scholarly journals EVALUATING GEOCHEMISTRY OF RARE EARTH ELEMENTS IN COPPER DEPOSIT OF AGHBOLAGH, NORTH OF OSHNAVIEH, WEST AZARBAIJAN PROVINCE-IRAN

Geosaberes ◽  
2020 ◽  
Vol 11 ◽  
pp. 199
Author(s):  
Kamal Dana ◽  
Nima Nezafati ◽  
Mansourvosouqi Abedini
Keyword(s):  
Contact Point ◽  
Copper Deposit ◽  
Segregation Coefficient ◽  
Calc Alkaline ◽  
Vein Deposit ◽  
High Potassium ◽  
Granite Intrusion ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Ree Pattern

AghBolagh region is located in southwest of West Azarbaijan Province that is 10 km far from north of Oshnavieh. Most of the rocky outcrops in the region include Cambrian deposits (carbonate deposits and clastic deposits (sandstone and shale)). These deposits were later influenced and altered by granite Intrusion. The Intrusion is made of granite and in term of nature, it is magmatic with High-potassium calc-alkaline and peralumin. Also the penetration of intrusion and Ore maker solvent in further distances from the contact point and inside the sequences of sandstone has formed quartzite rocks and ore bearing veins of cooper. The REE pattern normalized to Chondrite for granite, skarn, and marble intrusion and vein deposits shows the fact that, although the REEs pattern is a little smooth and unified, LREEs have more enrichment compared to HREEs in different lithology. The range of normalized numbers to Chondrite in AghBolagh deposit is clearly variable (2.58 to 141.93 for La and 0.14 to 27.27 for Yb). This indicates that there have been clear differences in increase and decrease of LREEs and HREEs during the   formation of AghBolagh deposit stones and rocks. The La / Y ratio shows the pH condition of the environment for formation of deposit. This ratio in AghBolagh deposit ranges from 0.09 to 2.26. The granite intrusion shows the most amount of La/Y which is equal to 2. Skarn Zone (Endoskarn and Exoskarn and Ore in Exoskarn) shows two different conditions. The first condition: the part in which LA/Y>1, and this can be observed in samples near the intrusion and Skarn ore is also found in this range. The second condition: the part that La/Y<1, which is near to marble lithology. Also, about vein deposit, the sample is ore making in alkaline conditions, and other samples show acidic conditions. To evaluate the segregation coefficient between REEs, different ratios of REEs including (La/Yb) n ', (La/Sm) n, and (Gd/Yb) n are used. The values of these ratios range from (0.42 to 50.56) for (La/Yb) n; and from (0.25 to 80.125) for (La/Sm) n’; (from 0.006 to 48.8) for (Gd/Yb) n. The highest segregation was between LREEs and HREEs (more than 125) and the least segregation was between MREEs and HREEs during the Skarn process.

Adsorptive removal of trace oxytetracycline from water by acid-modified zeolite: influencing factors

2013 ◽  
Vol 68 (11) ◽  
pp. 2473-2478 ◽  
Author(s):  
Wenhao An ◽  
Hua Xiao ◽  
Man Yu ◽  
Xiaoyang Chen ◽  
Yuxin Xu ◽  
...  
Keyword(s):  
Humic Acid ◽  
Removal Efficiency ◽  
Natural Zeolite ◽  
Opposite Effect ◽  
Swine Wastewater ◽  
Adsorption Efficiency ◽  
Tetracycline Antibiotics ◽  
Modified Zeolite ◽  
Alkaline Conditions ◽  
Acidic Conditions

Because of the wide use of antibiotics in the livestock industry, trace tetracycline antibiotics are frequently detected in swine wastewater and water bodies near pig farms. Based on natural zeolite, modified zeolite was synthesized by treatment with nitric acid. As one kind of typical tetracyclines, oxytetracycline (OTC) was chosen as the target adsorbate. Removal of trace OTC by modified zeolite and the effects of several main water matrices on OTC adsorption were studied in detail. OTC removal efficiency by acid-modified zeolite was about 90%, compared to less than 20% by natural zeolite. In general, in acidic conditions the removal efficiency of OTC by modified zeolite was about 90%, which was much higher than 20–35% in alkaline conditions. An increase in ionic strength from 0.01 to 1.0 M led to a decrease in adsorption efficiency from 90 to 27%. The presence of 10.0 mg L−1 dissolved humic acid accelerated sorption of OTC on modified zeolite, while 100.0 mg L−1 humic acid resulted in the opposite effect. An increase in temperature contributed to enhancing the adsorption efficiency.

