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3 results on '"S. Kawadiya"'

1. Determination of distribution ratios of Zr(IV), Co(II), Sb(V) and Nb(V) using polyaniline in acid solutions

Author

Rakesh Verma, A. V. R. Reddy, P.S. Remya Devi, and S. Kawadiya

Subjects
Materials science, Health, Toxicology and Mutagenesis, Metal ions in aqueous solution, Batch method, Zirconium alloy, Oxalic acid, Public Health, Environmental and Occupational Health, Analytical chemistry, 02 engineering and technology, Human decontamination, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Pollution, 0104 chemical sciences, Analytical Chemistry, chemistry.chemical_compound, Nuclear Energy and Engineering, chemistry, Polyaniline, Radiology, Nuclear Medicine and imaging, Heavy water reactors, 0210 nano-technology, Spectroscopy
Abstract

In this work, we report the distribution ratios of Zr(IV), Co(II), Sb(V) and Nb(V) using polyaniline in HCl, HF, oxalic acid and HF + HCl solutions. Distribution ratios were determined by batch method using radiotracer technique. Further, the separation factors and the %-uptake of metal ions were calculated and compared. Among the media studied, separation factors for Co(II), Sb(V) and Nb(V) with respect to Zr(IV) were the highest in 1 M HCl and the values are 52, 108 and 404 respectively. The results of this study can be utilized for designing an ion-exchange process for the decontamination of zircaloy pressure tubes used in the Pressurized Heavy Water Reactors.

Published
2018
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2. Evaluation of the effect of heating on the ion exchage capacity of polyaniline

Author

N. Raje, M.N. Deo, S.R. Vishwakarma, S. Kawadiya, P.S. Remya Devi, A. V. R. Reddy, and Rakesh Verma

Subjects
Thermogravimetric analysis, Chemistry, Mechanical Engineering, Inorganic chemistry, Metals and Alloys, Analytical chemistry, Fluorescence spectrometry, Infrared spectroscopy, Condensed Matter Physics, Chloride, Electronic, Optical and Magnetic Materials, Thermogravimetry, chemistry.chemical_compound, Mechanics of Materials, Polyaniline, Materials Chemistry, medicine, Thermal stability, Fourier transform infrared spectroscopy, medicine.drug
Abstract

Thermal stability of polyaniline was evaluated to assess its use as ion-exchanger at elevated temperatures. Thermogravimetric analysis of salt (chloride) and base form of polyaniline revealed the decomposition pattern and volatile products. Structural modifications in PAni upon heating upto 500 °C were studied using UV–vis spectroscopy, Fourier Transform Infrared spectroscopy, and viscometry. The gaseous decomposition products of polyaniline were identified using high resolution infrared spectroscopy for the first time. Anion exchange capacity of polyaniline, in terms of ionizable chlorine, determined using Energy Dispersive X-ray Fluorescence spectrometry, was found to be 3.25 meq g −1 . Polyaniline was found to retain ∼90% of the original capacity on heating upto 200 °C. These studies evinced the superior thermal stability of polyaniline over conventional anion exchangers.

Published
2015
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3. Fecal Malodor Detection Using Low-Cost Electrochemical Sensors.

Author

Kawadiya S, Welling C, Grego S, and Deshusses MA

Subjects
Humans, Sanitation instrumentation, Ammonia analysis, Electrochemical Techniques instrumentation, Feces chemistry, Hydrogen Sulfide analysis, Odorants analysis
Abstract

Technology innovation in sanitation is needed for the 4.2 billion people worldwide, lacking safely managed sanitation services. A major requirement for the adoption of these technologies is the management of malodor around toilet and treatment systems. There is an unmet need for a low-cost instrumented technology for detecting the onset of sanitation malodor and triggering corrective actions. This study combines sensory data with low-cost gas sensor data on malodor emanating from feces. The response of 10 commercial electrochemical gas sensors was collected alongside olfactometric measurements. Odor from fecal specimens at different relevant dilution as well as specimens with pleasant odors as a control were evaluated for a total of 64 responses. Several of the sensors responded positively to the fecal odor, with the formaldehyde, hydrogen sulfide, and ammonia sensors featuring the highest signal to noise ratio. A positive trend was observed between the sensors' responses and the concentration of the odorant and with odor intensity, but no clear correspondence with dilution to threshold (D/T) values was found. Selected sensors were responsive both above and below the intensity values used as the cutoff for offensive odor, suggesting the possibility of using those sensors to differentiate odor offensiveness based just on the magnitude of their response. The specificity of the sensors suggested that discrimination between the selected non-fecal and fecal odors was possible. This study demonstrates that some of the evaluated sensors could be used to assemble a low-cost malodor warning system.

Published
2020
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