Concomitant uptake of microcystin-LR and -RR by peat under various environmental conditions

Abstract

Uptake of two widely studied microcystins (MCs), microcystin-LR (MCLR) and microcystin-RR (MCRR), by peat was investigated under various environmental conditions. MCRR showed better removal (98.6 μg/g) compared to MCLR (87.8 μg/g) in a binary system. The uptake was very rapid with 90% of the toxins being removed from the aqueous phase in initial 15. min of contact. Acidic pH was slightly favorable for the uptake, but removal of MCLR and MCRR can also be achieved in neutral pH. Adsorption isotherm and kinetic modelling provided insights into the simultaneous sorption of MCLR and MCRR onto peat. The influence of various counter ions in the aqueous solution on the adsorptive removal of MCs by peat was investigated under different environmental conditions. Leaching studies showed about 50% of the toxins get desorbed at high alkaline pH. Temperature did not have much effect on either the uptake or the leaching process. The potential of peat to sequester MCs from real reservoir waters was studied to validate the optimized sorption process. © 2011 Elsevier B.V.