Synthesis of Bamboo-like Multiwall Carbon Nanotube-Poly(Acrylic Acid-co-Itaconic Acid)/NaOH Composite Hydrogel and its Potential Application for Electrochemical Detection of Cadmium(II).

Luis F. Chazaro-Ruiz,Wei Zhang,Gabriela Vidal,Fatima Perez,Miguel Olvera-Sosa,J. Rene Rangel-Mendez,Gabriela Palestino

doi:10.3390/bios10100147

Abstract

A poly(acrylic acid-co-itaconic acid) (PAA-co-IA)/NaOH hydrogel containing bamboo-type multiwall carbon nanotubes (B-MWCNTs) doped with nitrogen (PAA-co-IA/NaOH/B-MWCNTs) was synthesized and characterized by SEM, absorption of water, point of zero charges, infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The possible use of the PAA-co-IA/NaOH/B-MWCNT hydrogel as an electrode modifier and pre-concentrator agent for Cd(II) sensing purposes was then evaluated using carbon paste electrodes via differential pulse voltammetry. The presence of the B-MWCNTs in the hydrogel matrix decreased its degree of swelling, stabilized the structure of the swollen gel, and favored the detection of 3 ppb Cd(II), which is comparable to the World Health Organization’s allowable maximum value in drinking water. A calibration curve was obtained in the concentration range of 2.67 × 10−8 to 6.23 × 10−7 M (i.e., 3 and 70 ppb) to determine a limit of detection (LOD) of 19.24 μgL−1 and a sensitivity of 0.15 μC ppb−1. Also, the Zn(II), Hg(II), Pb(II) and Cu(II) ions interfered moderately on the determination of Cd(II).

Highlights

Multiwall carbon nanotubes (MWCNTs) have been used in numerous applications, including biomedicine, energy conversion and storage, as well as in the construction of nanoscale electronic and electrochemical devices such as sensors and biosensors [1]
Covalently crosslinked MWCNTs with polymeric chains have led to the preparation of nanocomposite hydrogels, which have better mechanical, thermal, optical, and electrical properties compared to pure hydrogels [12]
−1 stretching at 3450 cm, which is typical for poly(acrylic acid) (PAA) and similar polymers [34,35]

Summary

Introduction

Multiwall carbon nanotubes (MWCNTs) have been used in numerous applications, including biomedicine, energy conversion and storage, as well as in the construction of nanoscale electronic and electrochemical devices such as sensors and biosensors [1]. To improve their manipulation and performance on mechanical and chemical operations, non-covalent and covalently crosslinked MWCNTs with polymeric materials have been prepared. The non-covalent wrapping of their surface with polyanionic materials [5], a hydrophilic non-charged polymer [6,7,8], a polyelectrolyte multilayer film [9], and the linear poly(acrylic acid) [10] have been reported. These interactions made the CNTs stable in water and preserved their electrocatalytic properties in the redox reactions. Covalently crosslinked MWCNTs with polymeric chains have led to the preparation of nanocomposite hydrogels, which have better mechanical, thermal, optical, and electrical properties compared to pure hydrogels [12]

Methods

Results

Conclusion