Gallic acid-functionalized graphene hydrogel as adsorbent for removal of chromium (iii) and organic dye pollutants from tannery wastewater. Issue 46 (29th August 2019)

• Record Type: Journal Article
• Authors: Liu, Gongyan; Yu, Ruiquan; Lan, Tianxiang; Liu, Zheng; Zhang, Peng; Liang, Ruifeng
• Is Part Of: RSC advances. Volume 9:Issue 46(2019)
• Page Start: 27060
• Page End: 27068
• Publication Date: 2019-08-29
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9ra05664e
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : The formation process of gallic acid functionalized graphene hydrogel (GA-GH). Abstract : The pollution caused by tannery wastewater containing high concentrations of trivalent chromium ions [Cr(iii )] and organic dyes has severely restricted the sustainable development of the leather industry. To address this problem, a three-dimensional (3D) porous graphene-based hydrogel with good mechanical strength and large surface area was fabricated by self-assembly of graphene oxide (GO) sheets reduced and modified by gallic acid (GA) through π–π interactions. As an adsorbent, this GA-functionalized graphene hydrogel (GA-GH) can effectively capture Cr(iii ) by coordination complexation between Cr(iii ) and deprotonated carboxylic groups of GA at pH ∼ 4.0. Moreover, GA-GH could be easily regenerated by desorption of adsorbed Cr(iii ) at pH 2.0 and maintained its high adsorption capacity after multiple adsorption–desorption cycles, which was also helpful for reusing desorbed Cr(iii ) as tanning agent. In addition, compared with a graphene hydrogel (GH) without modification by GA, adsorption capacity of GA-GH for organic dye was significantly improved due to the enhanced π–π interactions between the GA-GH and aromatic dyes.