Effective Separation Research Articles

Characterization of adeno-associated virus capsid proteins using denaturing size-exclusion chromatography coupled with mass spectrometry

Recombinant adeno-associated viruses (AAVs) are a highly effective platform for gene delivery for the treatment of many human diseases. Characterization of AAV viral protein attributes (VP), such as serotype identity, VP stoichiometry, and VP post-translational modifications, is essential to ensure product and process consistency. While size-exclusion chromatography (SEC) coupled with mass spectrometry (MS) is commonly used in the biopharmaceutical industry for analyzing protein therapeutics, its application to intact AAV VP components has not gained traction, presumably due to difficulties in achieving adequate resolution of VP(1−3) monomers. Herein, we describe the development of a denaturing SEC method and optimization of SEC parameters, including stationary phase pore size, column temperature, and mobile phase composition, to achieve effective chromatographic separation of VP(1−3). We demonstrate that an optimized dSEC-MS method featuring MS-compatible formic acid, can effectively separate VP(1−3) across AAV1, 2, 5, 6, 8, and 9 serotypes using a single column and mobile phase condition. A case study was included to showcase successful application of the dSEC-MS method in analyzing changes across different AAV production processes, yielding similar conclusions to an orthogonal approach, such as hydrophilic interaction chromatography (HILIC)- MS. Additionally, dSEC integrated with fluorescence (FLR) and ultraviolet (UV) detection can be used to semi-quantitatively identify both AAV DNA and VP components from empty and full AAV samples. Overall, this robust and MS-friendly methodological advancement could greatly streamline the development and analytical quality control processes for AAV-based gene therapies, providing a highly sensitive method for intact VP characterization.

Plant-Based Flocculants as Sustainable Conditioners for Enhanced Sewage Sludge Dewatering

With the aim to establish clean and sustainable sludge treatment, green conditioning using natural flocculants has recently gained a growing interest. In this study, a variety of plant materials, namely Moringa (Moringa oleifera) seeds, Fenugreek (Trigonella foenum-graecum) seeds, Potato (Solanum tuberosum) peels, Aloe (Aloe vera) leaves, Cactus (Opuntia ficus indica) cladodes, and Phragmites (Phragmites australis) stems, were evaluated for their potential bioflocculant activity in conditioning sewage sludge. They were thoroughly characterized to determine their active flocculating compounds. Sludge dewaterability was evaluated by assessing various sludge parameters, including specific resistance to filtration (SRF), dryness of filtration cake (DC), and total suspended solid removal (TSS) from sludge filtrate. The collected results from various physicochemical characterizations of plant materials suggest that the main flocculating agents are carbohydrates in Cactus and Fenugreek and proteins in Moringa, Potato, and Phragmites. Additionally, all tested plant-based flocculants demonstrated effective dewatering performance. Interestingly, compared to the chemical flocculant polyaluminum chloride, Moringa and Cactus showed superior conditioning effects, yielding the lowest SRF values and the highest DC. As a result, the use of these natural flocculants improved sewage sludge filterability, leading to a significant removal of total suspended solids from the filtrate. The conditioning properties of Moringa and Cactus can be attributed to their high protein and sugar content, which facilitates the effective separation of bound water from solids through charge neutralization and bridging mechanisms. Thus, green conditioning using plant-based flocculants, particularly Moringa and Cactus materials, presents a promising and eco-friendly approach to enhance sewage sludge dewatering for safer disposal and valorization.

Proposal automatic water purging system for machinery in high humidity environments controlled by an ECU

This paper presents an advanced automatic water discharge system tailored for diesel-powered machinery, particularly for vehicles operating in diverse climates, including humid coastal regions. The system is designed to protect fuel circuits in tanks and diesel engines of boats, offering either automatic or semi-automatic protection against oxidation and corrosion. This enhancement extends the lifespan of diesel components and pipelines while simultaneously reducing maintenance costs and intervention times. Additionally, the system improves fuel purity, resulting in increased engine power and efficiency. The proposed solution was experimentally validated using an Arduino board coupled with a water-sensitive detector in diesel fuel, suitable for installation in diesel filters or tanks. Experimental findings demonstrated a remarkably swift separation time of 150 microseconds for diesel and water at a pressure of 1 bar, achieving an impressive efficiency of 99.84%. The system's rapid and effective separation capability highlights its practical value, particularly in scenarios where efficient water removal is critical to sustaining engine performance and longevity.

