Filtering Effect Research Articles

Two Birds With One Stone: A Novel Nanocomposite Combining Silicon Nanoparticles and Carbon-Doped Titania as the Fluorescence Probe and Visible Light Photocatalyst for Simultaneous Detection and Removal of Oxytetracycline.

The monitoring and removal of environmental pollutants are vital for the sustainable development of society. Herein, a novel nanocomposite combining silicon nanoparticles and carbon-doped titania, C-TiO2/SiNPs, is designed as a fluorescence probe and visible-light photocatalyst to simultaneously monitor and degrade oxytetracycline (OTC). C-TiO2/SiNPs emit blue fluorescence, which can be quenched by OTC through inner filter effect. Meanwhile, green fluorescence is turned on upon OTC additionby aggregation-induced emission. Thus, C-TiO2/SiNPs successfully act as a fluorescence colorimetric probe for quantitation and semi-quantitation of OTC. Additionally, C-TiO2/SiNPs showadorable visible-light photocatalytic activity toward OTC, achieving a removal rate of 93.3% in 30min. This process is driven by the superoxide radicals, holes and hydroxyl radicals produced by C-TiO2/SiNPs under visible light irradiation. The total toxicities obviously reduce after OTC is degraded by C-TiO2/SiNPs. The concentration during the OTC degradation can be estimated by naked eyes through the change of fluorescence color, but also precisely quantified by a fluorometer. This study innovatively develops a one-stone-two-birds strategy to achieve simultaneous degradation and in situ real-time detection of OTC, paving a promising paradigm for the highly efficient monitoring and removal of residual drugs.

Vanadium Dioxide-Based Terahertz Metamaterials for Non-Contact Temperature Sensor

Temperature sensors play important roles in wide-spreading human activities. The non-contact method of using temperature sensors offers significant advantages but faces challenges in detection precision. In this work, a double-layer asymmetric terahertz (THz) metamaterial combined with phase transition oxide was proposed to realize non-contact temperature sensor with high sensitivity. The metamaterial exhibited band-stop filtering effects in the simulated transmission spectra. Temperature changes induced a reversible phase transition in VO2, resulting in altered conductivity. The numerical results indicated that the S21 parameter increases from −44.33 dB to −4.78 dB at a frequency of 1.22 THz as the conductivity of the VO2 film increases from 10 to 5000 S/m, achieving a modulation depth of 89%. In addition, the 86 nm thick VO2 film underwent a phase transition in the temperature range of 54.93 °C to 66.93 °C, achieving a sensitivity of 1.82 dB/°C for temperature sensing. This work provided great insights into the development of metamaterials based on high-precision temperature measurement.

High efficiency high brightness spectral beam combination based on an ultra-broad area laser diode stack

We demonstrate what we believe to be for the first time a high efficiency, high brightness laser source by external cavity spectral beam combination (SBC) in the fast axis based on the 1000 µm ultra-broad area laser diode (UBALD). Regarding the slow axis beam quality of UBALD, we propose a feedback model of the slow axis angle energy distribution in the oscillation process. By adding a structure with a filtering effect in the external cavity, both theory and experiment show that the beam quality of the slow axis can be effectively improved. With a 25-emitter UBALD stack, an SBC maximum CW output power reaches up to 730.6 W with an electro-optical efficiency of 63.7%. The SBC spectrum consists of 25 discrete peaks with a central wavelength of ∼967 nm and an overall spectrum width of 27.2 nm. The beam quality M2 values along the fast and slow axes are measured to be 5.2 and 22.8 at an output power of 623.4 W, corresponding to a brightness as high as 562.3 MW/(cm2•sr).

