Removal of cyanobacteria toxins from drinking water by adsorption on activated carbon fibers

Abstract

Natural fibers from macadamia nut shell, dried coconut shell endocarp, unripe coconut mesocarp, sugarcane bagasse and pine wood residue were used to prepare activated carbon fibers (ACF) with potential application for removing microcystins. The ACF from pine wood and sugar cane bagasse were used to remove [D-Leucine1 MCYST-LR from water. After 10 minutes of contact time, more than 98% of toxin was removed by the ACF. The microcystin adsorption monolayer, qm, in the ACF recovered 200 and 161 μg.mg-1, with the Langmuir adsorption constant, KL, of 2.33 and 1.23 L.mg-1. Adsorption of [D-Leucine1]MCYST-LR in continuous process was studied for a fixed-bed ACF prepared from coconut shell and sugar cane bagasse and for two commercial activated carbon samples from treatment water plants of two Brazilian hemodialysis centers. Saturation of the beds occurred after 80 to 320 minutes, and the adsorption capacity for that toxin varied from 4.11 to 12.82 μg.mg-1.