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|Title:||Speciation of chromium in aqueous samples by solid phase extraction using multiwall carbon nanotubes impregnated with D2EHPA|
|Keywords:||Solid phase extraction|
|Abstract:||A solid phase extraction system has been developed for the speciation of chromium(III) and chromium(VI). This method is based on the adsorption of chromium(III) on D2EHPA impregnated with multiwall carbon nanotubes and has been compared with commercially available activated carbon impregnated with D2EHPA. The chromium concentration has been determined by inductively coupled plasma atomic emission spectroscopy. The effect of parameters such as <i>p</i>H of the aqueous solution, amount of adsorbent, contact time, initial ion concentration, sample volume, eluent type and D2EHPA concentration have been investigated. The results indicate that the maximum adsorption of chromium(III) is at <i>p</i>H 4.5 ± 0.1 on the multiwall carbon nanotubes. Desorption studies have been carried out with 0.25 <i style="">M</i> Br<sub>2</sub> in 1.0 <i style="">M</i> NaOH wherein quantitative recovery of the chromium(III) has been observed. The adsorption capacity of MWCNTs- D2EHPA is found to be 0.96 mg g <sup>-1</sup> for chromium with detection limit of chromium 0.05 mg mL<sup>-1</sup>. The highest pre-concentration factor of 60 could be obtained for 300 mL of sample volume. The developed method has been applied for the speciation of chromium in natural water sample and the pre-concentration method is satisfactory (recoveries > 98 %, rsd < 10 %, <i>n </i>= 5) for chromium species determination.|
|Appears in Collections:||IJC-A Vol.49A(07) [July 2010]|
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