How can I choose the right solvent to remove pigment from cotton

[![the supposed pigment](https://i.stack.imgur.com/FiEry.png)](https://i.stack.imgur.com/FiEry.png)I’m trying to figure out how I might be able to dissolve a pigment without destroying the substrate(cotton, very thin). I don’t know the exact pigment, so it’s a guessing game. It is violet, I suspect it’s VP23. I thought to give it a try with a non ionic surfactant, but since they got recently banned I would like to be pretty sure before trying to get some. If you have any suggestions on how I can dissolve it(or make it colourless without the use of peroxide or bleach, since they destroy the substrate)




First, try soaking the cotton in transition metal rich tap water (a possible source of Fenton/Photo-Fenton generated hydroxyl radicals) and apply gentle aeration (as from a fish tank's air pump) in the presence of added citric acid (as from lemon juice) together with strong sunlight (or other especially, a UV rich light source).


This is actually a take off of historical mild sunlight assisted lemon juice bleaching, to quote [a source](https://www.healthline.com/health/lemon-juice-to-lighten-hair#how-it-works):



> 
> Lemon juice contains citric acid, which is a natural bleaching agent. Citric acid can whiten fabrics, and it's sometimes included in skin care products to help lighten dark spots. It's this ingredient that gradually whitens hair, making it appear lighter in color.
> 
> 
> 


If this is not effective enough, add a small amount of Washing Soda (Sodium Carbonate) to the procedure. This may introduce into the reaction mix, the powerful stain removing carbonate radical $\ce{.CO3-}$. It can be created from the action of the hydroxyl radical $\ce{.OH}$ on $\ce{HCO3-}$or, in basic conditions with $\ce{CO3^2-}$.


Some supporting background, see Figueroa, [“Quantification of carbonate radical formation by the bicarbonate-dependent peroxidase activity of superoxide dismutase 1 using pyrogallol red bleaching”](https://pubmed.ncbi.nlm.nih.gov/31102971/) that proposes to actually measure the carbonate radical concentration by its ability to remove a selected red dye.


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