Week 6: From Crushed to Powder
Taara S -
Hello and welcome back to my blog.
I took last week off for spring break, so I did not perform any experiments. Instead, I was working on my AZ Science Fair poster and presentation, which were due on March 15th, and preparing for a symposium through my internship which took place on March 23rd. The symposium was a great way for me to practice presenting my project to other people in a 3-5 minute time frame, since that will be the format of the science fair which is on April 5th.
The previous week, I was testing silica gel and activated alumina in the vertical setup, but many problems occurred. Even after performing adsorption for crushed activated alumina for several hours, the capacity was below 5% and the humidities of the bottom chamber kept fluctuating. Since the science fair registration deadline was rapidly approaching, I decided to change the direction of my project. Instead of comparing different desiccants against each other in the vertical setup only, I decided to compare the same desiccant and its adsorption rate and capacity between the vertical and horizontal setups. So, the bulk of my poster compares crushed zeolite at moderate humidity (~55-65%) in the vertical setup and horizontal setup.
Previously, I had run crushed zeolite in the horizontal setup at high humidity (~80-90%), so yesterday, I reran the experiment in the horizontal setup, ensuring that it was at moderate humidity in order to be comparable to the vertical setup experiment. I found that the zeolite adsorption capacity using the horizontal setup was slightly lower than the capacity of the vertical setup and also took about 20 minutes longer to complete adsorption.
Today, I discussed with my professor where to go next with my project. We decided to stick with zeolite for now and further crush the “crushed zeolite” into a fine powder to draw comparisons between the different particle sizes. We changed the mesh screen of the desiccant chamber in the vertical setup into a 400 mesh size to ensure the powder would not pass through. I then ran the adsorption experiment but found that a lot of the powder got stuck on the side of the clear cylinder chamber, severely decreasing the final weight calculation and in turn the adsorption capacity. Next time, I will run the air flow tube through the system using the port in the top chamber to flush all the powder that’s stuck on the side into the bottom of the desiccant chamber.
On Thursday, I plan to test the zeolite fine powder in the horizontal setup and hopefully have less of a powder loss following adsorption since the particles are confined and cannot fluidize. After zeolite, I will revisit silica gel and activated alumina and modify my experiments to ensure the desiccants aren’t too heavy or too big to fluidize, they have been stored in the oven for long enough, etc.
Thanks for reading and stay tuned for next week to hear more about my series of experiments!
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