Effects Of Ultrasonic Conditions Research Articles

Process intensification for synthesis of triglycerides of capric acid using green approaches

The present research focuses on intensified synthesis of tricaprin by esterification reaction between capric acid and glycerol catalysed by dry amberlyst-15 using ultrasonication approach. Effect of several reaction conditions like molar ratio, reaction temperature, and amberlyst-15 loading on the rate of conversion has been studied. Effect of ultrasonic conditions like duty cycle and irradiation time on the intensified synthesis is investigated. Recyclability of amberlyst-15 is studied to make process more economical. It is investigated that the optimum reaction conditions which gave maximum conversion of 95% were molar ratio of capric acid: glycerol as 3:5, reaction temperature 90 ​°C, 4% amberlyst −15 loading. It was further investigated that ultrasonic conditions which gave intensified synthesis were 70% duty cycle and irradiation time of 120 ​min. The ultrasonic assisted process was compared with conventional synthesis. Conventional synthesis gave 30% yield in 120 ​min and 82% in 18 ​h. Amberlyst-15 was successfully reused for 13 cycle without any change in the conversion (%) of reaction.

Synergistic sonoelectrochemical removal of substituted phenols: Implications of ultrasonic parameters and physicochemical properties

The effects of ultrasonic conditions and physicochemical properties on the synergistic degradation in synthetic solution were investigated. A wide range of ultrasound frequencies, including 35, 170, 300, 500 and 700kHz, and ultrasonic power densities, including 11.3, 22.5 and 31.5W/L were used. It was revealed that the physical effect of ultrasound plays a major role in synergistic mechanism and 35kHz was found to be the most effective frequency due to its more vigorous physical effect induced by high implosive energy released from collapse of cavitation bubbles. The highest ultrasonic power density (31.5W/L) showed the highest synergy index as it increases the number of cavitation bubbles and the energy released when they collapse. The synergy indexes of various substituted phenols under identical condition were investigated. These results were correlated with physicochemical properties, namely octanol–water partition coefficient (Log KOW), water solubility (SW), Henry’s law constant (KH) and water diffusivity (DW). Among these parameters, Log KOW and DW were found to have substantial effects on synergy indexes.

Effects of Ultrasonic Treatment on the Physicochemical Properties and DPPH Radical Scavenging Activity of Polysaccharides from Mushroom Inonotus obliquus

An ultrasonic technique was employed to extract polysaccharides from Inonotus obliquus (UPS). The effects of ultrasonic conditions on the recovery and 1, 1-diphenyl -2-picrylhydrazyl (DPPH) radical scavenging activity of UPS were evaluated. The physicochemical properties of UPS were analyzed by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and UV-visible spectrophotometry. Molecular weights of UPS were determined by gel permeation chromatography (GPC). The optimal ultrasonic conditions to obtain the highest recovery of polysaccharides were 80 min, 75 degrees C, and 100 w. While the optimal ultrasonic conditions to obtain the strongest DPPH scavenging activity of polysaccharide were 80 min, 95 degrees C, and 160 w. The differences were found by DSC, SEM, GPC analysis and no apparent differences were found from the UV-vis spectra of the polysaccharides after the ultrasonic treatment, which indicated that ultrasonic treatment might cause the physicochemical changes in UPS conformation and degradation of UPS chain but not the main groups. Ultrasonic technique was an effective method to extract bioactive polysaccharides from I. obliquus (UPS). Polysaccharides from Inonotus obliquus exhibited many biological activities including antitumor, antioxidant, hypoglycemic, immune-stimulating effects, and so on. Ultrasonic treatment is now an usual proceeding technique for the extraction of some bioactive constituents. But there was no information about the effects of ultrasonic treatment on the physicochemical properties and DPPH radical scavenging activity of polysaccharides from I. obliquus until now. Ultrasonic technique was an effective method to extract bioactive polysaccharides from I. obliquus (UPS) according to this study.

Development of Small Ultrasonic Reactor for On-Site Treatment of Wastewater Including Chlorinated Hydrocarbon

Tetrachloroethylene (PCE) aqueous solution was used as the sample to be decomposed, and the effects of ultrasonic conditions (intensity and frequency) and reactor diameter on the PCE decomposition performance were investigated under a constant volume of liquid. The spatial distribution of PCE concentration in the reactor and the decomposition conversion were measured. The liquid mixing time was measured, and the reaction fields were visualized by using sonochemical luminescence.The spatial distribution of PCE concentration was relatively uniform for 100 and 200 kHz, while the PCE concentration was higher at the lower part of the reactor than at the upper part of the reactor for 500 and 800 kHz. Under the present range of ultrasonic frequency (100–800 kHz), the decomposition conversion increased with decreasing frequency. The reactor diameter was found to have an optimum value for the decomposition performance under the constant liquid volume.