M.P. Singh

Inter- and intra-specific associations of non-human primates in Anaimalai hills, South India

The study reports on the inter- and intra-specific associations of Macaca radiata, M. silenus, Presbytis entellus and P. johnii in the Anaimalai Hills of south India. Whereas M. silenus and P. entellus are found to be habitat specialists inhabiting rain forest and deciduous forest respectively, IM. radiata and P. johnii are habitat generalists found in almost every forest type. Whereas individual groups of macaques can be found to occur in absence of any other groups of their species, the langurs occur only in large intra-specific associations. It is suggested that M. silenus can be considered as an umbrella species for the management of the entire ecosystem of these hills.

Electro-biocatalytic treatment of petroleum refinery wastewater using microbial fuel cell (MFC) in continuous mode operation

Refinery wastewater (RW) treatment in microbial fuel cell (MFC) was studied in batch mode operation followed by continuous mode operation with 8h and 16h hydraulic retention time (HRT). The MFC performance was evaluated in terms of power density, organics removal, specific contaminants (oil & grease, phenol and sulfide) removal and energy conversion efficiency with respect to operation mode. Higher power density of 225±1.4mW/m2 was observed during continuous mode operation with 16h HRT along with a substrate degradation of 84.4±0.8% including the 95±0.6 of oil content. The columbic efficiency during this operation was about 2±0.8% and the projected power yield was 340±20kWh/kg CODR/day. Batch mode operation also showed good substrate degradation (81±1.8%) but took longer HRT which resulted in significantly low substrate degradation rate (0.036±0.002kgCODR/m3-day) over continuous mode operation (1.05±0.01kgCODR/m3-day). Overall, current study depicted the possibility of utilizing RW as substrate in MFC for power generation along with its treatment.

Room temperature long range ferromagnetic ordering in (BiFeO3)1−x (PbTiO3)x nanocrystallites

Room temperature Mossbauer spectra of (BiFeO3)1−x (PbTiO3)x (xu2009=u20090, 0.1, 0.2, 0.3) nano multiferroic systems prepared by solution combustion technique reveal the long range ferromagnetic ordering, supported by M-H loop measurements. Magnetic hyperfine interaction field and isomer shift for these nanocrystallite indicate the presence of Fe3u2009+u2009 ion only, likewise confirmed by from X-ray photoelectron spectroscopy study, which is essential for enhancement of multiferroic properties. A small residual magnetic moment is observed for these nanoparticles, which may be attributed to size confinement at nanoscale and to spin canting. These nanomaterials are of great importance in basic as well as applied research.

Bio-electro catalytic treatment of petroleum produced water: Influence of cathode potential upliftment.

Treatment of petroleum produced water (PPW) was studied using bioelectrochemical system (BES) under uplifted cathode potential. The treatment efficiency in terms of COD and hydrocarbon removal was observed at 91.25% and 76.60% respectively, along with the reduction in TDS during BES operation under 400mV of cathode potential. There was also a reduction in concentration of sulfates, however, it was not significant at, since oxidative conditions are being maintained at anode. Improved oxidation of PPW at anode also resulted in good power output (-20.47mA) and also depicted improved fuel cell behaviour. The electrochemical analysis in terms of cyclic/linear sweep voltammetry also showed well correlation with the observed treatment efficiencies. The microbial dynamics of the BES after loading real field wastewater showed the dominance of species that are reported to be effective for petroleum crude oil degradation.

Electrochemical removal of sulfate from petroleum produced water

Petroleum produced water (PPW) is a waste-stream that entails huge cost on the petroleum industry. Along with other suspended and dissolved solids, it contains sulfate, which is a major hurdle for its alternative use intended toward enhanced oil recovery. This study proposes a two-step process for sulfate removal from PPW. A synthetic PPW was designed for the study using response surface methodology. During the first step, sulfate present in PPW was reduced to sulfide by anaerobic fermentation with 80% efficiency. In the second step, more than 70% of the accumulated sulfide was electrochemically oxidized. This integrated approach successfully removed sulfate from the synthetic wastewater indicating its applicability in the treatment of PPW and its subsequent applications in other oil field operations.

