Efficient adsorption and reduction of Cr(VI) by Zr4+ cross-linked magnetic chitosan/polyaniline composite. Issue 6 (December 2022)

• Record Type: Journal Article
• Authors: Xu, Chunzi; Xu, Yunlan; Zhong, Dengjie; Chang, Haixing; Mou, Jiaxin; Wang, Hui; Shen, Hongyu
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 6(2022)
• Publication Date: 2022-12
• Subjects: Chitosan -- Cross-linking -- Hexavalent chromium -- Adsorption -- Reduction; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2022.108977
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: In this work, Zr 4+ cross-linked magnetic chitosan/polyaniline (Fe3 O4 @CTS-Zr-PANI) composite was synthesized for the first time and used to remove Cr(VI) from aqueous solution. The presence of CC bonds (benzenes and quinones), Zr-O and Zr-N in its FTIR spectrum confirmed the successful synthesis of it. The introduction of polyaniline enhances the stability of chitosan under acidic conditions and its ability to reduce Cr(VI). The addition of zirconium enables ion exchange and electrostatic adsorption to work together to remove Cr(VI). The maximum monolayer adsorption capacity is 491.43 mg g −1 at 298 K (pH=2.0). The adsorbent has excellent stability and regeneration ability, and the adsorption efficiency is still as high as 90.63% after six adsorption cycles. Real chromium-containing wastewater (Cr(VI) 241.21 mg L −1, pH= 3.5) was treated with a dosage of 0.08 g adsorbent, and its residual chromium concentration could not be detected. The removal of Cr(VI) by Fe3 O4 @CTS-Zr-PANI mainly includes electrostatic adsorption, ion exchange, reduction and complexation. XPS showed that 86.9% of Cr(VI) was reduced to Cr(III) by -OH groups of CTS and C-N groups of PANI at pH= 2.0. Then, Cr(III) was removed by complexing with COO- groups of CTS and C-N groups of PANI. Graphical Abstract: Adsorption mechanism of Cr(VI) by Fe3O4@CTS-Zr-PANI. ga1 Highlights: Zr, PANI and Fe3 O4 respectively enhance the ability of ion exchange and electrostatic adsorption, reduction and separating property. Effective removal of real chromium-containing wastewater. The Fe3 O4 @CTS-Zr-PANI exhibits good stability and regeneration performance. Cr(VI) removal by electrostatic adsorption, ion exchange, reduction and complexation.