Nonlinear Backstepping Control for Three-Phase Single-Stage Grid-Tied Photovoltaic Systems via an LCL-Filter

This paper examines the modeling and nonlinear control of a Three-Phase Single-Stage Grid-Tied Photovoltaic System (TPSS-GTPS). The system structure is relatively simple, comprising a Photovoltaic (PV) generator connected to the grid through a three-phase Voltage Source Inverter (VSI) and an LCL filter designed to reduce harmonics in the grid current. The primary objective of the control system is to maximize the extraction of power from the Photovoltaic Generator (PVG) and deliver it to the utility grid with a Unity Power Factor (UPF), while ensuring the asymptotic stability of the closed-loop system. In order to achieve these objectives, a novel nonlinear controller was developed in the synchronous dq-frame following the backstepping approach. Evaluating the effectiveness of the designed controller, simulations were performed in the MATLAB/Simulink environment under various scenarios to consider the effects of irradiance and temperature on the PVG. The simulation results demonstrated that the controller successfully achieved all the specified objectives. Additionally, this study highlights the effectiveness of the LCL filter in reducing Total Harmonic Distortion (THD).

Analysis of the Effectiveness of Using Active Filters and Passive Filters in Reducing Harmonics Using a Power Simulator (PSIM) at PT. Delta Jaya Mas

The Extruder Machine at PT. Delta Jaya Mas plays a critical role in the production of rubber and PVC hoses, as well as molded rubber products. This process involves the use of a 3-phase synchronous motor and Variable Frequency Drive (VFD), which can introduce harmonics into the electrical system due to their non-linear load. These harmonics can cause waveform distortion, leading to decreased efficiency and potential equipment damage. To overcome this issue, a comprehensive research is being conducted utilizing the Power Simulator (PSIM) program to analyze the impact of harmonics and evaluate the effectiveness of both active and passive filters in reducing these unwanted distortions. Initial assessments of the Extruder SDP panel revealed elevated levels of Total Harmonic Distortion (THD) in the current phases, while the voltage phases remained within acceptable thresholds. Simulation results demonstrated that the active filter was able to significantly reduce THD to an impressive 1.57%, showcasing its effectiveness in harmonic mitigation. On the other hand, the passive filter also proved beneficial, albeit to a slightly lesser extent, achieving a reduction in THD to 34.07%. This ongoing research not only aims to assist PT. Delta Jaya Mas in implementing appropriate harmonic reduction measures for their Extruder Machine but also seeks to advance the understanding of harmonic analysis and filter applications.

Preparation and application of copper nanoclusters as a fluorescent sensor for sensitive detection of tartrazine

As an important way to detect tartrazine, a probe with excellent fluorescence properties is of great significance in fluorescence detection method. Copper nanoclusters (Cu NCs) was prepared by chemical reduction method, in which copper sulfate as metal body, folic acid as capping reagent and ascorbic acid as reducing agent. In the light of inner filter effect and static quenching mechanism, a fluorescence sensor for tartrazine measurement was designed based on Cu NCs with excellent selectivity. The spherical Cu NCs with uniform size emitted blue fluorescence at 443 nm when the excitation wavelength was located at 353 nm. Under the optimum detecting condition, the corresponding linear range and LOD were 0.5–50 μM and 0.071 μM, respectively. Coupled with pleasing recovery experiments in real samples, this as-proposed platform was very promising for tartrazine detection.

Transforming waste into multifunctional nanomaterials: Mg-doped carbon dots from cow dung for Y(III) detection and biomedical applications

