College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China E-mail:
Hunan Longe-Gallop Technology Co., Ltd, Changsha 410083, China.
Water Sci Technol. 2020 May;81(9):1840-1851. doi: 10.2166/wst.2020.209.
A novel composite (nZVI@K-GCN) was firstly synthesized by liquid phase reducing nanoscale zero-valent iron (nZVI) on potassium-doped graphitic carbon nitride (K-GCN). The results of Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) suggested that nZVI@K-GCN possessed abundant active functional groups such as terminal amino-groups (-NH or -NH groups) and -OH, and the specific surface area and pore volume from BET of nZVI@K-GCN were 4.7 times and 3.7 times higher than that of graphitic carbon nitride (GCN), respectively. These properties showed that the composite was especially suitable for heavy metal treatment. The application of the composite in the removal of chromium(VI) from aqueous solution showed that the maximum adsorption capacity of nZVI@K-GCN towards Cr(VI) was 68.6 mg/g at 308 K when the initial concentration of Cr(VI) was 30 mg/L, and more than 99% removal was obtained at pH = 3. This adsorption was an endothermic and spontaneous process. XPS patterns and batch experiments proved that complexation, electrostatic attraction and reduction precipitation were the main adsorption mechanism for Cr(VI) on nZVI@K-GCN.
首次通过液相还原纳米零价铁（nZVI）在钾掺杂石墨相氮化碳（K-GCN）上合成了一种新型复合材料（nZVI@K-GCN）。傅里叶变换红外（FTIR）光谱、X 射线衍射（XRD）、扫描电子显微镜（SEM）和 Brunauer-Emmett-Teller（BET）的结果表明，nZVI@K-GCN 具有丰富的活性官能团，如末端氨基（-NH 或 -NH 基团）和-OH，并且 nZVI@K-GCN 的 BET 比表面积和孔体积分别比石墨相氮化碳（GCN）高 4.7 倍和 3.7 倍。这些特性表明该复合材料特别适合重金属处理。该复合材料在去除水溶液中的六价铬（Cr(VI)）中的应用表明，当 Cr(VI)的初始浓度为 30 mg/L 时，nZVI@K-GCN 对 Cr(VI)的最大吸附容量为 68.6 mg/g，在 pH = 3 时，去除率超过 99%。该吸附是一个吸热和自发的过程。XPS 图谱和批量实验证明，络合、静电吸引和还原沉淀是 Cr(VI)在 nZVI@K-GCN 上的主要吸附机制。