Perturbations and 3R in carbon management

Perturbations in various carbon pools like biological, geological, oceanic, and missing carbon sink affect its global data, which are generally neglected or ignored in routine calculations. These natural and anthropogenic events need to be considered before projecting a sustainable carbon management plan. These plans have both general and experimental aspects. General plans should focus on (a) minimizing emission; (b) maximizing environmentally sound reuse, reduce, and recycling; (c) effective treatment; and (d) converting carbon into valuable products with atom economy. Experimental carbon management plans involving various biological and chemical techniques with limitation in terms of research level and economic feasibility. Chemical options have benefits of higher productivity and wider product range, but it suffers from its higher-energy requirements and environmental unfriendliness. In contrast to this, biological options are more selective and less energy intensive, but their productivity is very low. Hence, there is a requirement of hybrid process where the benefits of both the options, i.e., biological and chemical, can be reaped. In view of above, the proposed review targets to highlight the various perturbations in the global carbon cycle and their effects; study the currently practiced options of carbon management, specifically in light of 3R principle; and propose various new hybrid methods by compatible combinations of chemical and biological processes to develop better and safer carbon management. These methods are hypothetical so they may require further research and validations but may provide a comprehensive base for developing such management methods.

Long-term operation of electro-biocatalytic reactor for carbon dioxide transformation into organic molecules

Electro-biocatalytic reactor was operated using selectively enriched mixed culture biofilm for about 320u202fdays with CO2/bicarbonate as C-source. Biocathode consumed higher current (-16.2u202f±u202f0.3u202fA/m2) for bicarbonate transformation yielding high product synthesis (0.74u202fg/l/day) compared to CO2 (-9.5u202f±u202f2.8u202fA/m2; 0.41u202fg/l/day). Product slate includes butanol and butyric acid when CO2 gets transformed but propionic acid replaced both when bicarbonate gets transformed. Based on electroanalysis, the electron transfer might be H2 mediated along with direct transfer under bicarbonate turnover conditions, while it was restricted to direct under CO2. Efficiency and stability of biofilm was tested by removing the planktonic cells, and also confirmed in terms of Coulombic (85-97%) and carbon conversion efficiencies (42-48%) along with production rate (1.2-1.7u202fkg/m2 electrode) using bicarbonate as substrate. Selective enrichment of microbes and their growth as biofilm along with soluble CO2 have helped in efficient transformation of CO2 up to C4 organic molecules.

Carbonic Anhydrase II Based Biosensing of Carbon Dioxide at High Temperature: An Analytical and MD Simulation Study

Concentration of carbon dioxide (CO2) in the atmosphere has increased significantly due to anthropogenic activities and attributed as a major factor to global warming. Its detection by biosensing methods will provide an alternative for the assessment of CO2 concentration. Biomineralization of CO2 is one of the available methods for the biological conversion of CO2 to carbonate using a highly active enzyme, carbonic anhydrase II (CAII). CAII was used for the carbonation reaction to convert CO2 to CaCO3. The precipitation of calcium carbonate (CaCO3) was promoted in the presence of the CAII at 325 K. CAII showed an enhanced formation of solid CaCO3 through the acceleration of CO2 hydration rate at 325 K. Furthermore, the electrocatalytic properties of glassy carbon electrode enable us to determine the reduction peak potential values of CO2 through cyclic voltammetry at –1.75 and 0.3 V at 325 K. Molecular dynamic (MD) simulations were performed each at 50 ns time scale provided a deeper insight into the molecular basis of the CAII interaction with CO2 at different temperatures, highlighted that the CAII can detect CO2 up to 325 K. We assume that CAII could be an effective and economical biosensor for biomineralization of CO2 at high temperature 325 K.