Direct and indirect photolysis of tricyclic antidepressive drug

Conventional systems for water purification cannot completely remove organic pollutants from wastewater and for this reason, it is necessary to find more efficient processes for their removal. Advanced oxidation processes (AOPs) are very important methods for the oxidation and removal of a wide range of organic pollutants from natural and wastewater [1]. AOPs are characterized by various radical reactions involving a combination of chemical agents (O3, H2O2, transition metals, and metals oxides) and energy sources (UV-Vis irradiation, electricity, γ-irradiation, and ultrasound). In these processes, hydroxyl radicals represent primary oxidants [2]. Photolysis can be performed by a direct and indirect mechanism. Direct photolysis is a consequence of irradiation absorption, whereby the breakdown of chemical bonds in the molecule of the pollutant occurs in the case of overlapping of the absorption spectrum of pollutants with a wavelength of irradiation. On the other hand, indirect photolysis is performed in the presence of oxidants, resulting in a large number of reactive radicals, which then react with pollutants [3]. In recent years, great attention has been paid to drugs as potential bioactive substances in the environment. The high usage of antidepressants in the treatment of depression and anxiety disorders has led to the accumulation of active compounds of these drugs in the environment [4]. Amitriptyline is one of the most commonly used tricyclic antidepressant and since amitriptyline appears in the environment, it is necessary to well examine its stability and the possibility of elimination. In this paper, photodegradation of amitriptyline was studied using direct and indirect photolysis of amitriptyline under UV and simulated solar irradiation. Indirect photolysis was tested in the presence of H2O2, KBrO3, and (NH4)2S2O8. Besides, the effect of H2O2 concentration on the efficiency of the amitriptyline removal process was also observed

Effect of calcination temperature on the photoactivities of ZnO nanoparticles for degradation of the herbicide clomazone

The introduction of huge amount of organic pollutants such as dyes, pharmaceuticals, pesticides, etc. to the environment has caused many diseases to both aquatic and terrestrial lives due to their carcinogenic, toxic, and mutagenic poisonous nature. As environmental friendly and easy operational techniques, photocatalysis with semiconductors has been regarded as the most advanced and effective technique to replace the traditional methods used for the removal of organic pollutants [1-4]. Calcination temperature plays a key role in the crystallinity and photocatalytic activities of semiconductor photocatalysts [1]. The aim of this work was to investigate removal of the herbicide clomazone from double distilled water in the presence of novel ZnO nanoparticles under simulated sunlight. The ZnO photocatalysts were synthesized by precipitation method from the water and ethanol solutions of the acetate precursor and calcinated at 300–700 °C. The performances of the applied photocatalysts were correlated with their physic chemical properties. The efficiency of elimination the herbicide from double distilled water was monitored by UFLC–DAD technique

Photocatalytic degradation of mesotrione in the presence of TiO2 hombikat modified with different Au nanoparticles

Due to the harmful and toxic effects of organic pollutants scientists are searching for an effective method to remove these substances from the environment. One of the most efficient and environmentally friendly technologies for removing of organic water pollutants is photocatalytic degradation in the presence of various photocatalysts [1]. There are many metal-oxide photocatalysts which showed great photoactivity, but the most frequently used is TiO2 [2]. Recently, great attention has been paid to Au nanoparticles because in the case of TiO2 have showed extend of the spectral response to the visible light region in comparison with nonmodified TiO2 [3], and efficiently suppress the e– –h recombination [4]. Mesotrione [2-(4-methylsulfonyl-2-nitrobenzoyl)-1,3-cyclohexanedione] is a selective herbicide for preand post-emergence control of broad-leaf and grassy weeds in corn. It was developed by the company Syngeta Crop Protection and it was registered in Europe in 2000, and in the United States in 2001. Beside good properties in control of weeds mesotrione has harmful and toxic effects on non-target organisms. Low sorption of mentioned herbicide may indicate the leaching potential in the groundwater from maize production fields [5], wherein its presence in environmental waters can lead to negative consequences on the aquatic ecosystem. In this paper, photocatalytic degradation of mesotrione using TiO2 Hombikat modified with Au nanoparticles (nonmodified and modified with 2-mercaptoethanol, as well as with 2- mercaptoethanol and fullerenol nanoparticles) under simulated solar irradiation was investigated. Different volumes of various nanoparticles were added in suspension in order to enhance activity of commercial TiO2 Hombikat under simulated sunlight