Rare earth metal Yttrium (Y3+) plays a vital role in many electronic devices however, discarding these devices eventually contaminates the environmental sources. Herein, we have developed a Mg-doped carbon dots (M-CDs) as a fluorescent probe for selective and sensitive determination of Y3+ in water bodies. The M-CDs having maximum emission at 420 nm upon 310 nm excitation with 20 % quantum yield and which was synthesized from upcycling of agricultural waste i.e., cow dung by simple carbonization followed by hydrothermal method. M-CDs were confirmed using different analytical and characterization techniques as well as stable in different pH and ionic strength solutions. The M-CDs was highly selective towards Y3+ ions over different metal ions with significant blue shift. This fluorescent probe performs a good linear relationship between the different concentrations of Y3+ ion and fluorescence intensity (R2 = 0.99) within the range of 0.2 to 20 μg/mL with a detection limit of 0.019 µg/mL. The study indicates quenching of Y3+ was result of dynamic quenching and the Inner Filter Effect (IFE) effect. Also, the cytotoxicity of M-CDs was checked via CAM assay and significant growth in blood vascularization with healthy growth of chick embryo confirmed the M-CDs were biocompatible. The nontoxic M-CDs was employed for MCF-7 breast cancer cell imaging which gives bright blue fluoresce under UV light excitation. Further, aiming to a circular economy approach the residual carbon remaining after hydrothermal was used as reactivated carbon for the abatement of environmental pollutants. The sustainable, cost-effective and agricultural waste-derived Mg-doped CDs have potential applications in analytical, environmental, forensic as well as biomedical fields.

One-component dual-mode sensor array for identification and quantification of biothiols

Biothiol analysis is significant to health assessment and early detection of potential diseases. Considering practical requirements, simple and rapid identification and determination of biothiols are still a great challenge due to the similar structures. Fortunately, the recently emerging colorimetric sensor array technique makes such a task possible. Herein, one-component dual-mode sensor array consisting of carbon dots (CDs) and Ag nanoparticles (AgNPs) system was designed for identification and quantification of biothiols. The identification principle is based on the inner filter effect (IFE) and different binding constants. Due to the IFE between CDs and AgNPs, the fluorescence of CDs was quenched, but recovered again after addition of biothiols because of the binding of biothiols with AgNPs. Significantly, the fluorescence recovered in varying degree due to the different binding constants of biothiols to AgNPs. Meanwhile, the absorbance of the system decreased and the color of the solution deepened. Therefore, the CDs-AgNPs system with fluorescence and absorbance response was used as the single sensing unit and generated the cross-responsive signal for different biothiols. The sensor array achieved 100% accuracy in identifying biothiols and biothiol mixtures. Moreover, the rapid quantification of biothiols in serum samples was also achieved by RGB-based smartphone colorimetry. The way to construct one component sensor array with dual mode signal outputs tremendously saves cost and time, providing a powerful tool for the identification of different biothiols. In addition, the rapid quantification of biothiols in serum samples based on RGB-based smartphone colorimetry demonstrated its powerful application prospects in disease diagnosis.

Filters comprised of sand and Zero Valent Iron hold promise as tools to mitigate risk posed by Cyclospora cayetanensis oocysts

Irrigation water contaminated by human fecal material may elevate the risk of produce contamination with the enteric parasite Cyclospora cayetanensis. Oocysts of C. cayetanensis are resistant to commonly used disinfectants and a method of removing C. cayetanensis from irrigation water would mitigate this risk. We evaluated zero valent iron (ZVI) sand filtration as one such method. We sought to determine if sand filters containing ZVI outperformed those without ZVI. We first evaluated the abundant poultry parasites Eimeria maxima, E. tenella and E. acervulina as surrogates for C. cayetanensis. We determined if a miniaturized gravity fed ZVI-sand filter, scaled to evaluate scarce supplies of C. cayetanensis oocysts, provided useful information about the performance of larger filtration systems. Filters were inoculated with oocysts, rinsed, and the resulting filtrate examined microscopically for oocysts. We performed experiments to measure the effect of varying ZVI concentrations, repeated filter use, simulated agricultural water, and oocyst size and condition. We then compared the performance of mini filters to that of larger, gravity-fed pool filters and found that ZVI-sand filtration was far more effective at removing Eimeria spp. from water when compared to sand filtration, at both scales. Sand mini filters retained 13–54 % of E. acervulina oocysts, and pool filters retained 82 %, but when combined with 50 % (mini filter) or 35 % (pool filter) v/v ZVI, mini filters retained 89–99 % of oocysts and pool filters retained >99 %. The effectiveness of the mini filters increased with increasing ZVI concentration, and the addition of ZVI far outweighed the influence of any other measured variable. We then performed experiments including C. cayetanensis, which provided similar results to those utilizing Eimeria; 59 % of inoculated C. cayetanensis oocysts were retained in sand mini filters, and 97 % in mini filters composed of 35 % v/v ZVI. In sum, ZVI is highly effective in removing oocysts from water and Eimeria is a useful surrogate for C. cayetanensis to assess filtration. ZVI-sand filtration shows promise as a tool to mitigate the risk of C. cayetanensis contamination of irrigation water. Further studies should evaluate the performance of ZVI-sand in pressurized fast filtration systems under a range of field conditions.

