Search Results (906)

The preparation of highly efficient adsorbents capable of simultaneously removing dyes and heavy metals is of great importance. Crab shell-derived biochar (BC) was successfully modified with magnesium and iron oxides (magnetic MgO@BC) via a simple impregnation–carbonization method. A series of characterizations revealed that magnetic MgO@BC possessed hierarchical porous structure with abundant oxygenated functional groups and good magnetic separability. The results of batch adsorption experiments showed that the actual maximum adsorption capacities of magnetic MgO@BC were 301.06, 1344.11 and 3232.10 mg/g for Cd²⁺, Pb²⁺ and CR, respectively. In addition, the adsorption of Cd²⁺, Pb²⁺, and CR exhibited minimal influence from pH and coexisting ions, except for Cd²⁺ adsorption, which was significantly affected by divalent cations. For Cd²⁺ and Pb²⁺ adsorption, the Langmuir model provided good fits for the adsorption isotherms, whereas CR adsorption was more suitable for the Freundlich model. The adsorption kinetic fitting results indicate that Cd²⁺ adsorption aligned well with the pseudo-first-order model, while Pb²⁺ and CR fitted better with the pseudo-second-order model. Regeneration tests revealed that after four cycles, Cd²⁺, Pb²⁺ and CR still maintained 85.87%, 52.43%, and 96.09% removal efficiencies, respectively. SEM, FTIR, XRD, and XPS results demonstrated that the mechanism for CR adsorption involved π-π interactions, electrostatic attraction, and hydrogen bonding. The adsorption mechanism of heavy metals was primarily governed by ion exchange, cation-π interactions, surface coordination, and coprecipitation mechanisms, where Pb²⁺ exhibited stronger and more preferential adsorption behavior. Binary adsorption experiments confirmed competitive and synergistic effects depending on pollutant pairs. This study offers a novel perspective on the preparation and mechanism of biochar materials for the efficient and synergistic removal of dyes and heavy metals. Full article

Smart microgrids are localized energy systems that integrate distributed energy resources, such as photovoltaics (PVs) and battery storage, to optimize energy use, enhance reliability, and minimize environmental impacts. This paper investigates the operation of a smart microgrid installed at the Hellenic Mediterranean University (HMU) campus in Heraklion, Crete, Greece. The system, consisting of PVs and battery storage, operates under a zero feed-in scheme, which maximizes on-site self-consumption while preventing electricity exports to the main grid. With increasing PV penetration and growing grid congestion, this scheme is an increasingly relevant strategy for microgrid operations, including university campuses. A properly sized PV–battery microgrid operating under zero feed-in operation can remain financially viable over its lifetime, while additionally it can achieve significant environmental benefits. The study performed at the HMU Campus utilizes measured hourly data of load demand, solar irradiance, and ambient temperature, while PV and battery components were modeled based on real technical specifications. The study evaluates the system using financial and environmental performance metrics, specifically net present value (NPV) and annual greenhouse gas (GHG) emission reductions, complemented by sensitivity analyses for battery technology (lead–carbon and lithium-ion), load demand levels, varying electricity prices, and projected reductions in lithium-ion battery costs over the coming years. The findings indicate that the microgrid can substantially reduce grid electricity consumption, achieving annual GHG emission reductions exceeding 600 tons of CO₂. From a financial perspective, the optimal configuration consisting of a 760 kWp PV array paired with a 1250 kWh lead–carbon battery system provides a system autonomy of 46% and achieves an NPV of EUR 1.41 million over a 25-year horizon. Higher load demands and electricity prices increase the NPV of the optimal system, whereas lower load demands enhance the system’s autonomy. The anticipated reduction in lithium-ion battery costs over the next 5–10 years is expected to provide improved financial results compared to the base-case scenario. These results highlight the techno-economic viability of zero feed-in microgrids and provide valuable insights for the planning and deployment of similar systems in regions with increasing renewable penetration and grid constraints. Full article

Optical synaptic transistors employing polymer dielectrics have emerged as promising building blocks for neuromorphic computing due to their low power consumption and rich photo-induced memory behaviors. While extensive experimental studies have demonstrated various synaptic functions, a unified physical understanding of the coupled charge trapping and ionic polarization processes governing device dynamics remains incomplete. In this work, we develop a unified physical model to investigate optical synaptic behaviors in polymer-based transistors with oxide interlayers. The model explicitly describes the time-dependent evolution of photo-induced charge trapping at the semiconductor–dielectric interface and ionic polarization within the polymer dielectric, which jointly modulate the effective threshold voltage of the transistor channel. Based on this framework, key synaptic functions including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), and pulse-dependent potentiation are quantitatively reproduced. The model further reveals how dielectric structure and trapping strength govern the transition between short-term and long-term plasticity. This study provides a physically intuitive and experimentally relevant modeling framework for understanding optical synaptic transistors, offering guidance for the rational design and optimization of polymer-based neuromorphic devices. Although simplified, the proposed model captures the essential physics governing optical synaptic behaviors and provides a general framework applicable to a wide class of ion–electronic neuromorphic devices. Experimental measurements are used as physically motivated proxies to validate the multi-timescale structure of the model rather than direct numerical fitting. Full article

