One-Pot Synthesis of Magnetic Polypyrrole Nanotubes for Adsorption of Cr(VI) in Aqueous Solution

Wenjuan Zhang,Xueyan Du,Qiancheng Feng,Yaxian Wang,Miao Kou,Yulong Fei,Zhaoxiong Zhang,Sheng Wang,Youliang Wang,Marco Rossi

doi:10.1155/2021/7068003

Abstract

A novel and efficient route is proposed to fabricate Fe3O4/polypyrrole (Fe3O4/PPy) nanotubes via a one-pot process. The one-pot strategy involves the synthesis of Fe3O4/PPy nanotubes by oxidative polymerization of pyrrole (Py) monomer using Fe3+ as an oxidant in the presence of methyl orange (MO) and Fe3+ used as iron source to form Fe3O4 simultaneously in basic conditions without adding any additional iron source and oxidant. The effects of Fe3+ concentration on the morphology and adsorption capacity of the Fe3O4/PPy nanotubes were investigated. The Fe3O4/PPy nanotubes exhibit a tubular structure. Fe3O4 nanoparticles are well dispersed among the PPy nanotubes. The Fe3O4/PPy nanotubes exhibit excellent magnetic property, which make them easy to separate from wastewater by magnetic separation. The diameter of the PPy nanotubes decreased with the increase of the Fe3+ concentration. The Fe3O4/PPy nanotubes showed strong adsorption capability for Cr(VI) with the maximum adsorption capacity of about 451.45 mg·g−1, which is significantly higher than bare Fe3O4 nanoparticles. Cr(VI) was adsorbed on Fe3O4/PPy nanotubes by ion exchange and chelation, where Cr(VI) was partially reduced to Cr(III) due to the existence of −NH+ on the Fe3O4/PPy nanotubes. Furthermore, the Fe3O4/PPy nanotubes are recyclable, retaining 90% of the initial removal efficiency after 5 adsorption/desorption cycles.

Highlights

With the rapid development of industry, water pollution is increasingly becoming a ubiquitous environmental problem.e pollution of toxic dyes and heavy metal ions exists widely because they are commonly used in or generated by a number of industrial processes
PPy nanotubes are explored by oxidative polymerization of Py monomer using various concentrations of FeCl3 as oxidant and methyl orange (MO) as a template
For S1, other diffraction peaks except for (002) diffraction peaks are not observed in Figure 2(a). is is because Fe3O4 is difficult to form under a low concentration of Fe3+ and reduced Fe2+ in the reaction system, which has been calculated by chemical titration method

Summary

Introduction

With the rapid development of industry, water pollution is increasingly becoming a ubiquitous environmental problem.e pollution of toxic dyes and heavy metal ions exists widely because they are commonly used in or generated by a number of industrial processes. Magnetic nanoparticles (MNPs) have attracted much attention to remove harmful heavy metal ions from wastewater because they have high adsorption capacity, high specific surface area, easy separation and regeneration, and surface functional group modification [7,8,9]. Ese reduced reactivity sites and the specific surface area of MNPs, which will further influence the removal of heavy metal ions by MNPs. At present, coating MNPs using functional polymers can improve properties of MNPs, in particular, conductive polymers [13] (e.g., polypyrrole, polythiophene, and polyaniline). E coating of PPy can avoid agglomeration and oxidation of MNPs. PPy has good adsorption properties for Cr(VI) from wastewater owing to their rich functional groups and environmental stability [17,18,19]

Methods

Results

Conclusion