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Study of nano-structured ceria for catalytic CO oxidation
No full textMesoporous, nano-structured ceria has been synthesized using a low-cost biopolymer chitosan as
a template, and the same material has been studied for its CO oxidation activity. The ceria thus
prepared shows low crystallite size (6.5 nm), high surface area (BET-SA 144.2 m2 g�1) and mesopores
(32.4 A ° ) without ordered structure. Different ceria samples have been synthesized by manipulating
the chitosan : cerium ratio and synthesis temperature. These ceria samples have been characterized using
XRD, BET-SA, SEM, FTIR, UV-DRS, PL and TEM techniques. The ceria samples show fluorite
structure with cubic symmetry and increased lattice volume. The nano-structured ceria thus synthesized
lowers the CO oxidation temperature by 30–60 �C as compared to the commercial ceria. The improved
catalytic activity primarily appears to be the effect of improved surface area and pore characteristics
of nano-structured ceria. Also the expansion in lattice cell volume leads to the improvement in redox
properties of ceria, thereby facilitating the formation of surface oxygen vacancies. Such mesoporous ceria
without ordered structure could be useful as an oxidation catalyst as well as a support for various
catalysts. The platinum incorporated mesoporous ceria also shows excellent CO oxidation
Functionalized Fly Ash Based Alumino-Silicates for Capture of Carbon Dioxide
No full textFly ash contains mainly alumina and silica as its main constituents. A novel method for the extraction of highly stable
alumino-silicates from fly ash has been developed. The as-extracted alumino-silicate has been further functionalized with APTES
((3-aminopropyl)triethoxysilane), TRIS buffer (tris(hydroxymethyl)aminomethane), and AMP (3-amino-2-methyl-1-propanol)
to impart basicity for carbon dioxide adsorption. A dynamic adsorption capacity of 6.62 mg/g has been observed for FAS (fly ash
based alumino-silicate) and has improved by a factor of 4.0, with an adsorption capacity of 26.5 mg/g for AMP-functionalized FAS at
55 �C with 15% CO2 inN2. The positive influence of water was observed with an improvement of adsorption capacity to 34.82 mg/g
at 55 �C with 15% CO2, 82% N2, and 3% water vapor. The adsorbent is studied for adsorption capacity at varying temperatures, and
the best performing adsorbent is characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier
transform infrared (FTIR) spectroscopy, thermal analysis, and elemental analysis to study the morphological properties of the
present adsorbent support. The excellent thermal stability of synthesized material suggested the formation of promising aluminosilicate
for CO2 adsorption
Mitigation of Air Pollution and Carbon Footprint by Energy Conservation Through CFLs: A Case Study
No full textElectricity consumption of compact fluorescent lamps (CFLs) is low, making them a useful tool for minimizing the rapidly increasing demand of electrical energy in India. The present study aims to project the likely electricity conservation in a scenario of complete replacement of existing Fluorescent Tubes (FTs) by CFLs at National Environmental Engineering Research Institute (NEERI) vis a vis the financial repercussions and indirect reduction in emissions of greenhouse gases e.g. CO2, N2O, CH4 and other air pollutants e.g. SO2, NO, suspended particulate matter (SPM), black carbon (BC) and mercury (Hg) from coal fired thermal power plants. The calculations show that the institute could save around 122850 kWh of electricity per annum, thereby saving approximately INR 859950/- (USD 18453.86) towards electricity cost per annum and would be able to minimize 44579.08 kg of CO2-C equivalent (over 100 year time horizon), 909 kg SO2, 982.8 kg NO, 9.8 kg of BC, 368.5 kg SPM, 18.4 Kg PM10 and 0.0024 kg Hg emissions per annum from a coal fired thermal power plant by conserving electricity at the institute level
A feasibility analysis of hydrogen delivery system using liquid organic hydrides
No full textThe paper discusses the techno-economic feasibility of a hydrogen storage and delivery system using liquid organic hydrides (LOH). Wherein, LOH (particularly cycloalkanes) are used for transporting the hydrogen in chemical bonded form at ambient temperature and pressure. The hydrogen is delivered through a catalytic dehydrogenation process. The aromatics formed in the process are used for carrying more hydrogen by a subsequent hydrogenation reaction. Cost economics were performed on a system which produces 10 kg/h of hydrogen using methylcyclohexane as a carrier. With proprietary catalysts we have demonstrated the possibility of hydrogen storage of 6.8 wt% and 60 kg/m3 of hydrogen on volume basis. The energy balance calculation reveals the ratio of energy transported to energy consumed is about 3.9. Moreover, total carbon footprint calculation for the process of hydrogen delivery including transportation of LOH is also reported. The process can facilitate a saving of 345 tons/year of carbon dioxide emissions per delivery station by replacing gasoline with hydrogen for passenger cars. There is an immense techno-economic potential for the process
Single enzyme nanoparticle for biomimetic CO2 sequestration
No full textNanoparticle technology is being increasingly
used in environmental sciences. We prepared
single enzyme nanoparticle (SEN) by modifying the
surface of carbonic anhydrase (CA) with a thin layer of
organic/inorganic hybrid polymer. SEN-CA appears to
be improving the stability of free enzyme. CA, as
ubiquitously found enzyme, is involved in gaseous
CO2 sequestration and is being looked as a promising
candidate for combating global warming. We report
here physical characterization of SEN-CA using
transmission electron microscope (TEM), Fouriertransform
infrared analysis (FTIR), X-ray diffraction
analysis (XRD), and energy dispersive X-ray (EDX).