Functionalized cements incorporated with nanocomposite photocatalysts for self-cleaning applications

The constantly escalating pollution on the surface of cement-based materials affects architectural aesthetics and residents′ health, necessitating frequent cleaning and maintenance, which contradicts the concept of sustainable development. This study aimed to develop a novel photocatalytic cement material to enhance the self-cleaning capabilities of cement-based materials, thereby extending their service life and reducing maintenance costs. To achieve this, carbon quantum dots (CDs) and g-C3N4 (CN) nanocomposite photocatalysts (CDs@CN) were synthesized and integrated into white cement to prepare photocatalytic cements. The materials were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy. Photocatalytic performance was evaluated by the degradation of Rhodamine B (RhB) under xenon (Xe) lamp, Vis light and UV light. The CDs@CN nanocomposite displayed superior photocatalytic activity, particularly under Xe lamp irradiation, achieving over 95 % degradation of RhB within 1 h. Even under Vis and UV light, the photocatalytic cement retains robust self-cleaning capabilities, achieving pollutant degradation rates of 81 % and 63 %, respectively, within 1 h. This performance exceeded that of pristine CN and control samples, demonstrating effective light absorption and charge separation. The optimal photocatalyst concentration in cement was identified as 0.1∼5.0 wt%, balancing performance and dispersion. The developed CDs@CN-based photocatalytic cement material offers a sustainable solution for self-cleaning and environmental purification. This study provides insights into the design of functional cementitious materials and contributes to the sustainable development of the construction industry.

Rice husk-derived self-healing superhydrophobic films using solvent-less approach for drag reduction and oil absorption behaviour

The present work focuses on a sustainable approach to transform rice-husk waste into self-healing superhydrophobic films with potential application for drag-reduction and oil absorption. Rice husk was transformed into amorphous nano silica particles (d50 ∼ 150 nm) exhibiting mesoporosity with a surface area of 400 m2/g. Superhydrophobic films fabricated using a solvent-less approach showed the transition from flattened to nano-globular morphology with increasing silica content in polydimethylsiloxane (PDMS), leading to exceptional superhydrophobicity. The optimized film with a particle fraction of 60 % exhibited high de-wetting (> 150º) and mechanical strength (∼7 MPa). The film showed extremely low water droplet adhesion of ∼19 μN, similar to lotus leaf owing to high negative Laplace pressure. Significantly, the film exhibited persisting de-wettability and endurance under harsh chemical, thermal, and mechanical conditions. The robustness is further fortified with room temperature self-healing and real-time self-regeneration characteristics, persisting even after exposure to strong acids and significant abrasion. The multidimensional aspects of the film embarked with a 70 % drag reduction and effective oil-water separation. The present work not only provides a sustainable pathway for managing agricultural waste but also a practical and easy-to-implement approach to tackle oil spill incidents.

Charge Separation Induced by Asymmetric Surface Charge Effects in Quasi‐Solid State Electrolyte for Sustainable Anion Storage

AbstractCompared with conventional lithium‐ion battery systems, anion‐intercalation in graphite cathodes opens avenues for the development of batteries with groundbreaking power density. This study explores the enhancement of dual‐ion batteries (DIBs) by gel polymer electrolyte (GPE) enhanced with surface‐charged nanoclays, focusing on overcoming traditional challenges such as electrolyte decomposition, anion‐solvent co‐intercalation, and interfacial instability at the graphite cathode. Three nanoclays including montmorillonite, kaolinite, and halloysite are compared by incorporating them into GPE and evaluating their effect on the electrochemical properties, ion conduction, and mechanical integrity of DIBs. Particular attention is paid to the halloysite because of its differential internal and external surface charges, which generate charge separation, facilitate optimal lithium‐ion transport, and mitigate undesirable anion‐solvent interactions. These results indicate that halloysite‐incorporated GPE (HS‐G) significantly improves DIB performance, as demonstrated by extended cycle life, robust capacity retention at fast charge/discharge rates of 20 C, and operational stability over a wide temperature range (0–60 °C). These improvements are attributed to the unique structural advantages of HS‐G, including effective charge separation, enhanced anion diffusion, and reduced solvent co‐intercalation, which provide an environmentally friendly and cost‐effective approach to advanced DIB applications.

