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Metal Exchanged ZSM-5 Zeolite Based Catalysts for Direct Decomposition of N2O
No full textCo?Pt/ZSM-5 and Ag?Pt/ZSM-5 type catalysts
were prepared by ion exchange method followed by
calcination. These Co and Ag based catalysts, promoted by a small amount of Pt have been studied for their catalytic activity towards N2O decomposition. Both the catalysts show high catalytic activity, however, cobalt–platinum based catalyst shows relatively better activity at higher temperature. At 550 �C almost 100% conversion of N2O is achieved over Co?Pt/ZSM-5 with a maximum of
0.08479 mmole of N2O decomposed per gram of the catalyst
per unit time. These catalytic materials have been
characterized for their structure, composition, morphology
and other details, using XRD, SEM, EDX, ICP, BET techniques.
Much improved catalytic activity for the bimetallic
zeolite than the mono-metal containing compositions clearly
demonstrate the synergistic effect of these transition metals,
while high surface area of ZSM-5 is also responsible for the
improved N2O decomposition activity
Immobilization of carbonic anhydrase enriched microorganism on biopolymer based materials
No full textThe whole cell of Bacillus pumilus was immobilized on different chitosan based materials while attempts
were also made to immobilize carbonic anhydrase (CA) enzyme. The screening of materials for esterase
activity resulted in the selection of biopolymer based beads as the potential material for whole cell
and CA immobilization. The materials were characterized by Fourier transform infrared (FTIR) spectroscopy,
X-ray diffraction (XRD), scanning electron microscopy (SEM), while physical characteristics
like BET surface area, particle size etc. were also determined. Esterase activity and other parameters, like
effect of swelling, were determined on immobilized cells. After cell immobilization, the esterase activities
of chitosan-NH4OH beads, multilayered beads, and sodium alginate were found to be 42, 36, and
30.5 U/ml, respectively, as compared to 27.15 U/ml for the free organism
Developmental strategies for sustainable ecosystem on mine spoil dumps: a case of study
No full textAn important goal of ecological rehabilitation is to accelerate natural successional processes to increase biological productivity, soil fertility and biotic control over biogeochemical fluxes within the recovering ecosystems. A new approach called Microbe Assisted Green Technology (MAGT) is an integrated biotechnological
approach developed at National Environmental Engineering Research Institute (NEERI) through exhaustive laboratory as well as field studies and serve as a model for land reclamation and development of lush green vegetation on mine overburdens. One year old seedlings of native tree
species were planted on 6.3 ha area of manganese mine overburden at Gumgaon under Manganese Ore India Ltd., Maharashtra, India. Continuous efforts resulted in nutrient rich soil with high N, P, K and organic carbon; well developed biodiversity, including bacteria, fungi, higher plants (more than 350 species) and different classes of animals. Planted trees accumulated 698 t ha−1 above ground biomass and 143 t ha−1 below ground mass. This was achieved in 18 years by MAGT, which otherwise takes hundreds of years
Utilization of molasses spentwash for production of bioplastics by waste activated sludge
No full textPresent study describes the treatment of molasses spentwash and its use as a potential low cost substrate for production of biopolymer polyhydroxybutyrate (PHB) by waste activated sludge. Fluorescence microscopy revealed the presence of PHB granules in sludge biomass which was further confirmed byfourier transform-infra-red spectroscopy (FT-IR) and 13C nuclear magnetic resonance (NMR). The processing of molasses spentwash was carried out for attaining different ratios of carbon and nitrogen
(C:N). Highest chemical oxygen demand (COD) removal and PHB accumulation of 60% and 31% respectively was achieved with raw molasses spentwash containing inorganic nitrogen (C:N ratio = 28) followed by COD removal of 52% and PHB accumulation of 28% for filtered molasses containing inorganic nitrogen (C:N ratio = 29). PHB production yield (Yp/s) was highest (0.184 g g�1 COD consumed) for deproteinized spentwash supplemented with nitrogen. In contrast, the substrate consumption and product formation
were higher in case of raw spentwash. Though COD removal was lowest from deproteinized spentwash, evaluation of kinetic parameters suggested higher rates of conversion of available carbon to biomass and PHB. Thus the process provided dual benefit of conversion of two wastes viz. waste activated sludge and molasses spentwash into value-added product-PHB
New modified chitosan-based adsorbent for defluoridation of water
No full textIn the present study, the metal-binding property of chitosan is used to incorporate titanium metal
and applied as an adsorbent for fluoride adsorption. Titanium macrospheres (TM) were synthesized
by a precipitation method and characterized by FTIR, SEM, and XRD. The Langmuir and Freundlich
adsorption models were applied to describe the adsorption equilibrium and the adsorption capacities
were calculated. Thermodynamic parameters of standard free energy change (�G◦), standard enthalpy
change (�H◦), and standard entropy change (�S◦) were also calculated. The effects of various physicochemical
