Degradation of Trichloroethylene Using Allophane–Titania Nanocomposite Supported on Porous Filter

Abstract

The allophane–titania composites were prepared on a macroporous filter. The allophane particles were dispersed in a titania sol, in which the filter was irradiated by ultrasonic waves, and then the resulting deposit on the filter was heated. During the photocatalytic degradation of trichloroethylene, the composite containing a small amount of allophane improved the adsorption ability of the titania and inhibited emission of the intermediate, phosgene. The appropriate UV irradiation intensity also inhibited the phosgene emission due to an effective adsorption–degradation relay.

Allophane, a natural nanoparticle present in andisols of equatorial Ecuador, properties and applications

“…Photocatalysis is a remediation technique involving the adsorption of UV-visible radiation, which allows the degradation of organochlorine compounds. The degradation of trichloroethylene, a hazardous organic pollutant, and acetaldehyde on allophane-titanium composites has been studied [7,52] . The presence of allophane leads to an increase in the adsorption of titanium and inhibits the emission of phosgene (COCl 2 ) and dichloroacetyl chloride; intermediate products of trichloroethylene decom-position, which once adsorbed on allophane are gradually degraded after diffusing towards titanium.…”

Alofán, una nanopartícula natural presente en andisoles del Ecuador, propiedades y aplicaciones

“…La partícula de alofán tiene la forma de una esfera porosa, con un diámetro entre 3 a 5 nm (Henmi y Wada, 1976), y está estructurada por una capa externa constituida por octaedros de aluminio (Al) y una capa interna constituida por tetraedros de silicio (Si). Presenta una gran área superficial, alta porosidad y carga variable, propiedades que permiten potenciales aplicaciones como adsorbente de cationes (Silva-Yumi y col., 2018), aniones (Nishikiori y col., 2017), compuestos derivados del benceno, ácidos grasos, detergentes, compuestos organoclorados (Arakawa, Matsuura y Okamoto, 2014; Baldermann y col., 2018; Garrido-Ramírez y col., 2013), ADN y aminoácidos (Saeki, Sakai y Wada, 2010), enzimas (Yu-Huang y col., 2016), en el área de catálisis (Garrido-Ramírez y col., 2013), en la elaboración de electrodos (Nishikiori y col., 2014), como ignífugo (Iyoda y col., 2012;Shukla y col., 2013) como elemento de tinta para impresoras , como anti inflamatorio y bactericida (Calabi-Floody y col., 2012), para la purificación de biodiesel (Yu-Huang y col., 2016), etc.…”