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Sharma MK Jain CK Singhal DC Choubey VK 《Environmental monitoring and assessment》2009,157(1-4):11-21
A number of low cost waste sorbent have been used for removal of heavy metals, however, few studies have been carried out on the sorption process on riverbed sediments in their natural state of occurrence. Stream sediments adsorb certain solutes from streams, thereby significantly changing the solute composition, but little is known about quantitatively describing sorption phenomena and rates of these processes. In the present investigation, sorption of lead ions on river bed sediments of river Hindon, a tributary of river Yamuna, India has been studied to demonstrate the role of bed sediments in controlling metal pollution. The effect of various operating variables, viz., initial concentration, solution pH, sediment dose, contact time and particle size has been studied. The sorption of lead ions increased with respect to pH and sorbent dose and decreased with sorbent particle size. Two important geochemical phases, iron and manganese oxide, also play important role in the sorption process. The sorption data were analysed using Langmuir and Freundlich isotherm models to determine the mechanistic parameters related to the sorption process. Further, although lead ions have more affinity for the fine fraction of the sediment, but the overall contribution of coarser fraction to sorption is more as compared to clay and silt fraction. The kinetic data suggest that the sorption of lead on bed sediments is an endothermic process, which is spontaneous at low temperature. The uptake of lead is controlled by both bulk and intraparticle diffusion mechanism. 相似文献
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Jha MK Choubey PK Jha AK Kumari A Lee JC Kumar V Jeong J 《Waste management (New York, N.Y.)》2012,32(10):1919-1925
Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50g/L and temperature 90°C in mixing time 165min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60min and pulp density 50g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment. 相似文献
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Purandara BK Varadarajan N Venkatesh B Choubey VK 《Environmental monitoring and assessment》2012,184(3):1371-1378
Belgaum city is a developmental hub of Karnataka State in India. In the recent time, the Government of Karnataka has planned
to set up many processing industries in the vicinity of Belgaum to meet the growing needs of the region and to ease out the
pressure on the already existing industrial hubs in Karnataka State. Ghataprabha, a tributary of river Krishna, is one of
the major sources of water supply to Belgaum city and adjoining areas. During the last decade, a lot of anthropogenic activities
such as unplanned agricultural activities are ongoing in many parts of the catchment. Therefore, people of Belgaum are more
concerned about the quality of water in Ghataprabha river. Considering the significance of water quality of the river, surface
water samples were collected during Pre- and Post-monsoon season from selected locations and analyzed for both physical and
chemical constituents in the laboratory. The results indicate that the chemical parameters such as bicarbonates, sulphates,
chlorides, sodium, potassium, calcium and magnesium are within the permissible limits. QUAL2E model was applied to assess
the impact of point and non-point sources of pollution on the river water quality. Results show that the water quality conditions
are highly acceptable all along the river stretch. Further, the variation of DO–BOD5 with river discharge was also estimated. Also, a significant variations in DO (decrease in DO) with the increase in river
flow was observed. However, at the downstream end, considerable improvement in DO was noticed which is attributed to the damming
effect of the reservoir. 相似文献
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Environment, Development and Sustainability - The environmental concern is on rise in all types of business; however, banking assumes a special niche due to its ability to influence the economic... 相似文献
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Monitoring of radon, thoron and their daughter products was carried out in houses of Kumaun Himalaya, India using LR-115 plastic track detectors. The measurements were made in residential houses from June 1999 to May 2000 at a height of 2.5 m from ground level using a twin chamber radon dosimeter. The twin chamber radon dosimeter can record the values of radon, thoron and their decay products separately. Maximum and minimum indoor radon and thoron concentrations were evaluated and activity concentrations of radon and thoron daughters were estimated. The resulting dose rates due to radon, thoron and their decay products varied from 0.04 to 1.89 microSv/h. A detailed analysis of the distribution of radon, thoron and their decay products inside the house is also reported. The observed dose rates inside the houses of Kumaun Himalaya were found to be lower than the ICRP recommended value of 200 Bq/m3 and thus are within safe limits. 相似文献
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Srivastava Vartika Choubey Abhay Kumar 《Environmental science and pollution research international》2023,30(13):35838-35852
Environmental Science and Pollution Research - By integrating the benefits of poly vinyl alcohol (PVA) and chitosan (CS) with α-MnO2 nanoparticles (MNPs), a novel type of nano-polymer... 相似文献
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