Functionalization of carbon-based materials for zoledronic acid removal

This work aims to study the feasibility for zoledronic acid (ZA) capture through adsorption process using two different adsorbent materials, which are the supported activated carbons (ACs) and the nitrogen-doped carbon spheres (CS). The surface of supported ACs was modified with magnesium oxide (MgO) by precipitation method, while the nitrogen-dope carbon spheres were successfully synthesized via modified Stöber sol-gel process using lysine as the source of nitrogen. Their physicochemical properties were characterized using various techniques, including SEM, TEM, FTIR, Raman, XRD, N2 sorption isotherm, TGA/DSC, NEXAFS, XPS, and XANES. The adsorption of ZA was carried out in batch system. It was found that MgO particles were well dispersed on the surface of AC which enhanced the ZA adsorption capacity. Interestingly, the presence of coexisting ions of K+ and NH4+ in buffer solution significantly enhanced the ZA adsorption capacity. The highest ZA removal (73 mg/g) was found when using 15%MgO/AC as an adsorbent. For the N doped-CS system, the highest ZA removal at 92 mg/g was observed when applying 0.2lys-CS in the system. Furthermore, the cell viability over the AC system was further tested and it was found that MgO/AC was nontoxic to human cell with the cell viability percentage greater than 80%. This evidence could imply that MgO/AC can be considered as a new potential adsorbent for ZA capture in biomedical applications.