Fabrication and Characterization of Ce3+-Doped Lithium Alumino-Silicate Scintillating Glass-Ceramic and Fiber.

Ce3+-doped lithium alumino-silicate (Li-Al-Si) scintillating glass was prepared using a melting method and crystallized via heat treatment. X-ray diffraction and transmission electron microscopy confirmed the presence of nanocrystals in the materials. Radioluminescence spectra, obtained by X-ray excitation, and luminescence spectra, obtained by 338 nm excitation, showed that the luminescence intensity increased after crystallization. The glass was combined with pure silica as the inner cladding to fabricate a hybrid fiber core using a melt-in-tube technique. The composition of the fiber core was examined using an electron probe microanalyzer. The glass fiber produced strong blue luminescence under UV excitation. After a micro-crystallizing heat treatment of the hybrid fiber at 850 °C in a reducing atmosphere, a Ce3+-doped lithium alumino-silicate glass-ceramic scintillating hybrid fiber was obtained. The nanocrystal structure of the fiber core was examined using micro-Raman spectroscopy. Excitation and luminescence spectra of the hybrid fiber before and after micro-crystallization were measured using microspectrofluorimetry. The results demonstrated that the fiber remained luminous after micro-crystallization. Hence, this work provides a new way to prepare scintillating glass-ceramic hybrid fibers for neutron detection.

The Distribution Pattern and Leaching Toxicity of Heavy Metals in Glass Ceramics from MSWI Fly Ash and Andesite Tailings.

The leaching of heavy metals (HMs) is the key factor affecting the resource utilization of municipal solid waste incineration (MSWI) fly ash. A novel fly ash and andesite-tailings-based (FAAT) glass ceramic is prepared with the full-component utilization of MSWI fly ash and andesite tailings. The effects of the content and distribution state of HMs on their leaching toxicity are studied by performing a sequential extraction procedure and leaching toxicity test. The results show that the MSWI fly ash content greatly impacts the HMs' leaching toxicity in glass ceramics. Thus, the addition of MSWI fly ash must be maintained at below 20% so as to meet the class III groundwater standard. Furthermore, the different distribution states of Zn and Cr also affect their leaching toxicity. Zn suits the requirements for leaching toxicity only in a 2080c sample, while Cr fulfills the class III groundwater standard for all the glass ceramics. Since this finding is mismatched with the calculated potential ecological risk index of glass ceramics, the latter can only be used as a reference. Therefore, the results of the present study are of great significance in the vitrification application of MSWI fly ash.

Combined hydrothermal treatment, pyrolysis, and anaerobic digestion for removal of antibiotic resistance genes and energy recovery from antibiotic fermentation residues.

A process combining hydrothermal treatment (HT), pyrolysis, and anaerobic digestion can efficiently treat antibiotic fermentation residues (AFR). The process characteristics and antibiotic resistance genes (ARGs) removal efficiencies of each unit have been investigated. HT of 180 °C improved the biodegradability and dewaterability of the AFR. Pyrolysis of 500 °C and upflow anaerobic sludge blanket (UASB) of 6.5 ± 0.5 kg COD•(m3•d)-1 recovered the organic matter in filter cake and filtrate of AFR. The biogas and pyrolysis gas can compensate the energy this system needs. HT of 180 °C could reduce 16S rRNA, ARGs, and mobile genetic elements (MGEs) by 2.3 to 7.4 logs. UASB increased the copy numbers of ARGs and MGEs, but the relative abundances of ARGs normalized against 16S rRNA were significantly declined. The ARGs and MGEs were enriched in suspended solids of digestate. The application of this process can promote the resources recycling of fermentation waste.

Trace Element Analysis by PIYE and ICP-AES of Raw Material and Ancient Serpentine Artifacts from China.

This work mainly talks about serpentine mineral with the aim to explore the possible raw materials sources of ancient serpentine artifacts by trace element content analysis. The major and trace elements of serpentine samples from several typical deposits in China were nondestructively determined by external-beam proton-induced X-ray emission (PIXE). For comparison, trace element concentrations were destructively measured by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results showed the trend of the trace element contents of serpentine jade obtained by the two methods have preferably coherence, which indicate that the nondestructive technique of PIXE can be applied to trace element analysis of serpentine. The relationship between trace element contents and serpentine formation mechanism was discussed. The difference of the trace elements contents in these serpentine minerals is obvious. It can be used to distinguish the different kinds of serpentine formed by different mechanisms. A low amount of Ni and almost no Cr and Co were found in type I serpentine group mineral, whereas significant amounts of Cr, Co and Ni were found in Type II serpentine group mineral. The chemical composition of 18 ancient serpentine artifacts were analyzed by PIXE, they were unearthed from 14 sites and tombs in provinces of Zhejing, Jiangsu, Henan, Anhui and Hubei and dated from Neolithic Age to the Warring States Period (4585 BC­231 BC). By comparing the trace element contents between ancient serpentine artifacts and two kinds of serpentine samples, the provenance of ancient serpentine artifacts were preliminarily inferred. It is beneficial to try to explore the possible raw material of ancient serpentine artifacts based on the relationship between the trace element contents and serpentine formation mechanism in this article.

[Coloration mechanism and chromaticity of Xiuyan Jade of China].

The coloration mechanism of Xiuyan Jade was studied with the chemical composition, valance and coordination states of transition metal ions. The result of inductively-coupled plasma atom emission spectrometer (ICP-AES) indicated that there are little other transition metal elements except for iron and manganese. Electron paramagnetic resonance (EPR) revealed that Fe3+ ions locate at both octahedral sites and tetrahedral sites. Optical absorption spectrum (OAS) showed the presence of Fe2+ and Fe3+ ions. Moreover, depending on the results of OAS, Fe2+ ions determine the green color of Xiuyan Jade, while the coexistence of Fe3+ and Fe2+ ions introduces the yellow color of Xiuyan Jade. The chromaticity coordinate was calculated according to diffuse reflectance spectrum. The result demonstrated that chromaticity coordinates can be used to quantitatively distinguish Xiuyan Jade with similar color, which can provide a scientific reference for the evaluation of the value of Xiuyan Jade.