You can use any of our passport to enter a country. But you will need to leave the country with the same passport you entered it with.
Is there a proper reason you want to leave Brazil on your Canadian passport?
Keep in mind that even if you leave Brazil on your Colombian passport, you can still enter whatever country you are heading to on your Canadian one. So even if you go back to Canada, you will need to leave Brazil on your Colombian passport, but that is perfectly fine.
You might want to show the airline both passports, so they know you are allowed to go to Canada.