Department of Environmental Engineering, National Chung Hsing University, Taichung City, 402, Taiwan.
Department of Chemistry, Chinese Culture University, Taipei, 111, Taiwan.
J Environ Manage. 2022 Dec 15;324:116278. doi: 10.1016/j.jenvman.2022.116278. Epub 2022 Sep 27.
While the effects of environmental factors (e.g., coexisting organic macromolecules and solar irradiation) on the phase transformation and oxidative dissolution of chemically exfoliated molybdenum nanosheets (ceMoS) have been recognized, the effects of environmental processes on the subsequent biological impacts of ceMoS are still poorly understood. In this study, the bioavailability and transitions in chemical speciation occurring during the aging process are demonstrated to be key factors causing ceMoS to affect aquatic organisms. The lower survival rate of embryonic zebrafish with aged (i.e., sunlight-irradiated and dark-ambient-aged) ceMoS, compared to that with freshly prepared ceMoS, was due to the release of ionic aging products (mainly acidic Mo species) throughout the oxidative dissolution of ceMoS. The released soluble molybdenum interacted with natural organic matter (NOM) depending on their functionality, and this attenuated the toxicity caused by ceMoS to different degrees. Toxicity triggered by aged ceMoS under both dark and irradiated conditions was significantly reduced by Suwannee River NOM due to the formation of complexes with ionic Mo species, which was established by Mo K-edge X-ray absorption spectroscopy. The findings provide useful insights for comprehending the impacts of ceMoS on aquatic organisms and guidance for the prevention measures necessary in the applications of MoS nanosheets.
尽管已经认识到环境因素（例如共存的有机大分子和太阳辐射）对化学剥离的钼纳米片（ceMoS）的相变和氧化溶解的影响，但环境过程对 ceMoS 随后对水生生物的影响仍知之甚少。在这项研究中，证明了老化过程中生物可利用性和化学形态转变是导致 ceMoS 影响水生生物的关键因素。与新制备的 ceMoS 相比，经过老化（即阳光照射和黑暗环境老化）的 ceMoS 的胚胎斑马鱼的存活率较低，这是由于 ceMoS 氧化溶解过程中释放出的离子老化产物（主要是酸性 Mo 物种）所致。释放的可溶性钼与天然有机物（NOM）相互作用取决于其功能，这在不同程度上减轻了 ceMoS 引起的毒性。由于形成了与离子 Mo 物种的配合物，苏万尼河 NOM 显著降低了黑暗和辐照条件下老化的 ceMoS 引发的毒性，这通过 Mo K 边 X 射线吸收光谱得到了证实。这些发现为理解 ceMoS 对水生生物的影响提供了有用的见解，并为 MoS 纳米片应用中必要的预防措施提供了指导。