Performance analysis of CKF algorithm for battery SoC estimation with its aging effect

The penetration of electric vehicle (EV) in automobile market is very much dependent on the battery technology. Its size, weight, and cost are issues of concern. To effectively utilize the battery expertise, precise estimate of state of charge (SoC) is vital which greatly depends on the battery model. Current models lack consideration for variations in battery capacity over their lifespan. This paper develops a battery model which depicts the depletion of battery capacity with its life. Subsequently, this model has been utilized for estimation using advanced Kalman filtering (KF) algorithms. For the developed model, the design and effectiveness of the cubature Kalman filter (CKF) is applied as a proposed robust state-estimator for this problem. Moreover, a comparative analysis was undertaken with existing non-linear KFs based on performance metrics. The optimal choice of estimator is identified, through the results obtained from the Octave/MATLAB simulation. The outcomes show CKF algorithm based SoC estimator is superior to others in ensuring high accuracy, strong robustness even under changes in initial conditions (i.e., initial SoC, process and sensor noise levels), system's ability to converge quickly while ensuring that the maximum error in state of charge (SoC) estimation remains within 1% after convergence.

The effect of long-term storage on the viability and properties of Alternaria alternata, Bipolaris sorokiniana and Fusarium solani strains of the Phytopathogenic Microorganisms State Collection of ARRIP

Relevance. Under conditions of prolonged storage of fungi on a nutrient agar medium, their pathogenic properties are gradually lost. Preservation of collection material with unchanged pathogenic properties is necessary for correct research, including the development of biological protection methods, monitoring of pathogen development dynamics, assessment of their virulence and aggressiveness, choice of selection material.Materials and Methods. The ability to the resumption of full-fledged species characteristics on the culture nutrient agar medium after long-term storage of the biomaterial in the form of a lyophilizate under conditions of low positive +4°C and ultra-low temperatures of -80°C of Alternaria alternata (Fr.) Keissl., Bipolaris sorokiniana Shoemaker and Fusarium solani (Mart.) Sacc. strains stored in the State Collection of Phytopathogenic Microorganisms of the All-Russian Research Institute of Phytopathology (ARRIP) was studied. The viability of fungi was judged by their ability to form spore-forming colonies on a nutrient medium, pathogenicity and phytotoxicity by the reaction of test culture seedlings to the effects of spore suspensions and culture fluid filtrates.Results. Long-term storage of Alternaria alternata, Bipolaris sorokiniana and Fusarium solani strains in a freeze-dried state, both at low and ultra-low temperatures, did not adversely affect their viability. On the 14th day of culture on a nutrient medium, fungal strains formed sporulating colonies comparable to the control variants. Comparison of pathogenicity signs in fungal strains before the experiment and after storage did not reveal significant differences between the variants. When studying the effect of the culture liquid filtrates of fungal strains on the development of the test culture, a differentiating effect of the storage regime at +4oC was established, while under ultra-low temperatures the results in the variants practically did not differ.Conclusion. The results of the study were showed that the lyophilization of biomaterial,including imperfect species of fungi for long-term storage at low positive and ultra-low temperatures is relevant and in demand in many scientific and industrial institutions.

