ORCID Profile
0000-0002-6578-3523
Current Organisations
Australian National University
,
University of New South Wales
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Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.BBAGEN.2018.05.005
Abstract: The inorganic core of the iron storage protein, ferritin, is recognized as being analogous to the poorly crystalline iron mineral, ferrihydrite (Fh). Fh is also abundant in soils where it is central to the redox cycling of particular soil contaminants and trace elements. In geochemical circles, it is recognized that Fh can undergo Fe(II)-catalyzed transformation to form more crystalline iron minerals, vastly altering the reactivity of the iron oxide and, in some cases, the redox poise of the system. Of relevance to both geochemical and biological systems, we investigate here if the naturally occurring reducing agent, ascorbate, can effect such an Fe(II)-catalyzed transformation of Fh at 25 °C and circumneutral pH. The transformation of ferrihydrite to possible secondary Fe(III) mineralization products was quantified using Fourier transform infrared (FTIR) spectroscopy, with supporting data obtained using X-ray absorbance spectroscopy (XAS) and X-ray diffraction (XRD). Whilst the amount of Fe(II) formed in the presence of ascorbate has resulted in Fh transformation in previous studies, no transformation of Fh to more crystalline Fe(III) (oxyhydr)oxides was observed in this study. Further experiments indicated this was due to the ability of ascorbate to inhibit the formation of goethite, lepidocrocite and magnetite. The manner in which ascorbate associated with Fh was investigated using FTIR and total organic carbon (TOC) analysis. The majority of ascorbate was found to adsorb to the Fh surface under anoxic conditions but, under oxic conditions, ascorbate was initially adsorbed then became incorporated within the Fe(III) (oxyhydr)oxide structure (i.e., co-precipitated) over time.
Publisher: American Chemical Society (ACS)
Date: 20-12-2017
Abstract: Iron (oxyhydr)oxides are widespread in natural and engineered systems, potent adsorbents of contaminants and a source of energy for iron-reducing bacteria. Microbial reduction of iron (oxyhydr)oxides results in the formation of Fe(II) which can induce the transformation of these iron minerals, typically from less crystalline to more crystalline forms, affecting the biogeochemical cycling of iron and the behavior of any species adsorbed to the iron (oxyhydr)oxides. Factors influencing the transformation rate of the poorly crystalline iron (oxyhydr)oxide, ferrihydrite, to more crystalline forms in the presence of the iron reducing bacterium Shewanella oneidensis MR-1 are investigated under controlled laboratory conditions in this work. In particular, the amount of Fe(II) produced increased the transformation rate while increasing concentrations of the electron donor, lactate, decreased the rate. Using kinetic parameters determined from abiotic controls, the results of transformation experiments in the presence of Shewanella oneidensis were modeled with this exercise revealing that less goethite and more lepidocrocite formed than expected. Conversely, studies using the Shewanella exudate only, containing biogenic Fe(II), displayed rates of transformation that were satisfactorily modeled using these abiotic control kinetic parameters. This result suggests that the physical presence of the microbes is pivotal to the reduction in ferrihydrite transformation rate observed in the biotic experiments relative to the analogous abiotic controls.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 04-2023
Publisher: Frontiers Media SA
Date: 09-02-2023
DOI: 10.3389/FENVS.2023.1042436
Abstract: Clarifying the evolution of international competitiveness for strategic and critical mineral articles is of great significance for promoting new energy development and achieving carbon neutrality in China. This study, therefore, calculates the series of indicators based on product space theory, for instance, international import & export shares, revealed comparative advantage (RCA) and product density, to analyze the competitiveness evolution. Results show that: the international competitiveness of China’s strategic and critical mineral articles demonstrated a declining tendency, and the rising percentage of imports was much larger than the decreasing export percentage. The evolution of the international competitiveness of 11 strategic and critical minerals is different. Among them, the international competitiveness of two articles is very strong, that of four articles is relatively weak, and that of three products is decreasing trend. From the perspectives of industrial sectors and trade, we analyze the underlying reasons for the competitiveness evolution of 11 strategic and critical mineral articles in detail and discuss the industry transformation and upgrade feasibility for strategic and critical mineral articles. Our work aims to provide strong support for the upgrading and high-quality development of the strategic and critical mineral products industry by providing corresponding policy suggestions.
Publisher: Frontiers Media SA
Date: 29-09-2022
DOI: 10.3389/FENVS.2022.993833
Abstract: As an important means to promote regional low-carbon development, environmental regulation has great theoretical and practical significance for achieving the goal of carbon-neutral development in China. Based on the panel data of 30 provinces and cities in China from 2005 to 2019, this paper first uses the intermediary effect model to analyze the impact of the implementation of environmental regulation policies on regional carbon emissions, discusses the relationship between environmental regulation, green technology innovation and carbon emissions, and further uses the threshold effect model to discuss the nonlinear relationship between environmental regulation and regional carbon emissions. The results show that: the improvement of formal and informal environmental regulation can play a role in “forced emission reduction” Green technology innovation plays a complete intermediary role in the impact of environmental regulation on regional carbon emissions At the same time, the impact of formal and informal environmental regulation on regional carbon emissions has a threshold effect. Among them, formal environmental regulation has a double threshold effect, the threshold values are 0.429 and 0.502 respectively, while informal environmental regulation has a single threshold effect, the threshold value is 1.803. The results of heterogeneity analysis show that there are obvious differences in the implementation effects of environmental regulation policies under different economic development levels and industrialization development stages. Therefore, we should pay attention to the mutual promotion effect of different types of environmental regulation, strengthen the collaborative emission reduction of environmental regulation and green technology innovation, and improve the level of regional green technology innovation, so as to better promote the realization of regional carbon neutrality goals.
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.TALANTA.2017.07.018
Abstract: The Fe(II)-catalyzed transformation of the poorly crystalline Fe(III) oxyhydroxide mineral, ferrihydrite (Fh), to more crystalline Fe(III) mineral species such as magnetite, goethite, and lepidocrocite has been quantitatively evaluated under various conditions using X-ray adsorption spectroscopy (XAS) and Fourier transform infrared (FTIR) spectroscopy. Using the peak height of signature FTIR peaks of sub-micron sized lepidocrocite and goethite references minerals, the FTIR results were comparable to the XAS results within experimental error. This was independent of whether the Fe(II)-catalyzed transformation was initiated by the Fe(III)-reducing bacterium Shewanella oneidensis MR-1 or by added ferrous ammonium sulfate in the presence or absence of lactate. Whilst the use of FTIR has not been previously employed to follow this transformation process, it has advantages relative to XAS including a lower s le requirement (approximately 30-fold lower), greater accessibility and greater safety of operation. Whilst problems with quantifying magnetite in the presence of lepidocrocite were identified in this study using reference Fe(III) oxyhydroxide suspensions, large amounts of magnetite were not produced during transformation under the conditions employed in this study. Reference spectra of lath-like nano-goethite particles (with dimensions of approx. 10 × 50nm) also resulted in higher IR absorbance and a slight red-shift in signature peak positions relative to sub-micron sized goethite particles with this shift potentially affecting the reliable quantification of s les of unknown size. Despite this, good agreement between the XAS and FTIR data for s les containing iron oxides undergoing continuous transformation was obtained suggesting that FTIR may be a convenient, inexpensive means of following such mineral transformations.
Publisher: American Chemical Society (ACS)
Date: 28-11-2022
No related grants have been discovered for Wei Xiao.