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Hydrothermal carbonization technology has attracted increasingly the amount of attention due to its efficient conversion of biomass resources. Such technology benefits both the economy and the environment. In this study, hydrothermal carbonization of reed was conducted in a hydrothermal reactor under laboratory conditions. The factors that control the hydrochar yield and the efficiency of methylene blue adsorption, such as temperature, residence time, and solid-liquid ratio were investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the structure of the reed hydrochar. The experimental results indicated that the order of the factors affecting hydrochar yield was as follows: residence time > maximum temperature > solid-liquid ratio. The order of factors that determine the extent of methylene blue adsorption was: solid-liquid ratio > maximum temperature > residence time. The optimum condition for hydrochar production was with a reaction temperature at 260 ℃, a residence time of 2 h, and a solid-liquid ratio of 1:10. The optimum condition for the highest amount of methylene blue adsorption was with a reaction temperature at 260 ℃, a residence time of 1 h, and a solid-liquid ratio of 1:10. The SEM imaging revealed a pore structure at the surface of the hydrochar comprising carbon microspheres and multilayer structure. Whereas the FTIR analysis indicated that the hydrochar had a high number of oxygen-containing surface functional groups. The environmental impact of the reed hydrochar preparation process was evaluated using the life cycle assessment approach by the SimaPro 9.2.0.2 software. The results revealed that the hydrothermal carbonization process majorly impacted the toxicity to the environment, the land use and the global warming. Future optimization of the hydrothermal carbonization process should focus on: (1) reducing the energy consumption during this process; (2) evaluating the environmental impact of the hydrochar-producing system, including the resource recycling of the by-products during this process.

Nanoscale zero-valent iron (nZVI) supported on polymeric graphitic carbon nitride (CN) composite (nZVI@CN) was synthesized via liquid phase reduction method as peroxymonosulfate (PMS) activator, and had been achieved efficient degradation of paraxylene (PX) in this study. The physicochemical properties of nZVI@CN were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectrometer, Scanning electron microscopy and Brunauer–Emmett–Teller. The results indicated that catalyst prepared with 1:1 of nZVI and CN mass ration showed the best catalytic performance for the PX degradation. The removal efficiency of PX was 90.9% within 30 min treatment with the optimal reaction conditions (1 mM PMS, 0.1 g/L nZVI@CN, 20 mg/L PX and pH 6.86), and the mineralization rate measured by the removal of total organic carbon had reached 82.6%. Radical quenching and Electron paramagnetic resonance detection confirmed that sulfate and hydroxyl radicals generated by PMS activation were responsible for the degradation of PX, and sulfate radicals were the dominant active species. In addition, the possible reaction mechanism was proposed based on the experimental results. The nZVI@CN can not only be suitable for wide pH range (3–9) to effectively remove PX, but also has good stability and reusability. The removal efficiency of PX was higher than 60% in the fifth reuse experiment, which indicated that nZVI@CN was a stable PMS activator for efficiently PX removal in water.

Previous studies have shown that visually impaired users face a unique set of pain points in smartphone interaction including locating and removing the phone from a pocket, two-handed interaction while holding a cane, and keeping personal data private in a public setting. In this paper, we present a ring-based input interaction that enables in-pocket smartphone operation. By wearing a ring with an Inertial Measurement Unit on the index finger, users can perform gestures on any surface (e.g., tables, thighs) using subtle, one-handed gestures and receive auditory feedback via earphones. We conducted participatory studies to obtain a set of versatile commands and corresponding gestures. We subsequently trained an SVM model to recognize these gestures and achieved a mean accuracy of 95.5% on 15 classifications. Evaluation results showed that our ring interaction is more efficient than some baseline phone interactions and is easy, private, and fun to use.

