Synthesis of Mn(II)-Loaded TixSi1-xO4 Composite Acting as a Visible-Light Driven Photocatalyst

Misriyani Misriyani (Department of Chemistry, Faculty of Mathematics and Natural Sciences, Hasanuddin University, Jl. Perintis Kemerdekaan KM 10, Makassar 90245)
Eko Sri Kunarti (Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Sekip Utara PO BOX BLS 21 Yogyakarta 55281)
Masahide Yasuda (Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Gakuen-Kibanadai Nishi, Miyazaki 889-2192)

Indonesian Journal of Chemistry
Vol 15, No 1 (2015)

The synthesis and characterization of Mn-loaded TixSi1-xO4 (x= 0.4-0.8) composites and a preliminary study of an activity testing their ability to work as photocatalysts for the degradation of methylene blue (MB) have been studied. Synthesis was conducted by the sol-gel method at room temperature using tetraethyl orthosilicate, titanium tetraisopropoxide, and manganese(II) chloride as precursors followed by thermal treatment at 500 °C. The characterizations were performed by X-ray diffraction, FT-IR spectrometry, UV-Vis diffuse reflectance spectrometry and a surface area analyzer. The photocatalytic activity test of composites for degradation of MB was carried out in a closed reactor equipped with UV and visible lights. In this test, the effects of ratio of Ti/Si composites, Mn2+ ion concentration, pH, and time of irradiation on the effectiveness of photodegradation of MB were studied. The results indicated that Mn-Ti0.6Si0.4O4 composite could be synthesized through the sol-gel method followed by thermal treatment with a molar ratio of Ti/Si=60/40 and the optimum concentration of manganese was 2.5 wt%. The Mn-Ti0.6Si0.4O4 composite significantly increased the photodegradation of MB at pH 10, with a percent degradation of 84.41% for 30 min under irradiation of visible light. The percent degradation of Ti0.6Si0.4O4 was only 18.23% under irradiation of visible light.