3 – 1 Preparation of ligand: 4 – tert-But-2,6- diformylphenolbis(4-aminoantipyrine)(H1L): The ligand was prepared according to our previous paper17 ; (0.4g, 2 mmol) of 2,6 – diformyl – 4 – ter-butylphenol dissolved in ethanol (10 ml) was added slowly with stirring to( 0.80g, 4 mmol) of 4 – amino antipyrine dissolved in ethanol (20 ml). The resulting mixture was stirred under reflux on water bath for 3 hrs and the yellow precipitate was filtered, dried and then recrys tallized from ethanol to afford bright yellow crystals with 90% yield (scheme 1). Elemental analysis data; Found (calculated); %C,70.73 (70.51); %H6.25 (6.16) %N 14.56 (14.39).
Spectrophotometric determination of the amounts of dissolved ironin produced water without and in the existence of 400 ppm of rareearthmetals after exposing coupons for 6 days at 25°C are summarized in Table (5). Iron content in the produced water before immersion of coupons is 0.30 ppm represented in Table (1). After data correction and rounded, the amount of dissolved iron is low in the case of rareearthmetals with respect to blank. The dissolution of metal in the existence of rareearthmetals is low with respect to the blank. From the amount of dissolved iron, the surface coverage (ϴ) and %IE were calculated as follows :
of 1.0 ml of the water samples to 10.0 mL with 0.3% ultrapure nitric acid and analyzed by ICP/MS. Each sample was analyzed three times and the results are expressed as mean ± SD (SD: standard deviation). Relative standard deviation (RSD) of the three results are calculated and found to be less than 5% for all samples for all heavy metals analyzed in this study, reflecting the precision of the method for the analysis of these heavy metals. Calibration curves for all heavy metals analyzed were constructed by plotting the ratio of the intensity of the analyte heavy metal to that of the internal stan- dard vs. concentration of the heavy metal (in ppb), and results showed that the calibra- tion curves are linear with correlation coefficient (r 2 ) greater than 0.999 for the heavy
Nowadays, rareearth elements and heavy metals are big challenges for industries both environmentally and economically with the increasing demand of rareearth elements. This work listed the different techniques used to extract them from aqueous solution with the goal to reuse those metals after their extraction in wastes.
E-beam evaporation utilizes the energy from an electron beam to melt and evaporate a material contained in a crucible. Deposition rates can be easily adjusted by changing the current and energy of the electron beam . Film thicknesses and deposition rates are determined in the systems used by a quartz crystal. Our e-beam evaporator capabilities allow deposition of up to five different materials in situ. Deposition of multiple materials is necessary because capping layers are required to prevent oxidation of magnetic metals. Multiple layers are also necessary to create spin valve structure which can be used to determine the presence and position of a domain wall as described in the next section. E- beam evaporation is a very directional process and consequently is good for lift-off applications. However, one of the limitations of e-beam evaporation is that it is difficult to deposit an alloy because the vapor pressures of the materials are not the same.
An isothermally jacketed calorimeter has been constructed to measure the changes in heat content accompanying the solution of some rareearthmetals and compounds. To check the performance of the apparatus, the integral heats of solution of potassium nitrate in water at 25°C have been measured. The values corrected to infinite dilution by use of relative apparent molal heat content data in the literature give 8384 +/- 12 cals/mole. The result agrees well with the values reported by others.
In this work, considering the rareearth with special 4f electronic structure [7, 19, 20], a typical rareearth doped lead dioxide electrode prepared by thermal decomposition electrodeposition technique was used for the treatment of simulated wastewater containing p-toluene sulfonic acid (p-TSA). Different doped moral ratios of rareearth had also been discussed for the optimal one. Chemical oxygen demand (COD) and total organic carbon (TOC) were tested to value the degradation efficiency of the Ti/SnO 2 -Sb 2 O 3 /PTFE-La-β-PbO 2 electrode. Finally, based on the results of scanning electron
Rareearth elements (REE) are known as ‘industrial vitamins’. They are vital components in the fields of metallurgy, military, petrochemical, glass, ceramics, agriculture and new materials science (1–2). The main REE sources in nature contain the minerals bastnasite, monazite, loparite and xenotime as well as ion-absorption clays. A set of mature technologies for REE extraction from these minerals have been developed in recent decades (3–8). However, some countries do not possess enough high-grade deposits and have to import or search for alternatives (9). For example, the EURARE project has recently studied the exploitation of promising REE resources in Europe (10). Eudialyte, as an unconventional REE resource, is one of the most potentially economic raw materials for REE production because of the large amounts of these deposits, low radioactivity and high chemical activity (11–13).
The Crystal field splitting is negligible against the separation of the spin-multiplet states. For the 4f levels there is no overlap with the neighborhood, and the states of the free atom remain largely intact. Exchange interaction between the localized spins of 4f shells is an indirect one, being mediated by the 6s and, if available, the 5d conduction electrons. To point out the prominent part of rare earths among the magnetic metals, a new approach with electronic structure of the rareearth 3+ ion cores and indirect exchange between their localized magnetic moments in the metal is described. Finally, the magnetic structure of holmium is discussed.
