HONOURABLE MENTION

Extracting Bismuth From Pepto Bismol

My project was about extracting bismuth from Pepto Bismol tablets. I used different methods to eliminate substances in the way of the bismuth being extracted and at the end I was able to extract a small yield of elemental bismuth.
Kainaat Imtiaz
Grade 8

Hypothesis

I think that bismuth will be able to be extracted from Pepto Bismol because of the chemical procedure. All of the obstacles in the way of the tablets turning into bismuth will be taken away one by one using different methods and I will be able to extract elemental bismuth from Pepto Bismol. 

 

Research

So how can bismuth be extracted from Pepto Bismol? I will answer that now. Pepto Bismol is a compound called bismuth subsalicylate meaning that it has bismuth and salicylic acid. The Pepto Bismol tablets need to be crushed so that the surface area increases and dissolving is more efficient. Once the powder reacts with the muriatic acid the salicylic acid separates from the solution as foam. The salicylic acid separates because it is not soluble in the muriatic acid and water. Once the salicylic acid is separated the bismuth subsalicylate is now bismuth chloride. Then when the solution is filtered aluminum foil is added which reacts with the bismuth chloride and black flakes precipitate out which are the bismuth ions. Then it is filtered again, dried and then melted. When little heat is added the colour of the little bismuth chunks will turn yellow because it has oxidized and so has become bismuth oxide. But you have to melt the metal to red hot so that when it dries it will actually be pure elemental bismuth. So that is how it works. 

 

Variables

I did not have variables in my experiment because my experiment was more of whether something will work or not rather than it being an experiment testing different things. But I do have my list of materials which is:

  • Something for crushing tablets like ziploc and hammer or mortar and pestle
  • Plastic Bowls for dissolving and carrying liquids
  • Glass mason jars for filtering
  • Something for stirring like coffee stirrers or a glass rod 
  • Coffee filters
  • Funnels
  • Toothpicks for picking of impurities
  • Small metal bowl to use as crucible for  melting the bismuth
  • Blowtorch
  • Safety equipment like: goggles to protect eyes against acidic fumes, plastic gloves to protect hands from contact with acid, mask to protect from breathing in acidic and metallic fumes and an apron to protect from any other contact with acid. 
  • Pepto Bismol tablets
  • Muriatic acid which is also known as hydrochloric acid
  • Aluminum foil

Procedure

  1. Gather all your materials.
  2. Crush the Pepto Bismol tablets into a fine powder. 
  3. Make a dilute solution of six parts water and one part muriatic acid. 
  4. Dissolve the Pepto Bismol powder into the water and muriatic acid solution and wait until the liquid is a pinkish colour and there is no more powder visible. There will be foaming so keep stirring to keep it down.  
  5. Filter the solution and keep the liquid that comes out. The stuff in the filter can be thrown away. 
  6. Put pieces of aluminum foil in the solution and black flakes will precipitate up to the top. Remove aluminum foil when if the solution is streaked on a piece of aluminum foil the streak stays clear.    

    7. Filter the solution once more but keep the black powder in the filter and the liquid can be thrown away. 

    8. Dry the powder as best as possible and melt it to red hot using a blowtorch. Pick of impurities during melting process. 

    9. Pour the molten bismuth into a mold and wait for it to harden. 

    10. Now you have your bismuth that you got from Pepto Bismol.    

Observations

During my experiment I observed many things. The first was that much foaming took place but then the foam dissolved in the solution but when it was filtered foam could be seen on the coffee filter. I also observed that the process of the aluminum foil causing black flakes to precipitate out was very fast and I don’t think it should have been that fast. At first I tried to melt the bismuth on the stove then the oven and then the grill outside. I thought it would work because of the low melting point of bismuth but it didn’t so I used a blowtorch. The last thing I observed was that the bismuth oxidized and after that it took very long to melt. I also did not have to put it into a mold because it hardened in the metal bowl. 

 

Analysis

At first I was quite frustrated by the results because the metal just wouldn’t melt. Bismuth has a low melting point compared to other metals and it is 271.4 degrees celsius but it still wouldn’t melt with a blowtorch that’s temperature could go up quite high. But after a long while of holding the blowtorch under the metal crucible I directed the flame from the top of the bowl straight to the metal chunks and it finally worked. My bismuth had an extremely low yield, it was small chunks of bismuth rather than one piece and it probably is not the most pure piece of elemental bismuth but I was proud and impressed of my results. Even after the the amount of frustration I am still happy about my result even though it is not perfect.   

 

Conclusion

I am overjoyed that my experiment worked and I was able to extract some bismuth from Pepto Bismol even if it wasn’t the best. But I would change a few things next time. I would definitely take more time in the process and be a bit more patient. I think it also would have been better if I did it during the summer because I did it in winter and it was extremely cold and the days are a lot shorter. I will also try to be more careful if I ever had to do this again because I had to redo the whole experiment because I dropped the pieces of metal that needed to be melted. They fell in the cracks of my deck so I was not able to retrieve them. If I ever had to do this again I definitely would hoping that I will get a larger yield and things would go more smoothly but overall I think it was a success. 

 

Application

This projects sole purpose of this project was to figure out if bismuth can be extracted from Pepto Bismol. I don't think that there are any practical applications for this project in life because the yield is quite low and it is more costly to extract a few grams then buy a few pounds online. So an application in this world is not quite practical but can be used to make bismuth crystals if you like but the yield will be low. This project was just for mere curiousity not for a purpose in life. 

Sources Of Error

I myself was a source of error in the experiment. Once I had completed most of the process I once again had to redo it all. That was because when I was at the melting step I dropped all of the little bismuth chunks and they fell through the cracks of my deck. I was worried and didn't think I would have enough time to finish it all. I once again had to buy packs of Pepto Bismol tablets for my project which cost another 30 dollars. Another source of error was information I found online. It said that since bismuth has a melting point of 271.4 degrees celsius it is able to be melted on a stove. It didn't work so I tried in the oven and on the grill outside but it still didn't work. I was so frustrated and finally used a blowtorch. Even with the bloewtorch it seemed that it wouldn't work but after minutes of holding the flame under, above and on the side of the crucible it finally worked. 

Acknowledgement

I acknowledge my family for helping out during the project to get materials and stuff and for supporting me through my trials and errors.