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https://read.qxmd.com/read/30777749/fe-0-36-4-pd-0-64-4-se-2-magnetic-spin-glass-polymorph-of-fese-2-and-pdse-2-stable-at-ambient-pressure
#1
Jianjun Tian, Valentin N Ivanovski, David Szalda, Hechang Lei, Aifeng Wang, Yu Liu, Weifeng Zhang, Vasil Koteski, Cedomir Petrovic
We report the synthesis and characterization of Fe0.36(4) Pd0.64(4) Se2 with a pyrite-type structure. Fe0.36(4) Pd0.64(4) Se2 was synthesized using ambient pressure flux crystal growth methods even though the space group Pa3 is high-pressure polymorph for both FeSe2 and PdSe2 . Combined experimental and theoretical analysis reveal magnetic spin glass state below 23 K in 1000 Oe that stems from random Fe/Pd occupancies on the same atomic site. The frozen-in magnetic randomness contributes significantly to electronic transport...
February 19, 2019: Inorganic Chemistry
https://read.qxmd.com/read/30775742/scalable-synthesis-of-fes-2-nanoparticles-encapsulated-into-n-doped-carbon-nanosheets-as-a-high-performance-sodium-ion-battery-anode
#2
Zhihua Lin, Xunhui Xiong, Mengna Fan, Dong Xie, Gang Wang, Chenghao Yang, Meilin Liu
Pyrite (FeS2) has been considered as one of the most potential anode materials for sodium ion batteries (SIBs) due to its low cost, environmentally friendly features and high theoretical capacity. However, the huge volume changes during a charge/discharge process and poor conductivity of FeS2 hindered its practical applications. Herein, we propose a facile scalable approach to prepare nanostructured FeS2 embedded in an N-doped carbon nanosheet composite (FeS2/CNS) via a combined template method and a solid state sulfuration method...
February 18, 2019: Nanoscale
https://read.qxmd.com/read/30771655/hexavalent-chromium-remediation-based-on-the-synergistic-effect-between-chemoautotrophic-bacteria-and-sulfide-minerals
#3
Min Gan, Chunyao Gu, Jijuan Ding, Jianyu Zhu, Xinxing Liu, Guanzhou Qiu
Hexavalent chromium (Cr(VI)) is an environmental concern due to the carcinogenic and mutagenic effect on living organisms. Sulfide minerals based Cr(VI) reduction is an economical and efficient strategy for Cr(VI) remediation. In this study, Cr(VI) reduction through the synergistic effect between chemoautotrophic bacteria and sulfide mineral is systematically investigated. Sulfide minerals dissolution and Cr(VI) reduction performance highly depends on mineral acid soluble property. Cr(VI) reduction capacity of pyrrhotite, pyrite, marcasite and sphalerite was 50, 104, 104 and 44 mg/g (Cr(VI)/mineral) respectively in the biotic system...
February 13, 2019: Ecotoxicology and Environmental Safety
https://read.qxmd.com/read/30769305/diclofenac-removal-by-pyrite-fenton-process-performance-in-batch-and-fixed-bed-continuous-flow-systems
#4
Ozlem Oral, Cetin Kantar
This study provides experimental results from batch and column studies to investigate diclofenac degradation by pyrite-Fenton process under variable chemical conditions (e.g., pyrite loading). Batch experiments show that diclofenac removal increased with increasing hydrogen peroxide and pyrite concentration. On the other hand, the addition of organic chelating agents such as citrate had an adverse effect on diclofenac removal by pyrite-Fenton process in batch systems due to scavenging effect of these agents for hydroxyl radicals...
February 6, 2019: Science of the Total Environment
https://read.qxmd.com/read/30767922/continuous-flow-ozonation-over-modified-ceramsite-implications-for-the-degradation-of-cation-red-x-grl
#5
Ying Liu, Deli Wu, Hongping He
Catalytic ozonation has been widely used for refractory dye wastewater treatment due to highly reactive HO·. In this study, a kind of low-cost and environmental-friendly modified ceramsite sphere derived from pyrite cinder, silty clay and kaolin was prepared as ozonation catalyst. The degradation performances of cation red x-GRL were performed under a continuous mode. Being close to the practical treatment, continuous-flow ozonation study is vital for applying heterogeneous catalytic ozonation in wastewater treatment at a large industrial scale...