Potential of TiO2 with various au nanoparticles for catalyzing mesotrione removal from wastewaters under sunlight

Nowadays, great focus is given to the contamination of surface and groundwater because of the extensive usage of pesticides in agriculture. The improvements of commercial catalyst TiO2 activity using different Au nanoparticles were investigated for mesotrione photocatalytic degradation under simulated sunlight. The selected system was 2.43 × 10−3% Au–S–CH2–CH2–OH/TiO2 (0.5 g/L) that was studied by transmission electron microscopy and ultraviolet-visible (UV-Vis) spectroscopy. It was found that TiO2 particles size was ~20 nm and ~50 nm, respectively. The Au nanoparticles were below 10 nm and were well distributed within the framework of TiO2 . For 2.43 × 10−3% Au–S–CH2–CH2–OH/TiO2 (0.5 g/L), band gap energy was 2.45 eV. In comparison to the pure TiO2, addition of Au nanoparticles generally enhanced photocatalytic removal of mesotrione. By examining the degree of mineralization, it was found that 2.43 × 10−3% Au–S–CH2–CH2–OH/TiO2 (0.5 g/L) system was the most efficient for the removal of the mesotrione and intermediates. The effect of tert-butanol, NaF and ethylenediaminetetraacetic acid disodium salt on the transformation rate suggested that the relative contribution of various reactive species changed in following order: h+ >•OHads >•OHbulk. Finally, several intermediates that were formed during the photocatalytic treatment of mesotrione were identified. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Zirconia based photocatalysts in degradation of selected herbicides

Hydrothermally synthesized zirconia nanopowders: pure and doped with Si4+ ions were spectroscopically characterized and used as photocatalysts for degradation of herbicides sulcotrione and fluroxypyr. Zirconia is wide band gap ceramic (Eg ~ 5 eV) however, synthesized nanopowders showed unexpected, modest absorbance in visible light range. That fact inspired photocatalytical degradation of herbicides with wide utilization, using solar irradiation (SI) in laboratory conditions. In the scope of this study, degradation of herbicides was only slightly achieved (irradiation time 2h).XV International Conference on Fundamental and Applied Aspects of Physical Chemistry : Proceedings. Vol. 1, September 20-24,2021, Belgrad

Comparative Study on the Removal Efficiency of Clomazone and Amitriptyline via Adsorption and Photocatalysis in Aqueous Media: Kinetic Models and Toxicity Assessment

This study aimed to compare the effectiveness of adsorption and photocatalysis techniques at removing the herbicide clomazone (CLO) and the antidepressant known as amitriptyline (AMI) from water. This study employed kinetic models to analyze the removal processes and assess the potential toxicity of the treated water. The structure and morphology of the prepared multi-walled carbon nanotubes were characterized as adsorbents by transmission electron microscopy, X-ray diffraction, Fourier transform infrared techniques, and Raman spectroscopy. The adsorption kinetics of CLO and AMI were studied on the pristine and functionalized multi-walled carbon nanotubes. Kinetic studies were performed by modeling the obtained experimental data using three kinetic models: pseudo-first-order, pseudo-second-order, and Elovich kinetic models. On the other hand, the efficiency of CLO and AMI photodegradation was examined as a function of the type of irradiation (UV and simulated solar irradiation) and type of TiO2 photocatalyst (Aeroxide and Kronos). Under the experimental conditions employed, the reaction followed pseudo-first-order kinetics. Additionally, in order to assess the toxicity of water containing CLO, AMI, and their intermediates, toxicity assessments were conducted using human fetal lung fibroblast cells. The results obtained indicate the effectiveness of both methods and provide valuable insights into their removal mechanisms, contributing to the advancement of sustainable water treatment strategies