Abstract
Discoloration and mineralization of Reactive Red HE-3B were studied by using a laponite clay-based Fe nanocomposite (Fe-Lap-RD) as a heterogeneous catalyst in the presence of H
2O
2 and UV light. Our experimental results clearly indicate that Fe-Lap-RD mainly consists of Fe
2O
3 (meghemite) and Fe
2Si
4O
10(OH)
2 (iron silicate hydroxide) which have tetragonal and monoclinic structures, respectively, and has a high specific surface area (472
m
2/g) as well as a high total pore volume (0.547
cm
3/g). It was observed that discoloration of HE-3B undergoes a much faster kinetics than mineralization of HE-3B. It was also found that initial HE-3B concentration, H
2O
2 concentration, UV light wavelength and power, and Fe-Lap-RD catalyst loading are the four main factors that can significantly influence the mineralization of HE-3B. At optimal conditions, complete discoloration of 100
mg/L HE-3B can be achieved in 30
min and the total organic carbon removal ratio can attain 76% in 120
min, illustrating that Fe-Lap-RD has a high photo-catalytic activity in the photo-assisted discoloration and mineralization of HE-3B in the presence of UV light (254
nm) and H
2O
2.