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Published in Radko Tiňo, Katarina Vizárová, František Krčma, Milena Reháková, Viera Jančovičová, Zdenka Kozáková, Plasma Technology in the Preservation and Cleaning of Cultural Heritage Objects, 2021
Radko Tiňo, Katarina Vizárová, František Krčma, Milena Reháková, Viera Jančovičová, Zdenka Kozáková
The last set of samples was prepared in the sulfuric acid environment. The samples of 50 × 20 × 5 mm3 were pre-prepared by the grinding as before. The samples were placed onto the ceramic plate in the desiccator and sprayed with concentred sulfuric acid. The Petri dish with 20 ml of concentrated sulfuric acid was put at the bottom part of the desiccator. The corrosion process took 5 weeks again. The samples were covered by white corrosion formed by the compact multilayer of crystals (see Figure 8.24) that corresponds to szomolnokite (FeSO4 · H2O) as was confirmed by XRD (see Figure 8.25). No other corrosion products were observed in this case. After the corrosion procedure, the samples were dried again and packed according to the procedure described in the first set of samples.
Performance and mechanism of FeS2/FeSxOy as highly effective Fenton-like catalyst for phenol degradation
Published in Environmental Technology, 2022
Yajing Wang, Quanxi Zhu, Taiping Xie, Yuan Peng, Jiankang Wang, Zhongping Yao
The phase compositions of the as-synthesized samples were analyzed by XRD measurement. Before solvothermal vulcanization, the XRD pattern of the precursor in Figure S1 showed that all diffraction peaks were indexed to FeOOH (JCPDS card no. 81-0462). However, after vulcanization, the diffraction peaks of the as-obtained sample in Figure 1 were well matched with the standard materials of pyrite (FeS2, JCPDS card no. 42-1340) and iron sulphate minerals consisting of kornelite (Fe2(SO4)3·7H2O, JCPDS card no. 44-1426) and szomolnokite (FeSO4·H2O, JCPDS card no. 81-0019). Iron sulphate minerals as oxidation products of FeS2 might be formed during synthesis under high temperature and pressure in ethanol solution and/or exposure to the atmosphere [23–25]. Each component amount in synthesized FeS2/FeSxOy was quantified by means of RIR quantitative analysis using MDI Jade software. After calculation, the mass percentages of pyrite, kornelite, and szomolnokite were 35.68%, 12.61%, and 51.71%, respectively.
Degradation of mechanical property of corroded water pipes after long service
Published in Urban Water Journal, 2019
Weigang Wang, Chun-Qing Li, Wenhai Shi
The XRD results are summarized in Table 3 and the typical XRD patterns of corrosion products are presented in Figure 4. It can be seen from Table 3 that some typical corrosion products, e.g. goethite, hematite, akaganeite and magnetite which are normally found in steel exposed to the atmosphere (De la Fuente et al. 2016; Rodrıguez, Hernández, and González 2002), are also found in current-exhumed pipes. The main corrosion product found is goethite as seen in the rust layers of most pipes. Siderite is found in Pipe 1, 5 and 6, and it was also found in a long-term (36 months) experimental corrosion test on cast iron pipes buried in clay soils by Wang et al. (2018). Some complex chemical compounds/minerals, e.g. fayalite, iron phosphate hydroxide and szomolnokite which were not formerly identified by Wang et al. (2018) and Mohebbi and Li (2011), are also found in current-exhumed pipes. It indicates the complex oxidation process of iron in soils. It also implies the variety of environment, e.g. soil properties, temperature and microorganisms.