THE SORPTION OF HG(II) ONTO SINGLE-WALL CARBON NANOTUBES EVALUATED WITH ESCHERICHIA COLI pMerR ':: LUX BIOSENSOR

Background. Carbon allotropes are traditionally used as polyvalent physicochemical antidotes, and carbon-based nanomaterials are investigated extensively now. Aim. The goal of this study is to evaluate the sorption of mercury ions on single-wall carbon nanotubes (SWCNTs) that was done according by bacterial lux-biosensor reaction. Methods. SWCNTs functionalized with F or NH2 groups were used to investigate the removal of Hg(II) ions from aqueous solutions. The recombinant luminescent strain Escherichia coli K12 MG1655, carrying the hybrid plasmid pMerR ':: lux with the Photorhabdus luminescens luxCDABE-genes cassette cloned under inducible mer-operon promoter was used for residual Hg(II) quantitative detection. Results. The high sorption capacity qE = (2 ± 0.2) x10- 6 mg / mg of the F-SWCNT was shown, while Hg (II) retention on the NH2-SWCNT was very low. The adsorption isotherm data for FSWCNT could be well described by the Temkin equations (sorption on inhomogeneous surface involving activated cites). X-ray phase analysis indicated the mercury ions stabilization in the sorbent matrix in HgF2, Hg2OCl, Hg4OCl2, and Hg2Cl2 forms. Discussion. The primary interaction between mercury ions and modifying groups on F-SWCNT surface may be due to the electrostatic forces, while final Hg stabilization in the sorbent matrix suggests additional hydrodysis and recovery reactions. These data has shown possibilities of F-SWCNT and other halogenated nanotubes as effective Hg (II) sorbents as well as analytical capabilities of the bacterial luminescent biosensor E. coli pMerR ':: lux for sorption evaluation.