6009
Decolourization of direct blue 15 by Fenton / ultrasonic process using a zero - valent iron aggregate catalyst .
 Chemical: direct blue 15; Chemical: zero - valent iron
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: direct blue 15; Chemical: zero - valent iron