The moisture content of combustible material on the forest floor is constantly changing due to environmental factors, which have a direct impact on the composition and emission intensity of ...particulate matter released during fire. In this study, an indoor biomass combustion analysis device was used to analyze the emission characteristics of fine particulate matter (PM2.5) from combustion of herbaceous combustible materials with different moisture contents (0%, 15%, and 30%). The composition of inorganic elements in PM2.5 (Zn, K, Mg, Ca, and other 13 measurable elements) were determined by inductively coupled plasma-mass spectrometer (ICP-MS). The results showed that the PM2.5 emission factor increased significantly with the increase of moisture content of combustible materials in the range of 11.63 ± 0.55 for dry samples to 36.71 ± 1.21 g/kg for samples with 30% moisture content. The main elemental components of PM2.5 were K, Zn, Ca, Mg, and Na and K, Ca, Mg, and Na emission factors increased with the increase of moisture content of combustibles. The proportion of macronutrients in PM2.5 released by combustion of each herb increased as the moisture content increased, but the proportion of trace elements gradually decreased. There was a good correlation between elemental composition of PM2.5 and that of herbaceous combustibles. The results provide evidence that the moisture content of combustible materials has a significant effect on the emission of inorganic elements in particulate matter, and hence cautions should be exercised during fuel reduction treatments, such as early prescribed fire.
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•PM2.5 emission from herbaceous fuel changes as the increase of moisture content.•The element emission of PM2.5 is closely affected by to the moisture content.•The macronutrients in PM2.5 positively related to the moisture content.•Moisture content of combustibles shall be considered during prescribed burning.
We report on the absolute quantification of nanoparticle interactions with individual human B cells using quadrupole-based inductively coupled plasma mass spectrometry (ICP-MS). This method enables ...the quantification of nanoparticle–cell interactions at single nanoparticle and single cell levels. We demonstrate the efficient and accurate detection of individually suspended B cells and found an ∼100-fold higher association of colloidally stable positively charged nanoparticles with single B cells than neutrally charged nanoparticles. We confirmed that these nanoparticles were internalized by individual B cells and determined that the internalization occurred via energy-dependent pathways consistent with endocytosis. Using dual analyte ICP-MS, we determined that >80% of single B cells were positive for nanoparticles. Our study demonstrates an ICP-MS workflow for the absolute quantification of nanoparticle–cell interactions with single cell and single nanoparticle resolution. This unique workflow could inform the rational design of various nanomaterials for controlling cellular interactions, including immune cell–nanoparticle interactions.
Self-absorption of spectral lines is known to lower the performance of analytical measurements via calibration-free laser-induced breakdown spectroscopy. However, the error growth due to this effect ...is not clearly assessed.
Here we propose a method to quantify the measurement error due to self-absorption based on the calculation of the spectral radiance of a plasma in local thermodynamic equilibrium. Validated through spectroscopic measurements for a binary alloy thin film of compositional gradient, the method evidences that measurement performance lowering due to self-absorption depends on the spectral shape of the analytical transition and on the intensity measurement method. Thus, line-integrated intensity measurements of Stark broadened lines enable accurate analysis, even at large optical thickness, if line width and plasma size are precisely known. The error growth due to self-absorption is significantly larger for line shapes dominated by Doppler broadening and for line-center intensity measurements. The findings present a significant advance in compositional measurements via calibration-free laser-induced breakdown spectroscopy, as they enable straightforward selection of most appropriate analytical lines.
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•Evaluation of measurement error due to self-absorption in calibration-free laserinduced breakdown spectroscopy.•Rigorous error calculation including all significant error sources.•Illustration of error dependence on spectral line profile.•Accurate simulation of emission spectra of laser-induced plasma.
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•New procedure developed to fractionate asphaltenes.•Asphaltene sub-fractions differ in amount of carbonyl, carboxylic acid or derivative groups present in them.•Higher adsorption on ...stainless steel observed for sub-fractions with more carbonyl, carboxylic acid or derivative groups.•Interaction between sub-fractions limits adsorption of unfractionated asphaltenes.
