热剥离法制备石墨烯纳米片对Pb2+和Cd2+的吸附

石墨粉氧化后,在氮气气氛下,快速高温剥离制得石墨烯纳米片。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(HRTEM)、拉曼(Raman)光谱、傅里叶变换红外(FT-IR)光谱和氮气吸附-脱附等分析手段对石墨烯样品进行了表征。这些分析测试结果显示:石墨烯样品主要由很薄的1-4层石墨组成,呈褶皱状态,比表面积为628.5 m²·g^-1。研究了石墨烯吸附水溶液中的Pb²⁺和Cd²⁺的pH值、吸附时间、吸附温度和金属离子初始浓度等影响因素, Pb²⁺和Cd²⁺的最大吸附量分别为460.20和72.39 mg·g^-1。结果表明,热剥离法制得的高质量石墨烯纳米片可以作为一种高效的从水中去除Pb²⁺和Cd²⁺的吸附材料。

Adsorption of Pb2+ and Cd2+ on Graphene Nanosheets Prepared Using Thermal Exfoliation

Graphene nanosheets (GNSs) were prepared using oxidation of graphite powder followed by rapid thermal exfoliation under a nitrogen atmosphere. The as-prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy. The specific surface area was determined using the nitrogen adsorption and desorption method. These analytic techniques revealed that the samples possessed a curled morphology consisting of a thin paper-like structure, which was made of a few graphite layers (approximately four layers) and a large specific surface area (628.5 m²·g^-1). The effects of pH, adsorption time, temperature and initial concentration of Pb²⁺ and Cd²⁺ on adsorption onto the GNSs were investigated. The maximum adsorption capacities of GNSs for Pb²⁺ and Cd²⁺ ions were approximately 460.20 and 72.39 mg·g^-1, respectively. These results indicate that the resulting high-quality GNSs can be used as an attractive adsorptive material for removing Pb²⁺ and Cd²⁺ from water.