What edible substances have adsorptive properties

Im doing a research assignment for school in biology. I was told by my tutor that a good experiment to do would be charcoals effect on preventing the absorption on aspirin in which i would get participants to split into two groups (maybe more division later but this it the basic idea), have both groups take a single dose of aspirin but one group ingesting activated charcoal straight after, and then testing urine for signs of aspiring. I like the idea of this experiment and have access to the right reading to be able to write a lab report and discussion to follow this, but I had an idea to edit the experiment by testing the effectiveness of other edible adsorptive substances against the effectiveness of activated charcoal. problem is, I have no idea what absorptive edible substances are accessible. any help or info would be appreciated