Preparation of a lignin/polyaniline composite and its application in Cr(VI) removal from aqueous solutions

Abstract

Lignin/polyaniline composites were prepared by adding kraft lignin for the synthesis of polyaniline (PANI), a typical conductive polymer. The composites were utilized as an adsorbent for the removal of hexavalent chromium (Cr(VI)). When lignin alone was used as an adsorbent, the removal efficiency of Cr was low. However, when the lignin/PANI composite was used, lignin and PANI adsorbed Cr(III) together. The PANI reduced Cr(VI), which resulted in the efficient removal of Cr. In addition, as the dosage of the lignin/PANI composite decreased as an adsorbent, the Cr removal efficiency of the composite decreased considerably compared with pure PANI. However, the composite with a lignin-to-PANI ratio of 1:1 showed a Cr removal efficiency similar to that of pure PANI. The morphology of the lignin/PANI composite was observed to synthesize PANI around the lignin surface. Both Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that an interaction between the carbonyl groups of lignin and the amine groups of PANI occurred. This study is expected to provide an opportunity to increase the utilization of lignin in the field of environmental science and provide several benefits.

Photocurable Printed Piezocapacitive Pressure Sensor Based on an Acrylic Resin Modified with Polyaniline and Lignin

“…The FT‐IR spectra of the PANI‐L 3D printed composite is plotted in Figure S2 in comparison with those of Lignin and PANI. Analysis of the spectra of lignin [ 55–57 ] and PANI [ 23,29 ] was based on assignments from the literature. The FTIR spectrum of PANI‐L is similar to that of PANI, except for the presence of a new band at 1716 cm –1 due to the stretching of C = O lignin groups, shifted towards lower wavenumbers with respect to pure lignin, probably due to the association with the PANI amine groups through the formation of hydrogen bonds.…”

“…Hydrogen bonding between PANI donor groups and lignin acceptor groups has been described in the literature, parallel to an increase in –NH + relative to –N = (Quinoid rings) or N amine (Benzenoid) observed by XPS. [ 56,58 ] Although no clear shifts are detected, the intensity of the PANI bands at 1300 and 1105 cm –1 clearly augmented and the latter band, related to the vibrational mode of protonated amines (δ C‐H, δ Q = N+‐B/B‐NH+, ‐B ) and characterizing the delocalization of π electrons, also became broad around 1060–900 cm −1 . These changes are also more clearly observed in the difference spectrum and have been ascribed to an interaction between PANI and lignin via π‐π stacking and electrostatic interaction.…”

Lignin as a High-Value Bioaditive in 3D-DLP Printable Acrylic Resins and Polyaniline Conductive Composite

“…Furthermore, the bands at 1239 and 1044 cm −1 may be ascribed to the C=O bending and aromatic CH in plane deformation of the guaiacyl (G) unit, whereas those centered at 1328 and 1117 cm −1 have been assigned to the same functional groups of the syringyl (S) unit. [ 16 , 48 , 49 ].…”

A Novel Biosorbent From Hardwood Cellulose Nanofibrils Grafted With Poly(m-Aminobenzene Sulfonate) for Adsorption of Cr(VI)

“…After adsorption, filtration was performed by using a polytetrafluoroethylene (PTFE) filter paper (0.45 μm), and the filtrate was collected. The DPC method was used for Cr(VI) determination, according to the methodology from a previous work ( Seo et al, 2019 ). To 20 ml of the filtrate were added 0.1 ml of concentrated nitric acid and 1.2 ml of DPC solution.…”