In this study, the sorption behaviour of 1,3-benzothiazole (BT) and
2-(methylthio)benzothiazole (MTBT) was investigated on Danube geosorbent
under equilibrium and nonequilibrium conditions. All sorption isotherms
fitted well with the Freundlich model (R2=0.932-0.993). The results showed
that organic matter of the Danube geosorbent has a higher sorption affinity
for the more hydrophobic MTBT compared to BT. However, sorption-desorption
experiments showed that MTBT was more easily desorbed than BT molecules,
which indicates the importance of absorption relative to adsorption in the
overall sorption mechanism of MTBT. In general, molecules of BT and MTBT were
more easily desorbed in the lower concentration range, which resulted in an
increase in the hysteresis indices with increasing concentrations. Column
experiments revealed that retention of the investigated compounds on the
aquifer material followed the compound?s hydrophobicity. BT showed a lower
retention, in accordance with its lower sorption affinity obtained in the
static experiments, while MTBT showed a greater sorption affinity, and thus
had a longer retention time on the column. Thus during transport BT represent
greater risk for groundwaters than MTBT. These results have increased our
understanding of benzothiazoles sorption and desorption process which
represent one of the most important factors which influence the behaviour of
organic compounds in the environment.
Sorption of benzothiazoles onto sandy aquifer material under equilibrium and nonequlibrium conditions
