Effect of inorganic ions, photosensitisers and scavengers on the photocatalytic degradation of nicosulfuron

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 336; pp. 146 - 155
• Main Authors: Dugandžić, Ana M., Tomašević, Anđelka V., Radišić, Marina M., Šekuljica, Nataša Ž., Mijin, Dušan Ž., Petrović, Slobodan D.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01-03-2017; Elsevier BV
• Subjects: Acetone; Aluminum; Ammonium; Anions; Calcium; Catalysts; Cations; Chloride; Degradation; High performance liquid chromatography; Hydrogen peroxide; Inorganic ions; Intermediates; Ion chromatography; Isopropanol; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Mineralization; Optimization; Organic carbon; pH effects; Photodegradation; Phytotoxicity; Seeds; Studies; Titanium dioxide; Total organic carbon; Ultraviolet radiation; Inorganic ions; Hydrogen peroxide; Titanium dioxide; Optimization; Isopropanol; Acetone
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2016.12.031

•The photocatalytic degradation of nicosulfuron using TiO2 was studied.•The optimization of the nicosulfuron photodegradation was performed.•The degradation is mainly due to the reaction of nicosulfuron with OH in solution.•Almost 100% of HPLC removal and 69% of TOC was achieved.•The phytotoxicity was reduced from 56.8% to 14.8%.
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In the present study, the photocatalytic degradation of nicosulfuron, using TiO2 as a catalyst under UV light (315–400nm), was studied. The optimization of the nicosulfuron photodegradation was performed. It was found that the optimal concentration of the catalyst was 1gL−1 at concentration of nicosulfuron solution of 20mgL−1 while the highest reaction rate was obtained using 2gL−1. The degradation rate was the highest at pH=5.0. Effects of anions (Cl−, SO42–, NO3− and F−) and cations (Na+, Ca2+, Al3+) were investigated. In addition, the influence of isopropanol, acetone, and hydrogen peroxide was studied. It was shown that the photocatalytic degradation is mainly due to the reaction of nicosulfuron with OH in solution.
Also, liquid chromatography coupled with mass spectrometry (HPLC–MS) was used to identify intermediates during the photocatalytic degradation of nicosulfuron. the mineralization was monitored with ion chromatography (IC) and total organic carbon (TOC) analysis. Although 100% HPLC removal of nicosulfuron was achieved, only 69% TOC removal after 90min was recorded. The results of ion chromatography showed that the mineralization resulted in ammonium and nitrate ions during the process. The phytotoxicity experiments using mung bean seeds showed a reduction in phytotoxicity.