Effective Separation Research Articles

Characterization of solid particles with different particle sizes in high-temperature coal tar pitch

ABSTRACT High-temperature coal tar pitch (HCTP) serves as a crucial precursor for high-quality carbon materials, while solid particle (SP) characteristics significantly influence the properties of the pitch. This study explores the compositional differences of SPs across various sizes to facilitate their effective separation. We employed ultrasonic graded centrifugation to isolate seven SP types of different sizes and analyzed their properties using SEM, SEM-EDS plane scanning, laser particle size analysis (LPSA), organic element analysis (EA), FT-IR, ICP-MS, and XRD. Our results reveal distinct variations in the SP distribution by particle size. As the particle size decreases, the proportion of particles in the 1–100 μm range decreases, while ultrafine particles (0.01–0.1 μm) become more prevalent. The carbon content in SPs initially increases and then decreases with smaller particle sizes, reaching a peak in medium-sized particles. Non-carbon impurities such as Si, S, Zn, Pb, Ca, Fe, and inorganic ash are concentrated in larger particles (SP1–SP2) and smaller particles (SP6–SP7). Notable inorganic compounds like PbS, ZnS, and FeS are found across all sizes, whereas SiO2 and CaCO3 are restricted to larger particles (SP1–SP2). Furthermore, smaller particles exhibit greater specific surface areas and pore volumes.

Process upgradation and kinetic modeling of high-ash non-coking coal flotation using bio-based collector for enhanced clean coal recovery

ABSTRACT The reduction of ash content, contributed by inorganic mineral matter, and recovery of carbon values in a high ash non-coking coal was studied in a laboratory-scale mechanical flotation cell using a bio-collector (PSO) derived from the pumpkin seeds for clean coal recovery. Surface characterization of PSO (GCMS, FTIR) and untreated/PSO-treated coal (contact angle, FTIR) indicated potential interaction between PSO and the coal surface, enhancing its hydrophobicity, while XRD analysis confirmed successful rejection of ash-forming inorganic gangue minerals into tailings, signifying effective clean coal separation from the gangue. The input parameters, such as PSO dosage, frother MIBC dosage, and airflow rate (AFR), were enhanced to attain best process responses, i.e. yield, ash, and fixed carbon of the final clean coal. The use of PSO significantly reduced the ash content of feed coal from 32% to as low as 9.86% in the final clean coal while simultaneously increasing the fixed carbon content from 35% to 61.15% and the gross calorific value from 4966 Kcal/Kg to 6318 Kcal/kg. A clean coal product having high fixed carbon of 61.15% with 11.29% ash content and 70.14% yield was obtained at PSO dosage of 10.73 Kg/t, MIBC dosage of 0.93 Kg/t and at AFR of 2.5lpm. The kinetic study revealed a high recovery of combustible materials (~88%) and low ash recovery (~46%) at a flotation time of 480 seconds. Based on the kinetic model discrimination analysis, it was found that the first-order fits well with the experimental data for combustible and ash recovery. This study illustrates the efficacy of pumpkin seed oil (PSO) as a potential bio-collector for the flotation of non-coking coal, enhancing the coal quality by selectively reducing mineral matter content and leading to substantial economic and environmental advantages.

Theoretical Design for Thorium-Containing Two-Dimensional Materials.

Actinide elements are characterized by their unique electronic correlations, variable valence states, and localized 5f electrons, leading to unconventional electronic and topological properties in their compounds. The distinctive physical properties of actinide materials are maintained in low-dimensional forms, yet two-dimensional (2D) actinide materials remain largely unexplored due to their scarcity and the experimental challenges posed by their radioactivity. To fill the knowledge gap in 2D actinide materials, we theoretically designed a series of stable thorium-containing 2D materials, including MXenes, chalcogenides, halides, and other compounds with unique structures. These novel thorium-containing 2D materials show excellent thermodynamic, mechanical, and dynamical stability. Their electronic structures and potential applications were investigated. Considering the proper band edge positions, strong visible light absorption, and effective separation of photogenerated electron-hole pairs, ThPSe3 is proposed as a promising photocatalyst for water splitting. Our work significantly expands the 2D actinide materials family, and further opens new avenues for their experimental realization and applications.