Possibility to synthesize $Z = 119$ superheavy nuclei with $Z>$ 20 projectiles

Abstract We employed the dinuclear system (DNS) model combined with statistical model to calculate the evaporation residue cross sections for the reaction systems $^{48}$Ca + $^{243}$Am, $^{48}$Ca + $^{248}$Cm, and $^{48}$Ca + $^{249}$Bk. The theoretical results successfully reproduced the experimental trends in the 3$n$ and 4$n$ evaporation channels of these reaction systems. In order to synthesize the new element $Z = 119$, we predicted the evaporation residue cross sections for three reaction systems ($^{54}$Cr + $^{243}$Am, $^{51}$V + $^{248}$Cm, and $^{50}$Ti + $^{249}$Bk) to select the most promising projectile-target combinations. We also noted that the maximum cross sections predicted by our model and other methods appear to be below the detection limits of current experimental facilities, given the projectile-target combinations feasible under current experimental conditions. Therefore, synthesizing superheavy nuclei with $Z = 119$ will require improvements in beam intensity, detection techniques, and effective separation methods.

Carbon Sequestration by Preparing Recycled Cement, Recycled Aggregates, and Recycled Concrete from Construction and Demolition (C&D) Wastes

As the world’s largest producer of construction waste, China’s recycling and related policies are of the biggest concern to the world. However, the effective disposal and reuse of this waste has become an important issue since currently China still has a very low recycling ratio compared to developed countries, and most of the waste concrete was only simply broken and used as low-grade recycled aggregates for subgrade cushion, cement stabilized crushed stone, and filler wall. In this paper, a concrete cycle model focusing on how to effectively recycle and utilize waste concrete is put forward to prepare high quality recycled concrete, especially through a series of technical means, such as effective separation, carbon sequestration, and reactivation. Producing high quality recycled concrete can not only replace traditional concrete but also effectively reduce the consumption and waste of raw materials. What’s more, the calculation results show a potential of significantly carbon sink; for every ton of recycled cement produced, the CO2 emission could be reduced by 0.35–0.77 tons compared to ordinary Portland cement, corresponding to a reduction of 47%–94%; and for every ton of recycled concrete produced, the CO2 emission could be reduced by 0.186 tons compared to normal concrete. A yearly CO2 sequestration of 1.4–3.08 gigatonnes could happen if the ordinary Portland cement could be replaced by the recycled cement around the world. Taking the currently accumulated construction and demolition (C&D) wastes globally, the production of recycled cement, recycled aggregates, and recycled concrete could induce a significant carbon sink in the world.

Influence of the annealing temperature on the self-powered CuO/ZnO NRs heterojunction photodetector

In this study, the fabrication and comprehensive analysis of CuO/ZnO nanorod (NR) heterojunction photodetectors were carried out, focusing on the influence of annealing temperatures (400 °C, 500 °C, and 600 °C) on their structural, optical, and electrical characteristics. The ZnO nanorods were synthesized via a hydrothermal method, followed by a spin-coating deposition of CuO thin films. The resultant heterojunctions were subjected to different annealing treatments to determine the optimal conditions for enhanced photodetector performance. Characterization techniques such as Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive x-ray Spectroscopy (EDX), x-ray Diffraction (XRD), and UV–vis spectroscopy were employed to assess the quality and composition of the heterostructures. The analyses revealed a polycrystalline structure with monoclinic phases for CuO and wurtzite phases for ZnO. Photodetectors annealed at 400 °C exhibited the highest performance metrics, achieving a photoresponse ratio (Iph/Idark) of 26.3, photosensitivity (Sph%) of 2531.6, and a specific detectivity (D*) of 4.58 × 1010 Jones under 405 nm UV light illumination. These devices also demonstrated rapid response times of 0.8 s without any external bias, indicating effective exciton separation and charge transport facilitated by the built-in electric field at the heterojunction interface. The study underscores the critical role of annealing temperature in optimizing the photodetector properties of CuO/ZnO NRs, positioning these self-powered devices as promising candidates for future ultraviolet sensor applications in optoelectronics.