Carbon dots (CDs) as a kind of environment-friendly fluorescent nanomaterial has been actively studied because of wide and potential applications, such as bioimaging and biosensors. It is worth mentioning that preparing CDs from the recycling of carbonaceous waste has received considerable research interest. We proposed a simple carbon dots synthesis technique, that is, using China grass carp scales (CGCS) as original and green materials by a one-step microwave hydrothermal method to prepare CDs. Since the mercury ion has strongly sulphophile, S atoms display higher thermodynamic affinity and faster integrating process with Hg2+ ions. Due to the presence of large amount of cysteine-containing sulfhydryl groups, the obtained CGCS-CDs can be used as a specific fluorescence probe for detecting Hg2+ ions. Subsequently, CGCS-CDs were characterized by HR-TEM, XRD, FT-IR and XPS analyses. The optical properties of CGCS-CDs were elucidated by fluorescence and UV–vis spectra. Additionally, the effects of pH values and salt concentrations on optical properties of CGCS-CDs were also researched by fluorescence spectra. Under optimal conditions, the decrease of fluorescence intensity displays a good linear relationship with allowable Hg2+ ion detection concentration range of 0.014–30 μmol/L and a limit of detection (LOD) of 0.014 μmol/L is acquired. Meanwhile, the effect of other metal ions on the detection of Hg2+ ions by using CGCS-CDs as fluorescence probe was studied, suggesting that the CGCS-CDs could be an excellent fluorescence probe for the detection of Hg2+ ions. Eventually, the CGCS-CDs were proven to be low toxicity and applied for Hg2+ ions detection in lake water and cosmetic, demonstrating their potential towards diverse applications.

Accurate and effective directional feedback is crucial for an electronic traveling aid device that guides visually impaired people in walking through paths. This paper presents Tactile Compass, a hand-held device that provides continuous directional feedback with a rotatable needle pointing toward the planned direction. We conducted two lab studies to evaluate the effectiveness of the feedback solution. Results showed that, using Tactile Compass, participants could reach the target direction in place with a mean deviation of 3.03° and could smoothly navigate along paths of 60cm width, with a mean deviation from the centerline of 12.1cm. Subjective feedback showed that Tactile Compass was easy to learn and use.

The adsorption-desorption performance of perfluorooctanoic acid (PFOA), one of the environmentally persistent pollutants which is refractory to degrade in soil, was investigated and reported. The adsorption-desorption process of PFOA was firstly conducted using different fractions (sand, coarse silt and fine silt) of soil collected from Shanghai, China. More than 50% of PFOA (2.0 mg/L) could be adsorbed by soils while only less than 10% of which could be desorbed once contamination occurs. The kinetics and particle diffusion rates of PFOA in different fractions of soil were calculated and analyzed in detail. Apart from this, the retention of short-chained PFCs, which can be generated as degradation products of PFOA, were also measured. In single solute systems, the adsorption of pollutants in soils dramatically increased as the chain length of PFCs grew longer. Similarly, in mixed solutions, preferential adsorption of longer-chained PFCs over shorter chains in soils were sited, attributable to the stronger hydrophobicity of the pollutants. However, the desorption of them performed in reverse, where the desorption rates of longer-chained PFCs were far lower than those of shorter ones. Furthermore, influencing factors including pH, temperature and co-existing matters were studied during the adsorption process. After comprehending the adsorption behavior of PFOA in soil fractions, the situation of the adsorption of PFOA in various soils chosen from nine provinces in China was investigated and compared. There was an obvious discrepancy, whether it be from the rate or the amount of adsorption of PFOA (approximately 10%), in the nine different soils. Finally, a multiple linear regressive equation was employed to sort influencing parameters which are prone to affect the adsorption of PFOA in soils, the contribution of these are provided in order of relevance. These results demonstrate the adsorption performance and behavior of PFOA and PFCs in different soils, which can be utilized as a scientific reference for maximizing remediation of PFOA polluted sites in the future.

International audience; The chemical degradation of perfluorooctanoic acid (PFOA), an -environmentally persistent contaminant, has recently attracted much attention. Still, very few reports have focused on the degradation of PFOA in soil due to the process's non-liquid, complex system and uneasy operation. In this study, thermal treatment was applied in the remediation of PFOA contaminated soil. Complementary to thermal activation of peroxymonosulfate (PMS), fresh activated carbon (FAC) and modified activated carbon (NAC), which were used as heterogeneous catalysts, were incorporated into the system to promote the production of sulfate radicals (SO4 center dot-) and the diminution of PFOA in soil. Two portions of soils, both homogenous but one with and the other without natural organic carbon (OC), were provided to study the impact of OC on the elimination of PFOA in soil. The degradation of PFOA was initiated using the combined methods in cohesion with heat activation. During the process, the effect of temperature, the dosing amount of catalyst and oxidant, the reaction time and the volume ratio between soil and solution on the degradation of PFOA in soil were fully studied and optimized. The results showed that over a 12 h period, a PFOA (1.0 mg/kg) removal of 76% and 70% by using FAC/PMS and NAC/PMS respectively could be achieved at 60 C. Furthermore, density functional theory (DFT) calculations were combined with experimental data and verify that the adsorption ability of both FAC and NAC for PFOA are 3 times stronger than that of soil grain. This greater adsorption can attract PFOA molecules from within soil and provide opportunities for interactions with oxidative radicals. This work sheds light on a much over-looked aspect of advanced oxidation of PFOA in soil systems, which might provide a potential option for the in-situ remediation of PFOA contaminated soil in the future.