Average size of SEN-CA particles appears to be in the
range of 70–80 nm. We also report the effect of SEN
formation on the kinetic parameters of free CA such as
Michaelis–Menten constant (Km), maximum reaction
velocity (Vmax), and storage stability of free CA and
SEN-CA. The Vmax of SEN-CA (0.02857 mmol/min/
mg) and free enzyme (0.02029 mmol/min/mg) is
almost similar. Km has decreased from 6.143 mM for
SEN-CAto 1.252 mMfor free CA. The stabilization of
CA by SEN formation results in improved the half-life
period (up to 100 days). The formation of carbonate
was substantiated by using gas chromatography (GC).
The conversion of CO2 to carbonate was 61 mg of
CaCO3/mg of CA and 20.8 mg of CaCO3/mg of CA
using SEN-CA and free CA, respectively
Equilibrium isotherm and kinetic modeling of the adsorption of nitrates by anion exchange Indion NSSR resin
No full textThis paper describes the adsorption capacity of ion exchange Indion NSSR resin for removal of nitrates from
aqueous solution. Adsorption capacity of resin was investigated under different conditions viz variations in
adsorbent dose, initial concentrations of nitrate and pH. The fitting of the Freundlich, Langmuir and Dubinin–
Radushkevich adsorption models to the equilibrium data was investigated. The equilibrium data obtained in
this study were found to follow the Langmuir adsorption isotherm. The maximum sorption capacity was
119 mg/g as per Langmuir isotherm at 35 °C under this particular study. The rate parameters for the intra
particle diffusion have been estimated for different initial concentrations. In batch adsorption processes, the
adsorbate molecules diffuse in porous adsorbent and rate process usually depends on t0.5 rather than the
contact time. The nitrate adsorption on Indion NSSR resin from aqueous solution follows first order reversible
model. The nitrate adsorption capacity of ca 77 mg/g was observed for the Indion NSSR resin from the column
study with specific conditions of operation
Equilibrium isotherm and kinetic modeling of the adsorption of nitrates by anion exchange Indion NSSR resin
No full textThis paper describes the adsorption capacity of ion exchange Indion NSSR resin for removal of nitrates from aqueous solution. Adsorption capacity of resin was investigated under different conditions viz variations in adsorbent dose, initial concentrations of nitrate and pH. The fitting of the Freundlich, Langmuir and Dubinin– Radushkevich adsorption models to the equilibrium data was investigated. The equilibrium data obtained in this study were found to follow the Langmuir adsorption isotherm. The maximum sorption capacity was 119 mg/g as per Langmuir isotherm at 35 °C under this particular study. The rate parameters for the intra particle diffusion have been estimated for different initial concentrations. In batch adsorption processes, the adsorbate molecules diffuse in porous adsorbent and rate process usually depends on t0.5 rather than the contact time. The nitrate adsorption on Indion NSSR resin from aqueous solution follows first order reversible model. The nitrate adsorption capacity of ca 77 mg/g was observed for the Indion NSSR resin from the column study with specific conditions of operation
Immobilization of carbonic anhydrase on chitosan beads for enhanced carbonation reaction
No full textCarbonic anhydrase (CA) has been immobilized on chitosan beads and has been tested for its activity
using p-NPA. CA immobilized chitosan beads were further tested for targeted application of carbonation
reaction to convert CO2 to CaCO3. It was observed that onset time for precipitation of CaCO3 was 40 s
for immobilized catalyst as compared to non-catalyzed system (100 s). Mechanistic and kinetic aspects
have been addressed for immobilized catalyst as well as free CA using p-NPA assay. Km and Vmax of the
immobilized CA was observed to be 2.36mM and 0.54�moles/min/ml as compared to Km and Vmax of
0.87mMand 0.93�moles/min, respectively, for free CA. Storage stability test was conducted up to 20 days
and it was observed that at −20 ◦C, the Half Life Period (HLP) of immobilized CA was 216 h as compared
to 192 h for free CA whereas at 25 ◦C the HLP for immobilized and free CA was observed to be 456 h and
408 h, respectively
Structural & Functional Prediction Of Hypothetical Proteins In Bacteriophages Against Halophilic Bacteria - An In Silico Approach
No full textThe hypothetical proteins of two Halophilic phages, alomonas phage phiHAP-1 (length 39245) and Halorubrum phage HF2 (length 77670) were studied. The structure and function predictions of hypothetical proteins were done by the use of bioinformatic web tools. In Halomonas phage phiHAP-1, function prediction for 9 and structure prediction for 3 hypothetical proteins whereas in Halorubrum phage HF2, function prediction for 32 and structure prediction for 6 hypothetical proteins were resolved. The probable function prediction was done by using Bioinformatics web tools like CDDBLAST,INTERPROSCAN, PFAM and COGs by searching sequence databases for the presence of orthologous conserved domains in the hypothetical sequences. The tertiary structure prediction was done by using PS2 server. This study revealed some of the uncharacterized hypothetical proteins in Halophilic phages whose complete genome sequence is known and can be used for the further understanding of phage genome and its life cycle