Department of Chemistry

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

CO2 Research and Green Technologies Centre

Transesterification of waste cotton cooking oil (WCCO) is reported here. The GC-MS analysis of WCCO oil was studied and the major fatty acids were found to be Palmitic acid (28.26%) and Linoleic acid (43.14%). The molecular weight of the oil was 872.049 g/mol (GC-MS). The results showed maximum biodiesel yield of 96% when the reaction temperature, time, methanol/oil ratio and catalyst loading were fixed at 65°C, 45 min, 6:1 and 2% (wt.%) respectively. Partial purification of the biodiesel was performed for better engine performance and improved emission characteristics. The flash point and fire point of WCCO biodiesel were found to be 158°C and 165°C respectively. The brake thermal efficiency of WCCO10 biodiesel was 26.64% for maximum load and the specific fuel consumption for diesel was 0.3479 kg/kWh at maximum load. The use of biodiesel blends showed a reduction of carbon monoxide and hydrocarbon emissions and a marginal increase in nitrogen oxide emissions. © 2016 Informa UK Limited, trading as Taylor &amp; Francis Group.

VIT Unitversity

Vellore Campus

Biofuels

Biodiesel production from waste cotton seed oil: engine performance and emission characteristics

Transesterification of Waste Cotton Cooking Oil was reported. Different catalysts were studied. A maximum yield of 92% was reported for calcined eggshells catalyst. KOH and pistachio shell reported 91% and 84% respectively. The temperature, reaction time and catalyst loading were optimized to be 60°C, 60 min and 3% (wt.%) respectively for egg shell and pistachio shells. The methanol to oil molar ratio suitable molar for transesterification catalyzed by calcined eggshell was 9/1 and 12/1 for pistachio shell. By using low cost catalysts from waste resources such as eggshell and pistachio shell for biodiesel from waste cotton cooking oil gives higher yield of production. It seems to be relatively easy to separate up to higher production of biodiesel, time saving, energy efficient and eco-friendly. © 2016 IEEE.

2016 International Conference on Energy Efficient Technologies for Sustainability (ICEETS)

Comparative studies on biodiesel production from Waste Cotton Cooking Oil using alkaline, calcined eggshell and pistachio shell catalyst

A sequential treatment strategy designed by integrating sequencing batch (anoxic/aerobic operation) reactor (SBR) with bio-electrochemical treatment (BET) was studied to enhance the remediation of real-field pharmaceutical wastewater (PW). Study was carried out by feeding PW to two SBR systems operated under aerobic (SBRAe) and anoxic (SBRAx) microenvironments. Comparatively higher substrate degradation (SD) and multi-pollutant removal was observed with SBRAx (68.69%) in comparison to SBRAe (60.27%), due to the switching of bacterial metabolism that facilitates redox reactions. In order to further enhance the treatment efficiency, the effluents resulting from SBRAx were fed to BET1 and SBRAe to BET2. Relatively higher bioelectrogenic activity and SD were exhibited by BET1 (Voltage: 536 mV; current: 1.21 mA; SD: 75%) than BET2 (Voltage: 323 mV; current: 2.67 mA; SD: 73%). Self-induced bio-potential developed in BET system due to electrode assembly enabled higher organic and inorganic compounds removal than SBR. Study illustrated the advantage of integration strategy in enhancing the treatment of PW with simultaneous bioelectricity generation. © 2016 Elsevier Ltd

World University root node

Renewable Energy

Coupling of aerobic/anoxic and bioelectrogenic processes for treatment of pharmaceutical wastewater associated with bioelectricity generation

Treatment of dye bearing wastewater through biological machinery is particularly challenging due to its recalcitrant and inhibitory nature. In this study, functional behavior and treatment efficiency of bio-electrochemical treatment (BET) system was evaluated with increasing azo dye concentrations (100, 200, 300 and 500 mg dye/l). Maximum dye removal was observed at 300 mg dye/l (75%) followed by 200 mg dye/l (65%), 100 mg dye/l (62%) and 500 mg dye/l (58%). Concurrent increment in dye load resulted in enhanced azo reductase and dehydrogenase activities respectively (300 mg dye/l: 39.6 U; 4.96 μg/ml). Derivatives of cyclic voltammograms also supported the involvement of various membrane bound redox shuttlers, viz., cytochrome-c, cytochrome-bc1 and flavoproteins during the electron transfer. Bacterial respiration during BET operation utilized various electron acceptors such as electrodes and dye intermediates with simultaneous bioelectricity generation. This study illustrates the synergistic interaction of biocatalyst with electrode assembly for efficient treatment of azo dye wastewater. © 2016 Elsevier Ltd

