Does "silica colloidal anhydrous" contain aluminium?
It will probably have some aluminium in it, likely to be less than 0.1%, and most probably less than 0.01%. Not only that, also expect Ti and Zr in those quantities.

This level of impurities does not matter for most practical applications. If you do require exceptionally pure silica, you can buy it for a premium.

A note about “anhydrous”: when exposed to air, powdered silica will absorb moisture. Particularly if it’s amorphous. If you want it to be really anhydrous, dry the thing before using. Above 100 C will remove most of it, but completely removing all traces of water will require firing at ~1000 C in a noble metal crucible such as platinum.