Enhanced transport and chromium remediation of nano-zero valent iron modified by tea polyphenol extracts and carboxymethyl cellulose in water–soil media

Purpose In order to reduce the hazards of Cr(VI) to environment, the novel nano-zero valent iron composite was synthesized via green method for enhanced transport and Cr(VI) remediation of engineered materials, which are required for effective in situ remediation in soil and underground water contam...
Ausführliche Beschreibung

Purpose In order to reduce the hazards of Cr(VI) to environment, the novel nano-zero valent iron composite was synthesized via green method for enhanced transport and Cr(VI) remediation of engineered materials, which are required for effective in situ remediation in soil and underground water contaminated by heavy metals. Materials and methods The TPs-$ nFe^{0} $CMC composite series with different synthesis ratios of CMC versus Fe (0.05, 0.1, and 1) were prepared by using tea polyphenols (TPs) extracted from green tea as a reductant, mediated by carboxymethyl cellulose (CMC) to reduce iron sulfate. The column and batch experiments were conducted for investigating the transport of TPs-$ nFe^{0} $@CMC composite series and their Cr(VI) remediation capacity at various ionic strengths (ISs, 0.1–10 mM) of NaCl solution in water/soil system. Results and discussion The varying ratios of CMC/Fe and the ISs showed the significant effect on the enhanced transportability of TPs-$ nFe^{0} $@CMC (compared with TPs-$ nFe^{0} $ without CMC). With the increase in CMC/Fe synthesis ratios, the suspensibility of TPs-$ nFe^{0} $@CMC increased and then decreased; while the high IS clearly inhibited the particle mobility. The transport behavior can be well simulated using the first-order irreversible attachment coefficients obtained from a two-site kinetic retention model fitting the breakthrough curves of TPs-$ nFe^{0} $@CMC in porous media. The TPs-$ nFe^{0} $@CMC (CMC/Fe = 0.1) showed the increased Cr(VI) remediation capacity after modified by CMC, which was 153.7 mg $ g^{−1} $ in solution and 76.22 mg $ g^{−1} $ in soil at pH 6.0. The enhanced transportability and remediation capacity might be attributed to the synergistic effects of TPs and CMC with the best mass ratio, in that the TPs covering around the $ Fe^{0} $ cores and the large-scope strain structure of CMC protected $ nFe^{0} $ from oxidation and aggregation, and subsequently the unwrapped TP-coverage facilitated the generation of $ Fe^{2+} $ and the massively exposed reaction sites to adsorption and reduction of Cr(VI). Conclusions Our findings benefit the knowledge of green synthesized TPs-$ nFe^{0} $@CMC (CMC/Fe = 0.1) composites mediated by CMC and TPs as a low-cost, “green”, and effective material with the sufficient mobility in the subsurface for the effective in situ remediation of Cr(VI). Graphical abstract Ausführliche Beschreibung

Autor*in:	Cheng, Xuyi [verfasserIn] Wang, Shiqi Xu, Nan Yang, Li Jing, Pengcheng Chen, Jianping

Format:	E-Artikel
Sprache:	Englisch

Erschienen:	2021

Schlagwörter:	Chromium TPs-nFe @CMC Transport Soil remediation Tea polyphenols (TPs) Carboxymethyl cellulose (CMC)

Anmerkung:	© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021

Übergeordnetes Werk:	Enthalten in: Journal of soils and sediments - Berlin : Springer, 2001, 22(2021), 1 vom: 25. Sept., Seite 196-207
Übergeordnetes Werk:	volume:22 ; year:2021 ; number:1 ; day:25 ; month:09 ; pages:196-207

Links:	Volltext

DOI / URN:	10.1007/s11368-021-03072-0

Katalog-ID:	SPR045908265