Effectiveness study of sensor based on modified cavity microelectrode by Algerian humic acid-polyaniline composites using square wave voltammetry

The response and efficiency of a new sensor based on cavity microelectrode (CME) modified with Algerian humic acid-polyaniline emeraldine base composites (HA-PEB) towards concentration of nickel and cadmium has been studied by square wave voltammetry technique (SWV). The developed mechanism is based on the electrochemical reduction of metal to CME modified with HA-PEB for different metal concentrations. The electrochemical study was performed in H2SO4 (0.5 mol/L) at room temperature in the potential range between -0.15 and -0.5 V towards saturated calomel electrode (SCE). The obtained results show that the CME modified with HA-PEB composites responds sensitively to variation of Ni2+ and Cd2+ concentrations, whatever the nature of humic acid. The measurements performed using CME modified with Yakouren humic acid (YHA)-PEB and Tamanrasset humic acid (THA)-PEB gave better sensitivity and good linearity of current versus metal concentration. The application of the sensor to detect heavy metals in water of the Sebaou River (Kabylia, Algeria) revealed that the CME modified with PEB does not detect different metals, while the sensor based on CME-HA-PEB has the ability to detect the presence of more metals in river water. Finally, it can be concluded that HA extracted from Algerian soils play an important role in the effectiveness of the sensor based on cavity microelectrode. (C) 2012 Elsevier B.V. All rights reserved.