Degradation of phosalone by silver ion catalytic hydrolysis

The study of kinetic of silver catalytic degradation of phoxim

In this study, we scrutinized the degradation process of phoxim in the presence of Ag+ ions, maintaining a 1:1 molar ratio under diverse temperature conditions. Phoxim was chosen as the model compound to devise experimental methodologies that would shed light on the kinetic and degradation pathways within a time span of 0 to 184 min across varying temperatures. The Arrhenius equation was harnessed to ascertain the activation energies linked with the degradation of phoxim. The application of the Arrhenius equation enables the computation of the reaction constant at a given temperature, thereby paving the way for the prediction of phoxim concentrations at different temperatures. The second-order rate constant for the reaction was observed to lie within the range of 0.035 to 0.128 L mol-1min-1, and the half-life of the reaction fluctuated between 5.2 and 17 min across different temperatures.•The study investigates the degradation of phoxim in the presence of Ag+ ions at various temperatures.•The Arrhenius equation was used to calculate the activation energies and predict phoxim concentrations at different temperatures.•The second-order rate constant for the reaction ranged from 0.035 to 0.128 L mol-1min-1, with the half-life varying between 5.2 and 17 min.

Pattern of bioterrorism in ancient times: lessons to be learned from the microbial and toxicological aspects

The current research aimed to analyze the history of bioterrorism in antiquity and to adapt the data to modern medical knowledge. To this end, a thorough evaluation of the literature related to the ancient history of bioterrorism and modern data was done using the Web of Sciences, Science Direct, Scopus, PubMed, and Google Scholar. Results showed that knowledge of bioterrorism has existed since antiquity in different civilizations. Biological and toxicological agents were used as an instrument of legal execution, as a warfare tool in battles, or to eliminate political rivals across nations. Ancient people researched bioterrorism to apply it against enemies and at the same time provide countermeasures in favor of themselves and allies. Despite the existence of the principles of bioterrorism since ancient times, adaptation of the data to modern research can assist in planning countermeasure efforts, preventive actions, and treatments in the framework of modern counterterrorism medicine.

Catalytic degradation of propetamphos and azamethiphos using silver ion

In this study, the degradation of two organophosphate pesticides, namely, propetamphos and azamethiphos, in the presence of Ag⁺ at different mole ratios was investigated. Moreover, the kinetic and degradation pathways of both chemicals in the range of 0-60 min were explored. Gas chromatography equipped with a thermionic specific detector was used to investigate the pesticide degradation kinetics and mechanism. The results show that the degradation rate of both pesticides follows first-order kinetic. The first-order rate constant and the half-life of reaction were in the range of 0.002-0.143 min^-1, 187-2.1 min, and 0.005-0.164 min^-1 and 60-1.8 min, for propetamphos and azamethiphos, respectively, at ambient temperature (25 ºC). Because group containing sulfur atom is a better leaving group than group containing nitrogen, the rate of degradation of azamethiphos is higher than propetamphos. In a higher mole ratio of Ag⁺ to pesticides, the degradation rate was increased, and it is possible to predict the rate of degradation of pesticides according to the chemical composition of leaving group.