SINTESIS DAN KARAKTERISASI MANGAN OKSIDA BERLAPIS BIRNESSITE DARI ASAM OKSALAT DAN KMnO4 MENGGUNAKAN METODA KERAMIK

Abstract

Birnessite is one phase of manganese oxides with layered structure. The formation of birnessite has been studied using ceramic method by reacting solids of KMnO4 with oxalic acid. The synthetic methods employed in the production of birnessite include variations of KMnO4 and oxalic acid mol ratios, temperature and calcination time. The products were characterized by X-ray powder diffraction (XRD) to determine crystallinity and purity. The surface area was determined by Spectrofotometer UV-Vis using methylen blue method. Scanning Electron Microscopy (SEM) is used to determine morphology and particle size. Whereas Absorption Atomic spectroscopy (AAS) was used to determine the concentration of Mn and K, and Fourier Transform Infrared (FTIR) is used to determine functional groups and acidity. The results showed improvement of crystallinity and purity in a 2:3 mol ratio, this is calcined at a temperature of 7000C for 7 hours as indicated by the data from XRD. This condition also produce the surface areas between of 0,1585 to 2,008 m2/g. The SEM data showed the particle has granule form with diameters ranging from 0,5 to 2,5 μm. The AAS measurement showed that Mn content is higher than K, ie Mn 88,06% and K 25,88%, respectively. Characterization of functional groups and acidity using FTIR showed that the absorption bands of the Mn-O vibration are about 418,57 cm-1. The bands at 1540 cm-1 is a Bronsted acid sites while those at 1633 cm-1 is a Lewis acid sites representing protonated and coordinated pyridine, respectively