Biodiesel is considered as an alternative fuel which can replace the traditional fuels easily with its less hazardous effects and economical pricing. This study compares an ultrasonic‐assisted catalytic transesterification using ZnO nanocatalyst for waste cooking oil (WCO) with the conventional stirring method. The structural and morphological characterizations of prepared catalysts were done by XRD and FESEM with EDX methods. The effect of reaction parameters such as oil to methanol ratio, catalyst amount and reaction time was investigated to optimize the transesterification conditions. GC/MS and FTIR analysis have been carried out to identify and confirm the presence of fatty acid methyl esters (FAME) under optimum conditions. The FAME conversion yield up to 96% under ultrasonication method was calculated. Two important fuel properties like density and viscosity were analyzed and compared with the standard biodiesel. These studies provided the clear evidence that WCO can be employed as a substantial source of biodiesel as fuel in diesel engines. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1176–1182, 2018

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This work demonstrates the fabrication of a composite nanomaterial consisting of spherical silica nanoparticles decorated onto the graphene sheets which has been prepared by the sonication-assisted method. Graphene/silica nanocomposites were fabricated by the hydrolysis of tetraethyl orthosilicate in the presence of graphene oxide which has been obtained by modified Hummer's method. The obtained nanostructures were characterised by the X-ray diffraction (XRD), Raman spectroscopy, Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD analysis depicts the coexistence of silica and graphene in the composite material. The morphology of synthesised silica-graphene nanocomposites was characterised by SEM and TEM. All images have been observed in the presence of SiO 2 nanoparticles of similar sizes which were grafted on the surface of graphene effectively. More significantly, the BET analysis revealed that the silica decorated graphene nanocomposites exhibit enhanced surface area than bare silica and graphene.

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Modern ultrasound induction is very much useful in crystallization process. It uses piezoelectric transducers or quartz crystals to convert mechanical waves to electrical signals and vice versa. Growth of a crystal is environment dependent. The characteristics of grown crystals depend on impurities, temperature, preparation of the solution and mechanical agitation. The properties and size of a crystal can be tailored by controlling any one or all the above factors. The most interesting fact is that the ultrasound influences the properties and size of a crystal. It is found that the characteristics are improved and tailored for a specific need of the industry when a crystal is grown by radiating ultrasonic wave. In some cases, it produces nanocrystals. We used a device which generates the Ultrasonic wave of 15 MHz, which is applied to the crystal right from the time before nucleation till the crystal formation. The Dextrose monohydrate crystals are grown by conventional slow cool batch method. In the same slow cool batch method, Ultrasonic waves of 15 MHz are allowed to pass, influence the nucleation, crystal formation and growing process. The crystal formation process under the exposure of Ultrasound is allowed to continue for a sufficiently long time to yield the desired nanocrystals. The FTIR, UV, microhardness and SEM analysis are taken for the crystals with and without ultrasound.