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ABSTRACT: Due to large growth in leather and textile industries to cater for the needs of a growing world population, contamination of soil and water resources by chromium has become a great threat for humans and animals. In this work, Laser Induced Breakdown Spectroscopy (LIBS) was applied to monitor the remediation process of soil contaminated with Chromium metal. This study was conducted at a laboratory scale by setting up an experiment in a container holding soil contaminated with chromium. This setup represents actual field conditions where remediation process could be applied and monitored for the removal of toxic metals like Cr. For generation of LIBS spectrum, the plasma was produced by focusing a pulsed Nd: YAG laser at 1064 nm on the soil contaminated with chromium under remediation process. The evaluation of the potential and capabilities of LIBS as a rapid tool for remediation process of contaminated sites is discussed in detail. Optimal experimental conditions were evaluated for improving the sensitivity of our LIBS system for monitoring of remediation process through parametric dependence study. The minimum detection limit of our spectrometer for chromium in soil matrix was 2 mg Kg(-1).
Journal of hazardous materials 09/2008; 163(2-3):1265-71. · 4.14 Impact Factor
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ABSTRACT: Study of various binding materials like potassium bromide, poly(vinyl alcohol), starch, silver and aluminum has been carried out using laser-induced breakdown spectroscopy (LIBS). The role of matrix effects using these five binders on LIBS signal intensity was investigated for better performance of LIBS technique as a quantitative analytical tool. For comparative study of different binders, the signal intensity of different Mg lines at 518.3, 517.2, 383.8 and 279.5nm wavelengths were recorded for pellets prepared with known concentrations of Mg in these binders. The influence of laser energy on ablated mass under different binding materials and its correlation with LIBS signal intensity has been explored. Optical scanning microscopy images of the ablated crater were studied to understand the laser ablation process. The study revealed that the binding material plays an important role in the generation of LIBS signal. The relative signal intensity measured for a standard Mg line (at 518.3nm) were 735, 538, 387, 227 and 130 for potassium bromide, starch, poly(vinyl alcohol), silver and aluminum as binders, respectively. This indicates clearly that potassium bromide is better as a binder for LIBS studies of powder samples.
Talanta 05/2007; 72(2):642-9. · 3.79 Impact Factor
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ABSTRACT: Laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of nutrients in the green house soil samples. We determined appropriate spectral signatures of vital nutrients and calibrated the method to measure the nutrients in a naturally fertilized plot, cultivated with tomato and cucumber plants. From the calibration curves we predicted the concentrations of important nutrients such as Ca, K, P, Mg, Fe, S, Ni and Ba in the soil. Our measurements proved that the LIBS method rapidly and efficiently measures soil nutrients with excellent detection limits of 12, 9, 7, 9, 7, 10, 8 and 12 mg/kg for Ca, K, P, Mg, Fe, S, Ni and Ba respectively with a precision of approximately 2%, The unique features of LIBS for rapid sample analysis demonstrated by this study suggests that this method offers promise for precision measurements of soil nutrients as compared to conventional methods in short span of time.
Environmental Monitoring and Assessment 02/2007; 124(1-3):131-9. · 1.40 Impact Factor
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ABSTRACT: Laser induced breakdown spectroscopy (LIBS) was applied for the elemental analysis of Arabian crude oil residue samples. The spectra due to trace elements such as Ca, Fe, Mg, Cu, Zn, Na, Ni, K and Mo were recorded using this technique. The dependence of time delay and laser beam energy on the elemental spectra was also investigated. Prior to quantitative analysis, the LIBS system was calibrated using standard samples containing these trace elements. The results achieved through this method were compared with conventional technique like inductively coupled plasma.
Talanta 08/2006; 69(5):1072-8. · 3.79 Impact Factor
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ABSTRACT: A novel photoacoustic spectrometer (PA) has been developed for
in-situ detection of SF<sub>6</sub> leaks in low concentrations. The
developed system is equipped with a sound alarm system and has been
tested in the laboratory for very minute SF<sub>6</sub> leaks. This
newly developed SF<sub>6</sub> detection device utilizes a high quality
factor resonant photoacoustic cell and continuous wave (CW) line tunable
CO<sub>2</sub> laser at 10.55 μm wavelength. Whenever SF<sub>6</sub>
is detected an acoustic signal is generated and no signal appears from
ambient air if there is no leakage of SF<sub>6</sub>. An electret
microphone is used for the detection of these acoustic signals. The
system is capable of detecting leaks of the order of 3.5 ppbv (parts per
billion by volume) concentration. This device has been proved to have
significant applications to industrial organizations that have electric
power gas insulated systems (GIS). It could be also applied for other
applications such as monitoring of environmental pollutants with minimal
adjustments
IEEE Transactions on Dielectrics and Electrical Insulation 07/2002; · 1.09 Impact Factor
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ABSTRACT: Laser induced breakdown spectroscopy (LIBS) was applied for the elemental analysis of Arabian crude oil residue samples. The spectra due to trace elements such as Ca, Fe, Mg, Cu, Zn, Na, Ni, K and Mo were recorded using this technique. The dependence of time delay and laser beam energy on the elemental spectra was also investigated. Prior to quantitative analysis, the LIBS system was calibrated using standard samples containing these trace elements. The results achieved through this method were compared with conventional technique like inductively coupled plasma.
Talanta.