Infrared optoelectronics in twisted black phosphorus

Electrons and holes, fundamental charge carriers in semiconductors, dominate optical transitions and detection processes. Twisted van der Waals (vdW) heterostructures offer an effective approach to manipulate radiation, separation, and collection processes of electron-hole pairs by creating an atomically sharp interface. Here, we demonstrate that twisted interfaces in vdW layered black phosphorus (BP), an infrared semiconductor with highly anisotropic crystalline structure and properties, can significantly alter both recombination and separation processes of electron-hole pairs. On the one hand, the twisted interface breaks the symmetry of optical transition states resulting in infrared light emission of originally symmetry-forbidden optical states along the zigzag direction. On the other hand, spontaneous electronic polarization/bulk photovoltaic effect is generated at the twisted interface enabling effective separation of electron-hole pairs without external voltage bias. This is supported by first-principles calculations and repeated experiments at various twisted angles from 0 to 90°. Importantly, these phenomena can be observed in twisted heterostructures with thickness beyond two-dimensional. Our results suggest that the engineering of vdW twisted interfaces is an effective strategy for manipulating the optoelectronic properties of materials and constructing functional devices.

Engineering Trifluoromethyl Groups in Porous Coordination Polymers to Enhance Stability and Regulate Pore Window for Hexane Isomers Separation.

Effective separation of hexane (C6) isomers is critical for a variety of industrial applications but conventional distillation methods are energy-intensive. Adsorptive separations based on porous coordination polymers (PCPs) offer a promising alternative due to their exceptional porosity and tunable properties. However, there is still an urgent need to develop PCPs with high stability and separation performance. This study investigates how substituting a methyl (-CH3) group with a trifluoromethyl (-CF3) group can regulate pores and hydrophobicity in PCPs. This precise adjustment aims to enhance stability and improve the kinetic separation performance of hydrophobic C6 isomers by considering the size and hydrophobicity of the trifluoromethyl group. Two isostructural PCPs with pcu topology, PCP-CH3 and PCP-CF3, were synthesized to vary pore diameters and hydrophobicity based on the presence of -CH3 or -CF3 groups. PCP-CF3 showed greater stability in water compared to PCP-CH3. While PCP-CH3 had high adsorption capacities, it lacked selectivity, whereas PCP-CF3 demonstrated improved selectivity, particularly in excluding dibranched isomers. Dynamic column separation experiments revealed that PCP-CF3 could selectively adsorb linear and monobranched isomers over dibranched isomers at room temperature. These findings highlight the potential of fluorine-modified PCPs for efficient isomer separation and underscore the importance of stability improvement strategies.

Gamma irradiation-induced degradation of hexachlorobenzene in methanol: Kinetics, mechanism and dehalogenation pathway

