Chitosan and biochar synergize the efficient elimination of lead from wastewater by sulfidised nano-zero-valent iron. Issue 1 (February 2022)

• Record Type: Journal Article
• Authors: Xu, Hao; Li, Xingong; Gao, Mengxi; Hu, Xinjiang; Zhang, Xuefei; Li, Yan; Xu, Xinyu; Hu, Jianjie; Tang, Chunfang; Hu, Xi
• Is Part Of: Journal of environmental chemical engineering. Volume 10:Issue 1(2022)
• Publication Date: 2022-02
• Subjects: Nano-zero-valent iron -- Dispersion -- Stabilization -- Pb2+ -- Removal; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2021.107101
• Languages: English
• ISSNs: 2213-2929

Abstract

Abstract: The safety of drinking water and food has been threatened by Pb 2+ pollution. A chitosan and biochar synergistically-modified sulfurized nano-zero-valent iron was synthetized by NaBH4 reduction and tested for Pb 2+ efficient removal from aqueous solution. The synthesized compound was characterized with X-ray photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Zeta potential, Brunauer-Emmett-Teller (BET), X-ray powder diffraction (XRD), and scanning electron microscope (SEM). The optimized synthesis parameters of CS@S-nZVI/TB were determined as a 0.14 molar ratio of S/Fe and a 4 mass ratio of Fe/biochar. The removal of Pb 2+ increased with the increase of the initial solution pH from 2 to 6, but it decreased slightly with the increasing ionic strength of NaCl in the solution. The removal processes fitted well with pseudo-second order, Langmuir, and Freundlich models, which indicated that both monolayer chemical and multilayer physical adsorption occurred during Pb removal. The removal process for Pb 2+ was exothermic, with a maximum removal of 281.97 mg/g of Pb 2+ at 25 °C. The removal mechanisms involved mainly adsorption, reduction reaction, and complexation reactions. Overall, these findings provide new ideas for the modification of Fe 0 and reveal the mechanism for the removal of heavy metals from wastewater by CS@S-nZVI/TB. Graphical Abstract: ga1 Highlights: Chitosan and biochar synergistically improved the stability and dispersibility of S-nZVI. The maximum adsorption capacity of CS@S-nZVI/TB for Pb 2+ was 281.97 mg/g. CS@S-nZVI/TB had better anti-oxidation and anti-agglomeration properties than S-nZVI.