TiO 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 TiO 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 TiO nanoparticles alters the extent of agglomeration and modifies the zeta potential and surface charges depending on the pH, thus potentially increasing the bioavailability of TiO nanoparticles in the environment.
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http://dx.doi.org/10.1021/acs.langmuir.8b00300 | DOI Listing |
Environ Sci Technol
January 2025
College of Marine and Environmental Science, Tianjin University of Science and Technology, Tianjin 300457, China.
Humic acid (HA) enhances colloidal transport in porous media, yet the mechanisms by which the HA adsorption conformation affects colloid transport remain unclear. This study investigated the influence of HA on the transport of petroleum-hydrocarbon-contaminated soil colloids (TPHs-SC) in saturated sand columns. The presence of TPHs on the colloidal surface occupied adsorption sites, hindering HA from forming a horizontal adsorption conformation, as observed on uncontaminated soil colloids (SC).
View Article and Find Full Text PDFJ Appl Microbiol
January 2025
Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Aveiro, Portugal.
Aims: In the present study, we tested if terrestrially-derived humic substances (HS) could mitigate the adverse effects of elevated temperature and UVB radiation on the bacterial communities of two hard corals (Montipora digitata and Montipora capricornis), one soft coral (Sarcophyton glaucum), sediment and water. We also examined the impact of temperature, UVB radiation and HS supplementation on coral photosynthetic activity, a proxy for coral bleaching.
Methods And Results: We performed a multifactorial experiment using a randomized-controlled microcosm setup.
J Hazard Mater
January 2025
Research Institute for Farm Animal Biology, Dummerstorf, Germany.
Human activities and climate change have significantly increased humic substances in freshwater ecosystems over the last few decades. This increase is particularly concerning during seasonal changes or after heavy rainfall, when concentrations can easily increase up to tenfold. This phenomenon, known as "browning," has unknown consequences for aquatic organisms.
View Article and Find Full Text PDFDrug Chem Toxicol
January 2025
Department of Histology & Embryology, Faculty of Medicine, Canakkale Onsekiz Mart University, Canakkale, Turkey.
Cisplatin-induced nephrotoxicity, a major limitation of this chemotherapeutic agent, involves oxidative stress, inflammation, and apoptosis. This study investigated the potential renoprotective effects of humic acid in a rat model of cisplatin-induced nephrotoxicity. Forty-two male Wistar rats were assigned to six groups: control, humic acid, cisplatin, cisplatin + humic acid 10 mg/kg, cisplatin + humic acid 20 mg/kg, and cisplatin + humic acid 40 mg/kg.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemistry, Yazd University, Yazd, Iran.
A new humic acid-based nanomagnetic copper(II) composite was prepared and used as an eco-friendly recoverable catalyst for synthesizing 1,4-disubstituted 1,2,3-triazoles. The synthesis was done via the three-component click reaction of alkyl halide, sodium azide, and terminal alkyne with good to excellent yield. A simple magnetic copper acetate composite, FeO@HA-Cu(OAc), was prepared using humic acid and characterized by SEM, TEM, XRD, EDX, EDS-mapping, VSM, TGA, AAS, and FT-IR.
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