Details

Autor(en) / Beteiligte

• Qian, Xiaoting
• Gu, Zhouhang
• Tang, Qing
• Hong, Aimei
• Filser, Juliane
• Sharma, Virender K.
• Li, Lingxiangyu

Titel

Sulfidation of sea urchin-like zinc oxide nanospheres: Kinetics, mechanisms, and impacts on growth of Escherichia coli

Ist Teil von

• The Science of the total environment, 2020-11, Vol.741, p.140415-140415, Article 140415

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Nanoscale zinc oxide (n-ZnO) with different morphology and sizes has been used in personal care products due to their antibacterial properties, resulting in discharge of n-ZnO into the environment with potential toxic effect to ecological systems. Sulfidation is one of pathways of transformation of n-ZnO, but a very limited information on the conversion of n-ZnO under sulfidic environment with special morphology such as sea urchin-like zinc oxide nanospheres (ZnO-NSs) is available to know the potential environmental risks of n-ZnO. Herein, sea urchin-like ZnO-NSs with an average size of 78 nm were synthesized and adopted as the model n-ZnO of special morphology. The ZnO-NPs at average sizes of 71 nm (ZnO-NPs-71), 48 nm (ZnO-NPs-48), and 17 nm (ZnO-NPs-17) nm were used to examine possible differences in the sulfidation between the sea urchin-like ZnO-NSs and ZnO-NPs. A new analytical method selectively dissolving ZnO over ZnS in partially sulfidized n-ZnO was developed and applied to understand the kinetics of n-ZnO sulfidation. The sulfidation rate constant (ks) of sea urchin-like ZnO-NSs was 2.9 × 10−3 h−1, comparable to that of ZnO-NPs-71 (4.1 × 10−3 h−1), but much lower than those of ZnO-NPs-48 (20.1 × 10−3 h−1) and ZnO-NPs-17 (67.8 × 10−3 h−1). This might be attributed to the differences in the specific surface area; ks positively correlated with the specific surface area (R2 = 0.97). Natural organic matter (NOM) decreased dissolution and sulfidation of the sea urchin-like ZnO-NSs. Aggregate ZnS nanocrystals instead of the original sea urchin-like ZnO-NSs were observed. We proposed that sea urchin-like ZnO-NSs were transformed to ZnS through a dissolution-precipitation pathway, consistent with the sulfidation pathway of ZnO-NPs. Sulfidation drastically reduced toxicity of sea urchin-like ZnO-NSs to Escherichia coli due to negligible dissolution of ZnS nanocrystals. These results greatly improved our understanding of the transformation and potential risks of n-ZnO with special morphology. [Display omitted] •The sulfidation of sea urchin-like zinc oxide nanospheres (ZnO-NSs) was investigated.•An analytical method dissolving ZnO over ZnS in sulfidized ZnO-NSs was developed.•The sulfidation rate of ZnO-NSs was comparable to that of ZnO-NPs with similar sizes.•ZnO-NSs were transformed to ZnS through a dissolution-precipitation pathway.•Sulfidation also drastically reduced the toxicity of ZnO-NSs to Escherichia coli.