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Degradation of tetracycline by solar photo-Fenton: Optimization and application in pilot photoreactor
摘要： The objective of this study is to analyze the photodegradation of the antibiotic tetracycline by the solar photo-Fenton process. The optimal conditions were obtained in a 22 (2 × 2) factorial design with the following input variables: reaction time and catalyst concentration (ferrous ion [Fe2+]). After statistical analysis using the Statistica 7.0 software, the optimal conditions determined, time = 120 min and Fe2+ = 166.81 mg/L, were applied in a pilot scale photoreactor, resulting in an 88.7% removal of the drug. In addition, in this stage we studied the reaction kinetics, biodegradability, and phytotoxicity of the products generated by the process. In the kinetic study, a constant of 1.82 × 10?2 min?1 was obtained. For this constant, a reaction time of 38.16 min is required for the initial tetracycline concentration to be reduced by 50%. The biodegradability tests indicated a gradual increase in the five-day biological oxygen demand/chemical oxygen demand ratio over time. The phytotoxicity tests showed an 18.5% decrease in the inhibition rate of the root growth of lettuce seedlings, indicating that the treatment applied reduces the toxicity of the substance.
关键词： photo-Fenton,photoreactor,solar photocatalysis,biodegradability,tetracycline,phytotoxicity
更新于2025-09-23 15:21:21
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Laser-induced breakdown spectroscopy as a promising tool in the elemental bioimaging of plant tissues
摘要： Laser-Induced Breakdown Spectroscopy (LIBS) is an optical analytical technique with a multi-element capability for element bioimaging in plants. During the years of LIBS development, the major application field has been in industry. However, during the last two decades, LIBS became a useful imaging tool in various biologic matrices, e.g. bones, mammals’ organs, and in the plant science. In this work, we present an overview of LIBS achievements in plant bioimaging which started in 2006. The progress in the assessment of spatial element distribution in plants is documented here with respect to the applications in phytotoxicity testing for the following reason: the information on the spatial distribution of elements can reveal a relationship between the exact location of an element and its toxic effect. This review discusses the state of the art of various elements’ bioimaging in plants using LIBS with a spatial resolution at micrometer scale.
关键词： crop plants,macronutrients,laser ablation,nanoparticles,element spatial distribution,micronutrients,2D-mapping,heavy metals,plants,model organisms,phytotoxicity,elemental imaging
更新于2025-09-12 10:27:22
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Ecotoxicity response of chlorpyrifos in Aedes aegypti larvae and Lactuca sativa seeds after UV/H2O2 and UVC oxidation
摘要： Chlorpyrifos (CP) is an organophosphate pesticide widely used in agriculture known to cause neurological and immunological effects in addition to interfering in the reproduction and development of organisms. In this study, CP degradation by UV/H2O2 process and UVC radiation was investigated, and the ecotoxicity and phytotoxicity was evaluated using bioassays of Aedes aegypti larvae and Lactuca sativa seeds. CP degradation was monitored by HPLC-DAD, and kinetic parameters were calculated for all processes evaluated. Results demonstrated that both processes are efficient, showing a reduction of over 97% of initial CP after 20 and 60 min of UV/H2O2 and UVC radiation, respectively. However, samples treated by UV/H2O2 process demonstrated increase of toxicity, leading to larvae mortality (> 90% of organisms) and inhibition effects in seed root growth. The relationship between increased toxicity and the CP byproducts formed was not confirmed due to its low concentration. However, the direct influence of acetonitrile solvent, specifically their toxic byproducts, was observed. This study provides insights into parent compound abatement using oxidative treatment and the changes in toxicity due to the transformation of CP byproducts and complex mixtures (acetonitrile as solvent and hydrogen peroxide).
关键词： Liquid chromatography,Chlorpyrifos,Bioassays,Phytotoxicity,Larvae mortality,Advanced oxidation processes
更新于2025-09-10 09:29:36