Fe–Mo alloy coatings as cathodes in chlorate production process

2016
Authors
Gajić Krstajić, Ljiljana
Elezović, Nevenka

Jović, Borka
Martelli, Gian N.
Jović, Vladimir
Krstajić, Nedeljko
Article (Published version)
Metadata
Show full item recordAbstract
The aim of this study was to gain a better understanding of the feasibility of partial replacement of dichromate, Cr(VI), with phosphate buffer, focusing on the cathode reaction selectivity for hydrogen evolution on mild steel and Fe-Mo cathodes in undivided cell for chlorate production. To evaluate the ability of phosphate and Cr(VI) additions to hinder hypochlorite and chlorate reduction, overall current efficiency (CE) measurements in laboratory cell for chlorate production on stationary electrodes were performed. The concentration of hypochlorite was determined by a conventional potentiometric titration method using 0.01 mol dm-3 As2O3 solution as a titrant. The chlorate concentration was determined by excess of 1.0 mol dm-3 As2O3 solution and excess of arsenic oxide was titrated with 0.1 mol dm-3 KBrO3 solution in a strong acidic solution. Cathodic hypochlorite and chlorate reduction were suppressed efficiently by addition of 3 g dm-3 dichromate at both cathodes, except that Fe-Mo... cathode exhibited higher catalytic activity for hydrogen evolution reaction (HER). The overvoltage for the HER was around 0.17 V lower on Fe-Mo cathode than on mild steel at the current density of 3 kA m-2. It was found that a dichromate content as low as 0.1 g dm-3 is sufficient for complete suppression of cathodic hypochlorite and chlorate reduction onto Fe-Mo catalyst in phosphate buffering system (3 g dm-3 Na2HPO4 + NaH2PO4). The overall current efficiency was practically the same as in the case of the presence of 3 g dm-3 dichromate buffer (98 %). However, for the mild steel cathode, the overall current efficiency for the chlorate production was somewhat lower in the above mentioned mixed phosphate + dichromate buffering system (95%) than in the pure dichromate buffering solution (97.5%).
Keywords:
chlorate production / current efficiency / Fe–Mo cathode catalyst / phosphate bufferSource:
Hemijska industrija, 2016, 70, 1, 81-89Publisher:
- Belgrade Association of the Chemical Engineers of Serbia
Funding / projects:
DOI: 10.2298/HEMIND150119014G
ISSN: 0367-598X (Print); 2217-7426 (Online)
WoS: 000372733800010
Scopus: 2-s2.0-84960342547
Institution/Community
Институт техничких наука САНУ / Institute of Technical Sciences of SASATY - JOUR AU - Gajić Krstajić, Ljiljana AU - Elezović, Nevenka AU - Jović, Borka AU - Martelli, Gian N. AU - Jović, Vladimir AU - Krstajić, Nedeljko PY - 2016 UR - https://dais.sanu.ac.rs/123456789/15969 AB - The aim of this study was to gain a better understanding of the feasibility of partial replacement of dichromate, Cr(VI), with phosphate buffer, focusing on the cathode reaction selectivity for hydrogen evolution on mild steel and Fe-Mo cathodes in undivided cell for chlorate production. To evaluate the ability of phosphate and Cr(VI) additions to hinder hypochlorite and chlorate reduction, overall current efficiency (CE) measurements in laboratory cell for chlorate production on stationary electrodes were performed. The concentration of hypochlorite was determined by a conventional potentiometric titration method using 0.01 mol dm-3 As2O3 solution as a titrant. The chlorate concentration was determined by excess of 1.0 mol dm-3 As2O3 solution and excess of arsenic oxide was titrated with 0.1 mol dm-3 KBrO3 solution in a strong acidic solution. Cathodic hypochlorite and chlorate reduction were suppressed efficiently by addition of 3 g dm-3 dichromate at both cathodes, except that Fe-Mo cathode exhibited higher catalytic activity for hydrogen evolution reaction (HER). The overvoltage for the HER was around 0.17 V lower on Fe-Mo cathode than on mild steel at the current density of 3 kA m-2. It was found that a dichromate content as low as 0.1 g dm-3 is sufficient for complete