The overall goal of the following experiments is to demonstrate the activation of ions and solids in homogenous and heterogeneous systems under acoustic cavitation. This is achieved by applying high frequency ultrasound to a chilled solution of urinal ions in phosphoric acid saturated with Argonne. The luminescence of excited uranium can be seen by eye in a dark room and measured by spectrometer.
As a second step, prepare the stable colloids of platinum nanoparticles using chemical reduction of platinum four in pure water, saturated with an argon carbon monoxide gas mixture. Next plutonium colloids are prepared simply by slys of the suspension of plutonium dioxide in pure water. Saturated with Argonne.
Results show that the saturating gas ultrasonic frequency, bulk temperature, and the composition of sonicated solution are the most critical parameters for efficient sono luminescence and sono chemical activity. Sono chemistry arises from acoustic cavitation, in other words, from employees collapse of cavitation bubbles in fluids, eradiated with ultrasound. In principle, each cavitation bubble can be considered as a micro reactor providing highly energetic processes at almost room temperature solutions.
The study of senescence can help answer key questions in the sono chemistry field, such as the nature of the extreme conditions reached at bubble collapse or the mechanisms of chemical reactions. The implication of this technique extend towards the formation of nanoparticle suspension and the synthesis of catalyst because of the possibility to reduce noble metal under ultrasonic radiation. We first had the idea for this method when we began studying the dissolution behavior of plutonium dioxide under ultrasound in complex systems.
We have been surprised about the results we obtain in pure water, therefore, offering the possibility of preparing plutonium OIDs in a simple and controlled way. Begin the measurement by preparing the equipment. Use a high frequency transducer connected to a multi frequency generator to provide ultrasound in the 200 to 600 kilohertz range.
Use a clamp to tightly attach to the transducer. A thermos stated cylindrical sono reactor. Place the transducer sono reactor assembly on a translation stage in a light tight box that is kept open at this point.
Then position it so the center of the reactor can be imaged onto the entrance slit of the spectrometer. The spectrometer coupled to a liquid nitrogen cooled CCD camera is used to record emission spectra, so there is a line of sight to the region of the sonar reactor. Next, add a prepared urinal solution in phosphoric acid to the sonar reactor.
Here, 250 milliliters is added in addition to the 200 to 600 kilohertz ultrasound. 20 kilohertz ultrasound can be used to produce it. Mount a one centimeter squared titanium horn in a Teflon lid that fits onto the sono reactor.
Place the lid snugly on the reactor. Now add a thermocouple to the sono reactor. Attach a source of Argonne to the gas inlet tube to the reactor.
Complete the connections to the sono reactor by connecting the outlet gas tube to the entrance of a quadruple mass spectrometer. To study hydrogen gas, turn on the cryostat and set it to about zero to one degrees Celsius. Start argonne flowing into the solution at a rate of 100 milliliters per minute.
Meanwhile, begin to monitor the argonne and hydrogen signals from the mass spectrometer when the mass spectrometer signals are constant. After about half an hour switch on the high frequency ultrasonic generator at 60 watts. Once a steady state temperature of about 10 degrees Celsius has been reached after 15 to 20 minutes, check that the molecular hydrogen mass spectrometer signal has increased indicating cavitation and water lysis.
A visual check of the sono reactor can also be made. Urinal sono luminescence can be observed with the naked eye. Close the light tight box.
To prepare for measuring spectra. Start measuring sono luminescence. Spectra recording for 300 seconds each.
After measuring the sauna luminescence spectra, switch off the ultrasonic generator. Measure emission spectra in the absence of ultrasound to allow for correction for presence of parasite light. Also continue to measure the mass spectrometry signals until a nice baseline is reached.
This experiment must be done under a fume hood. Begin by preparing a five grams per liter platinum four solution. Set up a 50 milliliter airtight double jacketed glass reactor.
Equip the reactor with a platinum 100 thermocouple and septum connect PTFE inlet and outlet tubes each with flow meters calibrated in the range of 100 milliliters per minute. Connect the inlet tube to a source of argon gas with 10%carbon monoxide. Connect the outlet tube to a water trap and ultimately to a gas mass spectrometer.
Introduce 50 milliliters of deionized water to the reactor at the top of the reactor. Fix a one centimeter square titanium probe with a positive electric transducer connected to a 20 kilohertz generator. Ensure the TRO tip is around two centimeters from the bottom of the reactor.
