Temat: potassium chromate - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Selective flotation of witherite from calcite using potassium chromate as a depressant
Autorzy:: Qiu, Yangshuai
Zhang, Lingyan
Jiao, Xuan
Guan, Junfang
Li, Ye
Qian, Yupeng
Tematy:: witherite
calcite
selective flotation
sodium oleate
potassium chromate; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110784.pdf Link otwiera się w nowym oknie
Opis:: Witherite has been widely used as an industrial and environmental source of barium, with calcite being the primary associated carbonate mineral. However, few studies have been conducted to effectively concentrate witherite from barium ores. In this work, with the treatment of potassium chromate (K2CrO4) and sodium oleate (NaOL), witherite was selectively separated from calcite through selective flotation at different pH conditions. In addition, contact angle, Zeta potential, adsorption and X-ray photoelectron spectroscopy measurements were performed to characterize the separation mechanisms. The results demonstrated that NaOL had a strong collecting ability for both witherite and calcite; nevertheless, witherite could be effectively selected from calcite with the highest recovery at pH 9 in the presence of K2CrO4. From the XPS measurements, NaOL and K2CrO4 were found to be primarily attached to the surfaces of witherite and calcite through chemisorption. The presence of K2CrO4 on the surface of calcite adversely influenced the NaOL adsorption, which could make the flotation separation efficient and successful.
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Inhibicje enzymu ureazy polutantami w kontekście aktywności enzymatycznej gleb ( K2CrO4 ).
Inhibitions of urease by pollutants in the context of enzymatic activity of soils (K2CrO4)
Autorzy:: Palus, Maria
Opis:: The study examined the impact of K2CrO4 on urease activity. The experiment was carried out in 200 mM HEPES buffer, pH = 7.2. The buffer was chosen to ascertain that the incubation mixture, urease-0.1 M K2CrO4, have pH close to the optimum pH of the urease activity (7-7.5), and to ensure that Cr(VI) is in the form of chromate and not dichromate. As a result of the reaction with 0.1 M K2CrO4 under the conditions used, urease lost 50 % of its initial activity after 80 min. This classifies K2CrO4 as a relatively weak inhibitor.
W pracy przebadano wpływ K2CrO4 na aktywność ureazy. Eksperyment przeprowadzono w 200 mM buforze HEPES o wyjściowym pH = 7,2. Bufor dobrano tak, by zapewnił on mieszaninie inkubacyjnej, ureaza-0,1 M K2CrO4, pH bliskie optimum aktywności ureazy (7-7,5) oraz by zapewnił, że Cr(VI) jest w formie chromianu, a nie dichromianu. W wyniku reakcji z 0,1 M K2CrO4 w zastosowanych warunkach ureaza straciła 50 % swojej wyjściowej aktywności po 80 min. Klasyfikuje to K2CrO4 jako stosunkowo słaby inhibitor.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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