Resistance Improvement of Aluminum Surface to Corrosion Through Reactions With Fluoride Ions

2017 ◽  
Vol 3 (3) ◽  
Author(s):  
Magal Saphier ◽  
Oron Zamir ◽  
Polina Berzansky ◽  
Oshra Saphier ◽  
Dan Meyerstein

The reaction of fluoride ions with alumina was found to strongly depend on the concentration of fluoride ions in the aqueous solution. At low concentrations ([fluoride ions] < 0.1 mol/l in the case of potassium fluoride), the aqueous concentration of aluminum ions is relatively high as measured by using inductively coupled plasma optical emission spectroscopy (ICP-OES), and the aluminum oxide dissolves as a fluoride complex. At high concentrations of fluoride ([fluoride ions] > 0.5 mol/l in the case of potassium fluoride), a new structure is formed on the alumina surface involving fluoride, aluminum, potassium, and oxygen (in the case of potassium fluoride). The structure was characterized by using X-ray powder diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS). The resulting structure improved the passivation of alumina, the solubility of aluminum ions decreasing compared to the untreated alumina. Aluminum surfaces that were fluoride-treated showed a better resistance to dissolution in both acidic and basic media.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Izabela Michalak ◽  
Krzysztof Marycz ◽  
Katarzyna Basińska ◽  
Katarzyna Chojnacka

The biomass ofVaucheria sessilisforms algal mats in many freshwaters. There is a need to find the method of algal biomass utilization.Vaucheria sessilisis a rich source of micro- and macronutrients and can be used as a soil amendment. In the paper, the elemental composition of enriched, via bioaccumulation process, macroalga was investigated. For this purpose, two independent techniques were used: scanning electron microscopy with an energy dispersive X-ray analytical system (SEMEDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The biomass was exposed to two microelemental solutions, with Cu(II) and Zn(II) ions. After two weeks of the experiment, macroalga accumulated 98.5 mg of Zn(II) ions in 1 g of dry biomass and 68.9 mg g−1of Cu(II) ions. Micrographs performed by SEM proved that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of cells. Mappings of all cations showed that in the case of the surface of biomass (biosorption), the elements constituted aggregations and in the case of the cross section (bioaccumulation) they were evenly distributed. The algal biomass with permanently bound microelements can find an application in many branches of the industry (feed, natural fertilizers, etc.).


Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 595 ◽  
Author(s):  
Radulescu ◽  
Stihi ◽  
Ion ◽  
Dulama ◽  
Stanescu ◽  
...  

This study is the first attempt to decipher the effect of particulate matter (PM) composition on people’s health and on historic sites, in correlation with the daily and seasonal microclimate monitoring of the indoor and outdoor areas of the Roman Mosaic Edifice museum (the maritime port of Constanta, Romania). More specifically, the increase of metal concentrations in particulate matter during the summer of 2018 and spring of 2019 in the museum under investigation could possibly be associated with the microclimates of both seasons, with coastal factors, as well as with the anthropic activities specific to the port of Constanta. FTIR and inductively coupled plasma mass spectroscopy (ICP-MS) techniques, used for the investigation of PM2.5–10 samples, revealed high concentrations of Fe, Al-rich, and soluble particles inside the investigated museum area. In this respect, the chemical measurements of the PM2.5–10 masses highlighted high concentrations of heavy metals (i.e., Al, Fe, Zn, Mn, and Pb) and low concentrations of trace metals (i.e., Cr, Ni, Cu, and Cd). Statistical analysis showed that the chemical compositions of the particulate matter in the indoor and outdoor areas of the Roman Mosaic Edifice were influenced by microclimatic conditions, mainly temperature and relative humidity (RH). A potential health risk for tourists is the thermal and humid conditions, alongside the toxic components of the particulate matter. This research seeks to provide solutions for improving the environmental conditions inside the Roman Mosaic Edifice and to offer useful suggestions concerning health promotion and the protection of museum exhibits against possible future deterioration.


Crystals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 647
Author(s):  
Mengqi Qian ◽  
Yuwei Zuo ◽  
Zhihao Chen ◽  
Xiaoshuang Yin ◽  
Ying Liu ◽  
...  

The effect of NaCl at extremely high concentrations from 3.5 to 14 wt. % on the crystallization of CaCO3 was investigated in depth. The static test experiment verified that the Ca2+ retention efficiency (η) of NaCl on CaCO3 scale increased from 31.06% (3.5 wt. %) to 41.56% (14 wt. %). Based on the calculation of supersaturation rations, the high concentration of NaCl could reduce the activity coefficients of [Ca2+] and [CO32−], thus reducing the actual concentration of CaCO3. The CaCO3 deposition rate constants (k) showed that NaCl slowed down the rate of CaCO3 crystallization. The X–ray diffraction (XRD) testing disclosed that the growth of (1 0 4) and (1 1 0) faces from calcite was impeded, while the formation of (1 1 1) face from aragonite was induced by the increasing concentration of NaCl. The inductively coupled plasma optical emission spectrometry (ICP–OES) results indicated that Na+ could be doped into CaCO3, leading to the one–dimensional crystal growth. It was further proved that NaCl heightens the efficiency of the typical phosphate inhibitors (2–phosphonobutane–1,2,4–tricarboxylic acid (PBTCA) and 1–hydroxyethane–1,1–diphosphonic acid (HEDP)) on prohibiting the scale of CaCO3.


Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 724-730 ◽  
Author(s):  
Qing Ge ◽  
Paul A. Cobine ◽  
Leonardo De La Fuente

Xylella fastidiosa is a xylem-limited plant pathogenic bacterium that causes disease in many crops worldwide. Copper (Cu) is an antimicrobial agent widely used on X. fastidiosa hosts to control other diseases. Although the effects of Cu for control of foliar pathogens are well known, it is less studied on xylem-colonizing pathogens. Previous results from our group showed that low concentrations of CuSO4 increased biofilm formation, whereas high concentrations inhibited biofilm formation and growth in vitro. In this study, we conducted in planta experiments to determine the influence of Cu in X. fastidiosa infection using tobacco as a model. X. fastidiosa-infected and noninfected plants were watered with tap water or with water supplemented with 4 mM or 8 mM of CuSO4. Symptom progression was assessed, and sap and leaf ionome analysis was performed by inductively coupled plasma with optical emission spectroscopy. Cu uptake was confirmed by increased concentrations of Cu in the sap of plants treated with CuSO4-amended water. Leaf scorch symptoms in Cu-supplemented plants showed a trend toward more severe at later time points. Quantification of total and viable X. fastidiosa in planta indicated that CuSO4-amended treatments did not inhibit but slightly increased the growth of X. fastidiosa. Cu in sap was in the range of concentrations that promote X. fastidiosa biofilm formation according to our previous in vitro study. Based on these results, we proposed that the plant Cu homeostasis machinery controls the level of Cu in the xylem, preventing it from becoming elevated to a level that would lead to bacterial inhibition.


2008 ◽  
Vol 22 (15) ◽  
pp. 1487-1495 ◽  
Author(s):  
YEXIA FAN ◽  
HONGTAO LI ◽  
LIANCHENG ZHAO

Congruent Ce (0.1 wt %): Cu (0.05 wt %): LiNbO 3 single crystals doped with 0, 1, 3, 4, 5, 6 mol% MgO respectively were grown by the Czochrolski method in air along the C direction. The inductively coupled plasma optical emission/mass spectrometry (ICP-OE/MS), the X-ray powder diffraction (XRD), the differential thermal analysis (DTA), the ultraviolet-visible (UV-Vis) absorption spectra and the infrared (IR) absorption spectrum were measured and discussed in terms of the spectroscopic characterization and the defect structure of the Mg:Ce:Cu:LiNbO 3 crystals. The results indicated that the Mg:Ce:Cu:LiNbO 3 crystal grown from the congruent composition melt showed large [ Li ]/[ Nb ] ratios, which was closer to stoichiometry, an increase in the Curie temperature and a non-linear shift in the absorption edge with MgO concentration increasing. The threshold concentration of MgO in Mg:Ce:Cu:LiNbO 3 of nearly 5.52 mol% was estimated.


2015 ◽  
Vol 6 ◽  
pp. 1957-1969 ◽  
Author(s):  
Jacek Wojnarowicz ◽  
Sylwia Kusnieruk ◽  
Tadeusz Chudoba ◽  
Stanislaw Gierlotka ◽  
Witold Lojkowski ◽  
...  

Zinc oxide nanopowders doped with 1–15 mol % cobalt were produced by the microwave solvothermal synthesis (MSS) technique. The obtained nanoparticles were annealed at 800 °C in nitrogen (99.999%) and in synthetic air. The material nanostructure was investigated by means of the following techniques: X-ray diffraction (XRD), helium pycnometry density, specific surface area (SSA), inductively coupled plasma optical emission spectrometry (ICP-OES), extended X-ray absorption fine structure (EXAFS) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and with magnetometry using superconducting quantum interference device (SQUID). Irrespective of the Co content, nanoparticles in their initial state present a similar morphology. They are composed of loosely agglomerated spherical particles with wurtzite-type crystal structure with crystallites of a mean size of 30 nm. Annealing to temperatures of up to 800 °C induced the growth of crystallites up to a maximum of 2 μm in diameter. For samples annealed in high purity nitrogen, the precipitation of metallic α-Co was detected for a Co content of 5 mol % or more. For samples annealed in synthetic air, no change of phase structure was detected, except for precipitation of Co3O4 for a Co content of 15 mol %. The results of the magentometry investigation indicated that all as-synthesized samples displayed paramagnetic properties with a contribution of anti-ferromagnetic coupling of Co–Co pairs. After annealing in synthetic air, the samples remained paramagnetic and samples annealed under nitrogen flow showed a magnetic response under the influences of a magnetic field, likely related to the precipitation of metallic Co in nanoparticles.


2020 ◽  
Author(s):  
Daniela Novembre ◽  
Domingo Gimeno ◽  
Alessandro Del Vecchio

Abstract This work focuses on the hydrothermal synthesis of Na-P1 zeolite by using a kaolinite rock coming from Romana (Sassari, Italy). The kaolin is calcined at a temperature of 650 °C and then mixed with calculated quantities of NaOH. The synthesis runs are carried out at ambient pressure and at variable temperatures of 65 ° and 100 °C. For the first time compared to the past, the Na-P1 zeolite is synthesized without the use of additives and through a protocol that reduces both temperatures and synthesis times. The synthesis products are analysed by X-ray diffraction, high temperature X-ray diffraction, infrared spectroscopy, scanning electron microscopy and inductively coupled plasma optical emission spectrometry. The cell parameters are calculated using the Rietveld method. Density and specific surface area are also calculated. The absence of amorphous phases and impurities in synthetic powders is verified through quantitative phase analysis using the combined Rietveld and reference intensity ratio methods.The results make the experimental protocol very promising for an industrial transfer.


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