Nanoscale zero-valent iron-decorated biochar for aqueous contaminant removal

Zhang, Xuefeng; Karunaratne, Tharindu N.; Navarathna, Chanaka; Zhang, Jilei; Pittman, Charles U.

doi:10.1016/b978-0-12-822225-6.00001-4

Cited by 4 publications

(1 citation statement)

References 109 publications

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“…Typical carbothermal reduction process impregnates iron salts or oxides into biomass precursors and heats at high temperatures (e.g., 600-800 °C) under oxygen-limited conditions. The biomass is converted to BC while iron salts or oxides are reduced to nanoFe 0 particles, which attach to biochar surfaces (Zhang et al 2022b). Generally, both solid carbon and released pyrolysis gases (CH 4 , CO, H 2 ) are the main reagents causing reduction to Fe 0 (Yan et al 2018c).…”

Section: Introductionmentioning

confidence: 99%

Pyrolytic synthesis of graphene-encapsulated zero-valent iron nanoparticles supported on biochar for heavy metal removal

Karunaratne

Nayanathara

Navarathna

et al. 2022

Biochar

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Biochar (BC)-supported graphene-encapsulated zero-valent iron nanoparticle composites (BC-G@Fe0) are promising engineering nanocomposites that can be used to scavenge heavy metal from wastewater. However, the production of BC-G@Fe0 through carbothermal reduction using biomass as a carbon source remains challenging because of biomass pyrolysis complications. Here, we examined two carbothermal reduction routes for preparing BC-G@Fe0 using bamboo as the carbon source. The first route impregnated Fe ions (Fe2+/3+) into unpyrolyzed bamboo particles initially, followed by carbonization at 600–1000 °C. This process produced BC-G@Fe0 dominated by iron carbide (Fe3C), which led to low heavy metal removal efficiency (i.e., Cu2+ capacity of < 0.3 mmol g−1). In the second route, bamboo particles were pyrolyzed (600 °C) to biochar first, followed by impregnating this biochar with Fe ions, and then carbonized at 600–1000 °C. This route produces zero-valent iron nanoparticles, which resulted in high heavy metal removal capacities (i.e., 0.30, 1.58, and 1.91 mmol g−1 for Pb2+, Cu2+, and Ag+, respectively). The effects of carbonization temperature (600–1000 °C), iron source (i.e., iron nitrates, iron sulfate, ferrous chloride, and ferric chloride), and iron loading (5–40%) on the morphology, structure, and heavy metal ion aqueous uptake performance of BC-G@Fe0 were also investigated. This study revealed the formation mechanisms of BC-G@Fe0 through biomass carbothermal reduction, which could guide the application-oriented design of multifunctional iron-BC composites for water remediation. Graphical Abstract

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Section: Introductionmentioning

confidence: 99%

Pyrolytic synthesis of graphene-encapsulated zero-valent iron nanoparticles supported on biochar for heavy metal removal

Karunaratne

Nayanathara

Navarathna

et al. 2022

Biochar

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Remediation of As(V) and Cd(II) Contamination by a ZVI-Biochar: Experimental and DFT Calculation

