Removal of acetylsalicylic acid (ASA) in packed microcolumns with carbon xerogel modified with TiO2 nanoparticles

Abstract

The adsorption capacity of acetylsalicylic acid was evaluated using carbon xerogel (CX) and carbon xerogel modified with TiO2 nanoparticles (CXM). These materials were characterized by different techniques such as Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), and Fourier Transform Infrared (FTIR) spectroscopy. BET surface area measurements found values of 762 m2/g and 214 m2/g for CX and CXM, respectively. Batch experiments show that the Langmuir-Freundlich model best represents the experimental adsorption isotherm, in addition to show a maximum adsorption capacity of 17,48 mg/g.  In continuous experiments, the effect of the inlet concentration and flow rate on the adsorption capacity of the micro-packed bed adsorber were evaluated. Breakthrough curves agree well with the axial dispersion model. In view of their adsorption capacity, carbon xerogels provide a potential material for the removal of emergent contaminants from the pharmaceutical industry. Besides, the incorporation of TiO2 nanoparticles allows the implementation of complementary techniques, e.g. photodegradation, as an alternative to achieve higher elimination of aqueous contaminants.