My first thought was to charge the titanium dioxide particles by first charging a balloon by rubbing it on my hair and then touching the balloon to the titanium dioxide powder, but that would be ineffective and the charge will escape when the powder is submerged in the water.
A better way would be to charge the titanium dioxide particles chemically after submerging them in the black-dyed water. How would I go about doing this safely, cheap and in home? (Maybe putting a non-dangerous alkaline in the final mix would charge the titanium dioxide?)