Cost-effective layered double hydroxides/conductive polymer nanocomposites for electrochemical detection of wastewater pollutants

Abstract

There is an urgent need to develop multifunctional cost-effective nanomaterials and nanocomposites that can be used in numerous applications while showing high efficiency and cheaper implementation compared to conventional techniques and/or materials. In this work, zinc/iron layered double hydroxide (LDH) and polyaniline (PANI) were synthesized as a model LDH/conductive polymer nanocomposite, which is a promising family of cheap multifunctional materials. This electrochemical properties of this nanocomposite was investigated for detection of heavy metal (HM) ions in water streams, using lead as a model HM. In the present work, zinc/iron LDH and PANI was assigned as carbon paste electrode modifier. The composite was fully characterized using various characterization techniques including X-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform InfraRed (FTIR). The electrochemical redox reactions of lead (II) ions at the modified electrode interface were investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), Accordingly, a linear relation of Pb2+ ions was achieved in the concentration range 1–80 µM with limit of detection (LOD) was 167.8 nM and limit of quantification (LOQ) was 559.4 nM. Furthermore, the cost of using such material for lead removal using a typical adsorption study was compared to using conventional inductively coupled plasma (ICP) or atomic absorption spectrometry (AAS) equipment for tracking HM removal during the adsorption process. Cost analysis revealed that the final overall cost of the modified carbon paste electrode is estimated as 1.25 USD. This cost represents less than 0.1% of the total cost required to conduct the same adsorption study using a typical ICP or AAS equipment. This composite can pave the road towards portable measurements for onsite detection of wastewater pollutants using cheap disposable-electrodes as compared to massive expensive off site equipment such as ICP and AAS.