709 research outputs found
Modified clays for environmental remediation: Wastewater treatment
No full textA comprehensive analysis of more than 7,000 topsoil and subsoil samples in Australia, matched with remote sensing and other data, confirms that clays are abundant, pervasive and regionally distributed across this significantly weathered continental landscape1. The predominant use of these clays within Australia is for building materials (e.g. paints, paper filler, bricks), ceramics and porcelain, horticulture and environmental remediation. Commercial use of clays in environmental remediation is as liners, geological barriers and containment walls in tailings dams, landfills, wetlands and water supply channels. Geosynthetic clay liners have widespread use in the construction/civil, mining and environmental sectors in Australia and involve forming bentonite within a flexible engineered fabric but the clay is essentially unmodified. This talk will focus on chemical modifications of clays resulting in either transformation of the source aluminosilicate or enhanced functionality due to adsorption of key compounds/elements
Data for: Crystal habit-directed gold deposition on pyrite: Surface chemical interpretation of the pyrite morphology indicative of gold enrichment
No full textThis dataset files are the raw_data for Crystal habit-directed gold deposition on pyrite: Surface chemical interpretation of the pyrite morphology indicative of gold enrichment"
A green and efficient technology to recover rare earth elements from weathering crusts
No full textHeavy rare earth elements (HREEs) such as Gd-Lu, Sc and Y are irreplaceable metals for a number of critical (including clean) technologies, but they are scarce. Ion-adsorption deposits, which form within weathering crusts, supply more than 95% of the global HREE demand. However, these deposits are currently mined via ammonium-salt-based leaching techniques that are responsible for severe environmental damage and show low recovery efficiency. As a result, the adoption of such techniques is restricted for REE mining, further exacerbating REE scarcity, which in turn could lead to supply chain disruptions. Here we report the design of an innovative REE mining technique, electrokinetic mining (EKM), which enables green, efficient and selective recovery of REEs from weathering crusts. Its feasibility is demonstrated via bench-scale, scaled-up and on-site field experiments. Compared with conventional techniques, EKM achieves similar to 2.6 times higher recovery efficiency, an similar to 80% decrease in leaching agent usage and a similar to 70% reduction in metallic impurities in the obtained REEs. As an additional benefit, the results point to an autonomous purification mechanism for REE enrichment, wherein the separation process is based on the mobility and reactivity diversity between REEs and metallic impurities. Overall, the evidence presented suggests that EKM is a viable mining technique, revealing new paths for the sustainable harvesting of natural resources
Infrared study of HDTMA+ intercalated montmorillonite
No full textIn this paper, FTIR spectroscopy using ATR and KBr pressed disk techniques has been used to characterize sorbed water and HDTMA+ in organo-clay. Sorbed water content decreases with the intercalation of HDTMA+. With the decrease of the sorbed water content, the position of the ν2 mode shifts to higher frequency dramatically while the stretching vibration shifts to lower frequency slightly, indicating that H2O is less hydrogen bonded. This might be resulted from the polarization of H2O molecules by the changeable cations and HDTMA+. FTIR spectra show that both antisymmetric and symmetric CH2 stretching absorption bands shift to low frequencies with increase of amine concentration within the galleries of montmorillonite, elucidating the increase of ordered conformation. Furthermore, the present study demonstrates that the antisymmetric CH2 stretching mode is more sensitive to the conformational ordering than the symmetric stretching mode does. When KBr pressed disk technique used, two well resolved absorption bands at 730 cm-1 and 720 cm-1, and at 1473 cm-1 and 1463 cm-1, corresponding to the methylene scissoring and rocking modes, respectively, could be observed in FTIR spectra of organo-clays with relative higher concentration of surfactant. However, the FTIR spectra using ATR technique only display singlets and they are independent of amine concentration and chain conformation. Our present study demonstrates that FTIR spectroscopy using KBr pressed disk technique is more suitable to probe the conformational ordering of surfactant in organo-clays than that suing ATR technique does
Serum ACTH and Cortisol Level is Associated with the Acute Gastrointestinal Injury Grade in ICU Patients [Erratum]
No full textXu W, Qiu Y, Qiu H, Zhong M, Li L. Int J Gen Med. 2024;17:127–134.
On page 127, the third author’s name should read from “Hongping Qiu” to “Hongping Qu”.
This error was introduced by the Editorial staff during the publication process
Raman spectroscopic study of organo-montmorillonites
No full textA Raman spectroscopic study on the organo-montmorillonites prepared at different concentrations has provided a detailed observation about the ordering conformation of HDTMA+ ions confined within the montmorillonite interlayer. The ordering conformation shows strong dependence on the concentration of the confined amine. Both wavenumber and band width of antisymmetric and symmetric stretching modes are sensitive to the ordering conformation of the inserted organic cation. Furthermore, the wavenumber of the antisymmetric stretching mode is more sensitive to the mobility of the tail of amine chain than that of symmetric stretching mode does. \ud
At room temperature, the conformational ordering is more easily to be effected by the packing density in the lateral model than in the paraffin-type model. However, at liquid nitrogen temperature, both the positions of antisymmetric and symmetric stretching modes are independent of the amine concentration, and the band width of symmetric stretching mode is sensitive to the ordering conformation of organic. Upon heating the organo-montmorillonites, both the position of the antisymmetric and symmetric stretching bands shift to higher wavenumbers, indicating the decrease of conformational ordering
Ecological Risk Assessment of Organochlorine Pesticides in Surface Waters of Lake Taihu, China
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Organoclays prepared from montmorillonites with different cation exchange capacity and surfactant configuration
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