A variety of metal elements have exhibited strong reductive and dehalogenative capabilities for the removal of persistent organic pollutants, owing to electron transfer or electron-hole activation through various methods. Herein, a bimetallic CNi-Al2O3 structure (AlCNi) was successfully synthesized to simultaneously function as sorbent and catalyst in the reduction of perfluoroalkyl carboxylic acids (PFOA) polluted wastewater. Using a reaction period of 3 h, 98% of PFOA was removed by AlCNi through a mechanochemical stirring method and 70.43% of fluorine ions was released from PFOA anchored onto the surface of AlCNi. Both thermocatalysis and photocatalysis technologies were incorporated and compared when utilized in tandem with AlCNi to mitigate the PFOA. In addition, peroxymonosulfate (PMS) and sodium sulfite (Na2SO3) were also integrated into experiments, separately, as a strong oxidant and reductant to improve the degradation effect of PFOA. However, the degradation efficiency of both were lower than that of AlCNi, even when assisted by elevated temperatures and ultraviolet irradiation. The feasibility of employing AlCNi for PFOA degradation was further investigated at various temperature and pH conditions. The data obtained from HPLC-MS/MS, TOC, and IC with multiple characterizations of AlCNi/PFOA, proposed the predominant degradation pathways comprising adsorption, defluorination-hydroxylation, and decarboxylation. This study provides a valuable remediation method without utilizing chemical agents and special activation for PFOA by AlCNi, which can be suitable for large-scale sewage treatment applications.

Two novel isomeric colorimetric probes are established for simultaneous determination of copper ions using 2-hydroxy-5-methoxybenzaldehyde fluorescein hydrazone (5-HMBA-FH) and 2-hydroxy-3-methoxybenzaldehyde fluorescein hydrazone (3-HMBA-FH). They are synthesized by reacting fluorescein hydrazide with 2-hydroxy-5-methoxybenzaldehyde and 2-hydroxy-3-methoxybenzaldehyde, respectively, and then characterized by 1H-NMR, 13C-NMR, and infrared spectrum. The addition of copper ions to the solutions of two novel colorimetric probes can generate the obviously peaks at 498 nm in UV–vis absorption spectra along with a rapid colour change from colourless to dark yellow. The detection limits of the method for Cu2+ ion were 3.442 × 10−6 mol/L and 3.682 × 10−6 mol/L separately for 5-HMBA-FH and 3-HMBA-FH, respectively. The additions of other metal ions hardly affect the determination of copper ions. The proposed method was successfully applied to the analysis of Cu2+ ions in various samples. This method possesses high sensitivity, high simplicity, and minimized interference and will provide a great advantage in detecting copper ions in the environment, food, and medical applications.

In this study, we developed a new fluorescent strategy for detecting glucose based on copper ions supported on N-doped carbon quantum dots (N-CQDs) to form Cu2+/N-CQDs nanocomplexes. The N-CQDs were characterized using high resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The optical properties of the N-CQDs were also determined by ultraviolet–visible and fluorescence spectroscopy. The proposed strategy comprises three steps: quenching the fluorescence from the N-CQDs with Cu2+ ions, producing Cu2O and gluconic acid via the Cu-catalyzed oxidation of glucose, and leaving Cu2+ ions on the surfaces of the N-CQDs to recover the fluorescence intensity. In the Cu2+/N-CQDs nanocomplexes, the Cu2+ ions act as quenchers to decrease the fluorescence from N-CQDs by surface energy transfer. The Cu-catalyzed oxidation of glucose reduces the Cu2+ ions to form Cu2O, which frees the Cu2+ ions from the surfaces of the N-CQDs and restores the fluorescence of the N-CQDs. Therefore, the change in the fluorescence depends on the concentrations of Cu2+ and glucose. Under optimal conditions, the quantitative analysis of glucose had a detection limit of 0.455 μM. Thus, Cu2+/N-CQDs can be applied as nonenzymatic glucose probes to detect low concentrations of glucose. This method also has advantages due to the facile preparation of the nanomaterials, as well as high analytical sensitivity and low experimental costs.

