Hi! My first thought on reading your thread was, why not boil it? Time-tested method of sterilising and cleaning anything. Then I found this article.
Driftwood needs preparing before adding it to your aquarium, or you can potentially harm your fish. Follow our how to guide to add it safely.
www.itsafishthing.com
I'm also thinking, the big piece of driftwood which dries quicker may be porous softwood. And the other piece which remains wet may be dense hardwood, suitable for aquariums.
Also, I live in tropical Asia. A lot of Asian rivers and coastal waters are disgustingly heavily polluted, with high levels of toxic chemicals and effluent. I would expect the same background for African Driftwood.
I think your piece of fine-looking driftwood can be salvaged.