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Debarati Mitra

Bio: Debarati Mitra is an academic researcher from University of Calcutta. The author has contributed to research in topic(s): Starch & Pervaporation. The author has an hindex of 10, co-authored 29 publication(s) receiving 328 citation(s). Previous affiliations of Debarati Mitra include Bidhan Chandra Krishi Viswavidyalaya.
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Journal ArticleDOI
Abstract: BACKGROUND Lubricants manufactured conventionally from non-renewable mineral oil resources are not biodegradable and are liable to cause adverse environmental impacts. Biodegradable vegetable oils present a promising lubricant feedstock alternative. Waste cooking oil (WCO), which otherwise finds no immediate potential utilization can be successfully used to synthesize bio-lubricant. A novel synthetic method was developed by using the two-step process of C. rugosa lipase-mediated hydrolysis of WCO to free fatty acids (FFA) followed by Amberlyst 15H esterification of FFA with octanol. The octyl esters produced was the desired biolubricant. RESULTS The effect of different physico-chemical parameters like temperature, catalyst loading, agitation speed, molar ratio of octanol:FFA and the presence of different desiccants on the esterification reaction was examined. The optimum conditions to get maximum yield of biolubricant in minimum time were, octanol:FFA molar ratio = 3:1, temperature = 80 °C, catalyst = 2 g and desiccant (preferably silica gel powder) = 50% weight of FFA. Fourier transform infrared spectroscopy confirmed that the product formed was ester. CONCLUSION Biolubricant (octyl esters) was prepared efficiently from WCO by the two-step process developed. This novel approach represents a viable means of producing lubricants from wastes which are renewable in nature and can be an alternative to non-renewable mineral oil feedstocks. Copyright © 2012 Society of Chemical Industry

56 citations

Journal ArticleDOI
Abstract: The enzymatic esterification of free fatty acids (FFA) from waste cooking oil (WCO) and octanol in a solvent free medium has been investigated. A statistical experimental design method (Taguchi L 9 orthogonal array) was implemented to optimize the experimental conditions to maximize conversion of FFA to the corresponding octyl esters. The optimum conditions inferred from the Taguchi analyses were: temperature = 60 °C, Novozyme 435 = 5 wt% of FFA, molar ratio of octanol:FFA = 2.5:1 and reaction time = 3 h. The product octyl ester was characterized by Fourier transform infrared spectroscopy (FT-IR) and Nuclear magnetic resonance ( 1 H-NMR and 13 C-NMR). The physico-chemical properties of the waste cooking oil and the product ester (developed from WCO) were determined following standard methods. The results revealed that the developed octyl esters have improved viscosity index, pour point, flash point and oxidation stability when compared to that of the raw material (WCO). Moreover the product is biodegradable (>90% biodegradability). Thus the synthesized octyl esters have shown potential to be used as an environment-friendly biolubricant base-oil.

38 citations

Journal ArticleDOI
Sonakshi Maiti1, Dipa Ray1, Debarati Mitra1Institutions (1)
Abstract: The effect of crosslinkers on the biodegradation behavior of starch/polyvinyl alcohol (PVA) blend films was investigated by weight loss study, Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Starch/PVA films were prepared by solution casting method and 5 weight% of four different crosslinking agents like epichlorohydrin, formaldehyde, zinc oxide and borax were used in four different sets to crosslink the films. These crosslinked starch/PVA films were biodegraded in compost. Weight loss study showed that crosslinking retarded the biodegradation of the films in the first 15 days, but after that, there was a significant increase in weight loss. The DSC analysis revealed that the consumption of starch and consequent rearrangement of the PVA molecules were distinctly different in the crosslinked films due to the effect of different crosslinking agents.

