scholarly journals Multi-Analytical Investigation of Stains on Dimension Stones in Master Valentim’s Fountain, Brazil

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 465 ◽  
Author(s):  
Roberto da Conceição Ribeiro ◽  
Patrícia Marques Ferreira de Figueiredo ◽  
Daniel Silva Barbutti

Master Valentim’s fountain has become an important historical patrimony for Brazil, being portrayed by famous artists, among them Jean-Baptiste Debret. In 1938, it was registered as cultural heritage by the Brazilian National Historical and Artistic Heritage Institute (IPHAN), and in 1990 it was subjected to excavation and restoration works. The fountain was built in Gneiss and Lioz limestone, with metallic plates and mortar connecting the Gneiss blocks. Currently, deteriorations in the fountain stones can be observed, such as light stains and some aesthetic modifications caused by inadequate restorations. Petrography, X-ray fluorescence (XRF), XRD, physical properties, colorimetry, electrical conductivity, inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), and TGA were performed in order to characterize the Gneiss blocks, the metallic plates, and the stones used in previous restorations, as well as light stains observed on the Gneiss blocks. The petrography and XRD analyses inferred that the light stains may have been caused by the formation of an insoluble salt as a result of the association of the lead from the plates with other elements. The XRD analysis on the light staining area indicated the presence of cerussite (PbCO3) and anglesite (PbSO4), which are the probable cause of the light stains. The SEM-EDX results suggested that sulfur is the main element associated to lead.

2020 ◽  
Vol 38 (12) ◽  
pp. 1331-1344
Author(s):  
Shohel Siddique ◽  
Kyari Yates ◽  
Kerr Matthews ◽  
Laszlo J Csetenyi ◽  
James Njuguna

Oil-based mud (OBM) waste from the oil and gas exploration industry can be valorised to tailor-made reclaimed clay-reinforced low-density polyethylene (LDPE) nanocomposites. This study aims to fill the information gap in the literature and to provide opportunities to explore the effective recovery and recycling techniques of the resources present in the OBM waste stream. Elemental analysis using inductively coupled plasma–optical emission spectrometry (ICP-OES) and X-ray fluorescence analysis, chemical structural analysis by Fourier transform infrared (FTIR) spectroscopy, and morphological analysis of LDPE/organo-modified montmorillonite (LDPE/MMT) and LDPE/OBM slurry nanocomposites by scanning electron microscopy (SEM) have been conducted. Further analysis including calorimetry, thermogravimetry, spectroscopy, microscopy, energy dispersive X-ray analysis and X-ray diffraction (XRD) was carried out to evaluate the thermo-chemical characteristics of OBM waste and OBM clay-reinforced LDPE nanocomposites, confirming the presence of different clay minerals including inorganic salts in OBM slurry powder. The microscopic analysis revealed that the distance between polymer matrix and OBM slurry filler is less than that of MMT, which suggests better interfacial adhesion of OBM slurry compared with the adhesion between MMT and LDPE matrix. This was also confirmed by XRD analysis, which showed the superior delamination structure OBM slurry compared with the structure of MMT. There is a trend noticeable for both of these fillers that the nanocomposites with higher percentage filler contents (7.5 and 10.0 wt% in this case) were indicated to act as a thermal conductive material. The heat capacity values of nanocomposites decreased about 33% in LDPE with 7.5 wt% MMT and about 17% in LDPE with 10.0 wt% OBM slurry. It was also noted, for both nanocomposites, that the residue remaining after 1000°C increases with the incremental wt% of fillers in the nanocomposites. There is a big difference in residue amount (in %) left after thermogravimetric analysis in the two nanocomposites, indicating that OBM slurry may have significant influence in decomposing LDPE matrix; this might be an interesting area to explore in the future. The results provide insight and opportunity to manufacture waste-derived renewable nanocomposites with enhanced structural and thermal properties.


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.


Author(s):  
Roberto Carlos da Conceição Ribeiro ◽  
Patrícia Marques Ferreira de Figueiredo ◽  
Daniel Silva Barbutti

Master Valentim’s fountain became an important historical patrimony for Brazil, being portrayed by famous artists among them Jean-Baptiste Debret. In 1938, it was registered as cultural heritage by the Brazilian National Historical and Artistic Heritage Institute (IPHAN), and in 1990 it was subjected to excavation and restoration works. The fountain was built in Gneiss and Lioz limestone, with metallic plates and mortar connecting the Gneiss blocks. Currently, deteriorations in the fountain stones can be observed such as light stains and some aesthetic modifications caused by inadequate restorations. Petrography, XRF, XRD, Physical Properties, Colorimetry, Electrical Conductivity, ICP-OES, SEM-EDX, and TGA were performed in order to characterize the Gneiss blocks, the metallic plates, the stones used in previous restorations, as well as light stains observed on the Gneiss blocks. The petrography and XRD analyses inferred that light stains may have been caused by the formation of an insoluble salt as a result of the association of the lead from the plates with other elements. The XRD analysis on the light staining area indicated presence of cerussite (PbCO3), and anglesite (PbSO4), which are the probable cause of the light stains. The SEM-EDX results suggested that sulfur is the main element associated to lead.


Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2214
Author(s):  
Sebastian Scherb ◽  
Mathias Köberl ◽  
Nancy Beuntner ◽  
Karl-Christian Thienel ◽  
Jürgen Neubauer

Systematic investigation of filtrates and filter residues resulting from a 24 h treatment of metakaolin in different alkaline solutions were performed. On filtered metakaolin particles, inductively coupled plasma-optical emission spectrometry (ICP-OES) measurements reveal an enrichment of iron and titanium, which suggests an inhomogeneous distribution of these cations. Since the SiO2/Al2O3 ratio remains constant in all filter residues examined, the dissolution of the Si and Al monomers is congruent. Structural differences, identified by attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR) as a consequence of alkali uptake, influence the X-ray scattering contribution of metakaolin, and thus quantifications with the partial or no known crystal structure (PONKCS) method. This leads to deviations between the degree of reaction calculated from Si and Al solubility from filtrate and that quantified by quantitative powder X-ray diffraction (QPXRD) using the filter residue. Nevertheless, the described changes do not cause a shift in the X-ray amorphous hump in case of congruent dissolution, and thus allow the quantification of the metakaolin before and after dissolution with the same hkl-phase model.


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