scholarly journals Use of Ecuadorian natural and acid-surfactant modified zeolites for remediation of oil- contaminated soils

2019 ◽  
Vol 9 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Gladys Cristina Pinto-Santamaría ◽  
Carlos Alberto Ríos- Reyes ◽  
Luz Yolanda Vargas- Fiallo
Keyword(s):  
Contaminated Soil ◽  
Contaminated Soils ◽  
Oil Spills ◽  
Magic Angle Spinning ◽  
Absorption Capacity ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Experimental Conditions ◽  
X Ray ◽  
Modified Zeolites

Oil spills have been one of the greatest environmental problems worldwide. The contamination of soils due to oil spills generates an oil migration down the soil until reaching groundwater. The research focused on remediation of oil-contaminated soils by Ecuadorian natural and acid-surfactant modified zeolites of the Cayo Formation. The natural and modified zeolites were characterized by wavelength dispersive X-ray fluorescence, X-ray powder diffraction, environmental scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and solid-state magic-angle spinning nuclear magnetic resonance spectroscopy. The natural and modified zeolites were added to an artificially oil-contaminated soil to immobilize and limit the uptake of contaminants by rape through changing soil physical and chemical properties in the pot experiment under greenhouse conditions. Several oil contaminated soil-zeolite mixes were tested in replicated laboratory analyses in terms of their ability to absorb oil. Results indicated that the addition of natural and modified zeolites could increase or decrease soil pH and absorption capacity, with high potential in removing oil from soil. Statistical analysis of the experimental data was performed by the variance test analysis. The absorption process had an efficiency of 46% under well-optimized experimental conditions, with an absorbent dose of 30-M, pH = 3.8 and 15 days of contact time.

Sol-gel synthesis of a nanoparticulate aluminosilicate precursor for homogeneous mullite ceramics

2006 ◽  
Vol 21 (5) ◽  
pp. 1279-1285 ◽  
Author(s):  
Jarkko Leivo ◽  
Mika Lindén ◽  
Cilâine V. Teixeira ◽  
Janne Puputti ◽  
Jessica Rosenholm ◽  
...  
Keyword(s):  
Spinel Phase ◽  
Sol Gel ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Density ◽  
Angle Spinning ◽  
Sol Gel Synthesis

An amorphous nanoparticulate aluminosilicate 3/2-mullite precursor has been synthesized and carefully characterized. The sol contained 2-nm particles of Q3(3Al) silica species together with six-coordinated alumina, which suggested an allophane-like structure of the nanoparticles. The sol remained stable for years, and formed an easily redispersible physical gel upon solvent evaporation. The gel crystallized to mullite at temperatures below 1000 °C, without going through any intermediate spinel phase. Thus, the nanoparticulate precursor is regarded as a homogeneous high-purity mullite precursor with a high Si–O–Al bond density, which is useful in the preparation of various nanostructured Al-rich aluminosilicate materials. The sols and gels were characterized by small-angle x-ray scattering, dynamic light scattering, x-ray diffraction, 27Al and 29Si magic-angle spinning (MAS) nuclear magnetic resonance spectroscopy, and differential thermal analysis.

Analytical chemical applications of high-resolution nuclear magnetic resonance spectroscopy of solids

1982 ◽  
Vol 305 (1491) ◽  
pp. 591-607 ◽  
Keyword(s):  
Solid State ◽  
High Resolution ◽  
Structural Data ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
General Applicability ◽  
Phenolic Resins ◽  
X Ray ◽  
Angle Spinning

The basis of the combined cross-polarization-magic-angle spinning (c.p.-m.a.s.) experiment, which yields high-resolution n.m.r. spectra of solid materials, is described and the general applicability of the technique, including its quantitative reliability, discussed. Solid-state n.m.r. is in many ways complementary to X-ray diffraction, as shown by its application to amorphous systems in which diffraction methods cannot be used (for example resins, coals, glasses and surface-immobilized catalysts) and also by its application to crystalline materials where X-ray structural data are available but where, for various reasons, a fuller description of the structure may be obtained by n.m.r. Examples include zeolites and chemically exchanging solid systems. The technique also provides a bridge between the solid-state structures of conformationally mobile and charged species as determined by diffraction techniques and the structures of these species in solution. Quantitative reliability of the c.p.-m.a.s. technique has been evaluated for phenolic resins and coals.

