The effect of humic acid on the adsorption of REEs on kaolin

For a better understanding of adsorption of the rare earth elements (REEs) onto minerals and its controlling factors, adsorption experiments were performed at pH range of from 3 to 10 with kaolin (1500 mg/L) in a matrix of various concentration of NaNO₃ and about 20 μg/L of the total REEs as well as various amounts of humic acid (HA). The adsorption of HA onto the kaolin occurred over a wide pH range and decreases with increasing pH and with increasing HA concentration. The results show that humic acid has ability to either increase or decrease the adsorption of the REEs onto kaolin, depending on pH, which may be related to their speciation distribution, interaction of HA with the mineral surface. Furthermore, the light REEs are more adsorbed onto kaolin in presence of higher concentration of HA, presumably because the increase in HA concentration in the solution enhance stronger complexing of HA with heavy REEs as compare to light REEs. The ionic strength has strong effect on the adsorption of HA and REEs onto the kaolin but little on the REEs fractionation. The results presented here indicate that mineral/water adsorption may generate the enrichment of the dissolved heavy REEs in the presence of a significant amount of humic acid, which is consistent with the fractionation of REEs in the most of natural waters.     

煤系高岭土表面改性的红外光谱研究

本文通过红外光谱分析研究了煤系高岭土生料和煅烧熟料的表面改性,发现改性后的高岭土在波数2919、2852、1850、1570、1641cm-1和波数1457cm-1附近的红外吸收峰随偶联剂有规律的变化,初步探讨了其改性机理。     

NMR Relaxation and Diffusion Measurements on Iron(III)-Doped Kaolin Clay

Kaolin clay samples were mixed with various amounts of Fe₂O₃ powder. The influence of this magnetic impurity on NMR relaxation and diffusion measurements on the water in this porous material was investigated. The NMR relaxation measurements showed a nearly mono-exponential decay, leading to the conclusion that the pore size distribution of the clay samples is either narrow and/or that the pores are interconnected very well. Both the longitudinal and the transverse relaxation rate depend linearly on the concentration of the Fe₂O₃ impurity. The NMR diffusion measurements revealed that the Fe₂O₃ causes internal magnetic field gradients that largely exceed the maximum external gradient that could be applied by our NMR apparatus (0.3 T/m). Additional SQUID measurements yielded the magnetization and magnetic susceptibility of the samples at the magnetic field strength used in the NMR measurements (0.8 T). A theoretical estimate of the internal magnetic field gradients leads to the conclusion that the water in the porous clay samples cannot be described by the commonly observed motional averaging regime. Probably an intermediate or a localization regime is induced by the large internal gradients, which are estimated to be on the order of 1 to 10 T/m in the pore volume and may exceed 1000 T/m at the pore surface.     

Impact factors and thermodynamic characteristics of aquatic humic acid loaded onto kaolin

The adsorption of humic acid (HA) on kaolin particles was studied at various conditions of initial solution pH, ionic strength and solid-to-liquid ratio. The resulting affinity of interactions between humic acid and kaolin was attributed to the surface coordination of HA in ambient suspensions of mineral particles and the strong electrostatic force at low pH. Addition of inorganic salt can also influence the adsorption behavior by affecting the HA molecular structure, the clay particle zeta potential and so on. Equilibrium data were well fitted by the Freundlich model and implied the occurrence of multilayer adsorption in the process. In addition, the enthalpy dependent of system temperature was 79.17 kJ/mol, which proved that the mechanism of HA adsorption onto kaolin was comprehensive, including electrostatic attraction, ligand complexation and hydrogen bonding.     

