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81.
82.
Deepika Kushwaha Ishita Mishra Neha Srivastava 《International Journal of Green Energy》2017,14(13):1110-1118
Present investigation was done to evaluate various algal genera found in water bodies of Varanasi city. The potential of any biomass for biofuels (bioalcohols, biohydrogen, etc.) production depends on the quantity of extractable sugar present in it. Acid (H2SO4) and alkali (NaOH) pretreatment were performed, and H2SO4 was chosen due to its nearly double yield as compared with alkaline pretreatment. Response surface methodology was utilized for the optimization of operating parameters such as treatment temperature, time, and acid concentration. Sugar yield up to 0.33 g/g of dry biomass was obtained using cyanobacterial biomass of Lyngbya limnetica, at 100°C, 59.19 min, and H2SO4 concentration of 1.63 M. 相似文献
83.
Aniza K. Verma Avanish K. Srivastava Beer Singh Dilip Shah Smriti Shrivastava Chandra Kant P. Shinde 《Chemosphere》2013,90(8):2254-2260
1-(4-Chlorophenyl))-N-hydroxymethanimine and cyclohexyl-N-hydroxymethanimine were synthesized and a well-established oxime, i.e., 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride was purchased. Thereafter; all were loaded over Al2O3 using incipient wetness technique. The prepared systems were characterized using surface area analyzer, scanning electron microscope, energy dispersive X-ray spectrophotometer, Fourier transform infrared spectrophotometer and thermogravimetric analyzer. Kinetics of the degradation of sarin (GB) and simulant, i.e. diethylchlorophosphate (DEClP) was studied over synthesized oxime impregnated Al2O3 and results were compared with well reported oxime impregnated Al2O3. Kinetics of reaction was found to be following the pseudo first order reaction kinetics. The order of reactivity of the prepared systems was found to be cyclohexyl-N-hydroxymethanimine/Al2O3 > 1-(4-chlorophenyl)-N-hydroxymethanimine/Al2O3 > 2-[(hydroxyimino)methyl]-1-methylpyridinium chloride/Al2O3 > Al2O3. From the reaction kinetics it was observed that the reaction with DEClP was faster than with GB. Cyclohexyl-N-hydroxymethanimine/Al2O3 was found to be the most reactive system with half-life of 0.94 and 15 h for DEClP and GB respectively. 相似文献
84.
J. K. Saha A. K. Sharma Ajay Srivastava 《Environmental monitoring and assessment》2014,186(4):2349-2356
This study was carried out in three different cities of western Madhya Pradesh (India) to investigate the effects of long-term irrigation with industrial waste water (IWW), contaminated groundwater (CGW), and untreated municipal sewage water (USW) on soil fertility as well as on wheat crop yield. Irrigation with these three types of polluted water increased organic matter content as well as contents of available P (with IWW and USW only), available K, available S, available Zn, available Cu (IWW only), and available Mn (IWW and CGW only). The magnitude of improvement in soil fertility status was the highest in the case of USW, followed by IWW and finally, by CGW. Concentrations of Na in wheat leaf tissue increased by 198 and 58 % whereas concentrations of Ca decreased significantly by 16 and 13 % due to the use of IWW and CGW, respectively, resulting in poor Ca nutrition to the crop. Although wheat grain yield increased considerably due to USW, the same recorded significant decreases with IWW and CGW. In spite of the enhancement in the available nutrient status, decrease in wheat grain yield with the use of IWW and CGW could be due to the build-up of salts in the soil and an imbalance in the Na/Ca ratio in wheat crops irrigated with IWW and CGW. The adverse effect on wheat productivity was more pronounced with IWW as compared to CGW. 相似文献
85.
Characterization and pollutant removal efficiency of biochar derived from baggase,bamboo and tyre 总被引:1,自引:0,他引:1
S. Ramola T. Mishra G. Rana R. K. Srivastava 《Environmental monitoring and assessment》2014,186(12):9023-9039
Conversion of broad-spectrum organic waste into carbonaceous biochar has gained enormous interest in past few years. The present study aims to characterize feedstock (FS), i.e. bagasse (Bg), bamboo (Bm) and biochar (BC), i.e. baggase biochar (BBg), bamboo biochar (BBm) and tyre biochar (Ty). Significant changes in elemental composition, atomic ratio, proximate analyses, mineral content and heavy metal content were observed which was well supported by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Impregnation with ferric hydroxide was done, and resultant modified biochars (MBC), i.e. iron-impregnated baggase biochar (FeBBg), iron-impregnated bamboo biochar (FeBBm) and iron-impregnated tyre biochar (FeTy), along feedstock and biochar were used for PO4 3?, Pb, Hg and Cu adsorption. In general, BBg, FeBBg, BBm, FeBBm, Ty and FeTy were found to adsorb PO4 3?, Pb, Hg and Cu better than Bg and Bm, except in few cases. Results from adsorption experiments were fitted into Langmuir, Freundlich and Temkin models of isotherms and pseudo-first-order, pseudo-second-order and Elovich models of kinetics. Result of batch study adsorption revealed that maximum adsorption of PO4 3?, Pb, Hg and Cu was done by FeBBg (adsorption mechanism explained by Freundlich model), FeTy (Temkin model), Ty (Langmuir model) and BBm (Langmuir model) respectively. According to R 2 values, pseudo-first-order reaction was well suited to PO4 3?, Pb, Hg and Cu adsorption. The optimum pH for maximum adsorption was observed to be 7.4 for PO4 3?, 5 for Cu and 6 for Pb and Hg respectively 相似文献
86.
