Biomass against emerging pollution in wastewater: Ability of cork for the removal of ofloxacin from aqueous solutions at different pH

• The cork ability in removing ofloxacin from aqueous solutions was evaluated.
• A characterization of ofloxacin protonation equilibria was performed.
• The hypothesis of ofloxacin micro-dissociation equilibria was ruled out.
• A new method for ofloxacin quantitative determination was developed.

A wide range of substances is reported in the literature as emerging pollutants. Biomass sorption has been found an effective way to remove these pollutants from wastewaters. In this work the ability of cork for the removal of ofloxacin from aqueous solutions has been evaluated. Cork and ofloxacin have been chosen as representative of biomass and of antibiotics, respectively. Ofloxacin is one of the most used fluoroquinolones, a potent broad spectrum oral antibiotic class.The sorption of ofloxacin by cork has been studied by equilibrium isotherms at three pH values (4, 7 and 9) using cork of two different sizes. The K and Qmax values obtained by fitting the data with Langmuir equation are discussed as a function of pH and cork size.In order to know the variously protonated species of ofloxacin that interact with cork at different pH, a potentiometric–spectrophotometric characterization of the protonation equilibria has been performed.A new spectrophotometric method for the quantitative determination of ofloxacin, based on the formation of colored iron(III) complexes, has been developed.

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