Facile preparation of Kaolin supported silver nanoparticles mediated by Thymbra spicata extract and investigation of the anti-human lung cancer properties

The present work demonstrates the synthesis of kaolin supported Ag nanoparticles (AgNPs@Kaolin) by using an aqueous extract of Thymbra spicata as a green reductant and capping agent. Physicochemical characteristics of the synthesized nanocomposite were studied by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), elemental mapping, X-ray diffraction (XRD) and inductively coupled plasma (ICP) techniques. The biogenic AgNPs are uniformly globular. Owing to the surface modification by the plant derived phytochemicals, the NPs are found to be distributed evenly on the kaolin surface. The AgNPs@Kaolin nanocomposite has been explored biologically in the anticancer and antioxidant assays. In the cellular and molecular part of the recent study, the treated cells with AgNPs@Kaolin nanocomposite were assessed by MTT assay for 48 h about the cytotoxicity and anti-human lung adenocarcinoma properties on normal (HUVEC) and lung adenocarcinoma cell lines i.e. lung well-differentiated bronchogenic adenocarcinoma (HLC-1), lung moderately differentiated adenocarcinoma (LC-2/ad), and lung poorly differentiated adenocarcinoma (PC-14). The viability of malignant lung cell line reduced dose-dependently in the presence of AgNPs@Kaolin nanocomposite. The IC50 of AgNPs@Kaolin nanocomposite were 509, 315, and 189 µg/mL against HLC-1, LC-2/ad, and PC-14 cell lines, respectively. In the antioxidant test, the IC50 of AgNPs@Kaolin nanocomposite and BHT against DPPH free radicals were 125 and 161 µg/mL, respectively. After the clinical study, AgNPs@Kaolin nanocomposite containing T. spicata leaf aqueous extract may be used to formulate a new chemotherapeutic drug or supplement to treat the several types of human lung adenocarcinoma.     

贵州丹寨清江高岭土矿床物质组份研究及成因

本文从研究二叠系下统梁山组硬、软质高岭石粘土岩的物质组份出发,阐明了高岭石的矿物学特征及其化学成分,以此论证了此系地层中的硬、软质粘土是以不同方式沉积而成。为在我国南方寻找和开发利用类似高岭土矿床提供了基础资料。     

氧化锑/高岭土复合阻燃微粉的结构分析

用球磨法制备了氧化锑／高岭土复合阻燃微粉,采用Ｘ射线衍射（ＸＲＤ）、红外吸收光谱（ＩＲ）对复合微粉的结构进行了分析,ＸＲＤ分析表明：随着复合微粉组分的变化,高岭土和氧化锑的ＸＲＤ特征衍射吸收峰发生移动,衍射强度发生变化,相应晶面间距发生膨胀和收缩,晶格畸变明显。ＩＲ分析表明：随着复合组分的变化,高岭土和氧化锑的ＩＲ特征振动吸收峰发生红移、蓝移、振动消失等系列变化。     

新石器时期西山遗址古陶器表面陶彩的分析及其与烧结温度的关系

本文应用Ｘ射线衍射仪和Ｘ光荧光光谱仪，对新石器时期河南西山遗址出土的古陶器表面的陶彩进行了分析，根据分析结果初步推断出当时陶器的烧结温度     

山西省应大力发展煤矸石煅烧高岭土精品

针对山西省煤矸石存量大且利用率低的现状，系统地介绍和分析了国内外煅烧高岭土产品的开发、应用及市场需求情况。为使山西的资源优势尽快转化为产品优势和经济优势，提出了应将用煤矸石生产高档煅烧高岭土作为山西省一个新的经济增长亮点来大力发展。     

高岭土细粉原位晶化合成NaY分子筛

我国的高岭土以其成因类型齐全、储量丰富、质量优良而闻名于世。高岭土广泛应用于石油化工、造纸、功能填料、耐火材料等方面。高岭土可用作载体担载催化剂,也可用作合成沸石分子筛的原料,因此是一种潜在的理想原位晶化载体。用高岭土原位晶化技术得到的沸石分子筛具有较高的水热稳定性,解决在工业生产中的过滤问题,同时降低生产成本。本论文对高岭土微球原位晶化合成沸石分子筛的原理提出了一定的见解,为进一步的研究发展打下了一定的基础。