The effect of metal loading on photocatalytic activity of graphitic carbon nitride for photoreduction of hexavalent chromium / Nur Faatihah Ahmad Redzuan

Hexavalent chromium Cr(VI) is toxic waste that lead to water pollution and give a negative impact on health and environment. The photocatalytic reduction is effective method to reduce Cr(VI) to harmless toxic. Graphitic carbon nitride (g-C3N4) as semiconductor photocatalysts shows a great potential for reduction of Cr(VI) such as visible light driven and excellent stability of physicochemical. However, g-C3N4 is modified with metal to enhance the performance of photoreduction of Cr(VI). In this study, the effect of different metal of Ag, Cu and Ni loaded on g-C3N4 were synthesized by using impregnation method. The physical and chemical properties of Ag, Cu and Ni loaded on g-C3N4 were analyzed using XRD, FTIR, FESEM and UV-vis/DRS techniques. The performance on photoreduction of Cr(VI) were determine as followed: Ag/C3N4 (87%) > Cu/C3N4 (85%) > Ni/C3N4 (80%) > pure g-C3N4 (77%). Ag/C3N4 was highest performance compared to other photocatalysts due to well dispersed of Ag particle on g-C3N4 as well as lowest bandgap which enhance the photoreduction of Cr(VI). Then, Ag/C3N4 was carried out for other parameters such as initial pH, catalyst dosage and concentration of Cr(VI). The result shows the highest performance at pH 9, concentration of Cr(VI) at 10 mg/L and catalyst dosage at 0.0094 g L-1. Overall, the Ag loaded on g-C3N4 was successfully contribute on photoreduction of Cr(VI) under visible light.