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Surface Adsorption of Suwannee River Humic Acid on TiO2 Nanoparticles: A Study of pH and Particle Size
Langmuir ( IF 3.7 ) Pub Date : 2018-01-31 00:00:00 , DOI: 10.1021/acs.langmuir.8b00300
Sanjaya Jayalath 1 , Haibin Wu , Sarah C. Larsen 1 , Vicki H. Grassian
Affiliation  

TiO2 nanoparticles are some of the most widely used metal oxide nanomaterials mainly because of their diverse industrial applications. Increasing usage of these nanoparticles raises concerns about the potential adverse effects on the environment. Humic acid is a ubiquitous component of the natural organic matter in the environment that is known to get adsorbed onto nanoparticle surfaces. In this study, adsorption of humic acid on TiO2 nanoparticles of two different sizes (5 and 22 nm) is studied at different environmentally relevant pH values using attenuated total reflectance Fourier transformation infrared spectroscopy. These vibrational spectra provide insights into the nature of the adsorption process (extent of adsorption and reversibility) as a function of pH as well as information about the bonding to the surface. Additionally, the impact of humic acid adsorption on surface charge and agglomeration has been investigated. Interestingly, the results show that the humic acid adsorption is strongly pH-dependent and that adsorption of humic acid on TiO2 nanoparticles alters the extent of agglomeration and modifies the zeta potential and surface charges depending on the pH, thus potentially increasing the bioavailability of TiO2 nanoparticles in the environment.

中文翻译:

Suwannee河腐殖酸在TiO 2纳米颗粒上的表面吸附:pH和粒径的研究

TiO 2纳米颗粒是最广泛使用的金属氧化物纳米材料中的一些,这主要是因为它们的工业用途广泛。这些纳米颗粒的越来越多的使用引起了人们对环境的潜在不利影响的担忧。腐殖酸是环境中天然有机物的普遍存在组分,已知它会吸附到纳米颗粒表面上。在这项研究中,腐殖酸在TiO 2上的吸附使用衰减的全反射傅里叶变换红外光谱法,在不同的环境相关pH值下研究了两种不同大小(5和22 nm)的纳米颗粒。这些振动光谱提供了洞悉吸附过程的性质(吸附程度和可逆性)与pH的函数关系,以及有关与表面结合的信息。此外,研究了腐殖酸吸附对表面电荷和团聚的影响。有趣的是,结果表明,腐殖酸的吸附强烈依赖于pH值,腐殖酸在TiO 2纳米颗粒上的吸附改变了团聚程度,并根据pH值改变了Zeta电位和表面电荷,从而潜在地提高了TiO的生物利用度。环境中的2个纳米粒子。
更新日期:2018-01-31
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