Obtaining high crystalline ball milled H-Y zeolite particles with carbon nanostructures as a damping material

Abstract

Abstract Nanosized zeolites have attracted interest for many applications including catalysis due to their higher surface area and hence more accessible active sites compared to the microsize zeolite particles. Ball milling is considered as a fast and an efficient technique to reduce the particle size down to nanometer range. However, it is usually accompanied by the formation of large undesired flakes and slabs with a loss of crystallinity and surface area. This study attempts to utilize carbon nanostructures (CNS) as a damping material to overcome the reported drawbacks. The idea of using CNS as a damping material is novel as this is the first study which reports the usage of CNS as damping material that prevents the zeolite micro particles from severe loss in crystallinity compared to the same process without CNS addition. Utilization of CNS gives two-fold advantages pertaining to its flexibility and superior mechanical properties and secondly the ease by which it can be removed off through oxidation after ball milling. Different parameters such as the ball milling solvent and post treatment conditions were varied and studied to observe the changes in final ball milled particle properties, such as morphology, crystallinity index, surface area and particle size distribution. Optimum ball milling and post treatment conditions registered a final zeolite surface area of 1522 m2/g compared to the initial 850 m2/g for micron sized particles. Moreover, x-ray diffraction and high resolution transmission electron microscopy (HR-TEM) images revealed highly crystalline zeolite nano particles with a crystallinity index of 38% which is more than 30% higher than previously reported study of ball milled zeolite particles without any damping material.