New trend on open solar photoreactors to treat micropollutants by photo-Fenton at circumneutral pH: Increasing optical pathway

Abstract Raceway Pond Reactors (RPRs) have arisen as an interesting and feasible scaling-up option for treating substantial amount of wastewater by solar photo-Fenton process, a technology with short-term perspective due to its high contaminants of emerging concern (CEC) removal efficiency associated with a low reagents’ consumption (Fe and H2O2) and different strategies to work at near-neutral pH. This work proposes to modify the RPR optical pathway by using a reflexive surface of aluminum at the bottom of it. In this study, modified neutral solar photo-Fenton process with EDDS (Ethylenediamine-N,N'-disuccinic acid) has been applied for the elimination of a mixture of six micropollutants (acetaminophen, caffeine, carbamazepine, diclofenac, sulfamethoxazole, and trimethoprim) at 20 and 100 µg L−1 in natural water with different low iron concentrations (0.018-0-1 mM) and liquid depths (7–15 cm). Results showed a similar treatment time for 80% removal of micropollutants with 0.054 mM of iron using the aluminum surface and for 0.1 mM of iron without the surface. Utilizing a reflexive aluminum surface to return to reaction non-absorbed photons permitted to lower the consumption of iron and EDDS without losing efficiency.