Simulation of adsorption of gold nanoparticles carried by gas ascending from the Earth’s interior in alluvial cover of the middle–lower reaches of the Yangtze River

The adsorption onto other minerals of charged gold nanoparticles, carried by gas ascending from the Earth’s interior, is an important component of their transport and deposition in surficial cover such as alluvial, aeolian, and glacial sediments. To simulate the adsorption of these particles, an experiment was conducted in which a flow of air that contained gold nanoparticles was passed upward through a sample of alluvium from the middle–lower reaches of the Yangtze River. These experiments showed that gold nanoparticles are adsorbed on kaolinite, halloysite, goethite, and hematite in the alluvial cover. Both the gold nanoparticles and minerals (i.e., kaolinite, halloysite, goethite, and hematite) carry surface charges that provide them with excellent adsorption properties. This study showed that the specific mineral composition of surficial alluvial cover affects the concentration of gold nanoparticles in the ascending gas. This phenomenon may plausibly be used in exploration for concealed gold, copper–gold, and silver–gold deposits in areas of thick alluvial cover. Geofluids (2010) 10 , 438–446     

基于氮气吸附法的古代丝织品纳米孔隙研究方法初探

孔隙不仅是纤维骨架的一部分，也是外界物质进出的重要通道。目前，关于古代丝织品纳米孔隙结构的相关研究极少，仅有孔径一项评价指标，较为单一。实验采用红外光谱法和电子顺磁共振波谱法研究古代丝织品的降解特征，在此基础上采用低温氮气吸附法表征蚕丝纤维内部固有的孔隙结构，首次从孔形、孔径分布、比表面积、孔体积、平均孔径、分形维数等多个角度对古代丝织品的微观孔隙结构进行综合研究。研究结果表明：与现代丝织品相比，清代黄山样品、北宋南陵样品及战国郴州样品的劣化程度依次加深。孔结构分析显示，所有样品中同时含有狭缝形孔和圆筒形孔，孔隙具有连续性，表明蚕丝内部存在复杂的多级结构。其中，劣化程度较高的北宋和战国样品内部存在更多的大孔或开放性孔隙。Barrett-Joyner-Halenda(BJH)法和非定域密度泛函(NLDFT)法的研究结果显示，样品孔隙以介孔为主，孔径主要分布在20 nm以下，最可几孔径基本稳定在2.8 nm左右，为蚕丝内部的有序孔。比表面积和孔体积的研究结果表明，劣化程度较轻的黄山样品具有较高的比表面积，其孔体积的增加主要来源于小孔，南陵样品和郴州样品孔体积的增加主要来源于大孔。分形维数的...