In our experiment, using methylene blue solution, we found that 2 g of activated carbon was needed to remove almost all the blue colour.
We know that the methylene blue solution contains 0.001 g per 100 ml and so 2 g of activated carbon adsorbed 0.001 g of methylene blue.
This corresponds to 0.0005 g of methylene blue per gram of carbon.
The relative formula mass of methylene blue is 320 g/mol.
This means that 0.0000016 moles (or 1.6×10-6 mol) of methylene blue is adsorbed.
This might not seem very much, but consider how many molecules of methylene blue this represents. We can use Avogadro’s number (6.02×1023 mol-1) to work this out.
1.6×10-6 × 6.02×1023 = 9.6×1017 molecules
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