Effect of acidity on the properties of silica-aluminas synthesized by sol-gel method

2020 ◽  
Vol 63 (7) ◽  
pp. 126-132
Author(s):  
Lyubov V. Furda ◽  
◽  
Evgenia A. Tarasenko ◽  
Sofya N. Dudina ◽  
Olga E. Lebedeva ◽  
...  
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Molar Ratio ◽  
Active Centers ◽  
Indicator Method ◽  
Synthesis Conditions ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Amphoteric Properties ◽  
Hydrolysis Of

In the present work amorphous silica-aluminas were synthesized by the coprecipitation method during the hydrolysis of an alcohol solution of tetraethoxysilane (with a tetraethoxysilane: alcohol mass ratio of 1: 1) and 6% aqueous solution of aluminum nitrate at pH values of 1, 3, and 10. The Si/Al molar ratio for all synthesized samples were 4.72 (± 0.29). The amorphous character of the investigated materials was confirmed by X-ray phase analysis. According to the results of scanning electron microscopy, it was found that the resulting powders have particles with a size of 1-20 μm. It was shown that the conditions of synthesis affected the specific surface area and porosity of the materials under study. By the method of low-temperature adsorption-thermodesorption of nitrogen it was established that silica-aluminas obtained under acidic conditions were microporous materials. For the sample obtained under alkaline conditions (pH = 10), the contribution of macropores is very significant. A decrease in surface area is observed as the pH of the synthesis increases. The Hammett indicator method was used to identify and quantify surface centers of different acidity. All studied silica-aluminas are characterized by the presence of both Brønsted basic (pKax from 7 to 12.8) and acidic (pKax from 0 to 7) centers, and Lewis basic (pKax from -4.4 to 0) with a pronounced maximum at pKax = 1.02. It was found that the synthesis conditions had a significant effect on the concentration of active centers. The values of the Hammett function are practically the same for the 3 studied silica-aluminas and describe the studied samples as materials of medium acidity. The variety of Lewis and Brønsted centers on the surface indicates the amphoteric properties of the materials under study. This gives the samples the properties of polyfunctional sorbents and catalysts.

scholarly journals Magmatic sulfides in high-potassium calc-alkaline to shoshonitic and alkaline rocks

Solid Earth ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Ariadni A. Georgatou ◽  
Massimo Chiaradia
Keyword(s):  
Solid Solution ◽  
Early Stage ◽  
Volcanic Field ◽  
Geodynamic Setting ◽  
Calc Alkaline ◽  
High Potassium ◽  
Western Turkey ◽  
Monosulfide Solid Solution ◽  
Magmatic Sulfides ◽  
Saturation Stage