parameters such as pH, initial concentration, adsorbent dose, and the presence of coexisting
anions were studied. The fluoride uptake was maximum at neutral pH 7 and decreased in acidic and
alkaline pH. The presence of coexisting anions has a negative effect on fluoride adsorption. TM was
found to have very fast kinetics in the first 30 min and then the rate slowed down as equilibrium was
approached. A comparison of fluoride removal in simulated and field water shows a high adsorption
capacity in simulated water
Assessment of environmental benefits of flyover construction over signalized junctions: a case study
No full textIn the present study, the impact of the
flyover construction to curb traffic congestion problem
has been assessed in terms of traffic decongestion, time
saving, fuel saving and emission reduction. A flyover
has also been constructed over four signalized
junctions in the main commercial area in Nagpur city,
India. It was found that about 35% of the total traffic is
diverted to the flyover, which results in a reduction of
about 32% in the total emission generation. Travel on
the flyover resulted in as much as 60–70% saving in
time, compared to the travel on the main road,
particularly when all the four signals are found to be
in the red phase. The loss of fuel for combustion and
the associated cost resulting from waiting for the signal
to change are also estimated, and these are found to be
significant
In Vivo Studies to Elucidate the Role of Extracellular Polymeric Substances from Azotobacter in Immobilization of Heavy Metals
No full textThe role of extracellular polymeric substances (EPS) produced by the heavy metal-resistant strain of Azotobacter spp. in restricting the uptake of cadmium (Cd) and chromium (Cr) by wheat plants cultivated in soils contaminated with the respective heavy metals has been demonstrated. A heavy metalresistant strain of Azotobacter spp. was isolated and identified. Minimum inhibitory concentrations (MIC) of Cd2+ and CrO4 2- were determined to be 20 and 10 mg L-1, respectively. Under in vitro conditions, the EPS produced by the strain could bind 15.17 ( 0.58 mg g-1 of Cd2+ and 21.9 ( 0.08 mg g-1 of CrO4 2-. Fourier transform infrared spectra of the EPS revealed the presence of functional groups like carboxyl (-COOH)andhydroxyl (-OH), primarily involved in metal ion binding. Under pot culture experiments, the isolated strain of Azotobacter was
added to the metal-contaminated soils in the form of free cells and immobilized cells. The total Azotobacter count and
plant metal concentrations under different treatments showed
a negative coefficient between the Azotobacter population
and plant Cd (-0.496) and Cr (-0.455). Thus it could be inferred that Azotobacter spp. is involved in metal ion complexation either throughEPSor through cell wall lipopolysaccharides (LPS
Diversity of birds at Panipat refinery, Haryana (India)
No full textAvifaunal study was carried out in Panipat refinery area before and after commissioning. A total of 63 birds were observed during the study, of which 39 and 49 birds were present during 1992 and 2001 respectively. Of these, 25
birds were common during both the study period. Blue rock pigeon was most dominant during 1992 whereas house sparrow was dominant during 2001. Species diversity index was found
to be 5.26 and 6.64 in respective years. Jaccard’s and Sorenson similarity indices were 0.40 and 0.57 respectively. Majority of birds were insectivorous in habits followed by granivorous birds in 1992 and piscivorous birds in 2001. The study reveals that less diversity was observed in 1992 when Panipat refinery was commissioned, but more birds especially aquatic ones were observed after the commissioning of the refinery. This has been attributed to increase in birds habitats due to developments of wetlands in and outside refinery, development of green belt around refinery and increase in green cover of area due to boosting of agroforestry and social forestry
Bio-sequestration of carbon dioxide using carbonic anhydrase enzyme purified from Citrobacter freundii
No full textThe increase in the atmospheric concentrations of one of the vital green house gasses, carbon dioxide, due to anthropogenic interventions has led to several undesirable
consequences such as global warming and related changes. In the global effort to combat the predicted disaster, several CO2 capture and storage technologies are being deliberated. One of the most promising biological carbon dioxide sequestration technologies is the enzyme catalyzed carbon dioxide sequestration into bicarbonates which was endeavored in this study with a purified C. freundii SW3 b-carbonic anhydrase (CA). An extensive screening process for biological sequestration using CA has been defined. Six bacteria with high CA activity were screened out of 102 colonies based on plate assay and presence of CA in these bacteria was further emphasized by activity staining and Western blot. The identity of selected bacteria was confirmed by 16S rDNA analysis. CA was purified to homogeneity from C. freundii SW3 by subsequent gel filtration and ion exchange chromatography which resulted in a 24 kDa polypeptide and this is in accordance with the Western blot results. The effect of host on metal ions, cations and anions which influence activity of the enzyme in sequestration studies suggests that mercury and HCO3
- ion almost completely inhibit the enzyme whereas sulfate ion and zinc enhances carbonic anhydras