Reducing degradation of azo dye by zero-valent iron in aqueous solution

The reducing degradation kinetics of five ate dyes, Acid orange II, Acid or ange IV, Acid orange GG, Acid red 3B and Orange I, by zero-valent iron powd er in aqueous solution were studied. It showed that the degradation is a tw o-step reaction, with the first step being reversible. Solution acidity and iron surface area are the factors greatly influencing the degradation rate s, and with increasing of acidity and iron surface area, the degradation ra tes increase. (C) 1998 Elsevier Science Ltd. All rights reserved.