Treatment and Valorization of Waste Wind Turbines: Component Identification and Analysis.

Recycling end-of-life wind turbines poses a significant challenge due to the increasing number of turbines going out of use. After many years of operation, turbines lose their functional properties, generating a substantial amount of composite waste that requires efficient and environmentally friendly processing methods. Wind turbine blades, in particular, are a problematic component in the recycling process due to their complex material composition. They are primarily made of composites containing glass and carbon fibers embedded in polymer matrices such as epoxies and polyester resins. This study presents an innovative approach to analyzing and valorizing these composite wastes. The research methodology incorporates integrated processing and analysis techniques, including mechanical waste treatment using a novel compression milling process, instead of traditional knife mills, which reduces wear on the milling tools. Based on the differences in the structure and colors of the materials, 15 different kinds of samples named WT1-WT15 were distinguished from crushed wind turbines, enabling a detailed analysis of their physicochemical properties and the identification of the constituent components. Fourier transform infrared spectroscopy (FTIR) identified key functional groups, confirming the presence of thermoplastic polymers (PET, PE, and PP), epoxy and polyester resins, wood, and fillers such as glass fibers. Thermogravimetric analysis (TGA) provided insights into thermal stability, degradation behavior, and the heterogeneity of the samples, indicating a mix of organic and inorganic constituents. Differential scanning calorimetry (DSC) further characterized phase transitions in polymers, revealing variations in thermal properties among samples. The fractionation process was carried out using both wet and dry methods, allowing for a more effective separation of components. Based on the wet separation process, three fractions-GF1, GF2, and GF3-along with other components were obtained. For instance, in the case of the GF1 < 40 µm fraction, thermogravimetric analysis (TGA) revealed that the residual mass is as high as 89.7%, indicating a predominance of glass fibers. This result highlights the effectiveness of the proposed methods in facilitating the efficient recovery of high-value materials.

Multiple Exciton Generation on Doped Wide-Band Semiconductor Photoanode with Hierarchical Quantum Structure.

The multiple exciton generation (MEG) effect, which produces multiple photo-generated charge carriers from a single high-energy photon absorption by a semiconductor with a narrow bandgap, has the potential to revolutionize photovoltaic, photoelectric detection, and other technologies. Here, this work finds that the surface carbon-modified wide-bandgap photoanode with hierarchical quantum structure can drive a photoelectrochemical reaction with a quantum efficiency exceeding 145% by the first time. More studies reveal that the presence of the MEG effect in the MEG-CdS photoanode is attributed to the formation of high-quality surface C-modified CdS quantum nanosheets on CdS bulk film by in situ, this hierarchical quantum structure leads to quantum confinement effects that increase effective Coulomb interaction for driving MEG and decrease competition for thermal exciton cooling. The acceptor level introduced by carbon reduces the MEG threshold (approximately twice the energy level difference) and collaborates with the built-in electric field of the C-CdS/bulk-CdS homojunction to enable the effective generation and separation of photo-generated charge carriers. The internal quantum efficiency of the MEG-CdS photoanode reaches up to a recording value of 145%, providing a novel perspective on the contribution of surface-modified wide-band semiconductors and their quantum effects in the application of MEG.

Strong Interfacial Interaction in Polarized Ferroelectric Heterostructured Nanosheets for Highly Efficient and Selective Photocatalytic CO2 Reduction.

Heterojunctions are sustainable solutions for the photocatalytic CO2 reduction reaction (CO2RR) by regulating charge separation behavior at the interface. However, their efficiency and product selectivity are severely hindered by the inflexible and weak built-in electric field and the electronic structure of the two phases. Herein, ferroelectric-based heterojunctions between polarized bismuth ferrite (BFO(P)) and CdS are constructed to enhance the interfacial interactions and catalytic activity. The intrinsic polarization field depending on the ferroelectric state causes significant electrostatic potential difference and energy-band bending. This helps overcome the unsatisfactory redox potential that differs from the classical catalytic mechanism, and synergy from the heterostructure facilitates effective separation and transfer of photogenerated charges with an extended lifetime (>20ns) and significantly enhanced photovoltage (1002 times that of BFO). The optimized charge carrier dynamics allow the heterojunction to achieve a much higher CO yield compared to state-of-the-art ferroelectric-based photocatalysts, and 85.46 and 23.47 times higher than those of pristine CdS and BFO, respectively. Moreover, it maintains an impressive 100% product selectivity together with excellent repeatability and cycling. This work not only sheds light on how a strong inherent polarity promotes the performance of heterojunction photocatalysts but also provides new insights for designing efficient photocatalytic CO2RR.

