Aplikasi Fotokatalis Komposit Fe3O4/SiO2 sebagai Degradasi Air Limbah melalui Uji Methylene Blue (MB)

Abstract

In this study, synthesis, characterization, and analysis of Fe3O4/SiO2 composite photocatalyst for degradation through methylene blue (MB) was done. Fe3O4/SiO2 composite prepared using coprecipitation method, started with mixing 3 g Fe3O4 into 40 mL ethanol solution and stirred for t = 1 hour; T = 30℃. Then 1,05 g SiO2 and 4,5 mL NH4OH added and stirred in a fume hood for t = 10 hours; T = 30℃. Aquabides and ethanol used to obtain neutral pH, then calcination with T = 100℃ until powder obtained and carried out to characterizing. The test result using Scanning Electron Microscope (SEM) shown Fe3O4/SiO2 composite has round agglomeration shape with average particle size 0,17 micrometer, 0,32 micrometer, 0,49 micrometer, 0,46 micrometer, and 0,52 micrometer. There are many gaps that indicated as pores due to addition of SiO2. X-Ray Diffraction (XRD) testing found Fe3O4 compound identified as magnetite with cubic crystal and SiO2 as amorphous monoclinic structure. The addition 1,05 g of SiO2 has 0,84 nm of lattice parameter, 33,57 nm of crystal size, and 49,94% of crystallinity degree. The addition of SiO2 causes crystallite size get smaller. The test used X-Ray Fluorescence (XRF) shown there are composites with the most impurity elements like Al, Ti, and Zn can reduce performance. Vibrating Sample Magnetometer (VSM) testing found the material in this study was soft magnet characterized by narrow hysterical curve area, with parameters Hc = 184,89 Oe; Ms = 21,62 emu/g; Mr = 5,32 emu/g. The addition of SiO2 mass will reduced the value coercivity field. The test result using Ultraviolet - Visible (UV-Vis) found measured absorbance Methylene Blue occurred at maximum wavelength 664 nm, decreased average solution concentration up to 2 ppm with 87% absorption efficiency, that indicated the addition Silica affects selectivity and absorbance in degrading MB dye.