2.5. Analytical method
Biodegradation mixtures were separated by filtration through a
0.45 lm membrane filter and then centrifuged at 7500 rpm for
15 min in a centrifuge (Sigma 2-16KCH, Germany). The supernatants
were analyzed using a UV–Vis spectrophotometer (Shimadzu,
Japan).
2.6. Calculation of rate constants
In this study, there was a linear region in plots of ln(C) vs. time.
The slope of the line was used to obtain the rate constant, the biodegradation
process using the first-order rate expression