Abstract. We investigate the occurrence and chemistry of magmatic sulfides and their chalcophile metal cargo behaviour during the evolution of compositionally different magmas from diverse geodynamic settings both in mineralised and barren systems. The investigated areas are the following: (a) the Miocene Konya magmatic province (hosting the Doğanbey Cu–Mo porphyry and Inlice Au epithermal deposits, representing post-subduction) and (b) the Miocene Usak basin (Elmadag, Itecektepe, and Beydagi volcanoes, the latter associated with the Kişladağ Au porphyry in western Turkey, representing post-subduction). For comparison we also investigate (c) the barren intraplate Plio-Quaternary Kula volcanic field west of Usak. Finally, we discuss and compare all the above areas with the already studied (d) Quaternary Ecuadorian volcanic arc (host to the Miocene Llurimagua Cu–Mo and Cascabel Cu–Au porphyry deposits, representing subduction). The volcanism of the newly studied areas ranges from basalts to andesites–dacites and from high-K calc-alkaline to shoshonitic series. Multiphase magmatic sulfides occur in different amounts in rocks of all investigated areas, and, based on textural and compositional differences, they can be classified into different types according to their crystallisation at different stages of magma evolution (early versus late saturation). Our results suggest that independently of the magma composition, geodynamic setting, and association with an ore deposit, sulfide saturation occurred in all investigated magmatic systems. Those systems present similar initial metal contents of the magmas. However, not all studied areas present all sulfide types, and the sulfide composition depends on the nature of the host mineral. A decrease in the sulfide Ni∕Cu (a proxy for the monosulfide solid solution (mss) to intermediate solid solution (iss) ratio) is noted with magmatic evolution. At an early stage, Ni-richer, Cu-poorer sulfides are hosted by early crystallising minerals, e.g. olivine–pyroxene, whereas, at a later stage, Cu-rich sulfides are hosted by magnetite. The most common sulfide type in the early saturation stage is composed of a Cu-poor, Ni-rich (pyrrhotite mss) phase and one to two Cu-rich (cubanite, chalcopyrite iss) phases, making up ∼84 and ∼16 area % of the sulfide, respectively. Sulfides resulting from the late stage, consisting of Cu-rich phases (chalcopyrite, bornite, digenite iss), are hosted exclusively by magnetite and are found only in evolved rocks (andesites and dacites) of magmatic provinces associated with porphyry Cu (Konya and Ecuador) and porphyry Au (Beydagi) deposits.

Effects of pH on photocatalysis of 2,4,6-trichlorophenol in aqueous TiO2 suspensions

1994 ◽  
Vol 30 (9) ◽  
pp. 47-57 ◽  
Author(s):  
Shuzo Tanaka ◽  
Uttam Kumar Saha
Keyword(s):  
Sodium Chloride ◽  
Degradation Rate ◽  
Parent Compound ◽  
Photocatalytic Decomposition ◽  
Illumination Time ◽  
Effects Of Ph ◽  
Alkaline Conditions ◽  
Na Ions ◽  
Acidic Conditions

The effects of pH on the photocatalytic decomposition of 2,4,6-trichlorophenol (TCP) were investigated in the presence of titanium dioxide suspensions illuminated by a high pressure mercury lamp over the wavelength range of 302-405 nm. Higher degradation rate was observed under alkaline conditions than acidic conditions. Although a rapid adsorption of TCP onto the TiO2 surface was observed at low pH and no adsorption at high pH, the role of adsorption of TCP was found insignificant in photocatalysis. With sodium chloride addition, a decrease in reaction rate was observed at pH 5 due to Cl− ions inhibition, but at pH 10 the same anions had no adverse effect on the measured photocatalytic efficiency and Na+ ions enhanced the degradation rate of TCP. With no oxygen, however, the photocatalytic decomposition of TCP in sodium chloride solution gives lower degradation rate than with dissolved oxygen and no sodium chloride at various pH. Complete mineralization requires a longer illumination time than the decomposition of the parent compound. A mechanism for the reaction based on photogeneration of hydroxyl radicals was proposed.

scholarly journals Intervention of Bro1 in pH-Responsive Rim20 Localization in Saccharomyces cerevisiae

2010 ◽  
Vol 9 (4) ◽  
pp. 532-538 ◽  
Author(s):  
Jacob H. Boysen ◽  
Shoba Subramanian ◽  
Aaron P. Mitchell
Keyword(s):  
Target Genes ◽  
Fluorescent Protein ◽  
Growth Conditions ◽  
Yeast Cells ◽  
Endosomal Trafficking ◽  
The Novel ◽  
Pathway Activation ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Green Fluorescent