Eu(III) encapsulation strategy to construct intelligent ratiometric luminescent sensor for efficient detection of phenylglyoxylic acid biomarker in bodily fluids

Herein, a desirable MOF-based luminescent sensor of Eu3+@ZnMOF is fabricated through post-synthesis strategy. Based on response differences of the inherent monitoring signal at 442 nm and the secondary monitoring signal at 699 nm introduced by encapsulating Eu3+ ions, the prepared Eu3+@ZnMOF displays great superior as a ratiomertic luminescent sensor with high sensitive and selective, rapid response time (less than 1 min), superior detection limit (3.89 ng·mL−1), and favorable recyclable performance (at least 6 cycles) in detecting phenylglyoxylic acid (PGA) biomarker over other urine and serum species. Furthermore, Eu3+@ZnMOF also demonstrates exceptional detectability and remarkable reliability in tracing PGA levels within actual serum and urine samples. On the basis of PGA levels controlled luminescence changes of Eu3+@ZnMOF under UV light, an intelligent detection platform is developed by integrating tandem combinational “AND” logic gates to achieve more convenient and intuitive detection of PGA levels in body fluids. Besides, photoinduced electron transfer and internal filtering effect are demonstrated to be responsible for the luminescence sensing. This work not only offers a validated strategy for the design of MOFs-based ratiometric luminescent sensors, but also presents an approach in efficient, rapid, and intelligent detection of biomarkers in body fluids.

Multi-functional spin-caloritronic device based on co-doped zigzag silicene nanoribbon heterojunction

The discovery of graphene has sparked significant interest in two-dimensional (2D) materials within the research community. Graphene’s discovery has led to the exploration of several 2D-materials with varied properties. Silicene, a silicon-based analogue of graphene, is one of the newer 2D-materials. Silicene is a promising material for electronic applications and novel fields like spintronics. In this study, we propose a spin-caloritronic device based on zigzag silicene nanoribbons (ZSiNRs). The device features a heterojunction between two ZSiNRs, one of which is doped with boron (B) and nitrogen (N) atoms. The ZSiNRs’ edges are terminated with hydrogen (H) atoms for both the nanoribbons in the heterojunction. We utilize the density functional theory (DFT) combined with non-equilibrium Green’s function (NEGF) to investigate the thermal-spin transport properties of this device under the influence of a thermal gradient. Notably, the device operates without any external bias, with spin transport driven solely by the thermal gradient. We find that a thermal colossal magnetoresistance (CMR) effect may be produced by modulating thermally generated spin currents by changing the magnetic configuration. Furthermore, the proposed device has superior transport properties, displaying phenomena including the spin-Seebeck diode effect (SSD), spin filtering effect (SFE), and spin-Seebeck effect (SSE). These characteristics position the proposed device as a strong candidate for multi-functional spin-caloritronic applications.

Convective Gravity Waves in the Stratosphere and the Mesosphere: A Case Study of Airglow Over West Africa Using the Weather Research and Forecasting Model

AbstractThe Weather Research and Forecasting (WRF) Model is employed to explore gravity waves excited by a storm complex over West Africa on 15 August 2020, propagating to the mesosphere and lower thermosphere. Although the simulation portrays gravity waves in the stratosphere in a complex structure, it reveals a concentric‐ring pattern of gravity waves in the mesosphere. The waves closely resemble the airglow image acquired by Suomi National Polar‐orbiting Partnership satellite near the mesopause. This intriguing phenomenon of the emergence of concentric rings after passing the stratopause is investigated by analyzing wave characteristics, including horizontal wavenumbers, frequency, and phase speed. The analysis reveals that the wind filtering effect directly influences the behavior of gravity waves, leading to variations in their appearance with altitude. The wind filtering effect, which typically breaks symmetric ring waves, could help reveal the ring pattern when the waves are subject to interference. Consequently, the concentric rings, propagating faster than the background winds, are shown to originate from the cloud tops of the storm complex. A wind duct at a specific location is identified through spectral analysis. This mechanism is further elucidated with the assistance of the dispersion relation of a classical linear theory.

