How do you concentrate hydrogen peroxide?

Answer 1

i just freeze a 3% solution for 7 hours. whatever liquid is not frozen, that is 10-30% h2o2. defrost the ice and repeat process as much as needed. you'll have about 20-40 ml of 10-30% h2o2 when done. beware it takes several days.

this stuff is corrosive too, have great care

Answer 2

Hydrogen peroxide can be concentrated by distillation under reduced pressure. The lower pressure allows for the hydrogen peroxide to boil and vaporize at a lower temperature, separating it from water and other impurities.