Weakly Supervised Nuclei Segmentation with Point-Guided Attention and Self-Supervised Pseudo-Labeling.

Due to the labor-intensive manual annotations for nuclei segmentation, point-supervised segmentation based on nuclei coordinate supervision has gained recognition in recent years. Despite great progress, two challenges hinder the performance of weakly supervised nuclei segmentation methods: (1) The stable and effective segmentation of adjacent cell nuclei remains an unresolved challenge. (2) Existing approaches rely solely on initial pseudo-labels generated from point annotations for training, and inaccurate labels may lead the model to assimilate a considerable amount of noise information, thereby diminishing performance. To address these issues, we propose a method based on center-point prediction and pseudo-label updating for precise nuclei segmentation. First, we devise a Gaussian kernel mechanism that employs multi-scale Gaussian masks for multi-branch center-point prediction. The generated center points are utilized by the segmentation module to facilitate the effective separation of adjacent nuclei. Next, we introduce a point-guided attention mechanism that concentrates the segmentation module's attention around authentic point labels, reducing the noise impact caused by pseudo-labels. Finally, a label updating mechanism based on the exponential moving average (EMA) and k-means clustering is introduced to enhance the quality of pseudo-labels. The experimental results on three public datasets demonstrate that our approach has achieved state-of-the-art performance across multiple metrics. This method can significantly reduce annotation costs and reliance on clinical experts, facilitating large-scale dataset training and promoting the adoption of automated analysis in clinical applications.

Construction of Cu2MoS4/ZnO Heterostructures and Mechanism of Photocatalytic Hydrogen Production.

Constructing wide and narrow band gap heterogeneous semiconductors is a method to improve the activity of photocatalysts. In this paper, CMS/ZnO heterojunctions were prepared by solvothermal loading of ZnO particles on the surface of Cu2MoS4 nanosheets. The photocatalytic H2 precipitation rate is about 545 μmol·g-1·h-1, which is 6.8 times that of Cu2MoS4 and 3 times that of ZnO without any cocatalyst. After etching modification of CMS, the photocatalytic hydrogen production efficiency of the ECMS/ZnO heterojunction is further improved. Its hydrogen production efficiency reaches about 1115 μmol·g-1·h-1, which is 9 times that of ECMS and 6 times that of ZnO. The reasons are mainly attributed to the following two factors: (1) the formation of the ECMS/ZnO type-II-type heterojunction facilitates the effective separation of photogenerated electrons and holes; (2) the band structure of Cu2MoS4 was optimized by etching modification, which made the ECMS/ZnO heterojunction have lower interfacial charge transfer resistance and improved the photocatalytic hydrogen production activity of the heterojunction.

Photocatalytic NO Removal by Ternary Composites Bi12GeO20/BiOCl/W18O49 Using a Waste Reutilization Strategy

Heterojunction creation is demonstrated as an effective strategy to enhance the transfer and separation of charge carriers, which is beneficial for subsequent photocatalytic reactions. In this study, “sea urchin-like” W18O49 was in situ-grown on the surface of Bi12GeO20 through a hydrothermal process, and the released Cl− anions tended to produce BiOCl simultaneously. Systematical characterizations confirmed the construction of ternary composites Bi12GeO20/BiOCl/W18O49 (GBW), in which Type I and Z-scheme models were integrated to promote charge carrier migration and separation by combining the structural merits of both models. Under UV–visible light, the catalytic performance of the as-synthesized samples was tested in terms of NO oxidation removal. Compared to pure Bi12GeO20, the composite GBW5 showed the highest NO photocatalytic removal efficiency of 42%, which was nearly four times that of pure Bi12GeO20. These improvements were mainly due to enhanced light absorption, suitable morphological features, effective separation of charge carriers, and the boosted generation of reactive species in the GBW series. This study paves the way for the construction of Bi12GeO20-based ternary composites using a comprehensive utilization of waste method and the employment of the composites for the photocatalytic removal of low concentrations of NO at the ppb level.

