Singlet oxygen mediated photocatalytic Antimonite decontamination in water using nanoconfined TiO2

The development of advanced strategies to decontaminate water polluted with emerging contaminants (e.g., antimony (Sb)) is considered a priority. Herein, we synthesized and evaluated nanoscale photocatalysts with TiO2 confined within and on the outer surface of carbon nanotubes (i.e., TiO2-in/out-CNT) for the simultaneous detoxification of toxic Sb(III) and adsorption of less toxic Sb(V). Under simulated solar irradiation, the TiO2-in-CNT system exhibited a Sb(III) removal efficiency of 100% over 40 min with O-1(2) as the dominant reactive species. In contrast, HO & BULL; was identified as the species contributed to the Sb(III) conversion in the unconfined TiO2-out-CNT system. In addition, the TiO2-in-CNT system exhibited faster Sb(III) removal kinetics (4 times) compared with that of TiO2-out-CNT. The system efficacy was tolerant of a wide pH range (3.2-9.5), and showed good selectivity and performance in the presence of several coexisting anions (e.g., NO3-, Cl-, HCO3-) and different water matrices. The outcomes of this study are dedicated to providing an effective design for the decontamination of highly toxic heavy metal ions in water by integrating a state-of-the-art nanoconfinement effect and photocatalysis.

Automated summary

In this study, nanoscale photocatalysts were synthesized and evaluated for the simultaneous detoxification of toxic Sb(III) and adsorption of less toxic Sb(V). The TiO2-in-CNT system exhibited high efficiency in removing Sb(III) under solar irradiation, while the TiO2-out-CNT system utilized HO· to facilitate the conversion of Sb(III). Additionally, the TiO2-in-CNT system showed faster removal kinetics and good selectivity and performance in different water matrices.