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Abstract: Recycling of sewage sludge and the endogenous phosphorus (P) is a promising strategy for sustainable development, while the disposal of heavy metals (HMs) in sewage sludge and the recovery of targeted P species remain challenges. An innovative method coupling electrokinetic treatment with pyrolysis was proposed in the present study to achieve the effective reclamation of available P and the separation of HMs from sewage sludge. The pristine and FeCl3-assisted electrokinetic treatment were employed for the removal of HMs from sewage sludge and to modify the P species, and the subsequent pyrolysis (300–700 °C) was conducted for the recovery of available P along with the production of biochar. The X-ray absorption near-edge spectroscopy (XANES), 31P liquid nuclear magnetic resonance (NMR) spectroscopy, and sequential chemical extraction were used to systematically determine the evolution of P during the combined treatment of sewage sludge. 19.69–24.80 % of Ni, Cu, and Zn were removed from sewage sludge after pristine electrokinetic treatment, and the HM removal efficiency was further elevated to 47.01–56.86 % with the assistance of FeCl3. Consequently, in comparison with the raw sewage sludge-derived biochars (SBs), the biochars derived from FeCl3-assisted electrokinetic treated sewage sludge (FESBs) contained much lower HM contents and showed higher stability of HMs. The FeCl3-assisted electrokinetic treatment converted alkaline biochars dominated by poorly soluble Ca-phosphates into neutral to slightly acidic biochars dominated by Al/Fe-associated phosphates. This transformation greatly improved the available P concentrations determined by diffusive gradients in thin film in FESBs by 0.6–1.3 folds compared to untreated SBs. Therefore, coupling FeCl3–assisted electrokinetic treatment with pyrolysis could be a promising strategy to achieve the reclamation of available P and the separation of HMs from sewage sludge.

Open Access

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Abstract: Operating lithium ion batteries (LIBs) to high charging cut off potentials allows us to accommodate a further push in energy density. However, it requires a thorough understanding of the interplay and temperature dependence of parasitic reactions that aggravate the aging of the electrolyte and the cathode/anode electrodes. In the present study we investigated the interplay of the chemical and the electrochemical electrolyte oxidation, how they are related to the dissolution of transition metal (TM) ions from the cathode active material (CAM), and how they shift or accelerate with temperature. Through an optimized electrochemical protocol an excellent potential dependence of the gas evolution of a LiNi0.80Co0.15Al0.05O2 (NCA) charged against a free standing graphite on a lithium metal electrode in a LP47 electrolyte was achieved. We identified O2 and PF5 gas as suitable proxies for the chemical and electrochemical electrolyte oxidation, respectively. Both processes are separated by at least 300 mV over a temperature range from 10 to 45°C. Through temperature-dependent operando hard X ray absorption spectroscopy measurements and their comparison with the gassing results, it will be shown, that the electrochemical oxidation of the electrolyte is directly linked to the dissolution of TMs, while the chemical electrolyte oxidation mainly leaves the transition metal dissolution unaffected.

Open Access

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Abstract: Glass ingots of lead silicate composition from the shipwreck of the Albion were studied to ascertain the chemistry and mineralogy of alteration products after exposure to seawater for 220 years. Alteration observed on natural samples was compared to that of the same glasses exposed to short-term, high temperature, laboratory dissolution tests in synthetic seawater and significant differences were observed. Alteration layers on natural samples were more chemically complex having sequestered high concentrations of elements present only at trace quantities in seawater. Electron microprobe analysis and microfocus x-ray absorption spectroscopy shows that P, most likely released by biological activity in the vicinity of the wreck, accumulated in naturally altered samples to form Pb–Ca-phosphate phases whilst Pb-sulphate phases formed in laboratory tests. Meanwhile Fe, present at < 0.3 wt % in the glass and ppb concentrations in seawater, accumulated to form Fe-silicates whilst Mg-silicates predominated in laboratory tests. Biologically induced corrosion of naturally altered samples was also considered. Experiments conducted to test barnacle settlement rates suggest that biotoxic elements within the glass, primarily Pb but potentially also Cu, Co and Ni deterred barnacle settlement. Despite this toxicity, some colonisation of the glass surface by both barnacles and bryozoan did occur and, whilst barnacles appeared to protect against chemical attack, bryozoan colonies caused increased cracking, possibly due stress created at the glass surface. Results highlight the challenges in recreating open, natural systems in laboratory settings and demonstrate that elements present at low concentrations can have a significant impact over long timescales.

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Abstract: Dental caries is the most prevalent oral disease that causes structural and compositional changes of the dental hard tissues due to a chronic demineralisation (combined with possible phases of remineralisation) process. The changes can affect most important oral functions and aesthetics, as well as causing pain and discomfort. Though considerable efforts have been directed at studying natural and artificial carious lesions, most characterisations remain either constrained to 2D analyses or have been unable to achieve fine resolution in 3D due to limited field of view. To overcome this challenge, the present study combined X-ray diffraction (XRD) and scanning transmission X-ray microscopy (STXM) tomography techniques to analyse the mineral density, scattering intensity, and crystallite size in normal, carious, 30 % artificially demineralised, and 50 % artificially demineralised dentine. Combined XRD and STXM tomography was performed on the I18 beamline at Diamond Light Source, using a 15 keV monochromatic beam with 2 × 2 μm spotsize and scanning with translation steps of 2 μm, providing a reconstructed voxel size of 2 × 2 × 2 μm. Natural carious dentine showed a reduction in hydroxyapatite (HAp) crystallite size due to chronic demineralisation. This was unlike artificially demineralised dentine samples that underwent short, continuous demineralisation, which created a zone of fully demineralised dentine, near the sample surface, and a zone of partially demineralised dentine that had a reduced mineral density but an increased average crystallite size.

Open Access

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Abstract: Prostate cancer remains the most common male cancer; however, treatment regimens remain unclear in some cases due to a lack of agreement in current testing methods. Therefore, there is an increasing need to identify novel biomarkers to better counsel patients about their treatment options. Microcalcifications offer one such avenue of exploration. Microfocus spectroscopy at the i18 beamline at Diamond Light Source was utilised to measure X-ray diffraction and fluorescence maps of calcifications in 10 µm thick formalin fixed paraffin embedded prostate sections. Calcifications predominantly consisted of hydroxyapatite (HAP) and whitlockite (WH). Kendall’s Tau statistics showed weak correlations of ‘a’ and ‘c’ lattice parameters in HAP with GG (rτ = − 0.323, p = 3.43 × 10–4 and rτ = 0.227, p = 0.011 respectively), and a negative correlation of relative zinc levels in soft tissue (rτ = − 0.240, p = 0.022) with GG. Negative correlations of the HAP ‘a’ axis (rτ = − 0.284, p = 2.17 × 10–3) and WH ‘c’ axis (rτ = − 0.543, p = 2.83 × 10–4) with pathological stage were also demonstrated. Prostate calcification chemistry has been revealed for the first time to correlate with clinical markers, highlighting the potential of calcifications as biomarkers of prostate cancer.