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•SERS as analytical tool to quantify thiabendazole (TBZ) using Ag colloid.•Propose a TBZ-metallic surface interaction supported by theoretical approach.•Sigmoidal isotherm is obtained ...instead the Langmuir isotherm.•Focused on the potential of SERS as analytical tool with linear response.
The application of surface-enhanced Raman scattering (SERS) as analytical tool remains a challenge due signal intensity fluctuations, which depends on experimental parameters such as size, shape, and aggregation of the metallic nanoparticles responsible for enhancing the Raman signal. Colloidal nanoparticles can overtake this difficulty by optimizing some experimental conditions for each analyte. Here, we applied SERS as analytical technique to detect thiabendazole (TBZ) at low concentrations using Ag colloid. TBZ stock solutions were added into Ag colloids and SERS spectra were recorded in triplicate. Within the TBZ concentration from 1.6 × 10−7 to 8.0 × 10−8 mol/L a linear regimen for SERS intensity was achieved, leading to a TBZ limit of detection of 13.8 ppb. Besides, the main enhanced bands of the TBZ SERS spectrum suggest the TBZ adsorption mechanism on Ag surface takes place by the thiazole moiety. Theoretical calculations support the experimental data and indicate the interaction is stablished by S atom. Complementary to analytical application and adsorption mechanism, the dependence of SERS intensity on TBZ concentration follows a sigmoidal adsorption isotherm, which has a direct relation with the extinction spectra of Ag colloid containing TBZ at different concentrations, revealing intermolecular TBZ interactions and formation of Ag nanoparticle aggregates with distinct morphologies.
X-ray fluorescence (XRF) emerges as a promising technique for estimating heavy metal elements. However, XRF spectra typically contain a significant amount of environmental information and signal ...noise, and the relationship between spectral intensity and element concentration is difficult to quantify using a single model, thereby reducing the predictive performance for low concentration elements.
This paper proposed a comprehensive framework for predicting elemental concentrations, encompassing preprocessing, variable selection, decision-making, to enable fast, non-destructive, and accurate estimation of element concentrations in soil. Firstly, an optimal denoising method based on fractional discrete wavelet transform (FDWT) was introduced to enhance signal quality. Furthermore, the frequency-based competitive adaptive reweighted sampling (FCARS) algorithm was employed for feature selection of XRF spectral variables, allowing extraction of the most informative features from the complex spectral data. Finally, a novel deep learning network, called ConvBiLSTM-Attention (CBLA-Net), was designed to achieve precise estimation of heavy metal elements concentration. Compared with other advanced algorithms, The CBLA-Net demonstrated the highest accuracy for V, Cr, Mn, Zn, Cd, and Pb, achieving the coefficient of determination (R2) of 0.9730, 0.9874, 0.9952, 0.9921, 0.9518, and 0.9741, respectively. The CBLA-Net not only effectively extract local features and capture global information, but also combines attention mechanism to focus on key information.
The proposed novel deep learning quantitative framework, including preprocessing, feature selection, and CBLA-Net decision-making, significantly enhances the accuracy of elemental content prediction. It provides a new approach for accurately assessing the concentration of heavy metal elements in soil.
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•CBLA-Net effectively reduces prediction errors for quantitative analysis.•A FDWT denoising algorithm is proposed to enhance the signal-to-noise ratio.•FCARS performs variable selection on XRF spectra to eliminate redundant information.
The quantitative assessment of main adsorption mechanism of NEO adsorption by bimetal ZIF derived-magnetic carbon.
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•A magnetic carbon showed superior adsorption performance for ...neonicotinoid pesticides compared to other adsorbents.•This adsorbent demonstrated outstanding anti-interference properties and effective performance in real-world water samples.•The contribution levels of each interaction and reaction sequence of functional groups were traced at different pH levels.•π-π interactions exhibited higher contribution levels in pH 3.0–10.0.•This adsorbent performed excellently in removing various neonicotinoid pesticides under trace concentrations.
Emerging organic contaminants, such as pesticides, pose significant environmental challenges and necessitate the development of advanced materials and technologies for their efficient removal. This study explored various morphologies of bimetal ZIF-derived magnetic carbon for the removal of three representative neonicotinoid pesticides from water. Among the materials investigated, Co-NP3-1000, carbonized at 1000℃ from Zn/Co-ZIF with a Zn/Co molar ratio of 3:1, demonstrated outstanding adsorption performance, even in the presence of varying water chemistry parameters (e.g., humic acid and particulate matter), and effectively removed neonicotinoid pesticides at low concentrations from diverse actual water samples. Due to its strong magnetic properties, Co-NP3-1000 could be easily separated from solutions and maintained over 70% adsorption efficiency after five consecutive cycles. Moreover, Co-NP3-1000 exhibited high efficiency in removing other neonicotinoid pesticides (i.e., acetamiprid, nitenpyram, and thiamethoxam). Microstructure analysis and density functional theory calculation identified pore filling, hydrogen bonding, and π-π interactions as the primary forces driving NEOs adsorption. Notably, the relative contribution of these interactions was quantitatively assessed across different solution pH levels, and their sequence was elucidated using two-dimensional Fourier transform infrared correlation spectroscopy. This work advances both the design of versatile materials for the removal of emerging organic contaminants and quantitative insights into the interaction mechanisms between advanced adsorbents and these contaminants.