High-performance broadband photodetectors based on MnSe/SnS2 heterojunction

Abstract Two-dimensional (2D) materials have emerged as promising candidates for broadband photodetectors due to their unique optoelectronic properties. However, intrinsic defects and limited spectral response hinder their practical applications. In this study, we developed a novel 2D heterojunction photodetector by combining non-layered p-type MnSe nanosheets with layered n-type SnS2 flakes. The MnSe nanosheets were synthesized using chemical vapor deposition, while the SnS2 flakes were obtained through mechanical exfoliation. The fabricated MnSe/SnS2 heterojunction device exhibited rectifying behavior with an impressive on/off current ratio over 5000. Remarkably, the photodetector demonstrated a broad spectral response ranging from ultraviolet to near-infrared (405–1060 nm), achieving an exceptionally high responsivity of 10 A W−1, a detectivity of 3.06 × 1010 Jones, and an external quantum efficiency of 3068%. The enhanced performance was attributed to the type-II band alignment and built-in potential of the heterojunction, which facilitated effective separation of photogenerated carriers. Furthermore, the device exhibited significant photovoltaic characteristics, enabling self-powered imaging in visible range. This study highlights the potential of 2D non-layered materials in combination with traditional 2D layered materials for the development of high-performance, broadband photodetectors with improved efficiency and self-powered capabilities.

κ/β-Ga2O3 Type-II Phase Heterojunction.

Ultrawide-bandgap gallium oxide (Ga2O3) holds immense potential for crucial applications such as solar-blind photonics and high-power electronics. Although several Ga2O3 polymorphs, i.e., α, β, γ, δ, ε, and κ phases, have been identified, the band alignments between these phases have been largely overlooked due to epitaxy challenges and inadvertent neglect. Despite having similar stoichiometry, heterojunctions involving different phases may exhibit band offsets. Here, β-Ga2O3/κ-Ga2O3-stacked "phase heterojunction" is demonstrated experimentally. This phase heterojunction has a sharp and well-defined interface, and subsequent measurements reveal an unbeknown type-II band alignment with significant valence/conduction band offsets of ≈0.65eV/0.71eV. This alignment is promising for self-powered deep ultraviolet (DUV) signal detection, necessitating an internal electric field near the junction and matching the absorption properties for effective electron-hole separation. The fabricated phase heterojunction photodetector displays a responsivity of three orders of magnitude higher at 17.8mA W-1, with improved response times (rise time ≈0.21 s, decay time ≈0.53 s) under DUV illumination and without external bias in comparison to the bare β-Ga2O3 and κ-Ga2O3 photodetectors, confirming the strong interfacial electrical field. This study provides profound insight into Ga2O3/Ga2O3 heterojunction interfaces with different polymorphs, allowing the use of phase heterojunctions to advance electronic device applications.

Spectroscopic Study on Identifying Synergistic Extraction Complexes of Nd(III) with Bis(2,4,4-Trimethylpentyl)Dithiophosphinic Acids and TBP

ABSTRACT Selective separation of trivalent actinide ions, An(III), from trivalent actinide ions, Ln(III), has been of great importance and considerable challenge in terms of the overall nuclear fuel cycle strategy. The construction of the hard-soft synergistic extraction system, commonly S containing-O containing ligands, aims to achieve the effective separation of the two metal ions. Nevertheless, the precise mechanism by which this system extracts metal ions remains the subject of controversy. Herein, the complexation of Nd(III) with bis(2,4,4-trimethylpentyl)dithiophosphinic acid (HL) and tributyl phosphate (TBP) has been investigated with spectroscopy and extraction experiments under different conditions to clarify the mechanisms in synergistic extraction. Five complex species, NdL3(HL)(TBP), NdL2(NO3)(TBP)3, NdL3(H2O)2(TBP), NdL3(H2O)(TBP)2, and NdL3(TBP)3, are identified in the synergistic extraction system, their molar absorption spectra are deconvoluted, and the corresponding extraction equilibrium constants are determined. In addition, a complex species of Nd(III) fully coordinated by TBP, NdL3(TBP)n (n ≥ 6), is found in titrations of organic solution containing NdL3(TBP)3 with more TBP, but it is not found in synergistic extraction. Furthermore, Density Functional Theory (DFT) is employed to confirm the stability of the complexes. Investigation of the mechanism of this system will facilitate the acquisition of further insights into the selection of O-containing ligands and the development of synergistic extraction process for the separation of An(III) and Ln(III).