December 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://read.qxmd.com/read/30743837/negative-ph-values-in-an-open-air-radical-environment-affected-by-acid-mine-drainage-characterization-and-proposal-of-a-hydrogeochemical-model
#6
Aguasanta M Sarmiento, José Antonio Grande, Ana T Luís, José Miguel Dávila, Juan Carlos Fortes, María Santisteban, Jesús Curiel, María Luisa de la Torre, Eduardo Ferreira da Silva
This paper presents the finding of a singular environment polluted by acid mine drainage in the Iberian Pyrite Belt. This situation is regulated by particular conditions, thus the analysed values can be considered as extreme, not only because of the high concentrations of toxic elements, but also due to the extreme low pH, reaching an average negative pH of -1.56, never found before in open-air environments contaminated by acid mine drainage. Concentrations up to 59 g/L of Fe, 2.4 g/L of Al, 740 mg/L of As, 4...
December 10, 2018: Science of the Total Environment
https://read.qxmd.com/read/30743061/biofilm-dynamics-and-eps-production-of-a-thermoacidophilic-bioleaching-archaeon
#7
Ruiyong Zhang, Thomas R Neu, Véronique Blanchard, Mario Vera, Wolfgang Sand
Bioleaching of metal sulfides represents an interfacial process where biofilm formation is important in the initial steps of this process. In technical applications of bioleaching, such as reactor leaching in the temperature range of 50 up to 90 °C and also in (self-heating) heaps, thermophilic archaea play an important role and often are the leaching organisms of choice. Nevertheless, to date there is little information available on the interactions between thermoacidophilic archaea and their natural mineral substrates such as pyrite...
February 8, 2019: New Biotechnology
https://read.qxmd.com/read/30710778/effects-of-waste-deposit-geometry-on-the-mineralogical-and-geochemical-composition-of-mine-tailings
#8
Dan Stumbea, Marius Marian Chicoș, Valentin Nica
The study tailing pond shows a particular geometry resulting from the tailings stockpiles deposited onto the northern part of the beach. This generated three types of superficial waste: (i) tailings of the stockpiles (A-type) (pH=2.2-2.6; soluble fraction average - SF=14.2%), subjected to intense oxidation and evaporation; (ii) tailings of the lowlands of waste, characterized by low oxidation and no evaporation (B-type) (pH=2.7-3.1; SF=7.7%); (iii) salt crusts (C-type) (pH=2.6-3.5; SF=81.5%), formed by the evaporation of leachates accumulated in stagnant pools...
January 23, 2019: Journal of Hazardous Materials
https://read.qxmd.com/read/30701355/biogeochemical-characterization-of-surface-waters-in-the-aljustrel-mining-area-south-portugal
#9
Ana T Luís, José António Grande, Nuno Durães, José Miguel Dávila, María Santisteban, Salomé F P Almeida, Aguasanta M Sarmiento, María Luisa de la Torre, Juan Carlos Fortes, Eduardo Ferreira da Silva
Aljustrel mining area (South Portugal) is a part of the Iberian Pyrite Belt and encloses six sulfide mineral masses. This mine is classified of high environmental risk due to the large tailings' volume and acid mine drainage (AMD)-affected waters generated by sulfides' oxidation. The use of biological indicators (e.g., diatoms) revealed to be an important tool to address the degree of AMD contamination in waters. Multivariate analysis has been used as a relevant approach for the characterization of AMD processes...
January 30, 2019: Environmental Geochemistry and Health
https://read.qxmd.com/read/30690231/oxidative-degradation-of-chlorophenolic-compounds-with-pyrite-fenton-process
#10
Cetin Kantar, Ozlem Oral, Ozge Urken, Nilgun Ayman Oz, Selda Keskin
Batch experiments, in conjunction with chromatographic and spectroscopic measurements, were performed to comparatively investigate the degradation of various chlorophenolic (CP) compounds (e.g., 2-CP, 4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP, 2,3,4,6-TeCP) by a modified Fenton process using pyrite as the catalyst. The batch results show that the CP removal by pyrite-Fenton process was highly dependent on chemical conditions (e.g., pH, CP and pyrite concentration), CP type, number and location of chlorine atoms on the aromatic ring...
