Fig. 11. Breakthrough curves (BTC) for toluene and o-xylene in (a) Cup 20 and (b) Cup 13 compared with the BTC for bromide. Bromide was applied during 3 d, thus only the first 3 d of this experiment was directly comparable with the hydrocarbon experiments. That is why only the first part of the BTC of bromide is shown. The concentration of CO₂ and O₂ as functions of time are shown for Cup 20 in (c) and (e), respectively, and for Cup 13 in (d) and (f), respectively. The vertical line indicates the cease of hydrocarbon application.