Synthesis and Characterization of New Ferrite-Lignin Hybrids.

Iuliana Spiridon,Adina Coroaba,Ioan-Andrei Dascalu,Irina Apostol,Adrian Iulian Borhan,Mircea Nicolae Palamaru,Alexandra Raluca Iordan

doi:10.3390/polym13152495

Iuliana Spiridon, Adina Coroaba + Show 5 more

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https://doi.org/10.3390/polym13152495

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Journal: Polymers	Publication Date: Jul 28, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: Alexandru Ioan Cuza University

Abstract

The paper presents the synthesis and characterization of new cobalt ferrite-lignin hybrids. The hybrids were obtained through the combustion of cobalt nitrate and ferric nitrate, two kinds of lignin being used as combustion agents. The temperatures of calcination were 500 °C and 900 °C, respectively. The hybrids were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The magnetic properties were also assessed by vibrating sample magnetometer system (VSM). This facile synthesis method made it possible to obtain cobalt ferrite-lignin hybrids with a spinel structure. Their particle sizes and crystallite sizes have increased with an increment in the calcination temperature. A different occupancy of cations at octahedral and tetrahedral sites also occurred upon the increase in temperature. The hybrids comprising organic lignin presented the best magnetic properties.

Highlights

Lignin represents the most abundant but underutilized natural polymer with aromatic structure, constituting up to 35% of wood biomass
For the first-time, we report the direct synthesis of cobalt ferrite-lignin hybrids, starting from organosolv and kraft lignin and the nitrates of Co and Fe
The absorption bands present at about 685 cm−1 and 410 cm−1 were due to the stretching vibrations of metal oxide in the octahedral group complex Co(II)–O2− and Fe(III)–O2− tetrahedral group complex of the cobalt ferrite phase, respectively, which proves the existence of spinel ferrite [28]

Summary

Introduction

Lignin represents the most abundant but underutilized natural polymer with aromatic structure, constituting up to 35% of wood biomass. Lignin is the result of the biosynthesis process of three phenylpropanoid units named p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S), derived from p-coumaryl, coniferyl, and sinapyl alcoholic precursors, respectively [1,2,3]. The proportion of these monomers varies as a function of the biomass source. Lignins separated by kraft pulping and sulfite pulping could contain sulfur, while the presence of phosphor was reported in organosolv lignin, due to the delignification of wood with organic solvents [4]

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