suppression of cathodic hypochlorite and chlorate reduction onto Fe-Mo catalyst in phosphate buffering system (3 g dm-3 Na2HPO4 + NaH2PO4). The overall current efficiency was practically the same as in the case of the presence of 3 g dm-3 dichromate buffer (98 %). However, for the mild steel cathode, the overall current efficiency for the chlorate production was somewhat lower in the above mentioned mixed phosphate + dichromate buffering system (95%) than in the pure dichromate buffering solution (97.5%). PB - Belgrade Association of the Chemical Engineers of Serbia T2 - Hemijska industrija T1 - Fe–Mo alloy coatings as cathodes in chlorate production process SP - 81 EP - 89 VL - 70 IS - 1 DO - 10.2298/HEMIND150119014G UR - https://hdl.handle.net/21.15107/rcub_dais_15969 ER -
@article{ author = "Gajić Krstajić, Ljiljana and Elezović, Nevenka and Jović, Borka and Martelli, Gian N. and Jović, Vladimir and Krstajić, Nedeljko", year = "2016", abstract = "The aim of this study was to gain a better understanding of the feasibility of partial replacement of dichromate, Cr(VI), with phosphate buffer, focusing on the cathode reaction selectivity for hydrogen evolution on mild steel and Fe-Mo cathodes in undivided cell for chlorate production. To evaluate the ability of phosphate and Cr(VI) additions to hinder hypochlorite and chlorate reduction, overall current efficiency (CE) measurements in laboratory cell for chlorate production on stationary electrodes were performed. The concentration of hypochlorite was determined by a conventional potentiometric titration method using 0.01 mol dm-3 As2O3 solution as a titrant. The chlorate concentration was determined by excess of 1.0 mol dm-3 As2O3 solution and excess of arsenic oxide was titrated with 0.1 mol dm-3 KBrO3 solution in a strong acidic solution. Cathodic hypochlorite and chlorate reduction were suppressed efficiently by addition of 3 g dm-3 dichromate at both cathodes, except that Fe-Mo cathode exhibited higher catalytic activity for hydrogen evolution reaction (HER). The overvoltage for the HER was around 0.17 V lower on Fe-Mo cathode than on mild steel at the current density of 3 kA m-2. It was found that a dichromate content as low as 0.1 g dm-3 is sufficient for complete suppression of cathodic hypochlorite and chlorate reduction onto Fe-Mo catalyst in phosphate buffering system (3 g dm-3 Na2HPO4 + NaH2PO4). The overall current efficiency was practically the same as in the case of the presence of 3 g dm-3 dichromate buffer (98 %). However, for the mild steel cathode, the overall current efficiency for the chlorate production was somewhat lower in the above mentioned mixed phosphate + dichromate buffering system (95%) than in the pure dichromate buffering solution (97.5%).", publisher = "Belgrade Association of the Chemical Engineers of Serbia", journal = "Hemijska industrija", title = "Fe–Mo alloy coatings as cathodes in chlorate production process", pages = "81-89", volume = "70", number = "1", doi = "10.2298/HEMIND150119014G", url = "https://hdl.handle.net/21.15107/rcub_dais_15969" }
Gajić Krstajić, L., Elezović, N., Jović, B., Martelli, G. N., Jović, V.,& Krstajić, N.. (2016). Fe–Mo alloy coatings as cathodes in chlorate production process. in Hemijska industrija Belgrade Association of the Chemical Engineers of Serbia., 70(1), 81-89. https://doi.org/10.2298/HEMIND150119014G https://hdl.handle.net/21.15107/rcub_dais_15969
Gajić Krstajić L, Elezović N, Jović B, Martelli GN, Jović V, Krstajić N. Fe–Mo alloy coatings as cathodes in chlorate production process. in Hemijska industrija. 2016;70(1):81-89. doi:10.2298/HEMIND150119014G https://hdl.handle.net/21.15107/rcub_dais_15969 .
Gajić Krstajić, Ljiljana, Elezović, Nevenka, Jović, Borka, Martelli, Gian N., Jović, Vladimir, Krstajić, Nedeljko, "Fe–Mo alloy coatings as cathodes in chlorate production process" in Hemijska industrija, 70, no. 1 (2016):81-89, https://doi.org/10.2298/HEMIND150119014G ., https://hdl.handle.net/21.15107/rcub_dais_15969 .