Evaluation of adsorption capacities of humic acids extracted from Algerian soil on polyaniline for application to remove pollutants such as Cd(Ⅱ), Zn(Ⅱ) and Ni(Ⅱ) and characterization with cavity microelectrode

Evaluation of adsorption capacities of humic acids extracted from Algerian soilon polyaniline for application to remove pollutants such as Cd(II), Zn(II) andNi(II) and characterization with cavity microelectrode

The adsorption capacities of new humic acids isolated from Yakouren forest (YHA) and Sahara (Tamenrasset: THA) soils (Algeria)and commercial humic acid (PFHA) on polyaniline emeraldine base (PEB) were studied at pH 6.6. Also the adsorption of heavymetals such as Cd2+, Zn2+ and Ni2+ on humic acid-polyaniline systems (HA-PEB) was investigated at the same conditions. HA-PEBcompounds were characterized by scanning electron microscopy (SEM), infrared spectrometry and cavity microelectrode. In addition,batch adsorption and cavity microelectrode were used in the adsorption study of Cd2+, Zn2+ and Ni2+ on HA-PEB. To develop biocaptorsof polluting metals using a cavity microelectrode modified by HA-PEB systems, the adsorption kinetic and adsorption capacity wereinvestigated. The SEM analysis showed that the presence of humic acid affected the PEB surface and caused the formation of agranular morphology. The maximum adsorption capacities (qmax) of PFHA, THA and YHA determined by adsorption isotherms were91.31, 132.1 and 151.0 mg/g, respectively. Batch adsorption results showed that qmax of Cd2+, Zn2+ and Ni2+ on HA-PEB followedthe order: THA-PEB > YHA-PEB > PFHA-PEB. The voltammograms obtained with HA-PEB modified cavity microelectrode showedthe appearance of new redox couples reflecting the adsorption of HA on PEB. Metal-humic acid-polyaniline voltammograms werecharacterized by appearance of oxidation-reduction couples or reduction wave corresponding to metal. Finally, the result may beexploited to develop a biocaptor based on the cavity microelectrode amended by THA-PEB and YHA-PEB.