Development of economical and highly efficient electrolyte using vanadium pentoxide for vanadium redox flow battery

Environmental Science and Pollution Research - Vanadium pentoxide can be an inexpensive replacement to vanadium sulfate in synthesizing vanadium redox flow battery (VRFB) electrolytes. In this...     

Comparative Biodegradation Studies of Non-poronized and Poronized LDPE Using Indigenous Microbial Consortium

Seventeen bacterial isolates were screened for the utilization of low density polyethylene (LDPE) as the sole carbon source, out of which five potential strains were selected for the development of a consortium. In vitro biodegradation efficiency of the consortium was studied for two differently textured forms of LDPE viz. non-poronized and poronized. Although, both the forms were acted-upon well by the consortium, but the degradation was found to be better in the poronized form. This was substantiated by λ-max shift, FTIR spectra and simultaneous TG-DTG-DTA. The analysis revealed the breakage and formation of chemical bonds in the polymer backbone, as a result of microbial activity. The biodegraded samples of non-poronized and poronized LDPE exhibited similar weight losses at 400 °C (24.12% and 24.48%, respectively) as compared to their controls (4% and 4.5% respectively), but the latter could achieve it with greater ease as reveled by its lower heat of reactions (ΔH values). The study signifies the influence of poronization of polyethylene on its rate of biodegradation.     

Dietary Spirulina platensis alleviates aluminum and aluminum fluoride induced histopathological and biochemical alterations in mice kidney

Aluminum and its salts widely used in our daily life have been reported nephrotoxic to humans and animals following prolonged exposure. Therefore, the present study was made to examine the renoprotective role of Spirulina platensis against Al³⁺ and AlF₃ in male Swiss albino mice. Exposure to these chemicals decreased feed and water intake, and body and kidney weights. Histology of kidney and their biochemistry were also markedly altered along with that of serum biochemistry. Spirulina not only minimize toxic effects of test chemicals but also favored faster recovery of treated mice after their withdrawal.     

Enumeration of methanogens with a focus on fluorescence in situ hybridization

Methanogens, the members of domain Archaea are potent contributors in global warming. Being confined to the strict anaerobic environment, their direct cultivation as pure culture is quite difficult. Therefore, a range of culture-independent methods have been developed to investigate their numbers, substrate uptake patterns, and identification in complex microbial communities. Unlike other approaches, fluorescence in situ hybridization (FISH) is not only used for faster quantification and accurate identification but also to reveal the physiological properties and spatiotemporal dynamics of methanogens in their natural environment. Aside from the methodological aspects and application of FISH, this review also focuses on culture-dependent and -independent techniques employed in enumerating methanogens along with associated problems. In addition, the combination of FISH with micro-autoradiography that could also be an important tool in investigating the activities of methanogens is also discussed.     

Influence of microbial and synthetic surfactant on the biodegradation of atrazine

The present study reports the effect of surfactants (rhamnolipids and triton X-100) on biodegradation of atrazine herbicide by strain A6, belonging to the genus Acinetobacter. The strain A6 was able to degrade nearly 80 % of the 250-ppm atrazine after 6 days of growth. The bacterium degraded atrazine by de-alkylation process. Bacterial cell surface hydrophobicity as well as atrazine solubility increased in the presence of surfactant. However, addition of surfactant to the mineral salt media reduced the rate and extent of atrazine degradation by decreasing the bioavailability of herbicide. On the contrary, addition of surfactant to atrazine-contaminated soil increased the rate and extent of biodegradation by increasing the bioavailability of herbicide. As compared to triton X-100, rhamnolipids were more efficient in enhancing microbial degradation of atrazine as a significant amount of atrazine was removed from the soil by rhamnolipids. Surfactants added for the purpose of hastening microbial degradation may have an unintended inhibitory effect on herbicide degradation depending upon contiguous condition, thus highlighting the fact that surfactant must be judiciously used in bioremediation of herbicides.     

Air quality mapping using GIS and economic evaluation of health impact for Mumbai City,India

Mumbai, a highly populated city in India, has been selected for air quality mapping and assessment of health impact using monitored air quality data. Air quality monitoring networks in Mumbai are operated by National Environment Engineering Research Institute (NEERI), Maharashtra Pollution Control Board (MPCB), and Brihanmumbai Municipal Corporation (BMC). A monitoring station represents air quality at a particular location, while we need spatial variation for air quality management. Here, air quality monitored data of NEERI and BMC were spatially interpolated using various inbuilt interpolation techniques of ArcGIS. Inverse distance weighting (IDW), Kriging (spherical and Gaussian), and spline techniques have been applied for spatial interpolation for this study. The interpolated results of air pollutants sulfur dioxide (SO₂), nitrogen dioxide (NO₂) and suspended particulate matter (SPM) were compared with air quality data of MPCB in the same region. Comparison of results showed good agreement for predicted values using IDW and Kriging with observed data. Subsequently, health impact assessment of a ward was carried out based on total population of the ward and air quality monitored data within the ward. Finally, health cost within a ward was estimated on the basis of exposed population. This study helps to estimate the valuation of health damage due to air pollution.

Implications: Operating more air quality monitoring stations for measurement of air quality is highly resource intensive in terms of time and cost. The appropriate spatial interpolation techniques can be used to estimate concentration where air quality monitoring stations are not available. Further, health impact assessment for the population of the city and estimation of economic cost of health damage due to ambient air quality can help to make rational control strategies for environmental management. The total health cost for Mumbai city for the year 2012, with a population of 12.4 million, was estimated as USD8000 million.     

Air flow and concentration fields at urban road intersections for improved understanding of personal exposure

This paper reviews the state of knowledge on modelling air flow and concentration fields at road intersections. The first part covers the available literature from the past two decades on experimental (both field and wind tunnel) and modelling activities in order to provide insight into the physical basis of flow behaviour at a typical cross-street intersection. This is followed by a review of associated investigations of the impact of traffic-generated localised turbulence on the concentration fields due to emissions from vehicles. There is a discussion on the role of adequate characterisation of vehicle-induced turbulence in making predictions using hybrid models, combining the merits of conventional approaches with information obtained from more detailed modelling. This concludes that, despite advancements in computational techniques, there are crucial knowledge gaps affecting the parameterisations used in current models for individual exposure. This is specifically relevant to the growing impetus on walking and cycling activities on urban roads in the context of current drives for sustainable transport and healthy living. Due to inherently longer travel times involved during such trips, compared to automotive transport, pedestrians and cyclists are subjected to higher levels of exposure to emissions. Current modelling tools seem to under-predict this exposure because of limitations in their design and in the empirical parameters employed.     

Thermoplastic vulcanizates from post consumer computer plastics/nitrile rubber blends by dynamic vulcanization

Due to depletion of natural resources and increasing greenhouse emissions, new technologies for the transformation of waste polymers into valuable materials represent one of our greatest current needs. Acrylonitrile–butadiene–styrene terpolymer (ABS) is one of the most widely used engineering plastics and is used as outer casing for electronic equipment. Nitrile rubber (NBR) is used in many applications that demand oil resistance. In an attempt to explore whether these materials can be successfully recycled, we prepared blends of scrap computer plastics (SCP) based on ABS with NBR and waste NBR powder (w-NBR), and investigated their mechanical properties and recyclability. Specifically, we assessed the effect of dynamic vulcanization and replacement of virgin NBR with w-NBR on the properties of 60/40, 70/30, and 80/20 NBR/SCP blends. These blends exhibited thermoplastic elastomeric behavior. The thermoplastic elastomeric blends showed excellent swelling resistance to standard lubricant oil (namely, IRM 903 oil).