Preparation, characterization, and application of TiO2/Carbon composite: Adsorption, desorption and photocatalysis of Gd-DOTA

Abstract

Abstract The preparation methodology of a photocatalytic acting composite consisting of TiO2/Carbon carrying 24.5% of TiO2 is described. The environmental friendly TiO2/Carbon bifunctional material combining immobilized photocatalytic properties with a macroparticular carbonaceous ad-/desorbent was prepared in one-step procedure at low temperature from guava seeds and Ti(IV) oxysulfate as carbon and photocatalyst precursors, respectively. With artificial solar radiation, the composite can act as a photocatalyst for the degradation of the emerging pollutant, gadolinium-based contrast agent Gd-DOTA in aqueous solution with a degradation yield of 95%. For its reuse, the composite can be separated from the solution without centrifugation. The TiO2/Carbon composite is also able to adsorb and desorb the non-complexed gadolinium (Gd3+) ion once the cyclic Gd-DOTA is destroyed. The resulting photodegradation /-transformation as well adsorption and desorption phenomena were studied by analyzing the occurring Gd-species using ion exchange chromatography coupled to element and molecule selective mass spectrometers on-line (IEC-ICP-MS/ESI-QToF-MS).