Binitha N. Narayanan

Utilization of palm empty fruit bunch for the production of biodiesel from Jatropha curcas oil

Transesterification reaction of Jatropha curcas oil with methanol was carried out in the presence of ash generated from Palm empty fruit bunch (EFB) in a heterogeneous catalyzed process. The ash was doped with KOH by impregnation to achieve a potassium level of 20 wt.%. Under optimum conditions for the EFB-catalyzed (65 °C, oil/methanol ratio of 15, 90 min, 20 wt.% EFB ash catalyst) and the KOH-EFB-catalyzed reactions (65 °C, oil/methanol ratio of 15, 45 min, 15 wt.% of KOH doped EFB ash), biodiesel (>98%) with specifications higher than those stipulated by European biodiesel quality standard EN 14214 was obtained.

Au/TiO2 Reusable Photocatalysts for Dye Degradation

Nanogold doped TiO2 catalysts are synthesized, and their application in the photodegradation of dye pollutants is studied. The materials are characterized using different analytical techniques such as X-ray diffraction, transmission electron microscopy, UV-visible diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. The results revealed the strong interaction between the metallic gold nanoparticles and the anatase TiO2 support. Au doped systems showed very good photoactivity in the degradation of dye pollutants under UV irradiation as well as in sunlight. A simple mechanism is proposed for explaining the excellent photoactivity of the systems. The reusability studies of the photocatalysts exhibited more than 98% degradation of the dye even after 10 repeated cycles.

Sodium aluminate from waste aluminium source as catalyst for the transesterification of Jatropha oil

Sodium aluminate is prepared from waste aluminium foils following an easy and low cost method. The crystalline NaAlO2 was found to have a uniform and highly porous morphology as revealed from the various characterization techniques. The developed catalyst showed high efficiency in the production of biodiesel from Jatropha oil. The reaction parameters were varied to find out suitable conditions for the transesterification reaction. The catalyst showed heterogeneity in methanol and is found to be reusable.

Sucrose-mediated mechanical exfoliation of graphite: a green method for the large scale production of graphene and its application in catalytic reduction of 4-nitrophenol

Graphene is one of the most important carbon nanostructures with potential applications in various fields. Although a significant number of efforts have been reported, a simple and economical strategy for the large scale production of graphene is still a challenge. Herein, we report an incredibly simple and green method for the large scale production of graphene by the ball-milling of graphite with sucrose as an auxiliary milling agent, plausibly assisted by the interaction of the sucrose molecules with the graphitic surface layers by virtue of non-conventional CH/π or OH/π interactions. Upon calcination, the graphene–sucrose mixture directly yields mono- and few-layer graphene nanosheets. The graphene thus produced forms stable suspensions in various organic solvents, enabling its further processing and fabrication. It is also demonstrated that the graphene produced can be used successfully for heterogeneous catalytic reduction of 4-nitrophenol.

Single step production of biodiesel from used cooking oil

Single stage production of biodiesel is achieved by the transesterification of used cooking oil. The presence of high free fatty acid (FFA) content showed insignificant effect on the transesterification reaction, and even the FFA was effectively converted into the methyl ester under basic medium. The reaction was done in a closed stainless steel reactor, where the solvothermal condition of methanol was achieved at the reaction temperature (65°C). The FAME (fatty acid methyl ester) content was more than 98% within 1.5 h of the reaction.

Nitrogen-doped sulphonated 3-dimensional holey graphene nanoarchitecture for selective oxidation of ethylbenzene

Herein, we report a facile and novel strategy for the synthesis of 3-dimensional holey graphene nanoarchitecture, which is appropriately functionalized with nitrogen and sulfur via hydrothermal-assisted chemical etching of graphene oxide using ammonium persulfate. The chemical functionalization of the material was proved from XPS and FTIR spectral analyses. Sulfur exists as sulfonic acid group, whereas nitrogen got doped into the graphene network as revealed from the XPS analysis. The 3-dimensional morphology as well as porous nature of the developed material was confirmed from SEM and TEM images, respectively. Raman spectral analysis indicated the defective nature of the holey graphene as expected. Both N doping and sulfonation could enhance the utility of holey graphene as a carbocatalyst when compared to graphene oxide or reduced graphene oxide. The prepared material showed high catalytic efficiency towards the selective oxidation of ethylbenzene to acetophenone.

