Ultramarine blue colour absorbing agent


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> 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.
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> Which chemical (from my understanding, it should be acid) can be used to make the blue color disappear in water (absorb the coloring agent)?
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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)