Sensitive Fluorescent Determination of Matrix Metalloproteinase-2 (MMP-2) Using the Inner Filter Effect (IFE) with Carbon Dots and Aggregated Gold Nanoparticles

Matrix metalloproteinase-2 (MMP-2) is a key biomarker involved in various pathological processes, so its sensitive and selective detection is of great clinical significance. A fluorescent sensor for the detection of MMP-2 was successfully designed based on the inner filter effect (IFE) between carbon dots (CDs) and gold nanoparticles (AuNPs). In the presence of MMP-2, peptide chains are hydrolyzed, releasing short peptides that contain thiol groups and positive charges, thereby inducing the aggregation of AuNPs. This aggregation disrupts the IFE between AuNPs and CDs, leading to a significant enhancement of the fluorescence. By monitoring the change in fluorescence intensity of CDs, the concentration of MMP-2 was accurately determined. The sensor exhibited a linear response across the concentration range from 1.0 to 150 ng/mL, with a detection limit as low as 0.23 ng/mL, which is lower than those of previously reported methods. Furthermore, the sensor demonstrated minimal interference from coexisting biochemical substances for MMP-2 in human serum. Notably, the sensor was successfully applied to determine MMP-2 in human serum, showing satisfactory recovery rates ranging from 98.8 to 1106.0%. In conclusion, this fluorescent sensor offers high selectivity and sensitivity for MMP-2 detection, making it a promising tool for clinical diagnosis of related diseases.

AIE Active Polymeric Fluorescent Nanoaggregates from Glycogen for Sensitive Detection of Tetracycline.

Detection and monitoring of environmental contaminants such as antibiotic residues in aquatic environments is challenging. To address this, a variety of detection methods has been developed; out of which optical sensing using fluorescence is found as one of the most robust methods. However, most of the reported sensors are made from metal ions using tedious synthetic processes, on the other hand, optical sensors using biosourced polymers are rarely reported. Herein, an anionic glycogen functionalized aggregation induced emission (AIE) active system; NCMCTPN was prepared using a simple Schiff base condensation reaction of tetraphenylethene amine (TPENH2) and carboxymethyl cellulose dialdehyde (NCMCA) and its self-assembled polymeric nanoaggregates were explored for sensitive and selective turn-off fluorescence detection of a broad-spectrum tetracycline antibiotic, in an aqueous medium with a limit of detection of 127.5 ppb. The combination of factors such as inner filter effect and photoinduced electron transfer from the polymeric nanoaggregates to tetracycline through activation of a non-radiative decay process is possibly responsible for the high sensitivity of the fluorescent nanoprobe towards the antibiotic.

Temperature-dependent luminescent copper nanoclusters with noncovalent interactions for determination of β-galactosidase activity.

The synthesis of anovel bidentate ligand-protected copper nanocluster via a solid-state strategyis reported. Single-crystal X-ray diffraction analysis result reveals that the copper nanocluster features an octahedral core (Cu6) coordinated by six ligands. Noncovalent interactions (C-H…π and π…π) exist between the copper nanoclusters. The copper nanocluster displays luminescence even at 250°C. The luminescence intensity is linearly correlated with temperature changes. The copper nanocluster can assemble into luminescent nanosheets whose emission is quenched by 4-nitrophenol. Spectroscopic analysis and theoretical calculations results demonstrate that the inner filter effect and electron transfer cause the above quenching effect. A probe based on luminescent nanosheets was constructed for β-galactosidase activity determination. The linearity range is 3.3-91.8 U·L-1, and the limit of detection is 0.45 U·L-1. This probe was also evaluated for determination of theβ-galactosidase activity in human serum via spiking experiments. The recoveries ranged from 96.2% to 101.8%.

