Resource efficiency analysis for photocatalytic degradation and mineralization of estriol using TiO2 nanoparticles

A resource efficiency analysis was developed that evaluated photocatalyst loading and temperature inputs, and assessed hydroxyl radical (center dot OH) production. Catalyst loading (Aeroxide (R) TiO2 P25) between 1 and 1500 mg L-1 and temperatures between 5 and 50 degrees C were analyzed as input resources for center dot OH production. After, the best experimental conditions were used to degrade and mineralize estriol (E3). The analysis showed that a low catalyst concentration lead to poor absorption of radiation and a slow reaction. When high catalyst concentrations were tested, most of the radiation was absorbed, which produced results near the top of the slowing rate of center dot OH generation. Temperature was found a relevant resource for increasing interfacial transfer to facilitate center dot OH production following the Arrhenius model. Two indices to measure resource efficiency were proposed: 1) the center dot OH generation index (OHI) and 2) the initial degradation efficiency (IDE). OHI was used to measure the efficiency of a catalyst using photonic flux to generate center dot OH production. IDE evaluated the relationship between the photocatalytic reactor setup, catalyst, and E3 degradation. It was observed that 1.18 center dot OH was produced when a photon interacts with a photocatalyst particle when a load of 5 mg L-1 of photocatalyst is used at 20 degrees C. It was found that at initial time, 2.4 center dot OH was generated in the systems to produce a degradation of one E3 molecule when using a photocatalyst load of 20 mg L-1 at 20 degrees C. Additionally, it was demonstrated that E3 mineralization was feasible under different catalyst loading scenarios. 2017 Elsevier Ltd. All rights reserved.