Ultramarine blue ($\ce{Na2Al2SiO8 + Na2S}$, a sulfide-silicate complex containing sodium and aluminium) is insoluble when mixed in water and gives a blue color appearance to the water solution.
Which chemical (from my understanding, it should be acid) can be used to make the blue color disappear in water (absorb the coloring agent)?
Possibly $\ce{H2SO4}$ will absorb the sodium, releasing $\ce{H2S}$. I want to understand basically
- What is the coloring agent (is it sodium only)
- Which chemicals can I think about to remove the color (absorption of coloring agents)
