Removal of methylene blue and rhodamine B from water by zirconium oxide/graphene

Methylene blue (MB) and rhodamine B dyes (RB) were degraded from water using zirconium oxide (ZrO2) and zirconium oxide/graphene composites (ZrO2/GR) as photocatalyst. The photocatalytic efficiency was calculated from absorption spectra obtained using UV-visible spectroscopy. It has been observed that photodegradation time as well as photocatalytic efficiency increase with the concentration of catalyst up to a certain limit after which effect was reversed. The degradation was studied as a function of pH also. It was found that photocatalytic efficiency was more in alkaline medium than acidic medium. Degradation of RB takes place at higher value of pH as compared to MB. The degradation time for MB was 1 h using ZrO2 which get reduced to 32 min using ZrO2/GR composite and for RB it reduced to 40 min (using ZrO2/GR) from 80 min (ZrO2).