Catalytic binary oxides decorated zeolite as a remedy for As(III) polluted groundwater: Synergistic effects and mechanistic analysis

Abstract

Inexpensively composites derived from industrial waste products are being extensively researched in water treatment, particularly in arsenic removal, to acquire safe water resources. Here, it is reported that a cheap and effective composite of marigold-flowered structured iron-manganese binary oxide decorated fly ash zeolite for efficient removal of As(III) from water, is fabricated using a two-step hydrothermal approach. Arsenite ions [As(III)] are highly harmful, soluble, mobile, and more challenging to eliminate from aqueous solution than arsenates [As(V)]. The synthesized composite is amorphous and has a high surface area (243.55 m2/g). The Z @ Fe3O4–MnO2 binary oxide composite showed a higher As(III) adsorption capacity than those of zeolite-free counterparts, their single-oxide components, and the pristine zeolite, in addition, to efficiently oxidative-adsorption of As(III) by Fe3O4–MnO2 system. The zeolite functioned as effective support that prevented aggregation of the oxide nanoparticles and contributed to the synergistic effects exhibited by Z @ Fe3O4–MnO2. The synthesized composite exhibited a maximum As(III)-removal capacity (80 mg/g) that was relatively higher than that competitive with that of most reported sorbents. Moreover, Z @ Fe3O4–MnO2 was able to eliminate 100% arsenic from natural groundwater, and the arsenic-loaded Z @ Fe3O4–MnO2 can be readily regenerated and repeatedly utilized for up to 4 cycles by maintaining WHO’s drinking water standard levels. The overall findings illuminate the effectiveness, feasibility, and reusability of the designed composite for water treatment.