Visible light driven photocatalytic degradation of aqueous acetamiprid over nitrogen and graphene oxide doped ZnO composites

Synthesizing Ag2Ox(3 wt%)-loaded ZnFe2O4 photocatalysts for efficiently saving polluted aquatic ecosystems

Herein, we report an Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts synthesized by co-precipitation and incipient wet impregnation approach for acetamiprid degradation, antibacterial, antioxidant, and toxicity assay. Initially, bare ZnFe2O4 nanostructures were made through a simple co-precipitation method. In the second step, 3 wt% of various transition metal oxides (CuOx, ZrOx, and Ag2Ox) were embedded on the surface of ZnFe2O4 photocatalysts via a wet impregnation method. Further, the prepared photocatalysts were systematically characterized using XRD, FTIR, FE-SEM, BET, HRTEM, and XPS analysis. The optimum Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts revealed higher degradation efficiencies for acetamiprid under sunlight irradiation. Additionally, the Ag2Ox (3 wt%)-loaded ZnFe2O4 photocatalysts showed more effective antioxidant and antibacterial activity than blank and bare ZnFe2O4 nanomaterials. The enriched catalytic efficiency can be accredited to the 3 wt% of Ag2Ox NPs loaded on ZnFe2O4 nanomaterials, possibly due to the boosted transport properties of the electron-hole pairs. This study will provide a new avenue for the development of simple and effective photocatalysts for efficiently saving polluted aquatic ecosystems.

Aqueous Acetamiprid Degradation Using Combined Ultrasonication and Photocatalysis Under Visible Light

Acetamiprid (ACE), a neonicotinoid pesticide widely used in pest control, was found in high concentrations in soils, rivers, and lakes. In the present study, ACE degradation was investigated using visible light driven photocatalysis over nitrogen-graphene oxide (N-GO) and palladium-graphene oxide (Pd-GO)-doped ZnO photocatalysts combined with ultrasonication implemented either as a pretreatment (sonolysis) or operated simultaneously with photocatalysis (sonophocatalysis). The effectiveness of the two ACE degradation processes was determined separately. The sonolysis pretreatment allowed reaching almost 40% acetamiprid conversion within 30 min of reaction. Pursuing with the photodegradation reaction in the presence of N-GO-ZnO and Pd-GO-ZnO resulted in a maximum conversion of 98% of ACE within 5 h. As for the sonophotocatalysis process, the reaction time was shortened from 5 to 2 h with 100% acetamiprid conversion. In addition, the photocatalysts were shown to keep their activity even after 5 sonophotocatalytic cycles, thus proving their reusability.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11270-022-05867-4.

Mitigating toxicity of acetamiprid removal techniques - Fe modified zeolites in focus

All remediation pathways in aqueous solutions come down to three dominant ones - physical, chemical, and combinations thereof. Materials proposed for adsorption and oxidative degradation can induce positive or negative effects on cells compared to the pollutants themselves. Present research deals with the effects different methods for pesticide remediation have and how they impact cytotoxicity. With this particular intention, Fe-modified zeolites (obtained via citrate/oxalate complexes) of three zeotypes (MFI, BEA and FAU) were prepared and tested as adsorbents and Fenton catalysts for the removal of the acetamiprid pesticide. The materials are characterized by AFM, FTIR spectroscopy and ICP-OES. A different effect of the zeolite framework and modification route was found among the samples, which leads to pronounced adsorption (FAU), efficient Fenton degradation (MFI) or synergistic effect of both mechanisms (BEA). The cytotoxic effects of acetamiprid in the presence of zeolites, in pristine and modified forms, were tested on the MRC-5 human fibroblast cell line. A complete survey of the toxicity effect behind different pesticide removal methods is presented. Since neither adsorption nor catalytic degradation is the best option for pesticide removal, the focus is shifted to a combination of these methods, which proved to be optimal for pesticide toxicity reduction.