Biosorption of pharmaceuticals to pyrolyzed Corbicula fluminea shells: the effect of pH under environmentally relevant conditions

This study aimed to assess the efficiency of shells from the invasive clam Corbicula fluminea for the removal of pharmaceuticals from different therapeutic classes from water. The removal efficiency was assessed at different but environmentally relevant pH values( 6-9). The pyrolyzed material showed a point zero charge of 10 and a specific surface area of 0.94 m 2 .g -1 . For each compound, the removal efficiency varied no more than 20 % among the tested pH values, except for ibuprofen, with removal values varying between negligible (pH 9) and 58% ± 6% (pH 6). At pH 7, which is relevant for most urban wastewaters, the removal efficiency varied in the following order, under the tested conditions: diclofenac (80% ± 2% ) > fluoxetine (67% ± 1%) > metformin (53% ± 3%) > caffeine (45% ± 8%) > carbamazepine (41% ± 5%) > ibuprofen (27% ± 5%) > paracetamol (23% ± 3%) > naproxen (13% ± 5%) > sulfamethoxazole (11% ± 2%). Given these results, allied to the ecological benefits of removing C. fluminea shells from invaded aquatic systems, the use of this biosorbent is potentially promising to improve strategies for the treatment of urban wastewaters.