Affiliation:
1. Department of Civil and Environmental Engineering, University of Brasília, Brasília, Brazil
2. Institute of Chemistry, Materials and Fuels Laboratory, University of Brasília, Brasília-DF, Brazil
Abstract
Cylindrospermopsin (CYN) is a toxic metabolite globally documented in aquatic environments, including human supply water sources. Adsorption onto activated carbon (AC) has emerged as a promising and cost-effective advanced technique to remove this cyanotoxin in water treatment utilities. In this context, this work aims to assess the influence of AC's surface chemical composition on kinetics and equilibrium behavior of CYN adsorption. For that, a pristine AC was synthesized by chemical activation with H3PO4 and then submitted to two different post-activation treatments: treatment under the reflux of a HNO3 solution (ACOx); heat treatment under inert atmosphere at 850 oC (ACHT). The modified ACs showed quite different contents of acidic oxygenated groups, which amounted 1.66 and 0.45 mmol g−1 for ACOx and ACHT, respectively. Despite its lower porosity and specific surface area, ACHT presented better kinetic and capacity for CYN adsorption, which suggests that the presence of acidic oxygenated functional groups hinders CYN adsorption at the studied conditions. Also, a full-scale adsorption column breakthrough was estimated by rapid small-scale column tests with granular ACHT and ultrafiltered superficial water collected from Paranoá Lake.
Funder
Coordination for the Improvement of Higher Education Personnel
Post-Graduate Board (DPG) of the University of Brasília