Mesoporous carbon for efficient removal of microcystin-LR in drinking water sources, Nak-Dong River, South Korea: Application to a field-scale drinking water treatment plant

Abstract

Microcystin-LR (MC-LR) is a growing issue as it is toxic and difficult to remove in drinking water treatment plants (DWTPs). Mesoporous carbon (MC) is evaluated as an alternative adsorbent for MC-LR removal and compared with three widely-used powdered activated carbons (PACs). MC was more favorable for MC-LR removal than PACs. MC-LR adsorption on MC was a rapid process (k(2) = 1.02 x 10(-4) g/mu g/min) that completed within 15 min, while adsorption on PACs took 60 min. The maximum adsorption capacity of MC-LR was 18,008 mu g/g (MC), which was higher than that of the PACs. Two mechanisms were associated with adsorption: the small hydro-dynamic diameter of MC in an aqueous solution increased the instantaneous attraction of MC-LR to its surface, and the numerous mesopores enhanced pore diffusion. The MC could remove MC-LR to meet the drinking water guidance level (1 mu g/L) from an the MC-LR concentration range of 5-20 mu g/L. in drinking water sources, and 10 min of treatment was sufficient to meet this level (MC dose = 20 mg/L). The field-scale DWTP was operated by adding 1 or 5 mg/L MC to the mixing basin, and 49.49% and 74.50% of MC-LR was removed, respectively. Geosmin and 2-methylisoborneol were slightly reduced when 5 mg/L of MC was applied. (C) 2017 Elsevier Ltd. All rights reserved.