28 citations

Journal ArticleDOI
Abstract: Micro/nano crystalline (MCC) cellulose particles were prepared from jute fibre by acid hydrolysis route. PMMA/cellulose (MCC) nanocomposites were prepared by in-situ polymerisation technique (IPC) and ex-situ dispersion technique (EPC). Biodegradation studies of IPC and EPC films were performed in a simulated aerobic compost environment for 60 days. IPC showed higher weight loss compared to that of EPC and unreinforced PMMA. The change in the molecular weights of PMMA in the biodegraded samples was determined by Gel Permeation Chromatography (GPC). The chemical structures of the biodegraded samples were examined with Nuclear Magnetic Resonance (NMR) study which indicated a significant change in the chemical structure of IPC after biodegradation. The surface morphologies of the samples before and after biodegradation were observed with Scanning Electron Microscope (SEM). The thermal transitions of PMMA in the biodegraded samples were examined with Differential Scanning Calorimetry (DSC).

27 citations

Journal ArticleDOI
Debarati Mitra1Institutions (1)
Abstract: Worldwide concerns over the environment have stimulated increasing interest both in academic and industry for the deep desulfurization of gasoline. Due to some inherent disadvantages associated with the conventional hydrodesulfurization, several non-conventional techniques are being tried by researchers. Pervaporation is such a recently developed technology for gasoline desulfurization. Its efficiency has attracted worldwide attention. Compared with conventional sulfur removal technology for gasoline, pervaporation exhibits advantages of little reduction of octane number, low energy consumption, environmental benefits, simple operation, and easy scale-up. The advances of pervaporative operation for gasoline desulfurization are reviewed in this paper. The membrane materials used for desulfurization include polysiloxane, poly(ethylene glycol), polyimide, polyurethane and organic-inorganic hybrid membranes. Analysis of the selectivity–permeability with varying feed composition and operating parameters are in...

25 citations

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TL;DR: This book by a teacher of statistics (as well as a consultant for "experimenters") is a comprehensive study of the philosophical background for the statistical design of experiment.
Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

12,326 citations

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Tiffany Abitbol1, Amit Rivkin1, Yifeng Cao1, Yuval Nevo1  +4 moreInstitutions (1)
TL;DR: This work discusses the main areas of nanocellulose research: photonics, films and foams, surface modifications, nanocomposites, and medical devices.
Abstract: Nanocellulose is of increasing interest for a range of applications relevant to the fields of material science and biomedical engineering due to its renewable nature, anisotropic shape, excellent mechanical properties, good biocompatibility, tailorable surface chemistry, and interesting optical properties. We discuss the main areas of nanocellulose research: photonics, films and foams, surface modifications, nanocomposites, and medical devices. These tiny nanocellulose fibers have huge potential in many applications, from flexible optoelectronics to scaffolds for tissue regeneration. We hope to impart the readers with some of the excitement that currently surrounds nanocellulose research, which arises from the green nature of the particles, their fascinating physical and chemical properties, and the diversity of applications that can be impacted by this material.

464 citations

Journal ArticleDOI
Khaliq Majeed1, Khaliq Majeed2, Mohammad Jawaid3, Azman Hassan1  +4 moreInstitutions (4)
01 Apr 2013-Materials & Design
Abstract: The increasing demand for new food packaging materials which satisfy people requirements provided thrust for advancement of nano-materials science. Inherent permeability of polymeric materials to gases and vapours; and poor barrier and mechanical properties of biopolymers have boosted interest in developing new strategies to improve these properties. Research and development in polymeric materials coupled with appropriate filler, matrix-filler interaction and new formulation strategies to develop composites have potential applications in food packaging. Advancement in food packaging materials expected to grow with the advent of cheap, renewable and sustainable materials with enhanced barrier and mechanical properties. Nanoparticles have proportionally larger surface area and significant aspect ratio than their micro-scale counterparts, which promotes the development of mechanical and barrier properties. Nanocomposites are attracting considerable interest in food packaging because of these fascinating features. On the other hand, natural fibres are susceptible to microorganisms and their biodegradability is one of the most promising aspects of their incorporation in polymeric materials. Present review article explain about different categories of nanoclay and natural fibre based composite with particular regard to its applications as packaging materials and also gives an overview of the most recent advances and emerging new aspects of nanotechnology for development of hybrid composites for environmentally compatible food packaging materials.

388 citations

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TL;DR: It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.
Abstract: The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2-C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.

355 citations

Journal ArticleDOI
John F. Nixon1Institutions (1)

316 citations

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Author's H-index: 10

No. of papers from the Author in previous years