Hexachlorobenzene (HCB), a persistent organic pollutant (POP) and organochlorine compound (OCC), poses significant environmental and health risks due to its high stability and solubility in fats, oils, and organic solvents. This study investigates the degradation of HCB in methanol using gamma irradiation with a60Co source. A 2 × 10−4 M solution of HCB in methanol was prepared and irradiated at a dose rate of 1.74 Gy/s. The degradation process was monitored using Gas Chromatography-Mass Spectrometry (GC-MS), with optimized parameters for effective separation and analysis of byproducts.The results demonstrated a 100% degradation of HCB at an absorbed dose of approximately 51 kGy. The degradation pathway involved successive dechlorination, forming various chlorinated benzene (CB) byproducts such as pentachlorobenzene (PCB), tetrachlorobenzenes (TeCB), trichlorobenzenes (TCB), dichlorobenzenes (DCB), and ultimately benzene.Ion chromatography (IC) analysis revealed a dose-dependent increase in Cl⁻ concentrations, confirming the efficiency of dechlorination. A chlorine mass balance was performed to evaluate the distribution of chlorine during the degradation process, tracking Cl⁻ ions, CBs, and residual HCB. As the dose increases, the chlorine content in residual HCB decreases significantly, with none remaining at 50.2 kGy and beyond. At 169.5 kGy, nearly all chlorine (99.96%) is unaccounted for, suggesting that it has likely been released as gaseous byproducts, such as Cl₂ or other volatile chlorinated compounds.The formation of solvated electrons and hydrogen radicals initiated the dechlorination process, as evidenced by the identified reaction mechanisms. Kinetic analysis indicated that the degradation followed pseudo-first-order kinetics, with a rate constant of 5 × 10−4 s−1. The study also outlines a dose-dependent trend in radiation chemical yields (G values), initially increasing to a peak of 7.3 × 10−2 molecules per 100 eV at 12.6 kGy and subsequently decreasing to as low as 5.4 × 10−4 at 50.2 kGy.This study highlights the effectiveness of gamma irradiation for the complete degradation of HCB in methanol, offering a promising method for the remediation of POPs-contaminated environments. The proposed mechanism and kinetic properties provide a comprehensive understanding of the radiolytic degradation process, paving the way for further applications in environmental cleanup technologies.

Facile Preparation of Raspberry-Like SiO2@Polyurea Microspheres with Tunable Wettability and Their Application for Oil-Water Separation.

Raspberry-like microspheres have been widely used as superhydrophobic materials, photonic crystals, drug carriers, etc. Nevertheless, their preparation methods, usually consisting of multiple steps, are generally time- and energy-consuming. Herein raspberry-like SiO2@polyurea microspheres (SiO2@PUM) are readily prepared via a one-step precipitation polymerization of isophorone diisocyanate in a H2O/acetone mixture with the presence of SiO2 particles. The sphere size, surface roughness, and SiO2 content of SiO2@PUM are easily adjustable by varying the experimental conditions. TEM and SEM observations reveal that the final SiO2@PUM exhibits a core-shell structure, with polyurea (PU) in the core and SiO2 particles as the shell. In the process, the SiO2 particles were initially located on the PUM surface as a monolayer. With the reaction proceeding, the monolayer of SiO2 particles became thicker, forming a thicker layer of SiO2 particles on PUM due to the accumulation of SiO2 particles, leading to a multilayer structure of SiO2 particles on the shell of SiO2@PUM. The formation mechanism of the raspberry-like SiO2@PUM was thoroughly discussed and ascribed to electrostatic attraction between the positively charged PU and negatively charged SiO2 particles. Once dried, SiO2@PUM was superhydrophobic and turned hydrophilic if water-wetted. Using a layer of SiO2@PUM, effective separation with good reusability for a variety of oil-water mixtures was achieved regardless of the oil density and types of oil-water emulsions. This work presents a novel protocol for the preparation of raspberry-like microspheres with tunable wettability via a rapid and green process, and the resulting microspheres are highly effective for the separation of diverse types of oil-water mixtures.

Promoting fine particle removal in cyclone by spray agglomeration and heterogeneous condensation

