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- Mahanta, C., et al.
(författare)
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Evaluation of arsenic removal potential of few indigenous materials through batch study
- 2012
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Ingår i: Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment. - : CRC Press. - 9780415637633 ; , s. 289-290
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Konferensbidrag (refereegranskat)abstract
- Adsorption potential and characteristics of the four different indigenous materials i.e. Naturally Oxidized Iron Scrap (NOIS) sand, red soil and murum, (a type of lateritic soil which is a mix of finer and coarser grained sized particle and available in some parts of eastern India; for experimental purpose the coarser particles were used) were investigated with different operating parameters like pH, contact time, temperature, adsorbent dose and initial arsenic concentration in batch mode. From the pH study, it was found that the adsorbents were efficient in adsorbing Arsenic (As) in acidic media. Adsorption kinetics of arsenic sorption on the selected adsorbents followed Lagergren pseudo second order reaction model. The thermodynamic study evaluated that the adsorption processes of all adsorbents were exothermic in nature. The experimental equilibrium data obtained were applied to several isotherm models. Results revealed that the Freundlich isotherm was the best-fit model. The maximum adsorption capacity (q m) was found to be highest for NOIS [156 %mu;g/g for As (III) and 245 %mu;g/g for As (V)]. The batch studies ensured that the NOIS can be used as a promising adsorbent for arsenic remediation in developing indigenous treatment technologies.
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| 2. |
- Mahanta, C., et al.
(författare)
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Geochemical evidences in the release processes of Arsenic into the groundwater in a part of Brahmaputra Floodplains
- 2012
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Ingår i: METALS AND RELATED SUBSTANCES IN DRINKING WATER. - : IWA PUBLISHING. ; , s. 268-271
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Konferensbidrag (refereegranskat)abstract
- To understand the sources and mobilization processes responsible for arsenic enrichment in groundwater in the Brahmaputra Basin where higher arsenic concentration have been reported, the geochemical features of the aquifer sediments were studied. Six boreholes were drilled near the tubewells (1 and 2) where aqueous arsenic concentration varies between 250 - 350 mu g/l. The soil sediment was collected at 3 m (10 ft) interval and it was drilled to the depth of 45 m (150 ft) which is the common depth of the tubewell installed in the study area. The bulk chemical studies on the sediments show that the pH of soils varies from 4.2 to 5.2 with a mean value of 4.75. The groundwater composition in the study area is of Na-HCO3-. The major anions HCO3- is likely from the decomposition of organic matter and originates from weathering of silicate and calcite minerals by atmospheric or respired CO2. Selective sequential extraction (SSE) method proposed by Wenzel et al., (2001) for extraction of arsenic from soil was used. Results of sequential extraction experiment show that solid-phase arsenic is present predominantly in the reducible fraction (Ext_5 and Ext_6), and residual fraction (Ext_7) contributes to highest fraction in many soil sediment. The major processes of arsenic mobilization probably linked to desorption of As from Fe oxides/oxyhydroxides and the reductive dissolution of Fe rich phases in the aquifers sediments under reducing and alkaline conditions.
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