Synthesis of aluminium oxide nanoparticles and iron based magnetic aluminium oxide nanocomposites by solution combustion method and applications

In recent years, nanotechnology is attracting many researchers due to its increasing applications areas. Nanotechnology provides a variety of applications areas in many branches of science such as material science, chemical engineering, electrical engineering, pharmacology, organic chemistry, molecular biology, micro-fabrication and etc. Aluminium oxide or alumina as a metal oxide is composed of aluminium and oxygen atoms and its chemical formula is indicated Al2O3. Aluminium oxide has many crystal phases. However, alpha and gamma phase are the most common crystalline phases of aluminium oxide. The alpha phase aluminium oxide is known as the most stable one. The gamma phase aluminium oxide is mostly defined as amorphous and porous structure of aluminium oxide. Aluminium oxide nanoparticles are widely used in several applications due to their large surface area, homogeneous particle size distribution, spherical morphology and porous structure. There are many novel application areas have appeared in nanotechnology by using magnetic nanoparticles. In particular, iron based aluminium oxide nanocomposites allows for many implementations because of its superior magnetic properties. These nanocomposites are utilized as catalyst, drug carrier, adsorbent and etc. In the present study, aluminium oxide nanoparticles and iron based magnetic aluminium oxide nanocomposites were synthesized by solution combustion method using various fuels at various fuel amounts. Aluminium oxide nanoparticles were synthesized with two fuel types as urea and glycine at their various amounts, respectively. On the other hand, iron based magnetic aluminium oxide nanocomposites were synthesized with three fuel types as urea, glycine and sucrose at their various amounts, respectively. For the characterization studies of the synthesized samples, the following devices were used: X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), Thermogravimetric and Differential Thermal Analysis (TG/DTA) and Brunauer-Emmett-Teller (BET). From the characterization studies, aluminium oxide nanoparticles and iron based magnetic aluminium oxide nanocomposites successfully synthesized by solution combustion method with nanoscale particle size. Moreover, iron based magnetic aluminium oxide nanocomposites synthesized by solution combustion method using stoichiometric amount of glycine as a fuel, have higher porous surface, small and homogeneously distributed particle size compared to other synthesized samples. After evaluation of the data obtained from XRD and SEM analysis and magnetic attraction of the samples synthesized by solution combustion method, the sample synthesized using stoichiometric amount of glycine as a fuel (coded as SC-FA-G2) was chosen for further adsorption studies. For this purpose, Reactive Blue 19 (RB19) dye removal percentages at various process conditions were investigated onto SC-FA-G2 from aqueous solutions. The experimental set was planned by using a Design Expert 11.0 experimental design programme according to the Response Surface Methodology (RSM). According to Box-Behnken Design, 17 experiments were performed to investigate the effects of various process conditions. The effects of pH, temperature and adsorbent amount of SC-FA-G2 were investigated on the adsorption process, and a model was developed using the Box-Behnken methodology. Besides, the adsorption isotherm models and kinetic models were examined according to the data obtained from the adsorption experiments at the optimum process conditions obtained. As a result, after evaluation of the experimental data obtained from the adsorption studies, RB19 dye removal percentage onto SC-FA-G2, was found as 100 % at pH of 2, 400 mg adsorbent amount/50 mL and 25 C. The maximum adsorption capacity value (Qmax) for this sample was calculated as 55.248 mg/g.