Anomalous photovoltaics in Janus MoSSe monolayers

The anomalous photovoltaic effect (APE) in polar crystals is a promising avenue for overcoming the energy conversion efficiency limits of conventional photoelectric devices utilizing p-n junction architectures. To facilitate effective photocarrier separation and enhance the APE, polar materials need to be thinned down to maximize the depolarization field. Here, we demonstrate Janus MoSSe monolayers (~0.67 nm thick) with strong spontaneous photocurrent generation. A photoresponsivity up to 3 mA/W, with ~ 1% external quantum efficiency and ultrafast photoresponse (~50 ps) were observed in the MoSSe device. Moreover, unlike conventional 2D materials that require careful twist alignment, the photovoltage can be further scaled up by simply stacking the MoSSe layers without the need for specific control on interlayer twist angles. Our work paves the way for the development of high-performance, flexible, and compact photovoltaics and optoelectronics with atomically engineered Janus polar materials.

Anion vacancy engineered Cu/ZnIn2S4-VS/TiO2-VO S-scheme heterojunction for enhancing photocatalytic overall water splitting.

Heterojunction materials for photocatalytic overall water splitting (POWS) become popular in recent times. However, even in the superior S-scheme heterojunction, the two semiconductor materials still do not have an efficient activity to separate and migrate photogenerated carriers. To further improve the charge separation and enhance the activity of POWS, a novel S-scheme heterojunction photocatalyst, Cu/ZnIn2S4-VS/TiO2-VO, was synthesized using solvothermal and calcination methods. The photocatalyst consists of Cu/ZnIn2S4 with sulfur vacancies (Cu/ZIS-VS) and TiO2 with oxygen vacancies (TiO2-VO). The resultant photocatalyst exhibited optimal hydrogen and oxygen evolution rates of 1245.3μmol/g/h and 621.4μmol/g/h, respectively. The apparent quantum efficiency reached 5.8% at 365nm. The corresponding characterization and theoretical calculations demonstrated the S-scheme heterojunction between Cu/ZIS-VS and TiO2-VO was successfully synthesized and resulted in a notable enhancement in the effective separation of carriers. Sulfur and oxygen vacancies in ZIS and TiO2, respectively, led to a reduction in their band gaps, which is beneficial for electron migration. Moreover, copper doping augmented the light absorption capabilities. Sulfur vacancies caused charge delocalization which facilitated the transfer of electrons and consequently enhanced the photocatalytic activity. This research provided an innovative perspective on the exploration and development of S-scheme heterojunctions aimed at POWS.

Nanospace Engineering for C8 Aromatic Isomer Separation.

C8 aromatic isomers, namely para-xylene (PX), meta-xylene (MX), ortho-xylene (OX), and ethylbenzene (EB), are essential industrial chemicals with a wide range of applications. The effective separation of these isomers is crucial across various sectors, including petrochemicals, pharmaceuticals, and polymer manufacturing. Traditional separation methods, such as distillation and solvent extraction, are energy-intensive. In contrast, selective adsorption has emerged as an efficient technique for separating C8 aromatic isomers, in which nanospace engineering offers promising strategies to address existing challenges by precisely tailoring the structures and properties of porous materials at the nanoscale. This review explores the application of nanospace engineering in modifying the pore structures and characteristics of diverse porous materials─including zeolites, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and other porous substances─to enhance their performance in C8 aromatic isomer separation. Additionally, this review provides a comprehensive summary of how different separation techniques, temperature fluctuations, enthalpy/entropy considerations, and desorption processes influence separation efficiency. It also presents a forward-looking perspective on remaining challenges and potential opportunities for advancing C8 aromatic isomer separation.

PdRu bimetallic nanoalloys with improved photothermal effect for amplified ROS-mediated tumor therapy.

