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Capture of carbon dioxide over porous solid adsorbents lithium silicate, lithium aluminate and magnesium aluminate at pre-combustion temperatures

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Frontiers of Chemical Science and Engineering 2011年第2期5卷 215-226页

作者： P.V.Korake A.G.Gaikwad CE&PD Division National Chemical LaboratoryPune 411008India

The capturing process for carbon dioxide over porous solid adsorbents such as lithium silicate,lithium aluminate,and magnesium aluminate at pre-combustion temperatures was *** silicate was prepared by the sol gel and solid fusion *** lithium silicate adsorbent was characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning elec-tron microscopy(SEM),nuclear magnetic resonance(NMR),and surface *** capturing of carbon dioxide over lithium silicate,lithium aluminate,and magnesium aluminate was explored at different experimental condi-tions such as exposure time,temperature variation,and exposure carbon dioxide *** capturing process for carbon dioxide was investigated over these adsorbents with variation of their metal mole *** effect of the addition of(promoter)sodium,potassium,and cesium in the lithium silicate adsorbent was explored to investigate the variation of the capture of carbon dioxide over these adsorbents.

关键词： capturing CO_(2) lithium silicate lithium alu-minate magnesium aluminate

Effect of Counter-Gradient in the Computation of Turbulent Fluxes of Heat and Moisture in a Regional Model

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Advances in Atmospheric Sciences 1993年第1期10卷 85-94页

作者： S. S. Vaidya V. N. Lykossov S. S. Singh Indian Institute of Tropical Meteorology Pune 411008 IndiaDepartment of Numerical Mathematics Soviet Academy of Science 29 Ryleev Street MoscowIndian Institute of Tropical Meteorology Pune 411008 India

The counter-gradient terms in the computations of turbulent fluxes of heat and moisture have been included in the PBL parameterization of a regional model for monsoon prediction. Results show that inclusion of counter... 详细信息

关键词： Effect of Counter-Gradient in the Computation of Turbulent Fluxes of Heat and Moisture in a Regional Model

Diurnal Variation of Southwest Monsoon Rainfall at Indian Stations

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Advances in Atmospheric Sciences 1994年第1期11卷 111-120页

作者： J.M. Pathan(Indian Institute of Tropical Meteorology, Pashan, pune-411008, India) 1. Indian Institute of Tropical Meteorology Pashan 411008 Pune India

The paper presents the patterns of rainfall behavior brought out by the diagrams depicting the diurnal variation of SW monsoon rainfall at selected indian stations. The stations in different geographical locations are found to exhibit different patterns of diurnal variation of rainfall. In general, coastal and island stations show enhanced rainfall from midnight to morning hours and below average rainfall during day time. Many inland stations show rainfall maximum towards afternoon/evening hours. Some hill stations show the same behavior as inland stations. However, at the heavy rainfall station of Cherrapunjee, the rainfall behavior is similar to that at the coastal stations. Possible physical mechanisms responsible for the diurnal variation of rainfall at stations under different categories, are briefly discussed. Harmonic analysis of hourly SW monsoon rainfall data of 33 stations show that for 19 stations, the first harmonic accounts for more than 50% of the variance of the rainfall series. These consist of (i) inland stations for which the maximum of the first harmonic is reached between 16 hours IST and midnight, and (n) coastal/island stations for which the maximum is seen between 03 and 07 hours IST. At most of the coastal and island stations, the first harmonic alone accounts for 75% orb more of the variance. For the heavy rainfall station of Cherrapunjee, the first harmonic which attains its maximum at 3.8 hours IST (-4.4 hours LT), is able to account for 96% of the variance of the rainfall series. It is hoped that the information contained in this paper about the pattern of diurnal modulation of monsoon rainfall may serve as background material to monsoon precipitation climatology.

关键词： Diurnal variation Monsoon rainfall Indian stations Harmonic analysis Hourly rainfall

Bromide ion mediated modification to digestive ripening process： Preparation of ultra-small Pd, Pt, Rh and Ru nanoparticles

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Nano Research 2016年第7期9卷 2007-2017页

作者： Jhumur Seth Bhagavatula L. V. Prasad Physical and Material Chemis try Division National Chemical Laboratory (CSIR-NCL) Dr. Homi Bhabha Road Pune 411008 India

