Measuring GAC Exhaustion With Methylene Blue

[Dan_P]

I was able to observe a change in methylene blue adsorption rate as a function of GAC exhaustion. All tests were run with one jar of GAC. The test procedure is a bit involved but I am happy to share the details if there is interest.

The bottom most curve is the adsorption rate for fresh GAC. The top curve is the adsorption rate with GAC that was ~75% saturated with methylene blue. There are two curves inbetween, one for ~25% saturated GAC and GAC used in my fish only saltwater aquarium for four weeks.

I set out to answer the question "how often should I change the GAC" and it seems once a month is often enough, though if this post was an article, there would have to be some discussion about the assumptions I am making.

 

[Boomer]

Nice work Dan. Been telling people for years about 1 / m but never had any real data to back it up. Excellent start.

 

[Dan_P]

Nice work Dan. Been telling people for years about 1 / m but never had any real data to back it up. Excellent start.

Thanks.

I am taking suggestions for next steps. I was so focused on answering my question, I probably missed some interesting studies.

 

[Geraud]

Thank you for this analysis Dan!