Process optimization with acid functionalised activated carbon derived from corncob for production of 4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane and 5-hydroxy-2,2-dimethyl-1,3-dioxane.

In this article, a two-step activated carbon preparation technique from corncob has been elucidated. The derived catalysts AAC-CC has been characterized using various techniques for the determination of their structural properties and compared with AC-CC, already reported with another article. The conjugated boat structure of AAC-CC resulted in a very high surface area (779.8 m2/g) and high pore volume (0.428 cc/g). This unveils the suitability of AAC-CC as better among the two catalytic pathways for solketal production. The activated carbons so prepared have been used for the valorization of glycerol to produce 2,2-Dimethyl-1,3-dioxolane-4-methanol (solketal), oxygenated additives to fuel. The face-centered composite design (FCCD) of RSM was applied for the optimization of the reaction parameters for the ketalisation reaction using AAC-CC as a catalyst. From the optimized results, the acidic catalyst AAC-CC resulted in a glycerol conversion, i.e. 80.3% under the actual laboratory experiment. Moreover, the catalyst could be reused for three consecutive batch reactions without (< 5%) much reduction of activity and no distinctive structural deformity.

Valorisation of crude glycerol to value-added products: Perspectives of process technology, economics and environmental issues.

The enormous production of glycerol, a waste stream from biodiesel industries, as a low-value product has been causing a threat to both the environment and the economy. Therefore, it needs to be transformed effectively and efficiently into valued products for contributing positively towards the biodiesel economy. It can either be converted directly into competent chemicals or can be used as a feedstock/precursor for deriving valuable derivatives. In this review article, a technical evaluation has been stirred up, various factors and technologies used for producing value-added products from crude glycerol, Environmental and economic aspects of different conversion routes, cost factors and challenges of integration of the different routes for biorefinery have been reviewed and elaborated. There are tremendous environmental benefits in the conversion of crude glycerol via the biochemical route, the product and residue become eco-friendly. However, chemical conversions are faster processes, and economically viable if environmental aspects are partially ignored.

Rib shaped carbon catalyst derived from Zea mays L. cob for ketalization of glycerol.

In the present work, the activated carbon was prepared from agricultural waste by an activation method using sodium hydroxide as an activating agent. The prepared AC-CC has been characterized by N2 adsorption-desorption isotherms, thermogravimetric analysis (TGA-DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD). The porous carbon was thus obtained with a specific surface area of 13.901 m2 g-1 and a total pore volume of 0.011 cm3 g-1. The catalytic activity of the activated carbon has been studied for the ketalization of glycerol and provides maximum glycerol conversion of 72.12% under optimum conditions. The activity of the AC-CC also did not change appreciably for three consecutive batch reaction sequences. The spent catalyst was further analysed for elemental composition using XPS and surface morphology was studied using SEM. There was little deformation in the structure although the percentage of carbon remains almost same (∼72%) as that of the original catalyst, which contributes to the reduction of conversion efficiency of glycerol to solketal by 5% in the 3rd consecutive reaction. Thus, AC-CC obtained from Zea mays L. cob could be a very promising renewable catalyst for glycerol conversion into solketal as a fuel-additive.

Assessment of a Novel Algal Strain Chlamydomonas debaryana NIREMACC03 for Mass Cultivation, Biofuels Production and Kinetic Studies.

A novel microalgae strain Chlamydomonas debaryana (KJ210856) was isolated from a freshwater lake of Punjab, India, and cultivated considering climatic sustainability and inherent adaptability concern. C. debaryana was grown in a 30-L indoor photobioreactor to study the mass cultivation prospect and biofuel potential. Physicochemical characterization of biomass and the lipid was performed with effect to nitrogen stress. It showed a higher biomass yield (1.58 ± 0.02 g L(-1), dry weight) and twofold increase in lipid yield (552.78 ± 9 mg L(-1)) with 34.2 ± 0.19 % lipid content under nitrogen deficient condition. Strikingly, increase in triglycerides achieved with nitrogen depletion containing over 96 % of total fatty acids (C 14, C 16, and C 18). Proximate and ultimate analysis suggested the presence of relatively higher volatile matter and carbon-hydrogen ratio. Furthermore, lower moisture and ash content signified C. debaryana biomass has promising features towards biofuel applications. The pyrolytic behavior of the whole biomass was also studied using thermogravimetric analyzer (TGA) and kinetic parameters were estimated using different methods. Promising growth rate and lipid yield leading to feasible biofuel feed stock production in indoor photobioreactor along with autosediment potential of cells validates C. debaryana NIREMACC03, a potential strain for mass cultivation.

Recent advances in material science for developing enzyme electrodes.

The enzyme-modified electrode is the fundamental component of amperometric biosensors and biofuel cells. The selection of appropriate combinations of materials, such as: enzyme, electron transport mediator, binding and encapsulation materials, conductive support matrix and solid support, for construction of enzyme-modified electrodes governs the efficiency of the electrodes in terms of electron transfer kinetics, mass transport, stability, and reproducibility. This review investigates the varieties of materials that can be used for these purposes. Recent innovation in conductive electro-active polymers, functionalized polymers, biocompatible composite materials, composites of transition metal-based complexes and organometallic compounds, sol-gel and hydro-gel materials, nanomaterials, other nano-metal composites, and nano-metal oxides are reviewed and discussed here. In addition, the critical issues related to the construction of enzyme electrodes and their application for biosensor and biofuel cell applications are also highlighted in this article. Effort has been made to cover the recent literature on the advancement of materials sciences to develop enzyme electrodes and their potential applications for the construction of biosensors and biofuel cells.