Nanoparticles of catalytically important transition metals, such as Pd, Pt, Rh, and Ru have been prepared by the well-known ＂digestive ripening＂（DR） and ＂modified digestive ripening＂（mDR） methods. In the traditional DR process, a polydisperse colloidal dispersion is refluxed in the presence of a surface-active molecule, such as alkanethiol. The mDR method involved a small modification in the procedure, wherein refluxing was performed with an alkanethiol and a tetra-alkylammonium bromide surfactant. This minor modification led to a dramatic change in the final particle size distributions, giving access to nano- particles in the 〈3 nm size regime; this was not possible with the traditional DR process. Bromide ions, which are present during refluxing, proved to be an important ingredient in the modification process. These bromide ions are revealed to act as etchants, resulting in ultra-small nanoparticles. All transition metal nanoparticles investigated displayed catalytic activity in the reduction reaction of p-nitro phenol. Pd nanoparticles, synthesized by a modified digestive ripening method, exhibited the best catalytic activity among the systems investigated.

关键词： digestive ripening ultra-small nanoparticles halide ions catalysis

Molecular dynamics study on growth of carbon dioxide and methane hydrate from a seed crystal

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Chinese Journal of Chemical Engineering 2019年第9期27卷 2074-2080页

作者： Prajakta Nakate Bappa Ghosh Subhadip Das Sudip Roy Rajnish Kumar Chemical Engineering and Process Development National Chemical LaboratoryPune 411008India Physical and Materials Chemistry Division National Chemical LaboratoryPune 411008India Department of Chemistry Chaudhary Ranbir Singh UniversityfindHaryana-126102 Department of Chemical Engineering Indian Institute of TechnologyMadrasChennai 600036Tamil NaduIndia

In the current work,molecular dynamics simulation is employed to understand the intrinsic growth of carbon dioxide and methane hydrate starting from a seed crystal of methane and carbon dioxide *** comparison was carried out because it has relevance to the recovery of methane gas from natural gas hydrate reservoirs by simultaneously sequestering a greenhouse gas like *** seed crystal of carbon dioxide and methane hydrate was allowed to grow from a super-saturated mixture of carbon dioxide or methane molecules in water *** different concentrations(1:6 and 1:8.5)of CO2/CH4 molecules per water molecule were chosen based on gas–water composition in hydrate *** molecular level growth as a function of time was investigated by all atomistic molecular dynamics simulation under suitable temperature and pressure range which was well above the hydrate stability zone to ensure significantly faster growth *** concentration of CO2 molecules in water played a significant role in growth kinetics,and it was observed that maximizing the CO2 concentration in the aqueous phase may not result in faster growth of CO2 *** the contrary,methane hydrate growth was independent of methane molecule concentration in the aqueous *** have validated our results by performing experimental work on carbon dioxide hydrate where it was seen that under conditions appropriate for liquid CO2,the growth for carbon dioxide hydrate was very slow in the beginning.

关键词： CH4 recovery Natural gas hydrate CO2 sequestration Kinetics F4 order parameter Cage dynamics Thermodynamics

Observations of NO_2 and O_3 during Thunderstorm Activity Using Visible Spectroscopy

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Advances in Atmospheric Sciences 1996年第3期13卷 359-374页

作者： D.B.Jadhav A.L.Londhe S.Bose Indian Institute of Tropical Meteorology Dr.Homi Bhabha MargPashanPune-411008MaharashtraIndiaIndian Institute of Tropical MeteorologyDr.Homi Bhabha MargPashanPune-411008MaharashtraIndiaIndian Institute of Tropical MeteorologyDr.Homi Bhabha MargPashanPune-411008MaharashtraIndia

Simultaneous observations for the total column densities of NO2,O3 and H2O were carried on using the portable Spectrometer (438-450 nm and 400-450 nm) and the visible Spectrometer (544.4-628 nm) during premonsoon thunderstorms and embedded hail storm activity at pune (18°32'N & 73°51'E),*** observations confirm the fact that there is an increase in O3 and NO2 column densities during *** increase in O3 was observed following onset of thunderstorm,while the increase in NO2 was observed only after the thunder flashes *** implies that the production mechanisms for O3 and NO2 in thunderstorm are *** observed column density of NO,value (1 to 3×1017molecules cm-2) during thunderstorm activity is 10 to 30 times higher than the value (1×10th molecules cm-2) of a normal day total column *** spectrometric observations and observations of thunder flashes by electric field meter showed that 6.4×1025molecules/flash of NO2 are *** increased to-oil column density of ozone during thunderstorm period is 1.2 times higher than normal (clear) day ozone *** multiple scattering in the clouds is estimated from H2O and O2 absorption bands in the visible spectral region Considering this effect the calculated amount of ozone added in the global atmosphere due to thunderstorm activity is 0.26 to 0 52 DU,and the annual production of ozone due to thunderstorm activity is of the order of 4.02×10 molecules/year The annual NO2 production may be of the order of 2.02×1035molecules/year.