A new fractionation procedure was developed based on adsorption of asphaltenes onto calcium carbonate. The fractions obtained were characterized by elemental analysis, Fourier Transform Infrared Spectroscopy (FTIR) and Quartz Crystal Microbalance with Dissipation (QCM-D). FTIR analysis indicated that the sub-fractions obtained differed in the amount of carbonyl, carboxylic acid or derivative groups present in them. The adsorption of these fractions on stainless steel was studied by QCM-D. While the unfractionated asphaltenes exhibited a maximum saturation adsorption (Γmax) of 3.4mg/m2, the sub-fractions did not however show a Γmax within the concentration range tested (0.01–1.5g/l). The asphaltene fraction with highest concentration of carbonyl, carboxylic acid or derivative groups formed visco-elastic layers on stainless steel and also exhibited maximum adsorption (around 8mg/m2). Finally, results obtained from QCM-D measurement suggest that the interaction of the asphaltene sub-fractions tend to prevent an adsorption of unfractionated asphaltenes onto stainless steel.
Lignin-rich digested stillage as a novel feedstock for biochar production was subjected to slow pyrolysis. The lignin residue stemmed from a lignocellulosic ethanol pilot run with poplar, from which ...the stillage was anaerobically digested prior to pyrolysis. Pyrolysis conditions were optimized to meet guidelines put forth by the International Biochar Initiative and the European Biochar Certificate (molar H/Corg ratio <0.7 and O/Corg ratio <0.4), as biochar could be carbon-negative upon soil amendment, while reallocating nutrients to the field. Bench-scale pyrolysis of the lignin residue and straw were conducted according to a 33 factorial design with center runs (ranges: 370–450 °C highest treatment temperature, 5–45 min holding time and 5–50 °C.min−1 heating rate). Parametric and nonparametric statistics revealed that the highest treatment temperature was by far the most influencing factor for both feedstocks which ‘pushed’ H/C and O/C ratios within the desired range. Lignin-based biochar can be obtained with 50.7% yield, a H/C ratio of 0.70 and an O/C ratio of 0.20, already at 384 °C. This is considerably better when compared to straw-based biochar with identical H/C and O/C ratios, which came with a lower yield (33.7%) and required a modestly higher temperature (410 °C). Results from this study emphasize the feasibility to integrate slow pyrolysis in a lignocellulosic biorefinery.
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•Lignin residue from digested stillage was pyrolysed to biochar for the first time.•Temperature, heating rate and holding time were varied in a 33 factorial design.•Statistical models were used for process optimization to meet biochar standards.•The quality-quantity trade-off during pyrolysis was assessed.•At 384 °C, lignin-biochar with H/C = 0.7 and O/C = 0.2 is obtained with 50.71% yield.
This article examines the increasing importance of dried matrix spots (DMS), such as dried blood spots, dried urine spots, etc., in biomedical research, the challenges associated with their analysis ...when quantitative elemental information is aimed at, as well as the benefits deriving from the further usage of these types of samples. The article briefly reviews the historical evolution of this sampling approach in elemental clinical analysis, stressing prospective areas of applications (e.g., newborns or prosthesis control), the methodologies most recently developed to produce DMS of known volume, as well as novel strategies proposed to analyze them, often related to direct solid sampling techniques or fast lixiviation methods. Finally, the article discusses the type of information that could be obtained after isotopic analysis of DMS when targeting non-traditional stable isotopes (e.g., Cu, Fe or Zn), which can significantly help in the early diagnosis of some medical conditions (e.g. Wilson's disease).
•Importance of dried matrix spots in clinical analysis is introduced.•Advantages and challenges deriving from quantitative analysis of these samples are discussed.•Applications of elemental analysis of dried blood spots and dried urine spots are reviewed.•Potential benefits from isotopic analysis of dried matrix spots are highlighted.
