Copyright © 2018 Authors. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. International Journal of Engineering & Technology, 7 (4.37) (2018) 22-25 International Journal of Engineering & Technology Website: www.sciencepubco.com/index.php/IJET Research paper Hydrothermal Synthesis of TiO 2 /Al 2 O 3 Nanocomposite and its Application as Improved Sonocatalyst Assist. Prof. Ali S. Ali 1* , Alaa J. Mohammed 2 , Haider R. Saud 3 1,2 Physics Dept., College of Sci., Al-Muthanna University, Al-Muthanna, Iraq. 3 Chemical Dept. , College of Sci., Al-Muthanna University, Al-Muthanna, Iraq *Corresponding author E-mail: alisbasrah@yahoo.com Abstract The powder of TiO2/α-Al2O3 nanocomposite for Sonocatalysis decolorisation was successfully achieved in the Hydrothermal autoclave reaction for 6 hours and completely crystallized into Anatase phase at temperature of 220oC which more lower than normal required calcination temperature 500oC. The TiO2/α-Al2O3 nanoparticles examined using FT-IR, SEM, TGA, X-ray diffraction studies( XRD), The results indicate the formation of nanocomposite with tetragonal Anatase phase and average crystal size of 21.4nm for TiO2/α-Al2O3 while the average crystal size of 8.1nm for Al2O3, which are calculated according to Scherrer’s equation. This powder was mixed with methylene blue to study the effect of nanocomposite on it, the prepared nanocomposite show highly decolorisation percentage of meth- ylene blue solution. Keywords: Anatase, Hydrothermal, Methylene Blue, Nanocomposite, Sonocatalysis, TiO2/α-Al2O3. 1. Introduction Nanocomposites material formed by blending either polymers, metals, or ceramic with nanoparticles materials are attractive ma- terial due to create new material with new properties (D. C. C. Okpala 2014). Nanocomposite can classify into three different categories, according to their matrix materials to polymeric, metal- lic, and ceramic nanocomposites (T. Hanemann et al.,2010). The molecular structure and the stereo-hindrance of a matrix material play a major role in selection of the suitable matrix (I. Pleşa et al.,2016). The present of functional groups in the matrix molecular structure can ease the reaction with nanoparticles, while the ste- reo-hindrance of the matrix structure may prevent the nanoparti- cles from forming aggregation, thus enhancing the dispersion and uniformity of nanoparticles on the surface of matrix (J. Di et al., 2014). There are numeric methods to synthesis nanocomposite, such as sol-gel, direct mixing of matrix and nanofiller, and Inter- calation Method (M. Tanahashi 2010). Sol-gel is the most famous and flexible route for the production of nano metal oxides and nanocomposite especially, titanium oxides via the inorganic titani- um tetra chloride (TiCl4) or organometallic titanium tetra alkoxide (Ti (O-alkyl)4) precursors (T. K. Tseng et al.,2010). In a typical sol–gel process, organometallic precursors (Ti (O-alkyl)4) is sub- jected to a hydrolysis–condensation reaction to form a colloidal suspension of titanium particles, subsequent to which these parti- cles condense in a new gel form (H. S. Chen et al., 2012). in spite of simple the advantages of sol-gel, it has some drawbacks such as, shrinkage that happened during drying and sintering (M. Aparicio et al., 2012). The powder of TiO2 formed by sol-gel route requires higher temperatures (>400°C) for completely crystalliza- tion of the final product (G. Yudoyono et al., 2016). The crystalli- zation step can be done by another technique through hydrother- mal crystallization in supercritical water conditions pressures us- ing Morey autoclave (K. Byrappa et al., 2007). Shuxi Dai et.al were reported that preparation of high crystalline TiO2 nanoparti- cles through a facile inorganic acid-assisted hydrothermal treat- ment using The autoclave under heated and maintained at 150°C for 24 h(S. Dai et al., 2010). The oxidation of organic compounds by ultrasound irradiation is one of the famous advanced oxidation process (AOP) that produce oxidative environment (i.e., produce reactive oxygen species) via cavitation process (B. Miljevic et al., 2014). Hydroxyl free radi- cals are one of these reactive oxygen species, which are unselec- tively attack the wide range of organic compounds in water (O. Moumeni et al., 2012). Highly reactive hydroxyl radicals which have one free electron pair are strong oxidizing agents and provide the main driving mechanism for degradation of various organic pollutants (M. M. Mahlambi et al., 2015). The presence of semi- conductor (i.e., TiO2, ZnO) particles enhanced the process of break up the micro bubbles created by the ultrasound irradiation into smaller bubbles, thus increasing the quantity of high of re- gions of high temperature and pressure, This leads to produce additionally amount of hydroxyl radicals which will attack the pollutant and resulting in degradation of the pollutant (D. Teresa et al., 2013). In this paper, we have study the focused on the Son- ocatalytic of TiO2–Al2O3 nanocomposite which prepared by hy- drothermal method. As improving catalytic properties of prepared nanocomposite, the Sonocatalysis degradation of pollutant will be more efficient. 2. Materials and Methods Materials: Hydrochloric acid (HCl, 37%), isopropyl alcohol ((CH₃)₂CHOH, 99.5%), and methylene blue were (C16H18ClN3S, 99%) purchased from BDH. nano-alumina (Al2O3), and titanium (IV) tetraisopropoxide (abbreviation: TTIP; molecular formula: Ti[OCH(CH3)2]4, 97%) and were purchased from Sigma-Aldrich and were used as received.