Removal and recovery of lead (II) ions from contaminated licorice extracts using oxidized multi-walled carbon nanotubes

A column with oxidized multi-walled carbon nanotubes (MWNTs) has been studied as a sorbent for removing and accumulating lead (II) from contaminated Licorice extracts. Under optimized situation, the adsorption capacity of lead (II) on oxidized MWNTs was 17 mg g(-1) at pH 7.0, and the lead (II) was eluted with 10 ml of 1% hydrochloric acid. Additionally, the effects of adsorptive parameters, including pH of the solution, sample volume, flow rates of the sample, matrix ions, and eluent type were investigated for optimization of the presented procedure. A fluorescence spectrophotometer was employed to determine the contents of lead (II). High-performance liquid chromatography (HPLC) was developed for the quantitative determination of main constituents of Licorice extracts. Oxidized MWNT cartridges were used to remove lead ions from contaminated Licorice extracts, high adsorption capacity, adsorption reversibility of lead (II), and low loss of major constituents. The results suggested that the oxidized MWNT column has the potential to remove heavy metal ions from herbal extracts.