Nano Express

Nanoscale Research Letters

, 4:709

First online:

Open Access This content is freely available online to anyone, anywhere at any time.

Photocatalytic Degradation of Two Commercial Reactive Dyes in Aqueous Phase Using Nanophotocatalysts

  • Sushil Kumar KansalAffiliated withDepartment of Chemical Engineering & Technology, Panjab University Email author 
  • , Navjeet KaurAffiliated withDepartment of Chemical Engineering & Technology, Panjab University
  • , Sukhmehar SinghAffiliated withDepartment of Chemical Engineering & Technology, Panjab University


This study involves the photocatalytic degradation of Reactive Black 5 (RB5) and Reactive Orange 4 (RO4) dyes, employing heterogeneous photocatalytic process. Photocatalytic activity of different semiconductors such as titanium dioxide (TiO2) and zinc oxide (ZnO) has been investigated. An attempt has been made to study the effect of process parameters through amount of catalyst, concentration of dye, and pH on photocatalytic degradation of RB5 and RO4. The experiments were carried out by varying pH (3–11), amount of catalyst (0.25–1.5 g/L), and initial concentration of dye (10–100 mg/L). The optimum catalyst dose was found to be 1.25 and 1 g/L for RB5 and RO4, respectively. In the case of RB5, maximum rate of decolorization was observed in acidic medium at pH 4, whereas the decolorization of RO4 reached maximum in basic region at pH 11. The performance of photocatalytic system employing ZnO/UV light was observed to be better than TiO2/UV system. The complete decolorization of RB5 was observed after 7 min with ZnO, whereas with TiO2, only 75% dye degraded in 7 min. In the case of RO4, 92 and 62% decolorization was noticed in the same duration.


Decolorization Azo dye Reactive Black 5 Reactive Orange 4 Photocatalysis Zinc oxide Nanophotocatalyst