Organic structure and solid characteristics determine reactivity of phenolic compounds with synthetic and reclaimed manganese oxides

Trainer, Emma Leverich; Ginder‐Vogel, Matthew; Remucal, Christina K.

doi:10.1039/c9ew00859d

Cited by 17 publications

(49 citation statements)

References 61 publications

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“…With the exception of Mg 2+ with triclosan described above, we observe the same trend in cation co‐solute suppression regardless of the phenol, even though transformation rates vary greatly (i.e., pseudo‐first‐order rate constants for phenols oxidized by birnessite with Na + in solution range from 0.02 to 0.27 min −1 ) (Figure 1; Supplemental Table S2). This large range in reaction rates is attributable to the varying structures of the four phenols (Supplemental Figure S1), which leads to changes in oxidation rate similar to the trend seen here (Arnold et al., 2017; Trainer et al., 2020; Tratnyek, Weber, & Schwarzenbach, 2003). Despite this wide range in reaction rates, the oxidation rate constants of phenols under all conditions, except for Mg 2+ with triclosan, follow the order of BPA > p ‐cresol > estrone > triclosan.…”

Section: Resultssupporting

confidence: 64%

“…Sorption to the manganese oxide surface is the first step in BPA oxidation, followed by electron transfer and diffusion of products from the surface (Stone, 1987). The mechanism for BPA oxidation is electron transfer limited, meaning that the sorption process is faster than the electron transfer (Trainer et al., 2020). Percent sorption was calculated by the difference in BPA concentration in solution (i.e., determined by filtration) and total BPA concentration (i.e., determined by dissolution of manganese oxide).…”

Section: Resultsmentioning

confidence: 99%

“…The phenolic compounds used in this study include bisphenol A (BPA), 5-chloro-2-(2,4-dichlorophenoxy) phenol (triclosan), estrone, and 4-methylphenol (p-cresol) (Supplemental Figure S1). Phenolic compounds such as these are found in wastewater effluents that discharge into natural ecosystems (Bina, Mohammadi, Amin, Pourzamani, & Yavari, 2018;Bulloch et al, 2015;Charbonnet, Duan, van Genuchten, & Sedlak, 2018;Grebel et al, 2013Grebel et al, , 2016Huang, Zhong, Dai, Liu, & Zhang, 2018;Lin, Liu, & Gan, 2009b;Luthy & Sedlak, 2017;Montes-Grajales, Fennix-Agudelo, & Miranda-Castro, 2017;Yang, Ok, Kim, Kwon, & Tsang, 2017) and serve to show any differences in cation effects due to phenolic structure (Trainer, Ginder-Vogel, & Remucal, 2020). Cations can inhibit the reaction rate of phenols with manganese oxides (Remucal & Ginder-Vogel, 2014), which has implications for environmental oxidative degradation of phenolic contaminants because cations are ubiquitous in natural systems.…”

Section: Introductionmentioning

confidence: 99%

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Identifying the mechanisms of cation inhibition of phenol oxidation by acid birnessite

2020

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Many phenolic compounds found as contaminants in natural waters are susceptible to oxidation by manganese oxides. However, there is often variability between oxidation rates reported in pristine matrices and studies using more environmentally relevant conditions. For example, the presence of cations generally results in slower phenolic oxidation rates. However, the underlying mechanism of cation interference is not well understood. In this study, cation co-solutes inhibit the transformation of four target phenols (bisphenol A, estrone, p-cresol, and triclosan) by acid birnessite. Oxidation rates for these compounds by acid birnessite follow the same trend (Na + > K + > Mg 2+ > Ca 2+) when cations are present as co-solutes. We further demonstrate that the same trend applies to these cations when they are absent from solution but pre-exchanged with the mineral. We analyze valence state, surface area, crystallinity, and zeta potential to characterize changes in oxide structure. The findings of this study show that preexchanged cations have a large effect on birnessite reactivity even in the absence of cation co-solutes, indicating that the inhibition of phenolic compound oxidation is not due to competition for surface sites, as previously suggested. Instead, the reaction inhibition is attributed to changes in aggregation and the mineral microstructure.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Identifying the mechanisms of cation inhibition of phenol oxidation by acid birnessite

2020

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“…Rate constants for the dehalogenation of polybrominated diphenyl ethers (PBDE) and polychlorinated biphenyl (PCBs) by nano zero-valent iron (nZVI) ranged from 0.0001 to 0.1 h –1 . , Bokare et al determined that the rate constant for the reaction between TCS and nZVI was around 0.04 h –1 , which could be further accelerated by doping of palladium. Trainer et al found that rate constants for the oxidation of phenol compounds by manganese oxide (δ-MnO 2 ) ranged from 0.001 to 149 h –1 with a value of 7.6 h –1 for TCS. The relatively lower reaction rate constants for TCS in this study are primarily because the concentration of a-BC and associated electrons were much lower than the metals.…”

Section: Resultsmentioning

confidence: 99%

Anaerobic Dehalogenation by Reduced Aqueous Biochars

Lokesh

Kim

Zhou

et al. 2020

Environ. Sci. Technol.

