Topic
Vermiculite
About: Vermiculite is a research topic. Over the lifetime, 2320 publications have been published within this topic receiving 37142 citations.
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TL;DR: In this paper, it was suggested that the minerals studied are dioctahedral forms, which have resulted from the weathering of muscovite-type micas.
Abstract: X-ray and electron-diffraction studies, and differential thermal analyses of the clay fraction of some soils from Virginia, New Jersey, and Wisconsin indicate an abundance of minerals resembling vermiculite. Measurements of the 060 spacing for these minerals give values lower than those obtained for trioctahedral vermiculites. It is suggested that the minerals studied are dioctahedral forms, which have resulted from the weathering of muscovite-type micas.
11 citations
Patent•
05 Aug 2009
TL;DR: In this paper, a method for preparing a molecular self-assembly porous vermiculite air purifying material was proposed, which is easy to operate and suitable for industrial scale production.
Abstract: The invention relates to a method for preparing a molecular self-assembly porous vermiculite air purifying material. The method comprises that: (1) vermiculite is subjected to acid cleaning, alkali cleaning and alcohol cleaning sequentially; and finally, the vermiculite is washed by deionized water and dried; (2) the vermiculite is soaked in a 0.01 to 0.1mol/l surfactant solution; after the surface of the vermiculite is assembled with a layer of organic unimolecule film, the vermiculite is taken out; a surface physical adsorption composition is washed out; and the vermiculite is dried in vacuum; (3) the vermiculite is soaked in 0.15 to 0.35 mol/L sol; an SnCl2 solution is taken out and injected to the sol; PdCl2 is taken out and dripped to the sol; the mixture is kept stand, stirred and separated; a loose layer is washed out; and the mixture is dried; and (4) the step (2) and the step (3) are repeated for three to four times; and the mixture is calcined to obtain the molecular self-assembly porous vermiculite air purifying material. The preparation method is simple, easy to operate and suitable for industrial scale production; and the prepared air purifying material has good air purifying effect.
11 citations
TL;DR: Based on the characters of expanding and layer adsorbing of vermiculite, the authors in this article showed that the expanded times increase with the increasing of concentration of hydrogen peroxide.
Abstract: Based on the characters of expanding and layer adsorbing of vermiculite，industrial vermiculite samples from Weili Mine of Xinjiang Province were expanded by both chemical and microwave chemical methods. The influences to the exfoliation ratio of different parameters such as concentration of hydrogen peroxide, power of the microwave, heating time, ratio of solid-liquid, immersion time were discussed. And the expanded mechanism of vermiculite was also analyzed. The results indicate that the expanded times increase with the increasing of concentration of hydrogen peroxide, and the best expanding point appears when the concentration of hydrogen peroxide is 30%. The solid-liquid ratio of vermiculite and hydrogen peroxide has little effect on the expanding of vermiculite. The vermiculite samples could be expanded 8.5 times by heated 2 min under 800W microwave power after immersion for 12 h when the concentration of hydrogen peroxide is 30%. As a result, the vermiculite could be expanded because of the oxygen pressure produced by the decomposition of hydrogen peroxide into the vermiculite interlayer. When using the microwave chemical method, the pressure of both oxygen and interlayer water lead to the increases of the expanded times. And exfoliation vermiculite plays an important part in energy-saving and environmental treatment.
11 citations
TL;DR: Both minerals showed high efficiency in removing NH 4 + from solution which can then be slowly released as a nutrient in the soil, preventing soil acidification.
Abstract: In tropical environments, nutrient-poor soils are commonly found, leading to high fertilizers application rates to support agricultural activities. In contrast, anthropogenic activities generate large amounts of effluents containing nitrogen. In this study, two minerals (natural zeolite and vermiculite) were tested to remove NH4+ from an industrial effluent with high pH and contents in Na+ and K+. Afterwards, they were tested as an alternative slow-release fertilizer in the soil. To verify the best conditions to adsorb NH4+, batch tests were conducted using synthetic solutions and an industrial effluent. In general, the efficiency of both minerals in removing NH4+ was high (85% for zeolite and almost 70% for vermiculite) as well as the ability to decrease the industrial effluent pH. In this process, more NH4+ and K+ ions were removed in comparison with Na+, which remained in solution. These minerals were tested as slow-release fertilizers by leaching with distilled water (both minerals releasing 2 mg L−1 NH4+) and with an acid solution (releasing 10 mg L−1 NH4+ from zeolite and 50 mg L−1 NH4+ from vermiculite—corresponding only to 12% of total NH4+ retained by zeolite and 29% by vermiculite). During the test of soil incubation with zeolite-NH4+, the NH4+ ions of the exchangeable sites were retained for a longer period, minimizing their loss by leaching and biological nitrification. Consequently, soil acidification was prevented. Therefore, both minerals showed high efficiency in removing NH4+ from solution which can then be slowly released as a nutrient in the soil.
11 citations