There is increasing research interest on new industrial applications for the clay mineral halloysite where greater use is made of its natural tubular morphology, nano-scale diameter and contrasting ...chemistry on external and internal surfaces. Halloysite nanotubes, commonly referred to as HNTs, have potential applications as microfibre fillers, carriers for the supply and controlled or sustained release of active agents for drug delivery and anticorrosion coatings, in nanoreactors or nanotemplates, and for the uptake of contaminants or pollutants. In this study, various properties were measured on 6 halloysites from different geographical and geological environments from Australia, New Zealand and the USA. From the results, inferences were drawn on their comparative suitability for new uses. The characterisation included identification of impurities by X-ray diffraction (XRD), morphology, surface area and pore volume by electron microscopy and nitrogen absorption, the determination of exchangeable cations, and measurement of zeta potential over a wide range of pH. Halloysite content in individual samples ranged from 84 to 98%. Impurities included minor quartz, cristobalite, kaolinite, gibbsite, alunite, iron oxides and anatase. Variation in halloysite morphology and the levels of impurities had the most effect on surface area and internal pore volume. Samples with low levels of impurities and regular, thin-walled tubes reported the highest pore volumes associated with the cylindrical cavity or lumen in halloysite tubes. Surface areas varied from 22 to 81m2.g−1 and the proportion of pore space associated with the HNT lumen ranged from 11 to 39%. When the properties of the 6 different halloysites were assessed relative to the requirements for halloysite as nanotubes for either additives or carriers, one showed exceptional characteristics for both types of application but it occurs only rarely. Another halloysite that is moderately suitable for use as an additive but not a carrier occurs in a large deposit. The other samples each showed some limitations of suitability for use as an additive and/or as a carrier.
► Six halloysites were characterised for potential new applications in nanotechnology. ► Our results confirm significant differences in halloysites from different sources. ► Tailoring choice of halloysite to particular application should optimise performance.
As widely used Al-based coagulants, poly aluminum chloride (PAC) and aluminum sulfate (AS) were adopted in a short term at the start-up stage (from 10th to 16th) to enhance the formation of aerobic ...granules, and their effects on aerobic granulation were elucidated. The results suggested that both PAC and AS facilitated the granulation by improving the physicochemical properties of sludge. The reactor performance in pollutant removal was also enhanced. Specifically, in terms of extracellular polymeric substances (EPS), PAC dosing mainly stimulated the production of loosely bound EPS (LB-EPS), whereas more tightly bound EPS (TB-EPS) were secreted with the presence of AS. Based on the elemental analysis, polymeric Al hydrolyzed from PAC mainly worked on the exterior of microbial aggregates, and thus the attached aluminum in granules was gradually eliminated by ion exchange and hydraulic shear force. In contrast, the aluminum species in AS hydrolyzed into monomeric and oligomeric Al, and thus could diffuse into the interior of microbial aggregates and eventually created an “Al-core” in the granules. Overall, the present study describes the AGS formation with Al-based coagulants and the mechanisms of PAC- and AS-enhanced aerobic granulation.
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•Both PAC and AS significantly reduce the start-up period of aerobic granulation.•AGS cultivated with Al-based coagulants exhibited better physiochemical properties.•PAC and AS had shown the different effects on the secretion of EPS fractions.•Elemental analysis presented the distinct fate of PAC and AS in aerobic granules.
A new simple, fast and environmentally friendly deep eutectic solvent based dispersive liquid-liquid microextraction (DES-based DLLME) methodology assisted by vortex is presented for the separation ...and preconcentration of three elements (i.e., Fe, Cu and Pb) from edible oil samples (i.e., soybean, sunflower, rapeseed, sesame, and olive oil) prior to the determination by microwave-induced plasma optical emission spectrometry (MIP-OES). The deep eutectic solvent selected as extractant (i.e., choline chloride and ethylene glycol, 1:2) is synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR) and differential scanning calorimetry (DSC), and the extraction conditions are optimized by a two steps experimental design. Under the optimum extraction conditions (i.e., diluted sample weight: 8.6 g; DES volume: 100 μL; extraction time: 1 min; centrifugation time and speed: 3 min and 3000 rpm; and dispersion system: vortex) the analytical method presents excellent linearity (i.e., R2 values higher than 0.99) in the range 10–500 μg kg−1, repeatability (i.e., CV values lower than 9.2%), and limits of detection (LOD) values of 3, 2 and 0.7 μg kg−1 for Pb, Fe and Cu, respectively. None of the analytes displayed amounts over the upper limit permitted by law, and recovery values of all analytes evaluated in the different samples using external standard calibration were close to 100%, which excludes significant matrix effects. Finally, AGREEprep metric has been used to evaluate the method greenness (final score of 0.47) and it has been compared successfully with previous publications for the same type of analytes and matrices.
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•A DES-based DLLME-MIP-OES method allows elemental quality control of edible oils.•DESs enhance the greenness of a DLLME.•The ecological nature of the method has been assessed using the AGREEprep metric.
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