Dual-functional millisphere of anion-exchanger-supported nanoceria for synergistic As(III) removal with stoichiometric H2O2: Catalytic oxidation and sorption.

Graphical abstract Highlights • Ce201 enabled catalytic H 2 O 2 oxidation and sorption for synergistic As(III) removal. • Stoichiometric H 2 O 2 (H 2 O 2 /As(III) = 1–2) greatly enhanced As(III) removal by Ce201. • As(III) was oxidized by Ce-OOH and resultant As(V) was fixed by –N+(CH 3) 3 groups. • As-laden Ce-201 could be well regenerated by NaOH−NaCl solution for cyclic runs. • Fixed-bed working capacity of Ce-201/H 2 O 2 was 20 times HFO-201 or twice of Ce-201. Abstract Aiming at efficient As(III) removal, a millimetric nanocomposite Ce-201, with dual functionalities of catalytic H 2 O 2 oxidation and sorption, was synthesized by confined growth of hydrous nanoceria in macroporous anion-exchanger host D201. The removal of As(III) by Ce-201 was significantly enhanced by H 2 O 2 at stoichiometric dosage (H 2 O 2 /As(III) molar ratio = 1–2), during which the catalytic oxidation of As(III) into As(V) played a vital role. The surface peroxide species formed on the surface of the embedded hydrous nanoceria induced by H 2 O 2 were proved the predominant reactive species for As(III) oxidation, and the resultant As(V) was mostly sequestered by the quaternary ammonium groups of the D201 host. The removal of As(III) by Ce-201/H 2 O 2 was favorable over wide pH range of 5–9, whilst the presence of chloride, carbonate (up to 10 mM), sulfate, silicate, nitrate (up to 1 mM), and humic acid (up to 30 mg DOC/L) posed negligible adverse effect on As(III) removal. The As-laden Ce-201 could be well regenerated by NaOH−NaCl binary solution for sustainable utilization without significant capacity loss. In fixed-bed mode, the working capacity of Ce-201 with H 2 O 2 spiked into the influent at trace level (2.67 μM) for continuous As(III) removal (∼6500 BV) was over twenty times that of the classic nanocomposite HFO-201 or twice of Ce-201 without H 2 O 2. Therefore, the Ce-201/H 2 O 2 technique showed great potential for full scale application of highly efficient decontamination of As(III) from water. [ABSTRACT FROM AUTHOR]