Search

Carbon nanotubes (CNTs) have been considered as an excellent adsorbent in environmental engineering, especially for treatment of volatile organic compounds (VOCs). The paper presents a new approach for the selective adsorption of Xylene isomers from air samples using nanomaterial based on oxidized multiwalled carbon nanotubes. In the first study, the functionalization of two oxidized MWCNTs was achieved with hydrogen peroxide and sodium hypochlorite. The characterization of functionalized CNTs (CNT-NaOCl, CNT-H2O2) was performed by Fourier transform infrared spectroscopy (FT-IR) and X-Ray diffractometer (XRD). Afterthat, the applications of pristine CNTs and oxidized CNTs for removal of three Xylene isomers from air samples were discussed. The results demonstrate that the correlation of CNTs and three isomers was significantly different with an affinity order o-Xylene > m-Xylene > p-Xylene. The oxidized CNTs with carbonyl groups increased significantly its adsorption capacity for these isomers. A comparison in term of adsorption performance shows that the framework distinguishes among these adsorbents due to the dispersive properties and the electrostatic interaction between the Xylene isomers and oxidized CNTs surface.

Carbon nanotubes (CNTs) have been widely used as adsorbent in environmental treatment, especially for pollutants and volatile organic compounds (VOCs). The purpose of this work is to develop materials based on functionalized multiwalled carbon nanotubes (MWCNTs) for Benzene and Toluene removal. This will exploit adsorption propertiesof modified MWCNTS for Benzene and Toluene. In the first study, adsorption capacity of pristine MWCNTs to Benzene and Toluene in aqueous solution was investigated through isotherm study. The qe values of CNTs for Benzene and Toluene were 45,5 mg.g-1 and 56.3 mg.g-1, respectively and a contact time of 120 min. The modification of three oxidized MWCNTs were performed with acid solution (HNO3/H2SO4), hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl). The modified MWCNTs materials (CNT-COOH,CNT-NaOCl,CNT-H2O2) were characterized by Fouriertransform infrared spectroscopy (FT-IR). The effects of functional groups on the MWCNTs on the adsorption capacity of Benzene, Toluene in aqueous solution were studied and compared to pristine MWCNTs. The results demonstrated that the efficiency of adsorption was significantly enhanced with oxidized CNTs, and following the order CNTs-NaOCl > CNTs-H2O2> CNTs-H2SO4> pristine CNTs.

The coupling compound of Biotin (Vitamin H) and redox molecule ferrocene throughcovalent bonding was studied. Synthesis and structure identification of Biotinylated 1 - (- 2-aminoethyl) ferrocene were performed by 1H-NMR, 13C-NMR and MS. The ultimate goal of thispaper is to develop derivatives of ferroceneservingas an electrochemical probe that wouldenhance the performance of immunosensor.An immunosensor based on polypyrrole-streptavidinlayer as platform for immobilization of biotinylatedferrocene and antibodies was developed. Themeasurement of redox signal of ferrocene was analyzed by differential pulse voltammetry(DPV) method and underlined a variation of redox properties upon the antigen interaction. Theintroduction of the redox biotinylatedferrocene into streptavidin-polypyrrole layer affords a goodsensitivity of the biosensor with a detection limit of 0.16 pg.mL-1.