An emerging strategy in cancer therapy involves inducing reactive oxygen species (ROS), specifically within tumors using nanozymes. However, existing nanozymes suffer from limitations such as low reactivity, poor biocompatibility, and limited targeting capabilities, hindering their therapeutic efficacy. In response, the PdRu@PEI bimetallic nanoalloys were constructed with well-catalytic activities and effective separation of charges, which can catalyze hydrogen peroxide (H2O2) to toxic hydroxyl radical (·OH) under near-infrared laser stimulation. Through facilitating electron transfer and enhancing active sites, the enhanced peroxidase-like (POD-like) enzymatic activity and glutathione (GSH) depletion abilities of nanozymes are boosted through a simple co-reduction process, leading to promising anti-tumor activity. The electron transfer between Pd and Ru of PdRu@PEI nanoalloys contributes to POD-like activity. Then, by oxidizing endogenous overexpressed GSH, enzymatic cycling prevents GSH from consuming ROS. Furthermore, the surface plasmon resonance effect of near-infrared laser on bimetallic nanoalloys ensures its photothermal performance and its local heating, further promoting POD-like activity. The integrated multi-modal therapeutic approach of PdRu@PEI has demonstrated significant anti-cancer effects in vivo studies. The nanozymes exhibit high catalytic efficiency and excellent biocompatibility, offering valuable insights for the development of nano-catalysts/enzymes for biomedical applications.

Implementation of FSK modulation and demodulation: analysis the effects of frequency separations on BER

Implementation of FSK modulation and demodulation: analysis the effects of frequency separations on BER

Stationary phase effects in hydrophilic interaction liquid chromatographic separation of oligonucleotides.

The use of liquid chromatography coupled with mass spectrometry (LC-MS) for the characterization of oligonucleotides and nucleic acids is a powerful analytical method. Recently, hydrophilic interaction chromatography (HILIC) has been proposed as a reasonable alternative to ion-pair reversed phase separations of oligonucleotides prior to MS. A wide variety of HILIC stationary phase surface chemistries are currently available. Although their selectivity can be considerably different, few studies have compared these chemistries for LC-MS analysis of oligonucleotides. We evaluated ten different HILIC column chemistries to understand their capabilities for separating a variety of oligonucleotides. In general, we found that most columns were ineffective at separating larger (n > 15-mer) oligonucleotides under the mobile phase and gradient conditions evaluated here. However, several stationary phases were found to be effective for separating smaller oligonucleotides such as endonuclease digestion products. Given that early eluting oligonucleotides were found to be compatible with standard electrospray ionization conditions, several different HILIC stationary phase options are available for LC-MS studies of smaller oligonucleotides including those generated in RNA modification mapping experiments.

Effective extraction and separation of bioactive lignans from Forsythia suspensa leaves using deep eutectic solvents coupled with macroporous resin

Effective extraction and separation of bioactive lignans from Forsythia suspensa leaves using deep eutectic solvents coupled with macroporous resin

Enhancing the optoelectronic properties of SnS via mixed-phase heterostructure engineering.

SnS holds great promise in optoelectronics, especially in photovoltaic devices, due to its exceptional intrinsic electronic properties and optimal optical absorption. However, its prospective applications are often limited by structural instability or oxidation, leading to internal or external defect states. This study proposes a mixed-phase SnS/h-BN heterostructure to enhance chemical and thermal stability while preserving the intrinsic optoelectronic properties of SnS. High negative binding energy and ab initio molecular dynamics simulations confirm the structural and thermal stability of the heterostructure up to 600 K. The heterostructure exhibits a type-I band alignment with an indirect density functional theory (DFT) band gap of 1.38 eV, corrected to 2.20 eV using Green's function with screened Coulomb potential (GW) calculations. The vertical intralayer electric field, resulting from non-uniformity in charge dynamics within the heterostructure, influences the SnS bound excitons, causing reduction in their binding energies. The weakly bound excitons indicate effective charge separation, charge transport augmentation, and a prolonged recombination lifetime. The interface effectively combines the excellent light-harvesting capabilities of SnS with the remarkable stability of h-BN, retaining the desirable optoelectronic properties of SnS while offering enhanced charge transport and stability.