Synthesize of green silver nanoparticles by one pot microwave-assisted technique: Modeling and optimization

The use of nanoparticles (NPs) is recently increased due to their many applications in many different sectors. The majority of the methods used to manufacture of nanoparticles is mostly harmful to the environment and have high costs. The aim of the current work is to step forward in production silver NPs in a way with less cost and harm to environment using the green biosynthesis route. The Silver NPS colloidal suspension is produced based on the reaction of the metal precursor AgNO3 and a Cactus extract using Microwave instead of thermal heating. Optimization and modeling of NPs synthesis at lab scale is carried out throughout 10 experiments designed using software for experimental design and treating the responses statistically. The effect of concentration the metal precursor and power of microwave on the formation time of the NPs is investigated using Response Surface Methodology. The statistical results showed that the microwave power is more significant than the metal ions concentration, and the Ag NPs formation time decreased with increasing the microwave power and metal ions concentration. The optimum value for NPs formation time estimated is 10.27 minute. This formation time could be achieved using microwave power of 129.05 Watt and 1.8 ml of AgNO3 solution. The equilibrium adsorption data of methylene blue dye on the synthesized silver NPs were mathematically modeled by employing the pseudo-first-order kinetics equation and the photo-catalytic performance was inspected throughout the degradation of methylene blue under irradiation by sunlight. The dye was effectively nearly 99% degraded by the green synthesized silver nanoparticles after 72 hours of exposure to sunlight

Solubility of lumiracoxib in supercritical carbon dioxide

Abstract This study aims to use a static-based solubility method for measuring the solubility of lumiracoxib at a temperature of 308–338 K and pressure of 120–400 bar for the first time. The obtained solubility data for lumiracoxib is between 4.74 × 10−5 and 3.46 × 10−4 (mole fraction) for the studied ranges of pressure and temperature. The solubility values reveal that the lumiracoxib experiences a crossover pressure of about 160 bar. Moreover, the measured solubility data of these two drugs are correlated with density-based semi-empirical correlations namely Bartle et al., Mendez-Santiago-Teja, Kumar and Johnstone, Chrastil and modified Chrastil models with an average absolute relative deviation of 10.7%, 9.5%, 9.8%, 7.8%, and 8.7% respectively for lumiracoxib. According to these findings, it is obvious that all of the examined models are rather accurate and there is no superiority between these models for both examined drugs although the Chrastil model is slightly better in the overall view

Co₃O₄-rGO—Synthesis, Characterization, and Evaluation of Photocatalytic Activities

Water contamination with synthetic dyes is an escalating problem worldwide. Herein, Co3O4-decorated reduced graphene oxide (Co3O4-rGO) is reported as an effective heterogeneous photocatalyst for the decomposition of organic dyes. The synthesis of Co3O4-rGO was confirmed via spectroscopic techniques including XRD, XPS, TEM, and FTIR. After characterization, the prepared Co3O4-rGO composite was tested as a photocatalyst for the degradation of methylene blue and methyl orange. The photocatalytic efficiency of Co3O4-rGO was >95% after 60 min, corresponding to 200 mg/L as the initial concentration of each dye. The photodegradation of MB and MO was confirmed by BOD and COD measurements. Experimental parameters like the re-usability of Co3O4-rGO, the effect of catalyst dosage, and the effect of dye concentration on photocatalytic activity were also investigated. The photocatalytic activity of Co3O4-rGO for the degradation of MB was 2.13 and 3.43 times higher than that of Co3O4 and rGO, respectively. Similarly, the photocatalytic activity of Co3O4-rGO for the degradation of MO was 2.36 and 3.56 times higher than that of Co3O4 and rGO, respectively. Hence, Co3O4-rGO was found to be an efficient and reusable photocatalyst for the decomposition of selected dyes in the aqueous medium