Ozonation of aqueous solutions of salicylic acid

• Autorzy: Parisheva Z. , Nusheva L. N.

Warianty tytułu

PL

Ozonowanie wodnych roztworów kwasu salicylowego

• Języki publikacji: EN

Abstrakty

EN

In the present paper, ozonation of aqueous solutions of salicylic acid is studied. The influence of the main reaction parameters, i.e., pH of the medium and temperature, on the process efficiency was investigated. The effectiveness of the process was estimated based on the degree of conversion a [%]. It was observed that ozonation is more effective at alkaline reaction of medium, which can be explained by higher concentration of OH* radicals in such a medium. The degree of conversion achieved at the end of the process at pH 10 was 91% compared to 55% at pH 6. Another parameter used to quantify the reactivity of salicylic acid during ozonation was the rate constant k [min-1], being calculated from the first-order kinetic equation. The rate constant of the process was two times higher at the temperature rise from 283 K. to 303 K. A considerable improvement in chemical oxygen demand (COD) removal was observed at pH above 7. At pH 10 the reduction in COD at the end of the process reached 40%. whereas at pH 6 the reduction in COD under the same conditions was only 8%. It was found that ozonation of salicylic acid produced intermediate oxalic acid, which was identified spectrophotometrically.

PL

Przedstawiono wpływ odczynu i temperatury wodnych roztworów kwasu salicylowego na skuteczność ich ozonowania. Zaobserwowano, że proces przebiegał efektywniej w roztworach o odczynie zasadowym ze względu na wyższe stężenie rodników OH. Uzyskany stopień konwersji (a) na końcu procesu ozonowania wynosił 91% dla pH = 10 i 55% dla pH = 6. Wzrost temperatury z 283 K do 303 K skutkował dwukrotnym zwiększeniem stałej szybkości reakcji k obliczonej na podstawie reakcji pierwszego rzędu. Uzyskano znaczne obniżenie wartości ChZT badanych roztworów w zakresie zasadowego odczynu - 40% dla pH = 10 i tylko 8% dla pH = 6. Na podstawie identyfikacji spektrofotometrycznej stwierdzono, że w procesie ozonowania kwasu salicylowego następuje wytworzenie produktu pośredniego, jakim jest kwas szczawiowy.

Słowa kluczowe

EN

wastewater treatment; ozonization; salicylic acid

PL

oczyszczanie ścieków; ozonowanie; kwas salicylowy

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Environment Protection Engineering
• Rocznik: 2007
• Tom: Vol. 33, nr 1
• Strony: 143--150
• Opis fizyczny: Bibliogr. 17 poz.

Twórcy

autor

Parisheva Z.

autor

Nusheva L. N.

• Department of Chemistry. Technical University of Plovdiv, 8 Dustabanov St., Plovdiv, 4000, Bulgaria.

Bibliografia

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