Molecular Environmental Biogeochemistry Group

Sheng A, Liu J, Li X, Qafoku O, Collins RN, Jones AM, Pearce CI, Wang C, Ni J, Lu A, et al. Labile Fe(III) from sorbed Fe(II) oxidation is the key intermediate in Fe(II)-catalyzed ferrihydrite transformation. Geochimica et Cosmochimica Acta [Internet]. 2020;272:105 - 120. 访问链接 Abstract

Ferrihydrite (Fh) is a major Fe(III)-(oxyhydr)oxide nanomineral distinguished by its poor crystallinity and thermodynamic metastability. While it is well known that in suboxic conditions aqueous Fe(II) rapidly catalyzes Fh transformation to more stable crystalline Fe(III) phases such as lepidocrocite (Lp) and goethite (Gt), because of the low solubility of Fe(III) the mass transfer pathways enabling these rapid transformations have remained unclear for decades. Here, using a selective extractant, we isolated and quantified a critical labile Fe(III) species, one that is more reactive than Fe(III) in Fh, formed by the oxidation of aqueous Fe(II) on the Fh surface. Experiments that compared time-dependent concentrations of solid-associated Fe(II) and this labile Fe(III) against the kinetics of phase transformation showed that its accumulation is directly related to Lp/Gt formation in a manner consistent with the classical nucleation theory. 57Fe isotope tracer experiments confirm the oxidized Fe(II) origin of labile Fe(III). The transformation pathway as well as the accelerating effect of Fe(II) can now all be explained on a unified basis of the kinetics of Fe(III) olation and oxolation reactions necessary to nucleate and sustain growth of Lp/Gt products, rates of which are greatly accelerated by labile Fe(III).

Liu F, Li X, Sheng A, Shang J, Wang Z, Liu J. Kinetics and Mechanisms of Protein Adsorption and Conformational Change on Hematite Particles. Environmental Science & Technology [Internet]. 2019;53(17):10157-10165. 访问链接 Abstract

Adsorption kinetics and conformational changes of a model protein, bovine serum albumin (BSA, 0.1, 0.5, or 1.0 g/L), on the surface of hematite (α-Fe2O3) particles in 39 ± 9, 68 ± 9, and 103 ± 8 nm, respectively, were measured using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. As the particle size increases, the amount of adsorbed BSA decreases, but the loss in the helical structure of adsorbed BSA increases due to the stronger interaction forces between adsorbed BSA and the larger particles. On 39 or 68 nm hematite particles, refolding of adsorbed BSA can be induced by protein–protein interactions, when the protein surface coverage exceeds certain critical values. Two-dimensional correlation spectroscopy (2D-COS) analysis of time-dependent ATR-FTIR spectra indicate that the increase in the amount of adsorbed BSA occurs prior to the loss in the BSA helical structure in the initial stage of adsorption processes, whereas an opposite sequence of the changes to BSA conformation and surface coverage is observed during the subsequent refolding processes. Desorption experiments show that replacing the protein solution with water can quench the refolding, but not the unfolding, of adsorbed BSA. A kinetic model was proposed to quantitatively describe the interplay of adsorption kinetics and conformational change, as well as the effects of particle size and initial protein concentration on the rate constants of elementary steps in protein adsorption onto a mineral surface.

Li X, Qin F, Chen X, Sheng A, Wang Z, Liu J. Dissolution Behavior of Isolated and Aggregated Hematite Particles Revealed by in Situ Liquid Cell Transmission Electron Microscopy. Environmental Science & Technology [Internet]. 2019. 访问链接

Peng H, Pearce CI, N'Diaye AT, Zhu Z, Ni J, Rosso KM, Liu J. Redistribution of Electron Equivalents between Magnetite and Aqueous Fe²⁺ Induced by a Model Quinone Compound AQDS. Environmental Science and Technology [Internet]. 2019. 访问链接

刘娟∗, 盛安旭, 刘枫, 李晓旭, 琚宜文*, 刘国恒. 纳米矿物及其环境效应. 地球科学. 2018;43(5):1450-1463.

Redistribution of Electron Equivalents between Magnetite and Aqueous Fe2+ Induced by a Model Quinone Compound AQDS

Dissolution Behavior of Isolated and Aggregated Hematite Particles Revealed by in Situ Liquid Cell Transmission Electron Microsc

Reversible Fe(II) uptake/release by magnetite nanopartocles

Stimulatory effect of magnetite on the syntrophic metabolism of Geobacter co-cultures

Enhanced photocurrent production by the synergy of hematite nanowire-arrayed photoanode and bioengineered Shewanella oneidensis

Extracellular electron transfer mechanisms between microorganisms and minerals

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