ABSTRACT Yeast cells contain two Bro1 domain proteins: Bro1, which is required for endosomal trafficking, and Rim20, which is required for the response to the external pH via the Rim101 pathway. Rim20 associates with endosomal structures under alkaline growth conditions, when it promotes activation of Rim101 through proteolytic cleavage. We report here that the pH-dependent localization of Rim20 is contingent on the amount of Bro1 in the cell. Cells that lack Bro1 have increased endosomal Rim20-green fluorescent protein (GFP) under acidic conditions; cells that overexpress Bro1 have reduced endosomal Rim20-GFP under acidic or alkaline conditions. The novel endosomal association of Rim20-GFP in the absence of Bro1 requires ESCRT components including Vps27 but not specific Rim101 pathway components such as Dfg16. Vps27 influences the localization of Bro1 but is not required for RIM101 pathway activation in wild-type cells, thus suggesting that Rim20 enters the Bro1 localization pathway when a vacancy exists. Despite altered localization of Rim20, the lack of Bro1 does not bypass the need for signaling protein Dfg16 to activate Rim101, as evidenced by the expression levels of the Rim101 target genes RIM8 and SMP1. Therefore, endosomal association of Rim20 is not sufficient to promote Rim101 activation.

scholarly journals Re-Os and U-Th-Pb dating of the Rochovce granite and its mineralization (Western Carpathians, Slovakia)

2013 ◽  
Vol 64 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Milan Kohút ◽  
Holly Stein ◽  
Pavel Uher ◽  
Aaron Aimmerman ◽  
L’ubomír Hraško
Keyword(s):  
Oscillatory Zoning ◽  
Western Carpathians ◽  
Alkaline Magmatism ◽  
Calc Alkaline ◽  
Collisional Orogen ◽  
Granite Intrusion ◽  
Metallogenic Belt ◽  
Central Western Carpathians ◽  
Lower Crustal ◽  
Gemeric Unit

Abstract The subsurface Rochovce granite intrusion was emplaced into the contact zone between two principal tectonic units (the Veporic Unit and the Gemeric Unit) of the Central Western Carpathians (CWC), Slovakia. The Cretaceous age of this granite and its Mo-W mineralization is shown using two independent methods: U-Pb on zircon and Re-Os on molybdenite. The studied zircons have a typical homogeneous character with oscillatory zoning and scarce restite cores. SHRIMP U-Pb data provide an age of 81.5 ± 0.7 Ma, whereas restite cores suggest a latest Neoproterozoic-Ediacaran age (~565 Ma) source. Zircon εHf(81) values -5.2 to + 0.2 suggest a lower crustal source, whereas one from the Neoproterozoic core εHf(565)= + 7.4 call for the mantle influenced old precursor. Two molybdenite- bearing samples of very different character affirm a genetic relation between W-Mo mineralization and the Rochovce granite. One sample, a quartz-molybdenite vein from the exocontact (altered quartz-sericite schist of the Ochtiná Formation), provides a Re-Os age of 81.4 ± 0.3 Ma. The second molybdenite occurs as 1-2 mm disseminations in finegrained granite, and provides an age of 81.6 ± 0.3 Ma. Both Re-Os ages are identical within their 2-sigma analytical uncertainty and suggest rapid exhumation as a consequence of post-collisional, orogen-parallel extension and unroofing. The Rochovce granite represents the northernmost occurrence of Cretaceous calc-alkaline magmatism with Mo-W mineralization associated with the Alpine-Balkan-Carpathian-Dinaride metallogenic belt.

scholarly journals Symbiotic and non-symbiotic members of the genus Ensifer (syn. Sinorhizobium) are separated into two clades based on comparative genomics and high-throughput phenotyping

2020 ◽  
Author(s):  
Camilla Fagorzi ◽  
Alexandru Ilie ◽  
Francesca Decorosi ◽  
Lisa Cangioli ◽  
Carlo Viti ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Comparative Genomics ◽  
Phylogenetic Analyses ◽  
Carbon Sources ◽  
Associated Bacteria ◽  
Phenotypic Differences ◽  
Genetic Features ◽  
Alkaline Conditions ◽  
High Throughput Phenotyping ◽  
Acidic Conditions

