For disposal of other chemicals such as waste silica gel, solids, waste sulfuric acid, waste HF, waste nitric acid, waste hydrochloric acid, waste mixed acids, waste mixed alkalis, waste pump oils, please store them separately and arrange via Lab Supplies for disposal by the waste vendor. Be aware that concentrated acids especially nitric acid, being an oxidizer, can attack plastics over time. Therefore, do timely disposal.
If you have small quantities of acids or bases, you should dilute and neutralize the solution before drain disposal. This is strictly for acids/alkalis that do not contain heavy metals including copper, zinc, silver. These wastes should be sent for disposal.
Acids and bases must be rendered neutral before being disposed down a lab sink with copious amounts of water. Neutralization should be done in small quantities (i.e., no larger than 500 ml. You should not collect a quantity of the acid/base wastes from different experiments and do a batch neutralization. Do neutralizations in a fume hood as fumes and heat may be generated.
a. Slowly add the acid to a large amount of ice-cooled water to dilute to about 5 %.
b. For acid neutralization, prepare a 5 % basic solution of sodium carbonate, calcium hydroxide or sodium hydroxide. (For base neutralization, add 5 % hydrochloric acid solution.)
c. Slowly add the base solution to the diluted acid from (a).
d. Check that the pH is between 6 to 9 before turning on the tap.
e. Pour the solution down the drain keeping the tap on. Let the tap run for another 3 – 5 minutes after the container has been emptied.