16시간 후, 용액을 15분 동안 18,000 rpm에서 원 심분리하고 상등액을 제거한 침전물을 탈이온수에 분산시키는 과정을 2회 반복 수행하였다.
After 16 hours, the solution was centrifuged at 18,000 rpm for 15 minutes, and the process of dispersing the precipitate from which the supernatant was removed in deionized water was repeated twice.