Vol. 3, Issue 7, Part S (2017)

Malachite green is used for direct dying silk, wool, jute, leather and cotton after mordanting. It is also used as a biological stain and as spot test reagent for detecting sulphurous acid and cerium. Photocatalytic degradation of malachite green over zinc oxide powder suspended in aqueous solution has been carried out. Photo catalytic bleaching of the dye was observed spectrophotometrically. The effect of variation of various parameters such as the concentration of malachite green, pH, amount and particles size of the semiconductor and light intensity on the rate of photocatalytic reaction were observed. A tentative mechanism for the photocatalytic bleaching of malachite green is proposed.