January 22, 2019: Environmental Pollution
https://read.qxmd.com/read/30679710/sulphur-and-carbon-isotopes-as-tracers-of-past-sub-seafloor-microbial-activity
#11
Patrick Meister, Benjamin Brunner, Aude Picard, Michael E Böttcher, Bo Barker Jørgensen
Microbial life below the seafloor has changed over geological time, but these changes are often not obvious, as they are not recorded in the sediment. Sulphur (S) isotope values in pyrite extracted from a Plio- to Holocene sequence of the Peru Margin (Ocean Drilling Program, ODP, Site 1229) show a down-core pattern that correlates with the pattern of carbon (C) isotopes in diagenetic dolomite. Early formation of the pyrite is indicated by the mineralogical composition of iron, showing a high degree of pyritization throughout the sedimentary sequence...
January 24, 2019: Scientific Reports
https://read.qxmd.com/read/30677918/tungsten-from-typical-magmatic-hydrothermal-systems-in-china-and-its-environmental-transport
#12
Qinghai Guo, Yumei Li, Li Luo
Tungsten is of extraordinarily high concentrations in the geothermal waters discharging from several representative Tibetan magmatic hydrothermal systems (up to 1103 μg/L), which are also characterized by exceptionally high W/Mo molar ratios (up to 1182). The geochemical origins of the tungsten in these geothermal waters were investigated, with a comparison to those from Rehai, the sole magmatic hydrothermal system in Yunnan, which is another major part of the Yunnan-Sichuan-Tibet Geothermal Province of China...
March 20, 2019: Science of the Total Environment
https://read.qxmd.com/read/30665647/removal-of-cyanide-adsorbed-on-pyrite-by-h-2-o-2-oxidation-under-alkaline-conditions
#13
Yubo Tu, Peiwei Han, Lianqi Wei, Xiaomeng Zhang, Bo Yu, Peng Qian, Shufeng Ye
Large amounts of cyanide tailings are produced during the cyanidation process in gold extraction, which are hazardous solid wastes due to the toxic cyanide. Pyrite is one of the main minerals in cyanide tailings. The removal of cyanide adsorbed on pyrite by H2 O2 oxidation under alkaline conditions was investigated in this study. It was found that the removal efficiency was positively correlated with pH from 5 to 12, but remained almost constant when pH was higher than 12. The highest cyanide removal efficiency of 91...
April 2019: Journal of Environmental Sciences (China)
https://read.qxmd.com/read/30634090/unraveling-the-crucial-role-of-the-ascorbate-glutathione-cycle-in-the-resilience-of-cistus-monspeliensis-l-to-withstand-high-as-concentrations
#14
Luísa C Carvalho, Erika S Santos, M Manuela Abreu
Cistus monspeliensis L. is a species that grows spontaneously in contaminated mining areas of the Iberian Pyrite Belt. This species can accumulate high concentrations of As in the shoots without visible signs of phytotoxicity. In order to understand the physiological mechanisms underlying this tolerance, C. monspeliensis was grown in an Arenosol irrigated with aqueous nutrient solutions containing increasing concentrations of As (0, 1500, 5000, 10000, 15000 µM) and the effects of this metalloid on plant development and on the defence mechanisms against oxidative stress were monitored...
January 8, 2019: Ecotoxicology and Environmental Safety
https://read.qxmd.com/read/30632217/a-new-unspiked-k-ar-dating-approach-using-laser-fusion-on-microsamples
#15
Fei Wang, Wenbei Shi, Hervé Guillou, Weibin Zhang, Liekun Yang, Lin Wu, Yinzhi Wang, Rixiang Zhu
RATIONALE: Issues induced by neutron irradiation makes 40 Ar/39 Ar dating inapplicable in some cases. The first issue is 37 Ar and 39 Ar recoil effects during irradiation that affect fine-grained minerals (<50μm), such as lunar rocks, glassy groundmass, supergene minerals (e.g. illite, glauconite, Mg-oxide etc.). The second issue from neutron irradiation is the high radioactivity gain of iron-rich samples such as pyrite, and a third is the production of interference nuclides during irradiation...
