Details

Autor(en) / Beteiligte

• Chen, Xi
• Tong, Xin
• Gao, Jiabin
• Yang, Lijuan
• Ren, Jianuo
• Yang, Weijie
• Liu, Su
• Qi, Meng
• Crittenden, John
• Hao, Runlong

Titel

Simultaneous Nitrite Resourcing and Mercury Ion Removal Using MXene-Anchored Goethite Heterogeneous Fenton Composite

Ist Teil von

• Environmental science & technology, 2022-04, Vol.56 (7), p.4542-4552

Ort / Verlag

Easton: American Chemical Society

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The integrated system of gas-phase advanced oxidation process combined with sulfite-based wet absorption process is a desirable method for simultaneous removal of SO2, NO, and Hg0, but due to the enrichment of nitrite and Hg2+, resourcing harmless wastewater is still a challenge. To tackle this problem, this study fabricated a bifunctional β-FeOOH@MXene heterogeneous Fenton material, of which the crystalline phase, morphology, structure, and composition were revealed by using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy–energy dispersive x-ray spectroscopy, and transmission electron microscopy. It exhibits excellent performance on nitrite oxidation (99.5%) and Hg2+ removal (99.7%) and can maintain stable outstanding ability after 13 cycles, with superior Hg2+ adsorption capacity (395 mg/g) and ultralow Fe leaching loss (<0.018 wt %). The synergism between MXene and β-FeOOH appears as follows: (i) MXene, as an inductive agent, directionally converted Fe2O3 into β-FeOOH in the hydrothermal method and greatly reduced its monomer size; (ii) the introduced Ti­(III)/Ti­(II) accelerated the regeneration of Fe­(II) via rapid electron transfer, thereby improving the heterogeneous Fenton reaction; and (iii) MXene strongly immobilized β-FeOOH to greatly inhibit Fe-leaching. HO•, •O2 ––, and 1O2 were the main radicals identified by electron spin resonance. Radical quenching tests showed their contributions to NO2 – oxidation in the descending order HO• > 1O2 > •O2 –. Quantum chemical calculations revealed that •OH-induced oxidation of NO2 – or HNO2 was the primary reaction path. Density functional theory calculations combined with X-ray photoelectron spectroscopy and Raman characterizations displayed the Hg2+ removal mechanism, with Hg2Cl2, HgCl2, and HgO as the main byproducts. This novel material provides a new strategy for resourcing harmless wastewater containing nitrite and Hg2+.