By adding a spray chamber in front of the cyclone separator, spray agglomeration and heterogeneous vapor condensation were combined to improve the removal effect of the cyclone separator on fine particles, which is used for the deep treatment of high-humidity industrial flue gas and fine particles. Fine particles can form agglomerates through the capture effect of micron droplets, and can also grow in size through heterogeneous vapor condensation in supersaturated water vapor environment, thus being effectively removed by cyclone separators. Supersaturated water vapor environment was a necessary condition for heterogeneous vapor condensation. Numerical simulation results showed that supersaturated water vapor environment can be formed in the spray chamber when the relative humidity of the original flue gas was high, and the higher the relative humidity, the higher the supersaturation and the larger the supersaturation area. The experimental results indicated that spray agglomeration and spray coupling heterogeneous condensation increased the particle removal efficiency of the cyclone separator by 11.6 % and 22.6 %, and the removal efficiency in the 2–4 μm “fish-hook” range was increased by 21.6 % and 41.7 %, respectively. This technology was successfully applied for the first time in the deep treatment of the tail gas in Fluid Catalytic Cracking (FCC) catalyst production industry, which can ensure that the particle emission concentration was within 20 mg/Nm3.

Design of novel Z-scheme g-C3N4/TiO2/CuCo2O4 heterojunctions for efficient visible light-driven photocatalyic degradation of rhodamine B

One of the most important environmental challenges that needs to be resolved is the industrial discharge of synthetic dyes. Graphitic carbon nitride (g-C3N4), Titanium dioxide (TiO2) and flower-like copper oxide (CuO)/copper cobaltite (CuCo2O4) nanocomposites were synthesized in order to synthesis an effective visible light driven photocatalyst that could degrade Rhodamin B (Rh.B) dye under simulated solar light irradiation. The SEM and TEM results verifies that the flower-like CuO/CuCo2O4 (CCO) structure and g-C3N4/TiO2 (g-CN/TO) generated a smart hybrid structure with superior g-CN distribution. According to the photocatalytic studies, g- C3N4/TiO2/CuO/CuCo2O4 (g-CN/TO/CCO) shows good photodegradation of Rh.B dye (99.9%) in minmal times (1 h) in CCO: g-CN/TO (2:1) ratio by Z-Scheme mechanism. The enhanced visible light absorption and effective electron-hole pair separation provided by the synergistic dispersion of CuO/CuCo2O4 and g-C3N4 can be attributed to the improved photocatalytic performances. These novel insights into g-CN/TO/CCO based photocatalysts are useful for treating industrial effluent.

Optimizing ligand-to-metal charge transfer in metal–organic frameworks to enhance photocatalytic performance

Metal-organic frameworks (MOFs) have been widely investigated as active photocatalytic material for energy conversion and environmental purification. This review meticulously examines the charge transfer mechanisms within MOFs upon photoexcitation, with a particular emphasis on ligand-to-metal charge transfer (LMCT) and metal-to-ligand charge transfer (MLCT). These processes are essential for the generation and maintenance of effective charge separation, wherein LMCT is especially critical for the photocatalytic applications of MOFs. The analysis begins with an exploration of the charge transfer mechanisms within the MOFs’ structure, assessing the impact of various factors on LMCT, including the metal center, ligand structure, overall spatial configuration and reaction environment. Furthermore, the review provides an in-depth exploration of the advantages and applications of LMCT in photocatalysis. It concludes with an outlook on the future development of LMCT in the field of photocatalysis, underscoring its transformative potential with ongoing research and innovation.

Mechanisms of multi-layered Rayleigh noise in Brillouin optical correlation-domain reflectometry

In Brillouin optical correlation-domain reflectometry (BOCDR), sinusoidal modulation is applied to the output frequency of a light source, with spatial resolution inversely related to the modulation amplitude. We have developed an effective method to estimate the modulation amplitude using the width of the noise spectrum caused by Rayleigh scattering, eliminating the need for an optical spectrum analyzer or modifications to existing equipment. However, the Rayleigh noise spectrum often displays a three-layered structure, complicating the identification of the appropriate spectral components for estimating the modulation amplitude. In this work, we investigate the origins of this three-layered Rayleigh noise spectrum and identify the directivity of an optical circulator as the source of the third noise component. As replacing the circulator with alternative optical components is not easy, it remains an essential part of the system. Our analysis shows that the third noise component exhibits significantly small variation in spectral width with changes in modulation frequency compared to the first and second components. This characteristic allows for the effective separation and identification of the third noise component, thereby enhancing the accuracy and convenience of modulation amplitude estimation in BOCDR.