Geochemical sediment of the tropical Pinang River, Malaysia was carried out with the aim at do- cumenting elemental concentrations and pollution level assessment. Concentration of selected heavy metals (Cu, Cd, Cr, Pb, Zn and Mn), rareearth elements, TOC and grain size distribution of sediments were determined at 100 m sampling interval along the river. Sediment size showed a positive correlation with ƩREE and Mn and medium correlations with TOC, Zn, Cu, Cr and Pb con- tents showing enrichment in the clay size fraction. Results of enrichment factor and geoaccumula- tion index showed that most of the elemental sources were natural (especially REE) and mostly likely represented background values. However, pollution load index revealed the higher levels of Cr, Cd, Zn and Pb, and, therefore, indicating to the anthropogenic sources (i.e. fishing activities) especially in the downstream locations. Thus, the Pinang River is classified as moderately to high- ly polluted.
circular field, disturbing the upper decimeters of the sur- face sediment and removing the nodules from the surface (Thiel and Schriever, 1990). Geochemical investigations of nutrients, dissolved organic carbon (DOC), amino acids, solid phase and dissolved trace metals were conducted as part of the follow-up project ATESEPP in 1996 (Schriever et al., 1996). The geochemical work focused on the bio- turbated surface layer, where impacts of polymetallic nod- ule mining are expected (Haeckel et al., 2001; Koschinsky, 2001; Koschinsky et al., 2001a, b), whereas geochemical in- vestigations of deeper sediment layers down to 10 m were only performed on five cores (with only one of them lo- cated in the DISCOL area) (Haeckel et al., 2001). Miner- alogical investigations of long cores were, however, con- ducted extensively (Weber et al., 1995, 2000; Marchig et al., 2001). As part of recent work in the MiningImpact project (https://jpio-miningimpact.geomar.de, last access: 18 De- cember 2019), the focus lay again on the surface sediments (Haffert et al., 2020; Paul et al., 2018). To understand bio- geochemical processes over longer timescales and to resolve more steps of the redox zonation, the biogeochemical analy- sis of long sediment cores is crucial.
The results of the research interaction between ash and slag samples from Vladivostok TPP’s landfills saturated with underburning and ammonium hydrodifluoride were given. It was found out that the reactions of the main components of a concentrate with NH 4 HF 2 are flowing with creation of complex ammonium fluoro-metalate. It is shown that the distribution of REM (rareearthmetals) between foam and heavier products is going during the flotation process of carbon-containing ash and slag samples without significant concentrating. It is shown that the water leaching of fluoridated product lets transfer silicone, aluminum and iron salts into solution and concentrate rareearth elements in insoluble residue in the form of complex salts of NaLnF 4 general formula. We propose a schematic diagram of hydrodifluoride recycling of carbon-containing sample, which provides concentrating of REM with incomplete separation of macro-components.
atmosphere. Then, the tablet was placed in a mortar and ground easily into powders with a pestle. In this way, we have succeeded in reclaiming rareearthmetals from bond magnets. We believe that our assumption (i.e., slight sintering of the magnetic particles) was right and that the dissolution of the sintered layer led to the successful pulverization of the lightly-sintered particles. It should also be noted that the use of a diluted acid is crucially important for the dissolution of metals, because concentrated acids often lead to the passivation of the metals.
No drinking water standards are defined by EU, WHO or US EPA for Rb, Zr, La, Ce, Nd, P, Ti, and V. Several of these elements have documented health effects . For others, for example the rareearth elements, knowl- edge about health effects are rather limited . How- ever all of these elements are detected in all groundwater samples analyzed in this study. Additionally, some of these elements are unexpectedly and surprisingly detected with high concentrations e.g. P, V; the concentration of P ranges from 0.31 to 9.66 ppb with an average of 5.70 ppb, and the concentration of V ranges from 1.90 to 4.99 ppb with an average of 3.34 ppb. The concentration of Rb, Zr, La, Ce, Nd, and Ti was found to be in the range of 0.28 - 1.0 (average = 0.61 ppb), 0.02 - 1.13 (average = 0.30 ppb), 0.01 - 0.02 (average = 0.01 ppb), 0.02 - 0.09 (av- erage = 0.05 ppb), 0.01 - 0.03 (average = 0.01 ppb), 0.09 - 0.32 (average = 0.21 ppb), respectively. In addition to the potential pollution of groundwater with these rare elements, the concentrations of these elements such Bi, and rareearth elements, which are extremely low in na- tural waters, are of particular interest to fingerprint the groundwater sources .
The static polarizabilities ( ω = 0 ) have been calculated for the jellium atoms of the transition metals and the rareearthmetals. These are compared with the density functional-based code for the neutral atoms of these systems by Zangwill and Liberman , and the results are displayed in Figure 9. In the case of the TMs both the neutral and jellium atoms show monotonically decreasing static polarizabilities with increasing atomic number ( Z ). In fact, the values may be fitted to an exponential decay function of the form
earth chlorides can be directly used as raw material for the molten salt electrolysis or metallothermic reduction. How- ever, in practice, almost all rareearthmetals are presently pro- duced by the rareearth oxide electrolysis. Thus, if the chlo- rides are supplied as raw material for conventional process, we have to convert the obtained chlorides to oxides. In a flow containing oxygen gas, the conversion of the rareearth chlo- rides to oxychlorides is relatively easy. But, converting the rareearth oxychlorides to the corresponding oxides in a flow of dry air or pure O 2 requires very low partial pressure of chlo-
A high temperature dilatometric investigation of the rareearthmetals was undertaken as part of a broad program of study of these elements, the ultimate goal being better understanding of metals in general. The more immediate goal, in addition to determining the coefficients of expansion quantitatively, was to detect evidence of any crystalline transformations which may occur and particularly to cast some light on certain high temperature transitions already discovered in several of these metals. The rareearthmetals included in this investigation were lanthanum, cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, erbium, and ytterbiumo