6010
Decolourization of direct azo dye , direct blue 15 ( DB15 ) , by an advanced Fenton process coupled with ultrasonic irradiation ( Fenton / US ) was investigated .
 Chemical: azo; Chemical: direct blue 15; Chemical: DB15
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: azo; Chemical: direct blue 15; Chemical: DB15