions were then eluted by the aid of the acidic solution (HNO3) and analyzed via flame atomic absorption spectroscopy (FAAS). The prepared carbon materials were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), N2 adsorption-desorption and Fourier transform infrared spectroscopy (FT-IR). The characterization results indicated that the prepared porous carbon surface had functional groups such as -COOH, -OH, C O C, etc. which can act as active sites during the adsorption process. The capacity of the sorbent ranged from 520 to 375 mg g−1. Under the optimum condition, the calculated limits of detections were 0.21 and 0.40 μg L−1 for Cr(III) and Pb(II) ions, respectively. The relative standard deviations (RSDs) were lower than 5.0%. The surface area and pore volume of the prepared sorbent were 128 m2 g−1 and 0.25 cm3, respectively. In addition, the effects of foreign ions on the extraction capability of the sorbent were also investigated. The results indicated that the vast majority of transition, alkaline, and earth alkaline metals do not interfere with environmentally relevant concentrations. The presented method was validated through analyzing standard reference material. Different types of real samples were analyzed in order to investigate the capability of the method for facile preconcentration of Cr and Pb ions.

中文翻译：

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通过核壳结构的金属有机骨架衍生的 N 掺杂碳作为一种新型吸附剂，用于从水样中分散固相萃取 Cr(III) 和 Pb(II)，然后通过火焰原子吸收光谱法测定

摘要 高度多孔的碳材料是去除污水中Cr和Pb应用最广泛的吸附剂之一。此外，重金属离子 Pb(II) 和 Cr(III) 已成为全球健康和环境问题。本研究报道了一种源自 ZIF-8/ZIF-67 核壳的新型纳米多孔 Zn/Co/C。制备的吸附剂用于Cr(III)和Pb(II)离子的分散固相萃取。然后在酸性溶液 (HNO3) 的帮助下洗脱提取的离子，并通过火焰原子吸收光谱 (FAAS) 进行分析。通过X射线衍射（XRD）、扫描电子显微镜（SEM）、能量色散X射线光谱（EDX）、N2吸附-解吸和傅里叶变换红外光谱（FT-IR）对制备的碳材料进行表征。表征结果表明，制备的多孔碳表面具有-COOH、-OH、COC等官能团，可在吸附过程中充当活性位点。吸附剂的容量范围为 520 至 375 mg g-1。在最佳条件下，计算出的 Cr(III) 和 Pb(II) 离子的检测限分别为 0.21 和 0.40 μg L-1。相对标准偏差 (RSD) 低于 5.0%。制备的吸附剂的表面积和孔体积分别为 128 m2 g-1 和 0.25 cm3。此外，还研究了外来离子对吸附剂萃取能力的影响。结果表明，绝大多数过渡金属、碱金属和碱土金属不会干扰环境相关的浓度。通过分析标准参考物质验证了所提出的方法。分析了不同类型的实际样品，以研究该方法轻松预浓缩 Cr 和 Pb 离子的能力。