After that, the resulting suspension was diluted with three times amount of water to stop the reaction, and then washed with deionized water by repetitive centrifugations (3000 rpm, 20 min per cycle) until the pH remained constant.
After that, the resulting suspension was diluted with three times amount ofwater to stop the reaction, and then washed with deionized waterby repetitive centrifugations (3000 rpm, 20 min per cycle) until thepH remained constant.