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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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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author Allan Philippe
Sylvester Ndoli-Kessie
Christian Fricke
Jean-Michel Guigner
Benjamin Heider
Eliana Di Lodovico
author_facet Allan Philippe
Sylvester Ndoli-Kessie
Christian Fricke
Jean-Michel Guigner
Benjamin Heider
Eliana Di Lodovico
author_sort Allan Philippe
collection DOAJ
description 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.
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spelling doaj-art-3c32f6522e4a408a891f9c5a83d79aeb2025-08-20T02:18:15ZengMDPI AGSeparations2297-87392025-04-011249110.3390/separations12040091Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental StudiesAllan Philippe0Sylvester Ndoli-Kessie1Christian Fricke2Jean-Michel Guigner3Benjamin Heider4Eliana Di Lodovico5Group of Environmental and Soil Chemistry, iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstraße 7, 76829 Landau, GermanyGroup of Environmental and Soil Chemistry, iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstraße 7, 76829 Landau, GermanyGroup of Environmental and Soil Chemistry, iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstraße 7, 76829 Landau, GermanyInstitut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne University—UPMC University Paris 06, UMR CNRS 7590, MNHN, IRD UR 206, 75252 Paris, FranceDepartment of Chemistry, University of Kaiserslautern-Landau (RPTU), Erwin-Schrödinger-Str. 54, 67663 Kaiserslautern, GermanyGroup of Environmental and Soil Chemistry, iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstraße 7, 76829 Landau, GermanyTiO<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.https://www.mdpi.com/2297-8739/12/4/91extractiontitanium dioxidepigmentcryo-TEMcoatingTGA
spellingShingle Allan Philippe
Sylvester Ndoli-Kessie
Christian Fricke
Jean-Michel Guigner
Benjamin Heider
Eliana Di Lodovico
Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies
Separations
extraction
titanium dioxide
pigment
cryo-TEM
coating
TGA
title Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies
title_full Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies
title_fullStr Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies
title_full_unstemmed Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies
title_short Extraction and Characterization of TiO<sub>2</sub> Pigments from Commercial Paints for Environmental Studies
title_sort extraction and characterization of tio sub 2 sub pigments from commercial paints for environmental studies
topic extraction
titanium dioxide
pigment
cryo-TEM
coating
TGA
url https://www.mdpi.com/2297-8739/12/4/91
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AT christianfricke extractionandcharacterizationoftiosub2subpigmentsfromcommercialpaintsforenvironmentalstudies
AT jeanmichelguigner extractionandcharacterizationoftiosub2subpigmentsfromcommercialpaintsforenvironmentalstudies
AT benjaminheider extractionandcharacterizationoftiosub2subpigmentsfromcommercialpaintsforenvironmentalstudies
AT elianadilodovico extractionandcharacterizationoftiosub2subpigmentsfromcommercialpaintsforenvironmentalstudies