Powder diffraction of sodalite in a multiphase ceramic used to immobilize radioactive waste

2005 ◽  
Vol 20 (3) ◽  
pp. 212-214 ◽  
Author(s):  
S. M. Frank ◽  
T. L. Barber ◽  
M. J. Lambregts
Keyword(s):  
Radioactive Waste ◽  
Powder Diffraction ◽  
Lattice Parameter ◽  
Magic Angle Spinning ◽  
High Level Waste ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
X Ray ◽  
Angle Spinning ◽  
High Level

The title compound, ∣Na6Li1.6K0.4Cl2∣[Al6Si6O24]‐SOD, is similar to sodalite proper, but the introduction of Li and K into the structure creates a reduction in unit-cell volume and additional collapse of the framework tetrahedra. Refinement of an X-ray powder diffraction pattern of a multiphase material yielded for sodalite a lattice parameter of 0.88427 (2) nm, an Al–O–Si bond angle of 137.9(3°), and Al–O and Si–O bond lengths of 0.1730(5) nm and 0.1620(5) nm, respectively. The angle of the unique Al–O–Si bond corresponds well with the 138° obtained by 29Si solid-state magic-angle-spinning nuclear magnetic resonance spectroscopy. This characterization is important since the compound constitutes an essential part of a radioactive waste form intended for a high-level waste repository.

scholarly journals Synergy of diffraction and spectroscopic techniques to unveil the crystal structure of antimonic acid

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. F. Mayer ◽  
J. E. Rodrigues ◽  
I. Sobrados ◽  
J. Gainza ◽  
M. T. Fernández-Díaz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffusion Mechanism ◽  
Pyrochlore Structure ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Proton Diffusion ◽  
Antimonic Acid

AbstractThe elusive crystal structure of the so-called ‘antimonic acid’ has been investigated by means of robust and state-of-the-art techniques. The synergic results of solid-state magic-angle spinning nuclear magnetic resonance spectroscopy and a combined Rietveld refinement from synchrotron X-ray and neutron powder diffraction data reveal that this compound contains two types of protons, in a pyrochlore-type structure of stoichiometric formula (H3O)1.20(7)H0.77(9)Sb2O6. Some protons belong to heavily delocalized H3O+ subunits, while some H+ are directly bonded to the oxygen atoms of the covalent framework of the pyrochlore structure, with O–H distances close to 1 Å. A proton diffusion mechanism is proposed relying on percolation pathways determined by bond-valence energy landscape analysis. X-ray absorption spectroscopy results corroborate the structural data around Sb5+ ions at short-range order. Thermogravimetric analysis and differential scanning calorimetry endorsed the conclusions on the water content within antimonic acid. Additional 0.7 water molecules per formula were assessed as moisture water by thermal analysis.

scholarly journals MBRS-69. METABOLITE PROFILING OF SHH MEDULLOBLASTOMA IDENTIFIES A SUBSET OF CHILDHOOD TUMOURS ENRICHED FOR HIGH-RISK MOLECULAR BIOMARKERS AND CLINICAL FEATURES

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii410-iii410
Author(s):  
Christopher Bennett ◽  
Sarah Kohe ◽  
Florence Burte ◽  
Heather Rose ◽  
Debbie Hicks ◽  
...  
Keyword(s):  
High Risk ◽  
Metabolite Profiling ◽  
Unmet Need ◽  
Magic Angle Spinning ◽  
Molecular Biomarkers ◽  
Mycn Amplification ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
Metabolite Profiles ◽  
Cluster 2

Abstract SHH medulloblastoma patients have a variable prognosis. Infants (<3–5 years at diagnosis) are associated with a good prognosis, while disease-course in childhood is associated with specific prognostic biomarkers (MYCN amplification, TP53 mutation, LCA histology; all high-risk). There is an unmet need to identify prognostic subgroups of SHH tumours rapidly in the clinical setting, to aid in real-time risk stratification and disease management. Metabolite profiling is a powerful technique for characterising tumours. High resolution magic angle spinning NMR spectroscopy (HR-MAS) can be performed on frozen tissue samples and provides high quality metabolite information. We therefore assessed whether metabolite profiles could identify subsets of SHH tumours with prognostic potential. Metabolite concentrations of 22 SHH tumours were acquired by HR-MAS and analysed using unsupervised hierarchical clustering. Methylation profiling assigned the infant and childhood SHH subtypes, and clinical and molecular features were compared between clusters. Two clusters were observed. A significantly higher concentration of lipids was observed in Cluster 1 (t-test, p=0.012). Cluster 1 consisted entirely of childhood-SHH whilst Cluster 2 included both childhood-SHH and infant-SHH subtypes. Cluster 1 was enriched for high-risk markers - LCA histology (3/7 v. 0/5), MYCN amplification (2/7 v. 0/5), TP53 mutations (3/7 v. 1/5) and metastatic disease - whilst having a lower proportion of TERT mutations (0/7 v. 2/5) than Cluster 2. These pilot results suggest that (i) it is possible to identify childhood-SHH patients linked to high-risk clinical and molecular biomarkers using metabolite profiles and (ii) these may be detected non-invasively in vivo using magnetic-resonance spectroscopy.

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