Preparation of Potassium Ferrate for the Degradation of Tetracycline

[[abstract]]©2008 ACS - Tetracycline antibiotics are widely used in veterinary medicine and growth-promoting antibiotics for treatment and/or prevention of infectious disease because of their broad-spectrum activity and cost benefit. Tetracycline is rather persistent and a large fraction, which can be up to 75 %, of a single dose can be excreted in non-metabolized form in manures. In addition, potassium ferrate (Fe(VI)) is a powerful oxidant over a wide pH range and can be used as an environmentally friendly chemical in treated and natural waters. Therefore, the ability of ferrate (VI) to oxidize tetracycline in aqueous solution was examined in this study. The stability of Fe(VI) was monitored by the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) method. Results showed that the decomposition of Fe(VI) is highly dependent on pHs. A minimum decomposition rate constant of 1 x 10-4 s-1 was observed at pH 9.2. A stoichiometry of 1.4:1 was observed for the reaction of tetracycline with Fe(VI) at pH 9.2. In addition, tetracycline was rapidly transformed in the presence of low concentrations of Fe(VI) in the pH rang 8.3-10.0. The degradation efficiency of tetracycline is affected by both pH and initial Fe(VI) concentration. The degradation of tetracycline by Fe(VI) was also confirmed by ESI-MS and total organic carbon (TOC) analyses.[[department]]生醫工程與環境科學