The aim of this paper is offering a critical review of Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS), the approach of multi-elemental quantitative analysis of LIBS spectra, based on ...the measurement of line intensities and plasma properties (plasma electron density and temperature) and on the assumption of a Boltzmann population of excited levels, which does not require the use of calibration curves or matrix-matched standards. The first part of this review focuses on the applications of the CF-LIBS method. Quantitative results reported in the literature, obtained in the analysis of various materials and in a wide range of experimental conditions, are summarized, with a special emphasis on the departure from nominal composition values. The second part is a discussion of the simplifying assumptions which lie at the basis of the CF-LIBS algorithm (stoichiometric ablation and complete atomization, thermal equilibrium, homogeneous plasma, thin radiation, detection of all elements). The inspection of the literature suggests that the CF-LIBS method is more accurate in analyzing metallic alloys rather than dielectrics. However, the full exploitation of the method seems to be still far to come, especially for the lack of a complete characterization of the effects of experimental constraints. However, some general directions can be suggested to help the analyst in designing LIBS measurements in a way which is more suited for CF-LIBS analysis.
Industrialization has caused a significant global issue with cadmium (Cd) pollution. In this study, Biochar (Bc), generated through initial pyrolysis of rice straw, underwent thorough mixing with ...magnetized bentonite clay, followed by activation with KOH and subsequent pyrolysis. Consequently, a magnetized bentonite modified rice straw biochar (Fe3O4@B-Bc) was successfully synthesized for effective treatment and remediation of this problem. Fe3O4@B-Bc not only overcomes the challenges associated with the difficult separation of individual bentonite or biochar from water, but also exhibited a maximum adsorption capacity of Cd(II) up to 241.52 mg g−1. The characterization of Fe3O4@B-Bc revealed that its surface was rich in C, O and Fe functional groups, which enable efficient adsorption. The quantitative calculation of the contribution to the adsorption mechanism indicates that cation exchange and physical adsorption accounted for 65.87% of the total adsorption capacity. In conclusion, Fe3O4@B-Bc can be considered a low-cost and recyclable green adsorbent, with broad potential for treating cadmium-polluted water.
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•Magnetized bentonite/biochar composites were prepared for Cd(II) removal.•The maximum adsorption capacity of Fe3O4@B-Bc is 241.52 mg g−1.•Cation exchange and physical adsorption contributed 65.87% of the total capacity.
•A novel method via OMS has been applied in NO reduction over biomass char.•Overlapping fragments of CO, N2, and CO2 at similar m/z in OMS were split.•The mass flow rate of gases and mass conversion ...of C and N were calculated.
A novel quantitative analysis method via on-line mass spectrometer (OMS) was developed to calculate the mass flows of the reactants and products for the reaction between NO and biomass char in micro-fluidized bed. The experimental results showed that the quantitative method could accurately calculate the mass flow rate of each gas even though there were ion currents overlapping at mass-to-charge ratio (m/z) = 12,16, and 28 when CO, CO2 and N2 were simultaneously present in OMS. Furthermore, the method facilitated the quantitative analysis of gaseous reactants and products, thereby enabling the assessment of mass conversions of carbon (C) and nitrogen (N) in the NO reduction reaction. It was observed that CO was the predominant carbon-containing product in the reaction involving biomass char and NO at 900 °C, with over 96 % of nitrogen in NO participating in the reduction reaction being converted to N2. This study also revealed that increasing the fluidization number, NO concentration, and temperature in the micro-fluidized bed could significantly accelerate the conversion processes of C and N in the reduction of NO by biomass char. The peak mass flow rates of CO, CO2, and N2 were found to increase correspondingly with higher NO concentrations and temperature levels. The NO reduction process over sawdust char was compared to that of corncob char, showing a higher maximum NO reduction efficiency. The reaction order with respect to NO concentration was determined to be 0.82 for corncob char and 0.68 for sawdust char. Additionally, the apparent activation energies were determined to be 92.35 kJ/mol for corncob char and 125.60 kJ/mol for sawdust char, respectively.
Job crafting refers to changes to a job that workers make with the intention of improving the job for themselves. It may include structural (i.e., physical and procedural), social, and cognitive ...forms. We draw on two studies to develop a role–resource approach–avoidance taxonomy that integrates and extends the dominant role- and resource-based perspectives of job crafting according to characteristics of approach and avoidance. Study 1 used both qualitative and quantitative methods to analyze job crafting activities described during employee interviews to understand the nature and outcomes of specific job crafting activities. Study 2 provides quantitative support for the specific job crafting types emerging from Study 1, and further explores job crafting outcomes. Approach role crafting includes role expansion and social expansion, while avoidance role crafting includes work-role reduction. Role crafting outcomes include: increased enrichment, increased engagement, and decreased strain through changes in work role boundaries. Approach resource crafting includes work organization, adoption, and metacognition, while avoidance resource crafting includes withdrawal crafting. Resource crafting outcomes include: increased performance, increased engagement, and reduced strain through the development, acquisition, and conservation of resources. Avoidance crafting positively relates to work withdrawal and tends to have fewer relationships with positive outcomes compared to approach crafting.
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