Photocatalytic activity of ZnO nanoparticles on dyes removal from wastewater Restiani Alia Pratiwi(a), Fitri Dara(c), Mita Nurhayati(a,b), Muhamad Nasir(c), Hendrawan Hendrawan(a), Fitri Khoerunnisa(a*), Ng Eng Poh(d)
a) Graduate Program of Chemistry, Department of Chemistry Education, Indonesian University of Education, Setiabudhi 229, Bandung 40154, Indonesia
*fitri[at]upi.edu
b) Department of Advanced Science and Technology Convergence, Kyungpook National University, Gyeongsangbuk- do, Sangju-si, South Korea
c) Center of Environmental and Clean Technologies, BRIN, Bandung, Indonesia
d) School of Chemical Sciences, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia
Abstract
Azo dyes such as methylene blue are the most widely used dyes (50-70%) in the textile, paper-making, cosmetic, and food industries. The presence of dyes in waters can reduce water quality and interfere with organisms in water bodies. The photocatalytic method is considered an easy, effective and sustainable method to degrade dyes in liquid waste. Zinc (II) oxide (ZnO) nanoparticles are believed to be a catalyst material in the photocatalytic process for the degradation of azo dyes. In this study, ZnO nanoparticles were synthesized using the hydrothermal method with various precursor compositions (Zn(NO3)2.4H2O and NaOH). The optimum composition was determined from the % photocatalytic efficiency of ZnO nanoparticles. The characterization of ZnO nanoparticles was carried out using FTIR spectroscopy, X- ray diffraction, and scanning electron microscopy (SEM). Photocatalytic activity of ZnO nanoparticles on dye degradation was carried out using UV-A. % dye degradation was determined by UV-Vis spectroscopy method. The results showed that the optimum composition for the synthesis of ZnO nanoparticles was obtained at the composition of ZnO-3 with % degradation efficiency of methylene blue dye reaching 95.042%. The FTIR spectra show a typical peak for ZnO-3 with peak absorption at wave number 450-500 cm-1 which indicates the stretching vibration of Zn-O. X-ray diffraction (XRD) confirmed the formation of ZnO crystals with a hexagonal wurtzite structure having an average crystal size of 24.35 nm. Furthermore, SEM photos confirmed the crystal morphology of ZnO nanoparticles in the form of flower like structures. The particle size of the SEM obtained by the average nanostructure produced is 46.36 nm. It can be stated that the ZnO nanoparticle catalyst has been successfully synthesized by the hydrothermal method and has good photocatalytic activity, has the potential to be applied in dye removal in wastewater.