ABSTRACTRhizobium – legume symbioses serve as a paradigmatic example for the study of mutualism evolution. The genus Ensifer (syn. Sinorhizobium) contains diverse plant-associated bacteria, a subset of which can fix nitrogen in symbiosis with legumes. To gain insights into the evolution of symbiotic nitrogen fixation (SNF), and inter-kingdom mutualisms more generally, we performed extensive phenotypic, genomic, and phylogenetic analyses of the genus Ensifer. The data suggest that SNF emerged several times within the genus Ensifer, likely through independent horizontal gene transfer events. Yet, the majority (105 of 106) of the Ensifer strains with the nodABC and nifHDK nodulation and nitrogen fixation genes were found within a single, monophyletic clade. Comparative genomics highlighted several differences between the “symbiotic” and “non-symbiotic” clades, including divergences in their pangenome content. Additionally, strains of the symbiotic clade carried 325 fewer genes, on average, and appeared to have fewer rRNA operons than strains of the non-symbiotic clade. Characterizing a subset of ten Ensifer strains identified several phenotypic differences between the clades. Strains of the non-symbiotic clade could catabolize 25% more carbon sources, on average, than strains of the symbiotic clade, and they were better able to grow in LB medium and tolerate alkaline conditions. On the other hand, strains of the symbiotic clade were better able to tolerate heat stress and acidic conditions. We suggest that these data support the division of the genus Ensifer into two main subgroups, as well as the hypothesis that pre-existing genetic features are required to facilitate the evolution of SNF in bacteria.

scholarly journals pH-Dependent Degradation of Diclofenac by a Tunnel-Structured Manganese Oxide

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2203
Author(s):  
Ching-Yao Hu ◽  
Yu-Jung Liu ◽  
Wen-Hui Kuan
Keyword(s):  
Formation Control ◽  
High Performance ◽  
Degradation Kinetics ◽  
Removal Rate ◽  
Solution Ph ◽  
Mn Oxide ◽  
Highly Active ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Key Parameter

The mechanism of diclofenac (DIC) degradation by tunnel-structured γ-MnO2, with superior oxidative and catalytic abilities, was determined in terms of solution pH. High-performance liquid chromatography with mass spectroscopy (HPLC–MS) was used to identify intermediates and final products of DIC degradation. DIC can be efficiently oxidized by γ-MnO2 in an acidic medium, and the removal rate decreased significantly under neutral and alkaline conditions. The developed model can successfully fit DIC degradation kinetics and demonstrates electron transfer control under acidic conditions and precursor complex formation control mechanism under neutral to alkaline conditions, in which the pH extent for two mechanisms exactly corresponds to the distribution percentage of ionized species of DIC. We also found surface reactive sites (Srxn), a key parameter in the kinetic model for mechanism determination, to be exactly a function of solution pH and MnO2 dosage. The main products of oxidation with a highly active hydroxylation pathway on the tunnel-structured Mn-oxide are 5-iminoquinone DIC, hydroxyl-DIC, and 2,6-dichloro-N-o-tolylbenzenamine.

Genesis of high-potassium calc-alkaline peraluminous I-type granite: New insights from the Gaoligong belt granites in southeastern Tibet Plateau

Lithos ◽  
2020 ◽  
Vol 354-355 ◽  
pp. 105343 ◽  
Author(s):  
Ren-Zhi Zhu ◽  
Shao-Cong Lai ◽  
Jiang-Feng Qin ◽  
M. Santosh ◽  
Shaowei Zhao ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Calc Alkaline ◽  
High Potassium ◽  
Type Granite ◽  
Southeastern Tibet

A Variation of Favorskii Rearrangement Mechanism Under Weakly Acidic Conditions: The Case of Clobetasol Propionate Degradation in Solution

2020 ◽  
Author(s):  
Yun Tian ◽  
Haoran Zhang ◽  
Zach Zhu ◽  
Li Chen ◽  
Evelyn Wang ◽  
...  
Keyword(s):  
Critical Role ◽  
Clobetasol Propionate ◽  
Comprehensive Investigation ◽  
Favorskii Rearrangement ◽  
Rearrangement Mechanism ◽  
Alkaline Conditions ◽  
Propionate Degradation ◽  
Acidic Conditions

This paper describes our efforts in proposing a novel mechanism for the formation of the major degradant of clobetasol propionate under weakly acidic conditions through a comprehensive investigation. In the proposed mechanism, the key Favorskii intermediate plays a critical role. This variation of the original Favorskii rearrangement, which proceeds only under alkaline conditions, has not been reported before. This mechanism enriches the understanding of the degradation chemistry of corticosteroids containing the α-haloketone moiety on their 17-position.

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