(a) Effect of Fe (II)/Y catalysts on sonocatalytic degradation of ARB under
acidic, neutral and alkaline medium (catalyst dosage: 2.0 g/L, initial dye concentration:
80 lM). (b) Effect of Fe (III)/Y catalysts on sonocatalytic degradation of ARB
under acidic, neutral and alkaline medium (catalyst dosage: 2.0 g/L, initial dye
concentration: 80 lM).