In this study, a novel fluorescent probe, TbIII-dtpa-bis(2,6-diaminopurine) (Tb-dtpa-bdap), is designed based on the principle of complementary base pairing and synthesized for uric acid detection. The synthesized fluorescent probe is characterized by 1H NMR, 13C NMR, infra-red (IR) spectrum and ultraviolet-visible (UV–vis) spectra. It is found that the fluorescence of Tb-dtpa-bdap solution can be quenched obviously in the presence of uric acid. The affecting factors, including solution acidity, uric acid concentration and interfering substances, on the detection of uric acid using this probe are examined. Under optimized conditions, the fluorescence intensities of Tb-dtpa-bdap solution towards different uric acid concentrations show a linear response in the range from 1.00 × 10−5 mol·L−1 to 5.00 × 10−5 mol·L−1 with a linear correlation coefficient (R2) of 0.9877. And the obtained limit of detection (LOD) is about 5.80 × 10−6 mol·L−1, which is lower than the level of uric acid in actual urine. The mechanism on the detection of uric acid by using Tb-dtpa-bdap is inferred from the experimental results. The facts demonstrate that the proposed fluorescent probe can be successfully applied for the determination of uric acid in human urine samples.

In this study, secondary municipal solid waste composts (SC) and wood vinegar treated secondary compost (WV-SC) was prepared to investigate the capability for single-heavy metals and multi-metal systems adsorption. The adsorption sequence of WV-SC for the maximum single metals sorption capacities was Cd (42.7mgg-1) > Cu (38.6mgg-1) > Zn (34.9mgg-1) > Ni (28.7mgg-1) and showed higher than that of SC adsorption isotherm. In binary/quaternary-metal systems, Ni adsorption showed a stronger inhibitory effect compared with Zn, Cd and Cu on both SC and WV-SC. According to Freundlich and Langmuir adsorption isotherm models, as well as desorption behaviors and speciation analysis of heavy metals, competitive adsorption behaviors were differed from single-metal adsorption. Especially, the three-dimensional simulation of competitive adsorption indicated that the Ni was easily exchanged and desorbed. The amount of exchangeable heavy metal fraction were in the lowest level for the metal-loaded adsorbents, composting treated by wood vinegar improved the adsorbed metals converted to the residue fraction. This was an essential start in estimating the multiple heavy metal adsorption behaviors of secondary composts, the results proved that wood vinegar was an effective additive to improve the composts quality and decrease the metal toxicity.

A novel Eu III -dtpa-bis(cytosine) complex was designed and synthesized to serve as a fluorescent probe for the determination of 6-Thioguanine (6-TG). The detection mechanism of 6-TG using this fluorescent probe was studied by ultraviolet-visible (UV–vis) and fluorescence spectroscopy. Meanwhile, the interference of other some similar base compounds on the detection of 6-TG using Eu III -dtpa-bis(cytosine) probe was also studied. It was found that the sensitivity and specificity of the Eu III -dtpa-bis(cytosine) in the 6-TG detection could be confirmed. A linear response of fluorescence emission intensity of Eu III -dtpa-bis(guanine) at 575 nm as a function of 6-TG concentration in the range of 0.00–7.50 × 10 −5 mol L −1 was observed. The detection limit is about 5.11 × 10 −7 mol L −1 . The corresponding correlation coefficient of the linear equation was 0.989. In addition, we have also studied the detection of 6-TG in the actual urines. It was found that the developed fluorescent probe could be reliable and effective for the determination of 6-TG in the actual urines.

