Ureasil-Poly(ethylene oxide) Hybrid Matrix for Selective Adsorption and Separation of Dyes from Water

Author(s)

Molina, Eduardo F. ^[1] ; Parreira, Renato L. T. ^[1] ; De Faria, Emerson H. ^[1] ; de Carvalho, Hudson W. Pereira ^[2] ; Caramori, Giovanni F. ^[3] ; Coimbra, Daniel F. ^[3] ; Nassar, Eduardo J. ^[1] ; Ciuffi, Katia J. ^[1]

Affiliation

^[1] Univ Franca, BR-14404600 Franca, SP - Brazil

^[2] KIT, D-76131 Karlsruhe - Germany

^[3] Univ Fed Santa Catarina, Dept Quim, BR-88040900 Florianopolis, SC - Brazil

• Document type: Journal article
• Source: Langmuir; v. 30, n. 13, p. 3857-3868, APR 8 2014.
• Web of Science Citations: 29

Abstract

Herein, we present a cross-linked ureasil-polyether-siloxane hybrid (labeled PEO500) that can function as a stimuli-sensitive material; it swells or shrinks in response to changes in the environmental conditions and it can also, effectively and selectively, remove dyes from water solution. We also developed a methodology to separate a mixture of cationic and anionic dyes present in water. Addition of PEO500 to an aqueous solution of the anionic orange II (OII) or the ponceau S (PS) dye rendered the solution colorless, but an aqueous solution of cationic methylene blue (MB) remained unchanged after 2 h of contact with the insoluble matrix. In situ small-angle X-ray scattering (SAXS) showed that the distance of siloxane nanodomains are strongly affected by the swelling or shriking. By in situ UV-vis adsorption experiments, we found that the kinetics of OII and PS removal followed a pseudo-first-order rate equation. We accomplished B3LYP calculations, to establish which sites on the matrix interacted with the dyes and to investigate the nature of the matrix-dye chemical bonds. On the basis of the experimental and theoretical investigations, we proposed some mechanisms to explain how PEO500 adsorbs anionic dyes efficiently. This ``smart{''} matrix is potentially applicable as an efficient, fast, selective, and convenient device in water treatment and stimuli-sensitive response materials. (AU)

• FAPESP's process: 12/05514-0 - Development of new adsorbents for the removal of reactive species and heavy metal-based organic-inorganic hybrids
• Grantee: Eduardo Ferreira Molina
• Support type: Scholarships in Brazil - Post-Doctorate