Assessment of the effectiveness of combined adsorption and photocatalysis for removal of the herbicide isoproturon

• Published in: Physics and chemistry of the earth. Parts A/B/C 2016-02, Vol.91, p.77-86
• Main Authors: Dávila-Jiménez, Martín M., Elizalde-González, María P., García-Díaz, Esmeralda, Santes-Aquino, Alba M.
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon; Guava; Herbicides; Isoproturon; LC-MS; Photocatalysis; Product identification; Surface chemistry; TiO2-Carbon; Titanium dioxide
• ISSN: 1474-7065; 1873-5193
• DOI: 10.1016/j.pce.2015.09.011

The aim of this research was to decompose isoproturon and adsorb its photoproducts by developing a carbon material from a juice industry waste. Carbon-TiO2 hybrid materials were obtained by impregnating carbonized guava seeds with TiO2 gels prepared from TiOSO4⋅xH2O and NH4OH using glycerol as a binder and thermally treating the materials at 500 °C. Raman studies confirmed the anatase phase of TiO2. SEM images showed isolated TiO2 agglomerates firmly attached to the carbon surface. The adsorption behavior of isoproturon on guava carbon was studied and yielded S-type adsorption isotherms. The photocatalytic activities of the prepared hybrid materials were monitored to study the kinetics and elimination process both of the herbicide and its photoproducts. The reaction was monitored by UV–Vis spectrophotometry, LC-DAD and LC-MS, enabling identification of some intermediate species. Among the photoproducts produced by carbon-TiO2 hybrid materials, amino-isopropylphenol was detected. [Display omitted] •Carbonized guava psidii seeds support TiO2 nanoparticles in a hybrid material.•Guava carbon develops microporous granules and allows adsorption of the herbicide isoproturon.•The material demonstrated degradation efficiency with a minimum load of TiO2.•Hydroxylated compounds identified by LC-MS as products.