碳纳米管对水铁矿相转化的影响与机制

doi:10.19657/j.geoscience.1000-8527.2024.116

摘要/Abstract

摘要：

表面性质活泼的纳米材料在使用及处理过程中会进入土壤及水体环境,进而影响近地表环境中的矿物成分及其物理化学性质和相对含量。然而,纳米材料对土壤或者水中矿物相转变的机制及转化过程仍不清楚。本研究以典型的纳米材料-碳纳米管(CNT)为代表,通过X射线衍射、扫描电镜、Zeta电位、傅里叶变换红外光谱及草酸铵提取实验等手段,探究其对土壤中广泛分布的天然矿物水铁矿(Fh)相转变的影响。结果表明Fh的转化产物主要为赤铁矿,带有异号电荷的CNT和Fh通过静电引力作用及形成Fe—O—C键结合,该作用抑制Fh的转化过程,但不改变产物类型。另外,添加CNT使产物中赤铁矿的平均粒径减小。本研究为了解土壤中矿物相转变机制,进而探究人造物质对土壤影响机理提供实例。

关键词: 水铁矿, 碳纳米管, 矿物转化, 赤铁矿

Abstract:

Nano materials inevitably enter the soil and water environment in the process of usage and treatment, and then affect the composition, physicochemical properties, and the relative content of minerals in the near surface environment. However, the mechanism and process of mineral phase transformation in soil and soil by nanomaterial are still unclear. In this work, carbon nanotube (CNT), a typical nano material, was used to explore its effect on the phase transformation of ferrihydrite (Fh), a widely distributed nano mineral, by means of X-ray diffraction, scanning electron microscope, zeta potential, Fourier transform infrared spectroscopy and ammonium oxalate extraction experiment. The obtained results show that the main transformed product of Fh is hematite. The oppositely charged CNT interacts with Fh through electrostatic attraction and the formation of Fe-O-C bonds, which inhibit the transformation process of Fh without changing the type of the product. In addition, the coexisting CNT reduces the average particle size of hematite in the product. This work provides an example to understand the mechanism of mineral phase transformation in soil and explore the impact of artificial substances on soil.

Key words: ferrihydrite, carbon nanotube, mineral transformation, hematite

中图分类号:

闫丽霞, 任子贺. 碳纳米管对水铁矿相转化的影响与机制[J]. 现代地质, 2025, 39(03): 628-636.

YAN Lixia, REN Zihe. The Effect and Mechanism of Carbon Nanotube on the Phase Transformation of Ferrihydrite[J]. Geoscience, 2025, 39(03): 628-636.

图/表 8

图1 碳纳米管的氧化方法(a)及结果(b)

Fig.1 Oxidation methods (a) and results (b) of CNT

表1 测试中使用的仪器

Table 1 Instruments used in the test

仪器名称	型号	生产厂家
X射线衍射仪	D8 Advance	Bruker
傅里叶变换红外光谱仪	VERTEX 70v	Bruker
扫描电子显微镜	Supra 55	ZEISS
Zeta电位仪	Zetasizer Nano ZS90	Malvern

图2 氧化处理前后的样品表征

Fig.2 Characterization of samples before and after oxidation treatment XRD(a);FTIR(b);XPS(c);TEM((d)—(e))

图3 Fh及Fh-CNT混合物的表征 Zeta电位分析(a);FTIR(b);Fh及Fh-CNT悬浊液的沉降情况((c)—(d))

Fig.3 Characterization of Fh and Fh-CNTs mixture

图4 Fh相转化过程的物相分析 (a)Fh体系;(b)2%CNT体系;(c)5%CNT体系

Fig.4 Phase transformation process of Fh

图5 Fh和5% CNT体系的转化动力学 Feo:溶解在草酸铵中的Fh含量; Fet:溶解在盐酸中的Fh含量

Fig.5 Transformation kinetics of the systems of Fh and 5%CNT

图6 转化产物的透射电镜图 (a)和(c)Fh转化产物图;(b)和((d)—(g))5%CNT转化产物图

Fig.6 TEM images of the transformed products

图7 Fh的转化机理图

Fig.7 Schematic drawing of the transformation process of Fh

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