Mechanistic modeling of solar photo-Fenton with Fe3+-NTA for microcontaminant removal

Abstract

This work presents, for the first time, a mechanistic model of the solar photo-Fenton process with ferric nitrilotriacetate (Fe3+-NTA), the most cost-effective iron source for microcontaminant removal at neutral pH. The model was developed in three stages, considering the thermal decomposition of Fe3+-NTA, the contribution of temperature on Fenton-like reactions and the effect of the photon absorption of Fe3+-NTA on photochemical reactions. To determine the kinetic parameters, the imidacloprid degradation data (100 µg L−1) obtained at lab scale with 1.47 mM of H2O2 and 0.1 mM of Fe3+-NTA at different temperatures, UVA irradiances and liquid depths were used. The model was successfully validated in raceway pond reactors, changing the scale from 0.84 L to 80 L. According to model predictions, more than 90% of microcontaminant removal could be attained in 30 min operating the photoreactor with liquid depths of 15 cm and 60 cm in winter and summer, respectively.