Statistical optimization for lithium silicate catalyzed production of biodiesel from waste cooking oil

Lithium silicate is one of the suitable heterogeneous catalysts for biodiesel production. The possibilities of large number of combinations of different reaction parameters make the optimization of biodiesel production process over various heterogeneous catalysts highly tedious, necessitating the development of alternate strategies for parameter optimization. Here, Box-Behnken design (BBD) coupled with response surface methodology (RSM) is employed to optimize the process parameters required for the production of biodiesel from waste cooking oil using lithium silicate as catalyst. Simple method of impregnation was performed for the material preparation and the catalyst was analyzed using different techniques. It was found that the activity is directly proportional to the basicity data obtained from temperature programmed desorption (TPD) of CO2 over various catalyst systems. The material exhibits macroporous morphology and the major crystalline phase of the most active catalyst was found to be Li2SiO3. The effects of different reaction parameters were studied and a biodiesel yield of 100% was obtained under the predicted optimum reaction conditions of methanol : oil molar ratio 15 : 1, catalyst amount 7 wt%, reaction temperature 55 °C and reaction time 2.5 h. The validation experiments showed a correlation coefficient of 0.95 between the predicted and experimental yield of biodiesel, which indicates the high significance of the model. The fuel properties of biodiesel obtained under the optimum conditions met the specifications as mentioned in ASTM D6751 and EN 14214 standards. Catalyst heterogeneity and low reaction temperature are the major attractions of the present biodiesel preparation strategy.

Functionalized carbon dot adorned coconut shell char derived green catalysts for the rapid synthesis of amidoalkyl naphthols

A one pot synthesis of carbon dot incorporated porous coconut shell char derived sulphonated catalyst is reported here for the first time and is effectively used in the multicomponent synthesis of amidoalkyl naphthol. Macroporous nature of the char is revealed from scanning electron microscopic (SEM) analysis, whereas the dispersion of carbon dots (CDs) on the porous coconut shell char is confirmed from the high resolution transmission electron microscopic (HRTEM) analysis. Fluorescence emission spectrum further confirmed the presence of CDs in the catalyst. Fourier-transform infrared (FTIR) spectral analysis of the materials indicated that sulphonation occurred both to the CD and to the porous char. X-ray photo electron spectroscopic (XPS) analysis of the most active catalyst confirmed the presence of both sulphonic acid and carboxylic acid groups in the catalyst. The coconut shell char derived materials prepared by varying the amount of H2SO4 are successfully utilized as efficient alternative green catalysts for the multicomponent reaction, where excellent activity in amidoalkyl naphthol synthesis is obtained within short periods under solvent free reaction conditions. A maximum yield of 98% is obtained in the synthesis of N-[Phenyl-(2-hydroxy-naphthalen-1-yl)-methyl]-benzamide, the representative amidoalkyl naphthol, with the best catalyst within 3 min of reaction. The catalyst is highly active for the reactions carried out with varieties of aldehydes and amides with a product yield in the range of 88-98%. The best catalyst system retained more than 90% of its initial activity even upto 6th repeated run.

Nanogold Loaded, Nitrogen Doped TiO2 Photocatalysts for the Degradation of Aquatic Pollutants Under Sun Light

Along with the rapid development of industry, various issues related to energy and environment got generated which are now grown into a significant level. The hazardous waste materials with high concentrations are being discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds. The World Bank estimates that 17 to 20 percent of industrial water pollution comes from textile dyeing and treatment causing a major global problem. A facile and cheap method for removing inorganic and organic pollutants from wastewater has much relevance in modern world. Dyes are an important class of aquatic pollutants. Its complexity and variety makes it difficult to find a unique treatment procedure that entirely covers the effective elimination of all types of dyes. Particularly, biochemical oxidation suffers from significant limitations since most dyestuffs commercially available have been intentionally designed to resist aerobic microbial degradation and also they may get converted into toxic or carcinogenic compounds. The physical methods such as flocculation, reverse osmosis and adsorption on activated charcoal are nondestructive and merely transfer the pollutant to other media, thus causing secondary pollution (Binitha, 2009, as cited in Belver, 2006) Heterogeneous photocatalysis with various oxide semiconductor photocatalysts is an efficient and rapidly expanding purification technique for water and air. Semiconductor-oxides are a popular class of materials because of their functionalities and applications in the field of photocatalysis and generation of photoelectricity.