Bioresource Technology

Functional behavior of bio-electrochemical treatment system with increasing azo dye concentrations: Synergistic interactions of biocatalyst and electrode assembly

The unprecedented climate change influenced by elevated concentrations of CO2 has compelled the research world to focus on CO2 sequestration. Although existing natural and anthropogenic CO2 sinks have proven valuable, their ability to further assimilate CO2 is now questioned. Thus, we highlight here the importance of biological sequestration methods as alternate and viable routes for mitigating climate change while simultaneously synthesizing value-added products that could sustainably fuel the circular bioeconomy. Four conceptual models for CO2 biosequestration and the synthesis of biobased products, as well as an integrated CO2 biorefinery model, are proposed. Optimizing and implementing this biorefinery model might overcome the limitations of existing sequestration methods and could help realign the carbon balance. © 2016 Elsevier Ltd.

Trends in Biotechnology

A Circular Bioeconomy with Biobased Products from CO2 Sequestration

Metal contamination is a global problem because metals are widely used, from building materials to information technology, and the bioavailable fraction of metals is increasing. The development of infrastructure highly depends on metals because of their useful properties. Because of metals necessity for infrastructure, industrialization causes a huge increase in metal use and waste. Before industrialization the functions were not mechanized and were primarily based on agriculture. As a result of mechanization, the use of metals increased tremendously and then later fell off or at a higher per-capita gross domestic product (GDP), as represented by the environmental Kuznets curve. The inverted U-shaped environmental Kuznets curve best models the amount of pollution emitted by a country as it develops, and shows a drastic increase in metals use followed by a gradual decline owing to regulatory policy. After 1974 there was a significant decrease in the demand for most metals except aluminum, which may correlate with slower growth in the GDP.Because of economic development in India, a many-fold increase in metal production has taken place for iron, aluminum, zinc, and copper, for example. With the increased production of metals comes an increase in environmental hazards. Metals are naturally found in soils but usually in concentrations below those posing significant health risks. Problems arise when metals are highly concentrated and bioavailable, both of which are a direct consequence of anthropogenic extraction and the use of these metals. Therefore, the slow, naturally occurring release of metals from ores will have a low fraction of bioavailable metals whereas drastic increases in metals from anthropogenic sources may have a high fraction of bioavailable metals. Because the development of infrastructure currently depends on the use of metals, the possible rate of development while maintaining a healthy environment depends on developing recycling and recovery technologies for metal contaminants. This is especially true for India, where the high population density and enormous growth over past decades has led to widespread metal contamination. India is entering the "developed phase.". Metal recovery to prevent pollution via developing cost-effective strategies to meet the environmental challenges of India's rapid growth is critical. Therefore, this chapter:. 1.Uses currently available data to predict major sources of metal contamination in the water, soil, and air in India2.Predicts how these sources may change in the near future3.Determined how these sources pose a threat by entering human food and water, as well as the air we breathe4.Reviews evolving scientific knowledge about recovery of metals to prevent pollution. © 2016 Elsevier Inc. All rights reserved.

Environmental Materials and Waste: Resource Recovery and Pollution Prevention

Metalliferous Waste in India and Knowledge Explosion in Metal Recovery Techniques and Processes for the Prevention of Pollution

