Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies

TiO<sub>2</sub> nanoparticles are found as pigments in coatings and paints and are, therefore, released into the environment through runoff. To assess their environmental impact, comprehensive fate and ecotoxicity studies necessitate particles closely resembling those released into the e...

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Bibliographic Details
Main Authors: Allan Philippe, Sylvester Ndoli-Kessie, Christian Fricke, Jean-Michel Guigner, Benjamin Heider, Eliana Di Lodovico
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Separations
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Online Access:https://www.mdpi.com/2297-8739/12/4/91
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Summary:TiO<sub>2</sub> nanoparticles are found as pigments in coatings and paints and are, therefore, released into the environment through runoff. To assess their environmental impact, comprehensive fate and ecotoxicity studies necessitate particles closely resembling those released into the environment. In response, we developed a method designed to isolate TiO<sub>2</sub> particles from commercial paints. Using six contrasting paints alongside a pure TiO<sub>2</sub> pigment, we evaluated two extraction methods in terms of recovery, purification rate, and preservation of both inorganic and organic particle coatings. The paints and extracts were characterized using cryogenic-TEM, ICP-OES, thermogravimetry, and infrared spectroscopy. In contrast to the alkaline-based extraction method, the extraction with acetic acid facilitated the retention of both inorganic and organic coatings and ensured good removal of organic polymers. Recovery rates exceeded 70% for all paints and extraction methods, yet the complete removal of SiO<sub>2</sub>, when present, was not achieved. CaCO<sub>3</sub> removal was effective with both extraction methods. Our developed extraction method enables the isolation of TiO<sub>2</sub>-particles similar to those aged within paints. However, we recommend using silicate-free paints when SiO<sub>2</sub> interference is of concern for the study design. Furthermore, this method could be interesting for pigment recycling, offering a gentler alternative to existing techniques which compromise particle coatings.
ISSN:2297-8739