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Dehalogenation is one of the most important reactions for eliminating trace organic pollutants in natural and engineering systems. This study investigated the dehalogenation of a model organohalogen compound, triclosan (TCS), by aqueous biochars (a-BCs) (<450 nm). We found that TCS can be anaerobically degraded by reduced a-BCs with a pseudo first-order degradation rate constant of 0.0011−0.011 h −1 . The 288 h degradation fraction of TCS correlated significantly with the amount of a-BCbound electrons (0.055 ± 0.00024 to 0.11 ± 0.0016 mol e − /mol C) available for donation after 24 h of pre-reduction by Shewanella putrefaciens CN32. Within the reduction period, the recovery of chlorine based on residual TCS and generated Cl − ranged from 73.6 to 85.2%, implying that a major fraction of TCS was fully dechlorinated, together with mass spectroscopic analysis of possible degradation byproducts. Least-squares numerical fitting, accounting for the reactions of hydroquinones/semiquinones in a-BCs with TCS and byproducts, can simulate the reaction kinetics well (R 2 > 0.76) and suggest the first-step dechlorination as the rate-limiting step among the possible pathways. These results showcased that the reduced a-BCs can reductively degrade organohalogens with potential applications for wastewater treatment and groundwater remediation. While TCS was used as a model compound in this study, a-BC-based degradation can be likely applied to a range of redox-sensitive trace organic compounds.

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“…Given that the oxidation rate of phenolic compounds varies among manganese oxide phases, the greater abundance of the phyllomanganate structure may explain why the geomedia reactivity was only partially restored by KMnO 4 treatment. In this study, we chose bisphenol A as a representative compound; however, different organic compounds have different rate-determining steps in reactions with manganese oxide, and additional research is needed to assess how the rates of different reaction mechanisms are impacted by the mineral phase, particularly after regeneration.…”

Section: Resultsmentioning

confidence: 99%

Regenerated Manganese-Oxide Coated Sands: The Role of Mineral Phase in Organic Contaminant Reactivity

Charbonnet

Duan

Genuchten

et al. 2021

Environ. Sci. Technol.

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Manganese oxide-coated sand can oxidize electron-rich organic contaminants, but after extended exposure to contaminated water its reactivity decreases. To assess the potential for regenerating geomedia, we measured the ability of passivated manganese-oxide coated sand to oxidize bisphenol A after treatment with oxidants, acid, or methanol. Among the regenerants studied, KMnO4, HOCl, HOBr, and pH 2 or 3 HCl solutions raised the average oxidation state of the Mn, but only HOCl and HOBr restored the reactivity of passivated geomedia to levels comparable to those of the virgin manganese-oxide coated sand. Treatment with HCl restored about one third of the reactivity of the material, likely due to dissolution of reduced Mn. Mn K-edge X-ray absorption spectroscopy data indicated that the reactive manganese oxide phases present in virgin geomedia and geomedia regenerated with HOCl or HOBr had nanocrystalline cryptomelane-like structures and diminished Mn(III) abundance relative to the passivated geomedia. KMnO4-regenerated geomedia also had less Mn(III), but it exhibited less reactivity with bisphenol A because regeneration produced a structure with characteristics of δ-MnO2. The results imply that manganese oxide reactivity depends on both oxidation state and crystal structure; the most effective chemical regenerants oxidize Mn(III) to Mn(IV) oxides exhibiting nanocrystalline, cryptomelane-like forms.

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Organic structure and solid characteristics determine reactivity of phenolic compounds with synthetic and reclaimed manganese oxides

Abstract: Phenolic substituents and manganese oxide characteristics influence oxidation kinetics and mechanism, as well as the utility of QSARs.

Cited by 17 publications

References 61 publications

Identifying the mechanisms of cation inhibition of phenol oxidation by acid birnessite

Identifying the mechanisms of cation inhibition of phenol oxidation by acid birnessite

Anaerobic Dehalogenation by Reduced Aqueous Biochars

Regenerated Manganese-Oxide Coated Sands: The Role of Mineral Phase in Organic Contaminant Reactivity

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