20661
Easy access and enhanced stability of metal oxides makes them interesting candidates for applications in industrial effluent treatments and water purifications .
 Chemical: metal oxides
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: metal oxides 
Answer:
 Chemical: metal oxides