文獻名： Interactions between cerium dioxide nanoparticles and humic acid: Influence of light intensities and molecular weight fractions

作者： Hongliang Dai^abc,Tongshuai Sun^a,Ting Han^a,Xiang Li^d,Zechong Guo^abc,Xingang Wang^a,Yong Chen^b

^a School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, No. 2 Mengxi Road, Zhenjiang, 212018, China

^b School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China

^c Jiangxi Jindalai Environmental Protection Co., Ltd, Nanchang, 330100, China

^d School Energy & Environment, Southeast University, 2 Sipailou Road, Nanjing, 210096, China

摘要：Cerium dioxide nanoparticles (CeO₂ NPs) are ubiquitous in the water environment due to the extensive commercial applications. The complexity of heterogeneous humic acid (HA) plays a significant role in affecting the physicochemical properties of CeO₂ NPs in aqueous environments. However, the effects of light intensities and HA fractions on the interaction mechanism between CeO₂ NPs and HA are poorly understood. Here, we provided the evidence that both light intensities (>3 E L⁻¹ s⁻¹) and molecular weights (>10 kDa) can effectively affect the interactions between CeO₂ NPs and HA. The absolute content of reactive oxygen species (ROS) and quantum yield (Φ) of ³HA* were inhibited when HA (10 mg of C L⁻¹) interacts with CeO₂ NPs. However, they were positively correlated with the increasing irradiation time and simulated sunlight intensities. High molecular weights of HA fraction (>100 kDa) restrained the ROS generation and Φ of ³HA* due to surface adsorption between HA and CeO₂ NPs blocking reactive sites, competitive absorption for simulated sunlight. Fourier transform infrared and three-dimensional excitation-emission matrix fluorescence spectroscopy confirmed that the carboxylic groups of HA have high complexation capacity with CeO₂ NPs. These findings are essential for us to improve the understanding of the impacts of HA on CeO₂ NPs under different conditions in natural waters.

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