Large-Scale Synthesis of Carbon Dots Driven by Schiff Base Reaction at Room Temperature

Photoluminescent carbon dots (CDs) have received increasing attention because of their admirable photophysical performances. The current strategies for synthesizing CDs typically require high energy consumption levels, and the ability to synthesize CDs at ambient temperature would be highly desirable. Herein, we design an energy-efficient approach to synthesize CDs through a Schiff base crosslinking between 2,5-dihydroxy-1,4-benzoquinone and tetraethylenepentamine at room temperature. The obtained CDs possess maximum photoluminescence (PL) emissions of 492 nm. Moreover, the proposed CDs possess good stability and a concentration-dependent PL and their maximum emissions can redshift from 492 to 621 nm as the CDs concentration increases. Because of their good luminescent properties, the CDs can be employed as optical probes for doxorubicin detection using the inner filter effect. This study develops a powerful approach for the large-scale synthesis of CDs with a superior performance.

High fluorescence quantum yield of methionine-doped carbon quantum dots for achieving rapid assay of tetracyclines in foodstuffs

The trace-level detection of tetracyclines (TCs) in food products is essential to ensure food safety and public health. Herein, we prepared the methionine-doped carbon quantum dots (Met-CQDs) using citric acid as the precursor. Met-CQDs exhibited a Gaussian unimodal peak centered at 440 nm in the fluorescent excitation spectrum, along with a remarkable greenish-blue emission and a fluorescent quantum yield of 33.5 %. Furthermore, the presence of TC (the quencher) caused a rapid quenching of the fluorescence of Met-CQDs, accompanying with a color transition from light blue to dark bule as TC concentrations increased. The coloring variation was also detected by the images captured by smartphones and RGB analysis software, facilitating portable detection of TC utilizing Met-CQDs as a fluoroprobe. The findings indicate that the Met-CQDs based fluoroprobe exhibits high selectivity, rapid response (only ∼1 min) according to an “ON-OFF” sensing model. This fluorescence sensing method gave a low detection limit (LOD) of 0.032 μM and excellent linearity for TC in the concentration range of 0.1–500 μM. Also, the smartphone-based fluorescence-visualizing approach displayed good linearity with a LOD of 0.33 μM. The interactions between this fluoroprobe and TC occurred by virtue of both inner filter effect (IFE) and static-quenching principle. The average recovery for TC in the milk, honey, and tap water samples was determined to be 98.46 ± 1.71 % by a fluorometric method. Overall, both fluorometric and RGB approaches demonstrate strong correlation with conventional LC-MS/MS, and thus the as-fabricated Met-CQDs are promising for the preliminary screening of TCs’ residues in food products.

Nutrient retention and availability of biochars prepared by co-pyrolysis of vinasse with sugarcane filter cake

The disposal of vinasse, a nutrient-rich by-product of ethanol production, is challenging because of the low pH and emissions of harmful gases and smells. Here, biochars were produced by pyrolysis of mixtures of filter cake and vinasse (0.25 w/v to 1 w/v) at 550℃. The effects of filter cake to vinasse ratios on the biochar yield, pH, ash content, total nutrient (P, K, Ca, and Mg) content, and nutrient availability were investigated. Increasing the filter cake to vinasse ratio increased the biochar yield and ash content and lowered the biochar pH from 10.3 for 0.25-BC to 8.2 for filter cake biochar (FC-BC). Lower filter cake to vinasse ratios increased the total K content from 7.9 g∙kg‒1 for FC-BC to 75.9 for 0.25-BC. Nutrient recovery in the biochars was high (79.5% to 130.2%). Whereas P, Ca, and Mg extractability in water was <5%, the K extractability was 80% for 0.25-BC and decreased to 7.6% for FC-BC. Extractability of K, P, Ca, and Mg in 2% formic acid from vinasse-containing biochars was high (>50%). These results highlight the potential suitability for use in agricultural applications. Conversion of vinasse into value-added biochar could reduce waste treatment cost and improve soil health.