TiO₂ Modified with Organic Acids for the Decomposition of Chlorfenvinphos under the Influence of Visible Light: Activity, Performance, Adsorption, and Kinetics

• Main Author: Piotr Zawadzki
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Materials
• Subjects: tio₂; pyruvic acid; succinic acid; chlorfenvinphos; adsorption; photocatalysis; radicals; scavenger test; modified photocatalysts; kinetics
• Online Access: https://www.mdpi.com/1996-1944/13/2/289

Photocatalytic decomposition of chlorfenvinphos (CFVP) in the presence of titanium dioxide (TiO₂) modified with organic acids: pyruvic (PA) and succinic (SA) under the visible light radiation has been studied. The following tests were examined: dose of photocatalysts, adsorption time, pH of the model solution, deactivation of catalysts, the role of oxygen, identification of free radicals for the CFVP decomposition, Langmuir-Hinshelwood kinetics. The synthesized materials were characterized by Scanning Electron Microscopy (SEM) and UV-Vis. At 10 wt.% of acid (90:10) decomposition of chlorfenvinphos was the most effective in the following conditions: dose of catalyst 50.0 mg/L, time of adsorption = 20 min, pH of model solution = 3.0. Under these conditions the order of photocatalyst efficiency has been proposed: TiO₂/PA/90:10 > TiO₂/SA/90:10 > TiO₂ with the removal degree of 85, 72 and 48%. The mathematically calculated half-life at this conditions was 27.0 min and 39.0 min for TiO₂/PA/90:10 and TiO₂/SA/90:10 respectively, compared to 98 min for pure TiO₂. It has been determined that the O₂^{•−} radicals and holes (h⁺) are the main reactive species involved in the photodegradation of chlorfenvinphos. The results of this study showed that method may be an interesting alternative for the treatment of chlorfenvinphos contaminated wastewater.