January 10, 2019: Rapid Communications in Mass Spectrometry: RCM
https://read.qxmd.com/read/30594832/heterogeneous-fenton-reaction-for-elimination-of-acid-yellow-36-in-both-fluidized-bed-and-stirred-tank-reactors-computational-fluid-dynamics-versus-experiments
#16
Mahdi Ebrahimi Farshchi, Hassan Aghdasinia, Alireza Khataee
Heterogeneous Fenton process is a kind of advanced oxidation processes (AOPs) that is significant for wastewater treatment. In the first part of this study, acid yellow 36 (AY36) degradation process has occurred in two kinds of reactors: fluidized-bed and stirred-tank reactors. Performances of these two semi-pilot reactors are compared by evaluating the removal ratio of the dye and pH changes during the process. Pyrite has been used as a heterogeneous catalyst. For obtaining the characteristics of pyrite, XRD, SEM, and FT-IR analysis have been carried out...
December 17, 2018: Water Research
https://read.qxmd.com/read/30592309/culture-dependent-hunt-and-characterization-of-iron-oxidizing-bacteria-in-baiyin-copper-mine-china-and-their-application-in-metals-extraction
#17
Wasim Sajjad, Guodong Zheng, Xiangxian Ma, Muhammad Rafiq, Muhammad Irfan, Wang Xu, Barkat Ali
The exploration of microbial diversity in extremely acidic habitats has provided a vital base for the progression of minerals biotechnology. Three indigenous iron-oxidizing acidophilic bacterial strains were isolated through serial dilution of enriched bacterial culture from Baiyin Copper Mine Stope, China. The morphological, biochemical, physiological, and phylogenetic characteristics of isolates were investigated. These isolates were motile, Gram-negative, and curved shape with pleomorphism except isolate WG101 that was a straight rod...
December 28, 2018: Journal of Basic Microbiology
https://read.qxmd.com/read/30577025/reduction-and-immobilization-of-hexavalent-chromium-in-chromite-ore-processing-residue-using-amorphous-fes-2
#18
Yunyi Li, Jialiang Liang, Zihao Yang, Hang Wang, Yangsheng Liu
In this work, a series of long-term treatment trials were conducted to evaluate the remediation performance of amorphous iron pyrite (FeS2( am) ) toward hexavalent chromium (Cr(VI)) in chromite ore processing residue (COPR). The effectiveness of FeS2( am) was assessed using alkaline digestion, the synthetic precipitation leaching procedure (SPLP) and the physiologically based extraction test (PBET). Reaction mechanisms were explored by monitoring the changes in the solid pH, redox potential (Eh), the chemical states of relevant elements as well as the crystal forms present in COPR...
December 5, 2018: Science of the Total Environment
https://read.qxmd.com/read/30562658/mineralization-of-organics-in-hazardous-waste-sulfuric-acid-by-natural-manganese-oxide-ore-and-a-combined-mno-2-activated-carbon-treatment-to-produce-qualified-manganese-sulfate
#19
Xiunan Cai, Fang Shen, Yanjuan Zhang, Huayu Hu, Zuqiang Huang, Yanzhen Yin, Xingtang Liang, Yuben Qin, Jing Liang
To effectively dispose and utilize the hazardous waste H2 SO4 generated from alkylation, an environmentally friendly and feasible technology for the simultaneous oxidative degradation of organics and consumption of H2 SO4 was developed. Pyrolusite, a natural manganese oxide ore, was used for the oxidative degradation and mineralization of the organics, and reduction leaching of Mn from the pyrolusite occurred simultaneously. The total organic carbon (TOC) removal and Mn leaching efficiency were 46% and 16.44%, respectively...
December 8, 2018: Journal of Hazardous Materials
https://read.qxmd.com/read/30561860/sulfur-isotope-analysis-of-microcrystalline-iron-sulfides-using-sims-imaging-extracting-local-paleo-environmental-information-from-modern-and-ancient-sediments
#20
Roger N Bryant, Clive Jones, Morgan R Raven, Maya L Gomes, William M Berelson, Alexander S Bradley, David A Fike
RATIONALE: Sulfur isotope ratio measurements of bulk sulfide from marine sediments have often been used to reconstruct environmental conditions associated with their formation. In-situ microscale spot analyses by secondary ion mass spectrometry (SIMS) and laser ablation multiple-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) have been utilized for the same purpose. However, these techniques are not often suitable for studying small (≤10 μm) grains or for detecting intra-grain variability...
December 18, 2018: Rapid Communications in Mass Spectrometry: RCM
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