Microbial electrochemical technologies have gained much attention in the recent years during which basic research has been carried out to provide proof of concept by utilizing microorganisms for generating bioenergy in an electro redox active environment. However, these bio-electrocatalyzed systems pose significant challenges towards up-scaling and practical applications. Various parameters viz., electrodes, materials, configuration, biocatalyst, reaction kinetics, fabrication and operational costs, resistance for electron transfer etc. will critically govern the performance of microbial catalyzed electrochemical systems. Majorly, the surface area of electrode materials, biofilm coverage on the electrode surface, enrichment of electrochemically active electrode respiring bacteria and reduction reactions at cathode will aid in increasing the reaction kinetics towards the upscaling of microbial electrochemical technologies. Enrichment of electroactive microbial community on anode electrode can be promoted with electrode pretreatment, controlled anode potential or electrical current, external resistance, optimal operation temperature, chemical additions and bioaugmentation. Inhibition of the growth of methanogens also increases the columbic efficiency, an essential parameter that determines the efficacy of bioelectricity generation. Considering the practical implementation of these microbial electrochemical technologies, the current review addresses the challenges and strategies to improve the performance of bio-electrocatalyzed systems with respect to the operational, physico-chemical and biological factors towards scale up. Besides, the feasibility for long term operation, the scope for future research along with the operational and maintenance costs are discussed to provide a broad spectrum on the role of the system components for the implementation of these bio-electrochemical technologies for practical utility. © 2015 Elsevier Ltd.

Renewable and Sustainable Energy Reviews

Microbial electrochemical technologies with the perspective of harnessing bioenergy: Maneuvering towards upscaling

Computational fluid dynamics analysis of the complex flows in a cryogenic turboexpander is essential for any improvement in its performance. This includes a detailed analysis of the unsteady turbulent flows imparted mainly by the rotor stator interactions. The flow unsteadiness due to rotor stator interaction is caused by the relative motion between the stationary and rotating component, interaction of the turbine wheel blades with the wakes and vortices generated by the upstream blades and at trailing edges. In order to minimize the loss generation due to this unsteadiness, the vaneless space length at the nozzle-Turbine wheel interface and the length of the straightening portion at the turbine wheel-diffuser interface should be optimised considering the mechanical constraints. In this paper three dimensional unsteady viscous flow analysis of a helium cryogenic turboexpander was carried out using Ansys CFX to investigate the origin and flow mechanisms that cause these unsteady phenomena. The analysis has been done for three different lengths of straightening duct at the turbine wheel diffuser interface. The performance parameters from the computational results were compared and analysed to understand the flow characteristics in each case. Copyright © 2016 by ASME.

Proceedings of the ASME Turbo Expo

Helium turboexpander for cryogenic refrigeration and liquefaction cycles: Transient analysis of rotor - stator interaction

A membrane-less anoxic bioelectrochemical treatment (AxBET) system was evaluated to study the influence of bioelectrogenic activity during the treatment of chemical wastewater (CW). Increment in power generation was observed with increase in substrate loading (61-204 mW/m2) indicating the ability of anodic bacteria in BET system to utilize the complex chemicals as the sole carbon source. Derivative analysis of voltammograms depicted by positive and negative peak potentials which relate to the extracellular electron transport sites (EETs) that presumably play a significant role in electron transfer. These self-driven redox mediators varied with respect to the substrate load. The microbial population was dominated by anaerobic microorganisms which are commonly involved in effluent treatment plants during the initial phase of operation. A gradual shift in the microbial community was observed towards enrichment of electrogenically active bacteria belonging to phyla viz., Firmicutes and Proteobacteria after prolonged operation. Shannon Index and principal component analysis correlated with the microbial profile studies. The feasibility of self-driven bioremediation of chemical wastewater in an AxBET system demonstrated bioelectricity production along with multipollutant removal simultaneously. © 2014 Elsevier Ltd.

Water Research

Bioelectrogenic role of anoxic microbial anode in the treatment of chemical wastewater: Microbial dynamics with bioelectro-characterization

Present study illustrates the significance of biocatalyst's reductive behaviour in the degradation of dye molecules using glucose as co-substrate. An anaerobic system was operated at a dye concentration of 50mg/l with an organic loading rate (OLR) of 1.36kg COD/m3-day. Decolourization and COD removal efficiencies were observed to be 42% and 48% respectively. Azo reductase (18.9U) and dehydrogenase enzyme (1.4μg/ml) activities showed increment with operation time. Anaerobic microenvironment showed dye reduction converting them into aromatic amines. The presence of mediators viz., cytochromes, quinines and Fe-S proteins depicted in the cyclic voltammetry profiles played a crucial role in transfer of electrons for the reduction of dye molecules. Bio-electro kinetic profiles obtained through Tafel analysis showed persistent reduction behaviour, which is in good correlation with dye degradation in the anaerobic microenvironment. © 2015 Elsevier Ltd.