关键词： Visible Spectroscopy Thunderstorm Ozone production NO2 production Atmospheric electricity Lightning flashes. Multiple scattering factor

The capture of carbon dioxide by transition metal aluminates, calcium aluminate, calcium zirconate, calcium silicate and lithium zirconate

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Frontiers of Chemical Science and Engineering 2011年第4期5卷 477-491页

作者： Ganesh TILEKAR Kiran SHINDE Kishor KALE Reshma RASKAR Abaji GAIKWAD Chemical Engineering and Process Development Division National Chemical LaboratoryPune 411008India

The capture of CO_(2) by transition metal(Mn,Ni,Co and Zn)aluminates,calcium aluminate,calcium zirconate,calcium silicate and lithium zirconate was carried out at pre-and post-combustion *** prepared metal adsorbents were characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),surface area analysis and acidity/alkalinity *** different experimental variables affecting the adsorbents ability to capture CO_(2),such as the mol ratio of metal ions,the pressure of CO_(2),the exposure time and the temperature of the adsorbent were also *** zirconate captured 13.85 wt-%CO_(2) at 650℃ and 2.5 atm and calcium silicate captured 14.31 wt-%at 650℃.Molecular sieves(13X)and carbon can only capture a negligible amount of CO_(2) at high temperatures(300℃–650℃).However,the mixed metal oxides captured reasonable amount of CO_(2) at these higher *** addition,calcium aluminate,calcium zirconate,calcium silicate and lithium zirconate adsorbents captured CO_(2) at both pre and post-combustion *** trend for the amount of captured carbon dioxide over the adsorbents was calcium aluminate

关键词： captured CO_(2) pre-combustion temperature characterization calcium silicate calcium zirconate

Monsoon Subdiyisional Rainfall Dimensionality and Predictability

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Advances in Atmospheric Sciences 1991年第3期8卷 351-356页

作者： J.R.Kulkarni Indian Institute of Tropical meteorology Pune-411008 India

For summer monsoon rainfall purpose India is divided into 35 *** daily rainfall series of one such subdivision(Konkan)has been analysed using the phase space *** years(1959-1973)of daily rainfall data have been utilised in this *** shows that the variability is due to the existing of strange attractor of dimension about *** predictability is estimated by computing the Lyapunov characteristic *** computations show that the predictability is about 8 days.

关键词： Monsoon Subdiyisional Rainfall Dimensionality and Predictability

Influence of cobalt on performance of Cu-CeO2 catalysts for preferential oxidation of CO

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Journal of Rare Earths 2020年第9期38卷 941-950,I0001页

作者： Sachin Malwadkar Parthasarathi Bera C.V.V.Satyanarayana Catalysis Division CSIR-National Chemical LaboratoryPune 411008India Surface Engineering Division CSIR-National Aerospace LaboratoriesBengaluru 560017India

Copper and cobalt oxides supported on CeO2 were investigated for preferential oxidation of carbon monoxide(CO-PROX)in the presence of excess hydrogen and CO2.(Cuo)1-x(Co3 O4)x/3-(CeO2)2.5(x=0,0.25,0.50,0.75,0.85 and 1)catalysts were prepared by coprecipitation *** mixed oxide catalysts were characterized by several physicochemical techniques,such as BET surface area(SBET),X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),temperature programmed reduction(TPR)and X-ray photoelectron spectroscopy(XPS).XRD studies show the peaks related to CuO and Co3 O4 phases in copper and cobalt containing CeO2 *** average particle size of the CeO2 crystallites is in the range of 8-10 nm as evaluated from HRTEM *** studies demonstrate that Cu,Co and Ce in(cuO)1-x(Co3O4)x/3-(CeO2)2.5 catalysts are presented in+2 and+1,+3 and+2 and+4 and+3 oxidation states,*** catalyst with x=0.75 shows better activity and selectivity towards *** the catalyst with only copper(CuO-CeO2,x=0)shows good activity but reverse water gas shift(RWGS)reaction is noticed at high *** the other hand,RWGS reaction is suppressed on the cobalt containing CuO-ceO2 *** on CeO2 with x=1 shows hardly any activity for PRoX reaction at low *** methanation activity is observed on CuO-CeO2 or Co3O4-CeO2 *** contrast,combination of copper and cobalt on CeO2 shows methanation of CO where enhanced activity is observed with increasing in cobalt content.

关键词： CO-PROX Cu-CeO2 XRD XPS Methanation H2O addition