Competitive adsorption of ibuprofen and amoxicillin mixtures from aqueous solution on activated carbons

This work investigates the competitive adsorption under dynamic and equilibrium conditions of ibuprofen (IBU) and amoxicillin (AMX), two widely consumed pharmaceuticals, on nanoporous carbons of different characteristics. Batch adsorption experiments of pure components in water and their binary mixtures were carried out to measure both adsorption equilibrium and kinetics, and dynamic tests were performed to validate the simultaneous removal of the mixtures in breakthrough experiments. The equilibrium adsorption capacities evaluated from pure component solutions were higher than those measured in dynamic conditions, and were found to depend on the porous features of the adsorbent and the nature of the specific/dispersive interactions that are controlled by the solution pH, density of surface change on the carbon and ionization of the pollutant. A marked roll-up effect was observed for AMX retention on the hydrophobic carbons, not seen for the functionalized adsorbent likely due to the lower affinity of amoxicillin towards the carbon adsorbent. Dynamic adsorption of binary mixtures from wastewater of high salinity and alkalinity showed a slight increase in IBU uptake and a reduced adsorption of AMX, demonstrating the feasibility of the simultaneous removal of both compounds from complex water matrices.The authors thank the financial support of MINECO (CTM2011/23378) and PCTI Asturias (Fondos Feder 2007-2013, grant PC10-002). HM, RJC and AGB thank the financial support of Univ. Gabes (mobility grant), PCTI Asturias (PhD Severo Ochoa fellowship) and MINECO (PhD fellowship BES-2012-060410), respectively. COA thanks C. Diaz for the help in the wastewater analysisPeer reviewe

Competitive adsorption of ibuprofen and amoxicillin mixtures from aqueous solution on activated carbons

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