Two novel lanthanide complexes, (EnH2)[NdIII(Egta)H2O]2 · 6H2O (I) and (EnH2)1.5[NdIII(Ttha)] · 5H2O (II), where En = ethylenediamine, H4Egta = ethyleneglycol-bis-(2-aminoethylether)-N,N,N′,N'-tetraacetic acid and H6Ttha = triethylenetetramine-N,N,N',N'',N''',N'''-hexaacetic acid, have been successfully synthesized through direct heating reflux and their molecular and crystal structures were determined by FT-IR spectroscopy, thermal analysis and single crystal X-ray diffraction (CIF files CCDC nos. 1436598 (I) and 1433221 (II)). X-ray diffraction reveals that I has a nine-coordinate mononuclear structure with pseudo-monocapped square antiprismatic conformation. Complex I crystallizes in a monoclinic system with P21/c space group; a = 13.0919(12), b = 12.6840(11), c = 16.9751(14) A, β = 122.069(3)° and V = 2388.7(4) A3. Complex II takes ten-coordinated structure with a distorted bicapped square antiprismaticprism belong to triclinic crystal system with P1 space group; a = 9.9376(10), b = 12.2178(12), c = 15.2671(16), β = 100.2480(10)° and V = 1609.5(3) A3. Each EnH2 2+ cation in I connects four adjacent [NdIII(Egta)H2O]– anions through hydrogen bonds. In II crystal cell, there are two types of cations, which form hydrogen bonds with the neighboring [NdIII(Ttha)]3– anions, leading to the formation of a 2D ladder-like layer structure. The results showed that the change of ligands can lead to change of the structure of the complexes, coordination numbers and coordination geometries. Thus, it can be concluded that the shape of ligands play a crucial role on the coordinate structure of complexes, coordination numbers and coordination geometries.

the reliable state awareness of modern distribution system relies on advanced measurement system, well-adapted calculation method as well as a better understanding of load and embedded power source. State estimator, as the most important tool to achieve real-time state awareness must take load model into consideration. In this paper, the ERL (Exponential Recovery Load) model is utilized to grasp the dynamic property during the disturbance periods. The proposed SE procedure is detailed in this paper and a simulation case with IEEE-33-bus system is conducted to verify the effectiveness.

An efficient novel amphiphilic material composed of core-double shells nanocomposite (CDSN) with nanoscale zero-valent iron (NZVI) as the core and PS100-b-PAA16 as inner shell and chitosan as outmost shell has been synthesized successfully. Its application to remove the trichloroethylene (TCE) in stimulated TCE solution with 7.3 ± 0.3 mg/L dissolved oxygen was investigated. The results showed that CDSN after exposure to air for a month could still remove 92.6% of TCE as compared to 61.5% removal rate of NZVI in 360 min (the gram ratio of material: TCE equals to 10:1), exhibiting the great oxidation resistance performance. Specifically, dynamic research of the total removal divided into adsorption by shell layer and degradation by reducibility of NZVI at a predetermined interval was engaged to understand the complete mass transfer process of TCE. The results revealed that CDSN adsorbed 1.5 to 2 folds time TCE as compared to NZVI in the same initial pH = 8.5 aqueous solution. Importantly, CDSN could sustain fixed reactivity to remove about 94.8% of TCE from the start to end. NZVI exhibited greater removal capacity in first 180 min, but later it lost the reducibility and finial removal rate was 89%. The selective adsorption to protonated CDSN was strengthened to increase the removal of TCE at pH 3.5 while NZVI had a worse removal in pH 3.5 performance than pH 8.5.

In this study, a novel fluorescent probe, Tb

In this paper, a novel fluorescent probe, dtpa-bis(cytosine), was designed and synthesized for detecting europium (Eu3 +) ion. Upon addition of Eu3 + ions into the dtpa-bis(cytosine) solution, the fluorescence intensity can strongly be enhanced. Conversely, adding other rare earth metal ions, such as Y3 +, Ce3 +, Pr3 +, Nd3 +, Sm3 +, Gd3 +, Tb3 +, Dy3 +, Ho3 +, Er3 +, Yb3 + and Lu3 +, into dtpa-bis(cytosine) solution, the fluorescence intensity is decreased slightly. Some parameters affecting the fluorescence intensity of dtpa-bis(cytosine) solution in the presence of Eu3 + ions were investigated, including solution pH value, Eu3 + ion concentration and interfering substances. The detection mechanism of Eu3 + ion using dtpa-bis(cytosine) as fluorescent probe was proposed. Under optimum conditions, the fluorescence emission intensities of EuIII-dtpa-bis(cytosine) at 375 nm in the concentration range of 0.50 × 10− 5 mol ∙ L− 1–5.00 × 10− 5 mol ∙ L− 1 of Eu3 + ion display a better linear relationship. The limit of detection (LOD) was determined as 8.65 × 10− 7 mol ∙ L− 1 and the corresponding correlation coefficient (R2) of the linear equation is 0.9807. It is wished that the proposed method could be applied for sensitively and selectively detecting Eu3 + ion.