Liu,

Zhou,

Zhang

et al. 2024

Water Air Soil Pollut

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A novel zero-valent iron loaded biochar (ZVI-CSC) was synthesized in this study for the remediation of As( ) and Cd(II) contamination. The impact of ZVI-CSC on the adsorption performance of As( ) and Cd(II) in solution, as well as their migration properties in soil, were investigated through adsorption kinetics and soil column leaching experiments, respectively. The results showed that the adsorption capacity of As( ) by ZVI-CSC was signi cantly improved to 14.42 g•kg -1 at pH=3, compared with unmodi ed biochar.However, the adsorption capacity of Cd(II) was not improved. In the leaching experiments, the addition of ZVI-CSC to As( )-contaminated soil resulted in a signi cant reduction of cumulative As( ) release rate from 32.26% to 3.11%, compared with CSC. Moreover, the role of ZVI in As(V)/Cd(II) remediation was analyzed. nZVI forms ≡Fe-OH and ≡Fe-OOH due to oxidation, which can form monodentate and bidentate complexes with As(V) via ligand exchange, thus promoting As immobilization. Furthermore, to further improve the adsorption performance of Cd(II), the electrostatic potential (ESP) of biochars with different surface functional group (C=O, C-O-C, -OH and -COOH) and their bond dissociation enthalpy (BDE) with As( ) and Cd(II) were calculated based on density functional theory (DFT). The results showed that -OH was the most effective for As(V) adsorption, and C-O-C was the most effective for Cd(II) adsorption. C=O and -COOH can be used to the simultaneous adsorption of As(V) and Cd(II). Therefore, the surface functional groups of ZVI-CSC can be selectively modi ed to improve its adsorption performance of As( ) and Cd(II).Highlights ZVI-CSC exhibited extraordinary performance of As(V) adsorption in solution.The migration of As(V) in soil was greatly reduced by ZVI-CSC.The shell structure of nZVI oxidation is the main cause of As(V) adsorption.-OH has better adsorption for As(V), while C-O-C is optimal for Cd(II). To improve the simultaneous remediation of As( ) and Cd( ) by ZVI-CSC, the ESP of biochar with different functional groups (C = O, C-O-C, -OH and -COOH) was analyzed based on DFT calculation. According to the results of ESP calculation, the O atom changes the electrostatic potential of biochar edge, promoting the electrostatic attraction and the complexation of AsO 4 3− and Cd 2+ .Moreover, the interaction between As( )/Cd( ) and these functional groups on biochar were also analyzed based on DFT calculation. The results showed that C = O and -COOH can be used for simultaneous adsorption of As(V) and Cd(II),and -OH showed the best adsorption effect for As( ) (ΔE=-147.91 kcal/mol, bond length 2.805Å). C-O-C showed the best adsorption effect for Cd( ) (ΔE=-111.46 kcal/mol, bond length 3.105Å).

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Remediation of As(V) and Cd(II) contamination by a ZVI-biochar: experimental and DFT calculation

Liu

Zhang

et al. 2023

Preprint

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A novel zero-valent iron loaded biochar (ZVI-CSC) was synthesized in this study for the remediation of As(Ⅴ) and Cd(II) contamination. The impact of ZVI-CSC on the adsorption performance of As(Ⅴ) and Cd(II) in solution, as well as their migration properties in soil, were investigated through adsorption kinetics and soil column leaching experiments, respectively. The results showed that the adsorption capacity of As(Ⅴ) by ZVI-CSC was significantly improved to 14.42 g·kg-1 at pH=3, compared with unmodified biochar. However, the adsorption capacity of Cd(II) was not improved. In the leaching experiments, the addition of ZVI-CSC to As(Ⅴ)-contaminated soil resulted in a significant reduction of cumulative As(Ⅴ) release rate from 32.26% to 3.11%, compared with CSC. Moreover, the role of ZVI in As(V)/Cd(II) remediation was analyzed. nZVI forms ≡Fe-OH and ≡Fe-OOH due to oxidation, which can form monodentate and bidentate complexes with As(V) via ligand exchange, thus promoting As immobilization. Furthermore, to further improve the adsorption performance of Cd(II), the electrostatic potential (ESP) of biochars with different surface functional group (C=O, C–O–C, –OH and –COOH) and their bond dissociation enthalpy (BDE) with As(Ⅴ) and Cd(II) were calculated based on density functional theory (DFT). The results showed that –OH was the most effective for As(V) adsorption, and C–O–C was the most effective for Cd(II) adsorption. C=O and –COOH can be used to the simultaneous adsorption of As(V) and Cd(II). Therefore, the surface functional groups of ZVI-CSC can be selectively modified to improve its adsorption performance of As(Ⅴ) and Cd(II).

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Nanoscale zero-valent iron-decorated biochar for aqueous contaminant removal

Cited by 4 publications

References 109 publications

Pyrolytic synthesis of graphene-encapsulated zero-valent iron nanoparticles supported on biochar for heavy metal removal

Pyrolytic synthesis of graphene-encapsulated zero-valent iron nanoparticles supported on biochar for heavy metal removal

Remediation of As(V) and Cd(II) Contamination by a ZVI-Biochar: Experimental and DFT Calculation

Remediation of As(V) and Cd(II) contamination by a ZVI-biochar: experimental and DFT calculation

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