School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, No. 2 Mengxi Road, Zhenjiang, 212018, China; School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China; Jiangxi Jindalai Environmental Protection Co., Ltd, Nanchang, 330100, China.
School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, No. 2 Mengxi Road, Zhenjiang, 212018, China.
Environ Res. 2021 Apr;195:110861. doi: 10.1016/j.envres.2021.110861. Epub 2021 Feb 15.
Cerium dioxide nanoparticles (CeO 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 CeO NPs in aqueous environments. However, the effects of light intensities and HA fractions on the interaction mechanism between CeO NPs and HA are poorly understood. Here, we provided the evidence that both light intensities (>3 E L s) and molecular weights (>10 kDa) can effectively affect the interactions between CeO NPs and HA. The absolute content of reactive oxygen species (ROS) and quantum yield (Φ) of HA* were inhibited when HA (10 mg of C L) interacts with CeO 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 HA* due to surface adsorption between HA and CeO 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 CeO NPs. These findings are essential for us to improve the understanding of the impacts of HA on CeO NPs under different conditions in natural waters.
二氧化铈纳米颗粒（CeO NPs）由于广泛的商业应用而在水环境中无处不在。异质腐殖酸（HA）的复杂性在很大程度上影响了 CeO NPs 在水环境中的物理化学性质。然而，光照强度和 HA 分数对 CeO NPs 和 HA 之间相互作用机制的影响还了解甚少。在这里，我们提供了证据表明，光照强度（>3 E L s）和分子量（>10 kDa）都可以有效地影响 CeO NPs 和 HA 之间的相互作用。当 HA（10 mg 的 C L）与 CeO NPs 相互作用时，活性氧物种（ROS）的绝对含量和 HA的量子产率（Φ）受到抑制。然而，它们与辐照时间和模拟太阳光强度的增加呈正相关。由于 HA 和 CeO NPs 之间的表面吸附会阻塞反应位点，竞争性吸收模拟太阳光，高分子量的 HA 分数（>100 kDa）会抑制 ROS 的产生和 HA的 Φ。傅里叶变换红外和三维激发发射矩阵荧光光谱证实，HA 的羧酸基团与 CeO NPs 具有很高的络合能力。这些发现对于我们提高对天然水中不同条件下 HA 对 CeO NPs 影响的认识至关重要。
