Optimization of ethylenediamine-grafted multiwalled carbon nanotubes for solid-phase extraction of lead cations

• IntroductionEthylenediamine-grafted multiwalled carbon nanotubes (MWCNTs-EDA-I and MWCNTs-EDA-II) are optimized and employed to investigate the preconcentration of lead ions (Pb(II)) in trace level.ResultsThe results show that Pb(II) can be adsorbed quantitatively on the optimized MWCNTs in the range of pH 4–7 and MWCNTs-EDA-I has a higher maximum Pb(II) adsorption capacity (157.19 mg/g) than MWCNTs-EDA-II (89.16 mg/g). The adsorbed Pb(II) can be eluted completely using 5 mL of 1 mol/L HNO3.DiscussionA new approach using a microcolumn packed with the obtained MWCNTs-EDA-I has been developed for the preconcentration of trace amount of Pb(II). Parameters influencing the preconcentration of Pb(II), such as pH of the sample, sample volume, elution solution, and interfering ions, have been examined and optimized in detail. Under optimum experimental conditions, the limit of detection is 0.30 ng/mL with the enrichment factor of 60. The relative standard deviation (R.S.D) was 2.6% at the 20 ng/mL Pb(II) level.ConclusionThe method has been applied for the preconcentration of trace amount of Pb(II) in environmental water samples with satisfying results.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

Carbon nanotubes

SPE

Preconcentration

Heavy metals

Lead cation

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