Arsenic occurrence and accumulation in soil and water of eastern districts of Uttar Pradesh, India 总被引:1,自引:0,他引:1
Saumya Srivastava Yogesh Kumar Sharma 《Environmental monitoring and assessment》2013,185(6):4995-5002
Arsenic in the soil and water of eastern districts of Uttar Pradesh (Ballia and Ghazipur) was estimated. Survey results revealed that arsenic in soil samples ranged from 5.40 to 15.43 parts per million (ppm). In water samples, it ranged from 43.75 to 620.75 parts per billion (ppb) which far exceeded the permissible limit of 10 ppb as recommended by the World Health Organization. Maximum concentration of arsenic in water was found in Haldi village of Ballia (620.75 ppb). However, mean arsenic concentration in water followed the order: Karkatpur (257.21 ppb) < Haldi (310.15 ppb) < Sohaon (346.94 ppb) < Dharmarpur (401.75 ppb). In case of soil, maximum arsenic was detected in soil of Sohaon (15.43 ppm). Mean arsenic levels in soils followed the order: Karkatpur (9.24 ppm) < Haldi (9.82 ppm) < Dharmarpur (11.32 ppm) < Sohaon (14.08 ppm). Arsenic levels were higher in soils collected from 15–30 cm depth than 0–15 cm from the soil surface. 相似文献
87.
Deepak Singh Amit Prakash A. K. Srivastava Krishan Kumar V. K. Jain 《Environmental monitoring and assessment》2013,185(2):1873-1882
The acoustic environment in urban areas has gained prominence in recent times due to rapid industrial and commercial development in metropolitan cities. Various attempts have been made to predict and model the trends in urban ambient noise levels using different statistical and dynamic models. The present study makes an attempt to examine the role of meteorological parameters affecting the ambient noise levels in Delhi. The results show significant improvement in overall noise scenario of Delhi since the introduction of compressed natural gas vehicles in public transport of Delhi. The noise level is significantly reduced by high vegetation cover as well as by low relative humidity over Delhi. The regression models developed for the present study clearly show the significant contribution of meteorological parameters in governing the ambient noise levels in Delhi. 相似文献
88.
Mass size distributions of total suspended particulate matter (TSPM) was measured from Sep 2002 to April 2003 in indoor kitchen environments of five locations in Jawaharlal Nehru University (JNU), New Delhi, with the help of a high volume cascade impactor. Particulate matters were separated in five different size ranges, i.e. >10.9 microm, 10.9-5.4 microm, 5.4-1.6 microm, 1.6-0.7 microm and <0.7 microm. The particle size distribution at various sites appears to follow uni-modal trend corresponding to fine particles i.e. size range <0.7 microm. The contributions of fine particles are estimated to be approximately 50% of TSPM and PM10.9, while PM10.9 comprises 80% of TSPM. Good correlations were observed between various size fractions. Regression results reveal that TSPM can adequately act as a surrogate for PM10.9 and fine particles, while PM10.9 can also act as surrogate for fine particles. The concentrations of heavy metals are found to be dominantly associated with fine particles. However, the concentration of some metals and their size distribution, to some extent is also site specific (fuel type used). 相似文献
89.
Jay Krishna Thakur P. K. Srivastava S. K. Singh Zoltán Vekerdy 《Regional Environmental Change》2012,12(1):133-144
Wetland ecosystems are of global significance having productive, regulatory and informative function. These wetlands are crucial
for the long-term protection of water sources, as well as the survival of its unique biodiversity. Most of the wetlands of
Turkey are now facing serious threat from the anthropogenic sources and now near to the verge of extinction. This study has
been carried out to monitor vegetation dynamics and ecological status of wetlands of Koyna basin at spatial and temporal scale.
This study has involved MODerate-resolution Imaging Spectroradiometer (MODIS) images of the year 2000, 2004 and 2008 on daily
basis with spatial resolution of 1 km. The MODIS 16 days composite NDVI time series products of 250-m spatial resolution from
year 2000 to 2008 has been utilized to monitor the ecological status of the wetlands. The European Nature Information System
habitat classification map, meteorological data (precipitation, temperature) coupled with field data has been utilized to
validate NDVI values of nine habitats in the wetlands. The time series analyses of NDVI data values have been correlated with
the groundwater level depth from 1996 to 2004. The overall analysis has shown a declining trend of NDVI over the year 2000
to 2008, indicated a degraded wetland condition in span of 9 years. 相似文献
90.
Ravi K. Srivastava Robert E. Hall Sikander Khan Kevin Culligan Bruce W. Lani 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1367-1388
Abstract Recent regulations have required reductions in emissions of nitrogen oxides (NOx) from electric utility boilers. To comply with these regulatory requirements, it is increasingly important to implement state-of-the-art NOx control technologies on coal-fired utility boilers. This paper reviews NOx control options for these boilers. It discusses the established commercial primary and secondary control technologies and examines what is being done to use them more effectively. Furthermore, the paper discusses recent developments in NOx controls. The popular primary control technologies in use in the United States are low-NOx burners and overfire air. Data reflect that average NOx reductions for specific primary controls have ranged from 35% to 63% from 1995 emissions levels. The secondary NOx control technologies applied on U.S. coal-fired utility boilers include reburning, selective noncatalytic reduction (SNCR), and selective catalytic reduction (SCR). Thirty-six U.S. coal-fired utility boilers have installed SNCR, and reported NOx reductions achieved at these applications ranged from 15% to 66%. Recently, SCR has been installed at >150 U.S. coal-fired utility boilers. Data on the performance of 20 SCR systems operating in the United States with low-NOx emissions reflect that in 2003, these units achieved NOx emission rates between 0.04 and 0.07 lb/106 Btu. 相似文献