Progress on Application of Ferrate(Ⅵ) for the Environmental Remediation

作者：Li, Yihao; Wu, Pingxiao^*; Jiang, Lu; Wu, Yixiao

来源：Cailiao Daobao/Materials Reports, 2020, 34(19): 19003-19009 and 19026.

DOI：10.11896/cldb.19100238

• Chemical and biologicals
• Colloidal particle
• Environmental remediation
• Further utilization
• Naphthalene moieties
• Oxidation mechanisms
• Reduction products
• Removal efficiencies

Ferrate (Fe(Ⅵ)) has been widely employed due to its oxidant/disinfectant and further utilization of the ensuing Fe(Ⅲ) oxides/hydroxide as coagulants in environmental remediation. Therefore, this review diverse synthesis recipes for Fe(Ⅵ) and their associated physicochemical properties as oxidants, coagulants, and disinfectants for the elimination of a diverse range of chemical and biological species from water/wastewater samples. These introduces involve: (1) Preparation and characteristics of ferrate. (2) The role of pH in the kinetics of the reactions and in determining the removal efficiency of pollutants is highlighted;the rates of competing reactions of Fe(Ⅵ) with itself, water, and the contaminants, which are highly pH dependent, determine the optimum pH ranges of maximum efficacy. (3) Oxidation mechanism of Fe(Ⅵ) through 1-e-and 2-e-transfer processes and further reactions of Fe(Ⅴ) and Fe(Ⅳ) with contaminants;the reduction products Fe(Ⅴ) and Fe(Ⅳ) can continue to react with pollutants through 1-e-and 2-e-electron transfer;cyanide has been studied for the comparative oxidizing capability of ferrates in various oxidation states. The result suggests the rates for the reactivity of ferrates with cyanide to be Fe(Ⅴ)>Fe(Ⅳ)>Fe(Ⅵ). (4) Fe(Ⅵ) can oxidize cell wall, protoplasm, DNA and other vital microorganism organs which kills them immediately. Meanwhile, Fe(Ⅵ) is gradually converted to Fe(Ⅲ) which is a strong coagulant, therefore, colloidal particles including the microorganisms are coagulated and removed from the water. (5) The high reactivity of most EDCs and PPCPs with ferrate(Ⅵ) may be attributed to electron donation by the specific group to the naphthalene moiety. (6) Ames and zebrafish embryos test indicate that Fe(Ⅵ) do not produce mutagenic by products for the study conditions. These results will make it possible to unlock the true potential of ferrates for degrading emerging toxins and pollutants, and in the purified and potable water for humanity in the 21st.
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• 单位
  华南理工大学