Polypyrrole modified magnetic reduced graphene oxide composites: synthesis, characterization and application for selective lead adsorption

• Published in: RSC advances Vol. 1; no. 3; pp. 17524 - 17533
• Main Authors: Liu, Zhanmeng, Gao, Zhimin, Xu, Lichun, Hu, Fengping
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 05-05-2020; The Royal Society of Chemistry
• Subjects: Adsorption; Chemistry; Endothermic reactions; Fourier transforms; Graphene; Heavy metals; Infrared analysis; Iron oxides; Magnetic properties; Magnetometers; Particulate composites; Photoelectrons; Polypyrroles; Selective adsorption; Similar metals; Spectrum analysis
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d0ra01546f

To enhance the ability to remove lead from water, polypyrrole modified magnetic Fe
3
O
4
/reduced graphene oxide composites (PPy-FG) were prepared
via in situ
polymerization and employed for the Pb(
ii
) adsorption. The physicochemical structure and adsorption mechanism of the prepared magnetic PPy-FG were studied
via
vibrating sample magnetometer, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and X-ray photoelectron spectroscopy. The effects of several factors on Pb(
ii
) adsorption were evaluated, including pH value, temperature, and competitive ions. Under the optimal conditions (pH 5 and 298 K), the maximum adsorption capacity of PPy-FG was 93.2 mg g
−1
giving an improvement of 31% over that of 71 mg g
−1
for Fe
3
O
4
/reduced graphene oxide (Fe
3
O
4
/rGO). Moreover, the experimental data were well fitted with the Langmuir adsorption model and the pseudo-second-order kinetics model, indicating that the adsorption process was mainly a monolayer chemical adsorption. Thermodynamic studies revealed a spontaneous and endothermic adsorption process. The selective adsorption of Pb(
ii
) by PPy-FG is superior to that of Fe
3
O
4
/rGO in the presence of similar metals in the same medium. In addition, the adsorption performance of PPy-FG showed great potential in the remediation of heavy metal contaminated water through using its magnetic properties and excellent affinity for heavy metals.
Compared to Fe
3
O
4
/rGO, the PPy-FG composites showed desirable adsorption capacity and selectivity for Pb(
ii
) from water.