Inorganic–organic hybrids based on sepiolite as efficient adsorbents of caffeine and glyphosate pollutants

• Main Authors: Hugo Baldan Junior, Evane da Silva, Michelle Saltarelli, Denise Crispim, Eduardo J. Nassar, Raquel Trujillano, Vicente Rives, Miguel A. Vicente, Antonio Gil, Sophia A. Korili, Emerson H. de Faria, Katia J. Ciuffi
• Format: Article
• Language: English
• Published: Elsevier 2020-11-01
• Series: Applied Surface Science Advances
• Subjects: Sepiolite; Glyphosate; Caffeine; Organically modified sepiolite; Clay mineral; Herbicide
• Online Access: http://www.sciencedirect.com/science/article/pii/S2666523920300106
• ISSN: 2666-5239

Sepiolite clay mineral was functionalized with (3-chloropropyl)triethoxysilane (ClPTES) or 3-[tri(ethoxy/methoxy)silyl] propylurea (TEMSPU) alkoxides and tested as adsorbent for herbicide glyphosate and also of caffeine, two pollutants with very different chemical composition. The materials obtained were characterized by X-ray diffractometry, infrared spectroscopy, thermal analysis, scanning electron microscopy and nitrogen adsorption at −196 °C, and submitted to toxicity and desorption tests. Silane functional groups blocked sepiolite active positions, and adsorption occurred within the zeolitic channels and on the surface of the functionalized solids. Caffeine and glyphosate effectively interacted with urea groups from grafted alkoxide, which could lower the mobility of the adsorbed contaminants. Glyphosate adsorbed on functionalized sepiolite derivatives showed low toxicity.