Enhanced degradation of venlafaxine induced by Fe2O3/CeO2 heterostructures through the thermal transformation from type I to direct Z-scheme in heterogeneous photo-Fenton

Heterostructures based on Fe2O3/CeO2 were synthesized by coprecipitating iron and cerium salts, with 70 % and 50 % atomic percentage of iron, and heat treatment at 600 and 800 °C (Fe70Ce600, Fe50Ce600, Fe70Ce800, Fe50Ce800). The catalytic activity in the Fenton and photo-Fenton process was evaluated in the degradation of venlafaxine (VEN) using UV/Vis LEDs. Treatment at 800 °C promoted greater crystallinity, increased crystallite size, decreased specific area, and high absorption between 200 and 600 nm, and bandgap energy (Eg) between 1.6 and 3.0 eV were observed. The heat treatment promoted different mechanisms in heterostructure materials with type I (straddling) schemes for Fe70Ce600 and Fe50Ce600, type II for Fe50Ce800, and direct Z for Fe70Ce800 responsible for generating a higher concentration of HO• radicals, high oxidation-reduction power (Fe2+/Fe3+) and (Ce4+/Ce3+), greater effective separation of charge carriers, providing improved catalytic activity due to the synergy between heterogeneous photocatalysis and photo-Fenton processes. LC-MS/MS analysis identified 12 transformation products (TPs), involving hydroxylation reactions, demethylation, and loss of cyclohexanol. The transformation products TP2 and TP9 were exclusive to Fe70Ce800, confirming different mechanisms among the heterostructures.

A sustainable network design for municipal solid waste management considering waste-to-energy conversion under uncertainty

This research proposes a sustainable municipal solid waste management (MSWM) system to address population growth, consumerism, and resource scarcity. It introduces a two-phase decision structure combining multi-attribute decision-making (MADM) tools. Phase one develops a hybrid risk-oriented fuzzy MADM tool for selecting optimal waste-to-energy technologies, considering environmental and technological factors. Phase two uses a fuzzy bi-objective multi-period mixed-integer linear programming model to design the MSWM supply chain efficiently under uncertainty. A case study in North Tehran demonstrates the framework’s practical applicability and effectiveness in real-world scenarios, highlighting that effective source separation boosts recycling, reduces costs, and provides social benefits. Sensitivity analyses offer insights to enhance waste segregation practices. The study emphasizes integrating economic, environmental, and social sustainability in waste management decision-making. By offering a novel, holistic approach, this research addresses existing gaps in systematic decision-making processes and provides a robust tool for municipalities to optimize strategies under uncertainty.

Building Asymmetric Zn-N3 Bridge between 2D Photocatalyst and Co-catalyst for Directed Charge Transfer toward Efficient H2O2 Synthesis.

Two-dimensional (2D) polymeric semiconductors are a class of promising photocatalysts; however, it remains challenging to facilitate their interlayer charge transfer for suppressed in-plane charge recombination and thus improved quantum efficiency. Although some strategies, such as π-π stacking and van der Waals interaction, have been developed so far, directed interlayer charge transfer still cannot be achieved. Herein, we report a strategy of forming asymmetric Zn-N3 units that can bridge nitrogen (N)-doped carbon layers with polymeric carbon nitride nanosheets (C3N4-Zn-N(C)) to address this challenge. The symmetry-breaking Zn-N3 moiety, which has an asymmetric local charge distribution, enables directed interfacial charge transfer between the C3N4 photocatalyst and the N-doped carbon co-catalyst. As evidenced by femtosecond transient absorption spectroscopy, charge separation can be significantly enhanced by the interfacial asymmetric Zn-N3 bonding bridges. As a result, the designed C3N4-Zn-N(C) catalyst exhibits dramatically enhanced H2O2 photosynthesis activity, outperforming most of the reported C3N4-based catalysts. This work highlights the importance of tailoring interfacial chemical bonding channels in polymeric photocatalysts at the molecular level to achieve effective spatial charge separation.