About five minutes before the experiments start the chiller and set the temperature to negative 18 degrees Celsius. Start the argon carbon monoxide gas flow at around 100 milliliters per minute. The gas should be bubbling deep within the solution, and the TRO tip should be one to two centimeters below the surface of the liquid.
After 10 to 15 minutes, fix the gas inlet slightly below the liquid surface. Once the chiller reaches the setup temperature, start the ultrasonic irradiation with an acoustic power of 17 watts per centimeter squared and wait 15 to 20 minutes for the temperature to be about 20 degrees Celsius. With the aid of a syringe equipped with a stainless steel needle, take a precise amount of the five grams per liter chloral platic acid solution one milliliter.
In this experiment, move the syringe to the septum on the reactor. Carefully introduce the needle through the septum and inject the solution within the cavitation zone. Below the sunde tip.
Clear out the syringe by gently pumping the solution in and out. Withdraw a one milliliter sample, then remove the syringe. Use the syringe to sample the solution at regular intervals of 15 to 30 minutes.
As they become available, divide each one milliliter sample to measure the platinum ion concentration here. UV visible spectroscopy of the 260 nanometer band shows the amount of platinum four ions within the system initially and after about half an hour, as soon as no platinum ions can be detected in the solution. Around three hours at 20 degrees Celsius, switch off the ultrasonic radiation, turn off the gas and the chiller.
Remove the platinum nanoparticle suspension from the reactor. Next to prepare a sample for transmission electron microscopy for this video, a few drops of the suspension are dispersed in one to four milliliters of absolute ethanol. Take one drop of this suspension and deposit it on a carbon coated copper TEM grid.
After total evaporation of the solvent, proceed with the analysis to study sono chemical reactions of actinides. Make use of a glove box like this one from the Atlan facility. The setup is similar to that used in the previous experiments with a 20 kilohertz Sona Road, a tight Teflon ring and access points for the gas source, temperature control, gas output sampling, or other needs.
Suspend plutonium oxide powder in pure water in the sono chemical reactor. Attach the ultrasonic probe, set the cryostat temperature and introduce argon gas sonicate for five to 12 hours to form colloids centrifuge the obtained solution and recover the snat colloids for UV visible spectroscopy and x-ray absorption fine structure spectroscopy. The black curve shows the emission spectrum of 0.2 molar per caloric solution without urinal ions in the presence of Argonne.
The solution is at 10 degrees Celsius and is irradiated with 203 kilohertz ultrasound at 65 watts. The spectrum has hydroxide radical emission centered at 310 nanometers and a broad continuum spanning from the ultraviolet to the near infrared. The blue curve shows the emission spectrum of the same solution in the presence of 0.1 molar urinal ions.
The photons in the 250 to 450 nanometer range emitted by collapsing bubbles are absorbed almost completely by urinal ions. The emission lines of excited ions at 512 and 537 nanometers are very weak. Compare these with a sono luminescence spectra of 0.5 molar phosphoric acid in black and in blue, 0.5 molar phosphoric acid in the presence of urinal ions.
The spectra are taken at 10 degrees Celsius with 203 kilohertz ultrasound at 61 watts. The strong emission lines at 496 nanometers 517 nanometers and 540 nanometers are attributed to excited urinal ions. They clearly show that complexation with phosphate efficiently protects urinal from quenching by water molecules.
The evolution of concentrations during the sono chemical reduction of platinum four in pure water under argon carbon monoxide atmosphere is shown here. The temperature is 20 degrees Celsius. The light blue and dark blue curves show the concentrations of molecular hydrogen and carbon dioxide respectively.
These curves start increasing when ultrasonic radiation is triggered at 10 minutes. With a power of 0.35 watts per milliliter. Platinum four is added 30 minutes later, it's measured.
Concentration steadily decreases with time. While that of platinum two rises steadily from zero to a maximum and then returns to zero, the estimated concentration of platinum zero increases monotonically. Under ultrasonic irradiation.
The system produces platinum nanoparticles, transmission electron microscope. Images of these nanoparticles are shown here along with the colloid in which they are suspended. Once master it, the multi frequency chemical device can be used for large variety of the systems.
While attempting this method is very important to remember to control all the experimental conditions, especially the gas atmosphere and the temperature, in order to induce the sono chemical reduction of platinum in the solution After its development. This technique of reminiscence paved the way for researchers in the sono chemistry field to explore excitation of utes under ultrasound. Don't forget that working with plutonium can be extremely hazardous.
It requires careful handling appropriate infrastructures and train experimenters.
