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Author |
Vanmeert, F.; Mudronja, D.; Fazinic, S.; Janssens, K.; Tibljas, D. |
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Title |
Semi-quantitative analysis of the formation of a calcium oxalate protective layer for monumental limestone using combined micro-XRF and micro-XRPD |
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A1 Journal article |
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Year |
2013 |
Publication |
X-ray spectrometry |
Abbreviated Journal |
X-Ray Spectrom |
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Volume |
42 |
Issue |
4 |
Pages |
256-261 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A current method for the protection of cretaceous limestone present in various monuments consists of performing a passivating treatment with ammonium oxalate (AmOx). A calcium oxalate protective layer is formed on the surface and enhances the acid resistance of the stone. The in-depth formation of the calcium oxalate layer was investigated on cross sections by using combined micro X-ray fluorescence and micro X-ray powder diffraction (mu XRF/mu XRPD). XRPD showed the presence of both whewellite and weddellite in the calcite stone matrix. A correction was made for sample misalignment, which was visible in both the fluorescence and the diffraction line measurements. A semi-quantitative analysis was performed on the basis of Klug's equation for a two-phase mixture (the presence of weddellite was neglected) without the need for a known reference sample. By assuming two extreme compositions for a reference weight fraction (1 and 99wt%), it was possible to obtain whewellite concentration profiles, which can be used for comparing the effectiveness of different methods for the application of AmOx to the stone surface and the effect of treatment time and AmOx concentration used. It is shown that for the relative amounts of whewellite formed, the differences due to the assumed weight fractions are smaller than the errors due to sample heterogeneity and preferred orientation. Copyright (c) 2013 John Wiley & Sons, Ltd. |
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Wos |
000320727900015 |
Publication Date |
2013-05-14 |
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ISSN |
0049-8246 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.298 |
Times cited |
5 |
Open Access |
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Notes |
; The authors would like to thank De Nolf W. for his valuable feedback on the analysis of the X-ray diffraction data. We acknowledge SOLEIL for provision of SR facilities (proposal ID 20100979), and we would like to thank Dr. C. Mocuta for his assistance at the DIFFABS beamline. This research was supported by the Interuniversity Attraction Poles Program – Belgian Science Policy (IUAP VI/16). The text also presents results of GOA 'XANES meets ELNES' (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. The EU Community's FP7 Research Infrastructures program for the CHARISMA Project (grant agreement 228330) and, within framework in particular, the access possibilities to the SOLEIL and IPANEMA facilities are also acknowledged. ; |
Approved |
Most recent IF: 1.298; 2013 IF: 1.187 |
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Call Number |
UA @ admin @ c:irua:109579 |
Serial |
5827 |
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Author |
Mudronja, D.; Vanmeert, F.; Hellemans, K.; Fazinic, S.; Janssens, K.; Tibljas, D.; Rogosic, M.; Jakovljevic, S. |
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Title |
Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods |
Type |
A1 Journal article |
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Year |
2013 |
Publication |
Applied physics A : materials science & processing |
Abbreviated Journal |
Appl Phys A-Mater |
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Volume |
111 |
Issue |
1 |
Pages |
109-119 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Samples of cretaceous limestone have been treated with three application methods (poultice, immersion and brushing) using different concentrations of ammonium oxalate solution (AmOx) and varying treatment time in order to test the efficiency of surface and in-depth formation of a protective layer of calcium oxalate (CaOx). Synchrotron-based microanalytical techniques (SR-mu XRD with 12.5 mu mx7.5 mu m (HxV) probe size, SR-mu FTIR with 10 mu mx10 mu m and 8 mu mx20 mu m probe sizes) and laboratory mu FTIR, XRD and SEM have been employed for analysis of the treated samples. Synchrotron-based techniques showed variations in the CaOx distribution along the surface on a micrometer scale. All treatments resulted in the development of a CaOx layer with a maximum thickness of approximately 40 mu m. Application by the brushing method with 10 1-min applications with 5-min breaks during one hour showed a development of the calcium oxalate layer equivalent to the poultice treatment taking 10 h. This treatment could be preferred for large marble or limestone surfaces where poultice usage is economically not feasible. |
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000316075700014 |
Publication Date |
2012-10-29 |
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ISSN |
0947-8396 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.455 |
Times cited |
13 |
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Notes |
; This research was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of GOA 'XANES meets ELNES' (Research Fund, University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0704.08 and G.01769.09. The research leading to these results has received financial support by the Access to Research Infrastructures activity in the 7th Framework Programme of the EU (CHARISMA Grant Agreement No. 228330). ; |
Approved |
Most recent IF: 1.455; 2013 IF: 1.694 |
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Call Number |
UA @ admin @ c:irua:108262 |
Serial |
5584 |
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Author |
Mudronja, D.; Vanmeert, F.; Fazinic, S.; Janssens, K.; Tibljas, D.; Desnica, V. |
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Title |
Protection of stone monuments using a brushing treatment with ammonium oxalate |
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A1 Journal article |
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Year |
2021 |
Publication |
Coatings |
Abbreviated Journal |
Coatings |
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Volume |
11 |
Issue |
4 |
Pages |
379 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-mu-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-mu-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5-15 mu m on the less porous stone, while a 20-30 mu m thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer. |
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000642940900001 |
Publication Date |
2021-03-25 |
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ISSN |
2079-6412 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.175 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
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Approved |
Most recent IF: 2.175 |
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Call Number |
UA @ admin @ c:irua:178271 |
Serial |
8428 |
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