Effect of pH on zinc oxide nanoparticles synthesized with banana peel extract

The extension of the synthesis of nanoparticles in green chemistry with use fruit, plant, bacteria, fungi etc. has become a green attention today. Green sol-gel method for synthesis Zinc oxide (ZnO) nanoparticles (NPs) have much attention due to their eco-friendly, simplest method, non-toxic by product, less time consumption and cost effective. Therefore, banana peels were chosen for green sol-gel synthesis of ZnO NPs. Banana peels was chosen due to the solid waste in Malaysia increase, therefore banana peels were choosing is the one way to minimize the waste. This synthesis to identify the crystallite size of the ZnO NPs while the pH value is different and the optimum pH of the synthesis ZnO NPs. The green synthesized ZnO NPs were characterized by Fourier Transform Infrared Red (FT-IR) Spectroscopy, UV-visible spectrometer (UV-Vis) and X-ray diffraction (XRD). FT-IR spectra were recorded for the as prepared nanoparticles to identify the functional group involved in the synthesis, at the stretch 350-390 cm-1, indicating the present of ZnO bond. The UV-Vis spectrometer was recorded to observe the absorption peak, the highest absorption peak at 367 nm and the band gap was 3.38 eV. XRD analysis showed the ZnO NPs formed to have hexagonal wurtzite structure and the crystallite size between 16 to 28 nm. BET analysis showed that the surface area of ZnO NPs between 15 to 53 m²/g and the average particles size of ZnO NPs between 20 to 66 nm. In conclusion, the optimum pH value from this synthesis zinc oxide nanoparticle is at pH 12 due to the UV-Vis analysis that has highest peak of absorbent and also get the band get is 3.38 eV. Besides that, the size of crystallite at pH 12 is 15.22nm.