Possible Monitoring and Removal of As(III) by an Integrated System of Electrochemical Sensor and Nanocomposite Materials

Xuan T Chu,Thanh D Pham,Quan V V Trieu,Tuan A Mai,Thinh Q Tran,Trung Q Vu,Thuy H Tran

doi:10.1155/2018/9250463

Abstract

In this study, nanocomposites composed of magnetite nanoparticles (MNPs) coated with polyaniline fabricated by in situ polymerization were prepared for arsenic adsorption. Properties of particular MNPs and their nanocomposites were characterized with scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. The As(III) concentration before and after adsorption on nanocomposites was detected by atomic absorption spectroscopy method and then compared with the results measured by a self-developed potentiostat system with anodic stripping voltammetry method. The polyaniline coating resulted in an improvement for As(III) adsorption ability of magnetite nanoparticles, and among the three compositions of PAni/MNP nanocomposites, the 5 wt% PAni showed the highest capability of As(III) adsorption (or removal) of 50 mg/g. Performing pH investigation, the concentration of remaining As decreased when pH increased from 2 to 5 and reached saturation value at higher pH. Above all, the electronic device can be integrated with As(III) removal system using PAni/MNP nanocomposites, proving to act as an independent monitoring system, and even more the adsorbent on the composites could be removed and the recyclability of the material was also investigated.

Highlights

Arsenite (As III) and arsenate (As V) are arsenic (As) compounds in water which are recognized globally by their extreme health hazards
We present a self-developed system on chip- (SOC-) based potentiostat for signal processing of sensors
The resulted solution samples were filtered through a 0.22 μm syringe filter with mixed cellulose ester membrane (Millipore, USA), and the final As(III) concentrations in the filtrates were determined by atomic absorption spectroscopy (AAS) analyses

Summary

Introduction

Arsenite (As III) and arsenate (As V) are arsenic (As) compounds in water which are recognized globally by their extreme health hazards. Among the materials used for arsenic adsorbents, magnetite nanoparticles (MNPs) provide various possibilities of cost per value reduction as well as removal efficiency. Such material is attracted by low magnetization field [15,16,17] and obtained in a massive amount through some hydrothermal synthesis. The strong magnetic dipole–dipole interaction and Vander Waals attractive forces among the nanoparticles cause the particles to aggregate [18] These problems reduce the magnetization degree and the affinity of magnetite toward arsenic [19, 20]. It is noticeably remarked that there has been no study informing PAni-coated MNPs to be an As(III) adsorbent as well as performing recyclability of this material in metal ion adsorption. The detection of As(III) was conducted with the ASV method using a selfdeveloped potentiostat and paired with AAS methods

Materials and Methods

Results and Discussion

Conclusions