Heteroatom functionalization of graphene is an effective strategy for designing more sustainable lithium-ion battery electrodes, as it can tune both interfacial adhesion and the electronic features of the carbon lattice. In this work, we investigated the interfacial compatibility between three graphene sheets—pristine graphene, graphene doped with one nitrogen atom (Graphene–N), and graphene doped with one sulfur atom (Graphene–S)—and three lignocellulosic binders (carboxymethylcellulose (CMC); coniferyl alcohol (LcnA); and sinapyl alcohol (LsiA)) using density functional theory (DFT). Geometries were optimized using CAM-B3LYP and M06-2X in combination with the LANL2DZ basis set, while ωB97X-D/LANL2DZ was employed for dispersion-consistent single-point refinements. The computed adsorption energies indicate that all binder–surface combinations are thermodynamically favorable within the present finite-model framework (ΔE_int ≈ −22.6 to −31.1 kcal·mol⁻¹), with LSiA consistently showing the strongest stabilization across surfaces. Nitrogen doping produces a modest but systematic strengthening of adsorption relative to pristine graphene for all binders and is accompanied by electronic signatures consistent with localized donor/basic sites while preserving the delocalized π framework. In contrast, sulfur doping yields a more binder-dependent response: it maintains strong stabilization for LSiA but weakens LCnA relative to pristine/N-doped sheets, consistent with an S-induced local distortion/polarizability pattern that can alter optimal π–π registry depending on the adsorption geometry. A combined interpretation of adsorption energies, electronic descriptors (including ΔE_gap as a model-dependent HOMO–LUMO separation), and topological analyses (AIM, ELF, LOL, and MEP) supports that Graphene–N provides the best overall balance between electronic continuity and chemically active interfacial sites, whereas Graphene–S can enhance localized anchoring but introduces more heterogeneous, lone-pair–dominated domains that may partially perturb electronic connectivity. Full article

Soil salinization and alkalinization critically constrain alfalfa (Medicago sativa L.) productivity, yet the regulatory mechanisms underlying its responses to salt–alkali stress are not fully understood. In this study, the alfalfa variety “Zhongmu No. 1” was used as experimental material. The seeds were subjected to salt stress (75 mM NaCl), alkali stress (15 mM NaHCO₃), and combined salt–alkali stress (50 mM NaCl + 5 mM NaHCO₃) in dishes, with ddH₂O serving as the control (CK). After 7 days of germination, the seedlings were transferred to a hydroponic system containing Hoagland nutrient solution supplemented with the corresponding treatments. Following 32 days of stress exposure, leaf and root tissue samples were collected for morphological and physiological measurements, as well as mRNA and miRNA sequencing analyses. Physiological assays revealed significant growth inhibition and increased electrolyte leakage under stress conditions. Transcriptome profiling identified over 5000 common differentially expressed genes (DEGs) in both leaves and roots under stress conditions, mainly enriched in pathways related to “iron ion binding”, “flavonoid biosynthesis”, “MAPK signaling”, and “alpha-Linolenic acid metabolism”. MiRNA sequencing detected 453 miRNAs, including 188 novel candidates, with several differentially expressed miRNAs (DEMs) exhibiting tissue- and stress-specific patterns. Integrated analysis revealed 147, 81, and 140 negatively correlated miRNA–mRNA pairs across three treatment groups, highlighting key regulatory modules in hormone signaling and metabolic pathways. Notably, in the ethylene and abscisic acid signaling pathways, ERF (XLOC_006645) and PP2C (MsG0180000476.01) were found to be regulated by miR5255 and miR172c, respectively, suggesting a post-transcriptional layer of hormonal control. DEM target genes enrichment pathway analyses also identified stress-specific regulation of “Fatty acid degradation”, “Galactose metabolism”, and “Fructose and mannose metabolism”. qRT-PCR validation confirmed the expression trends of selected DEGs and DEMs. Collectively, these findings reveal the complexity of miRNA–mRNA regulatory networks in alfalfa’s response to salt–alkali stress and provide candidate regulators for breeding stress-resilient cultivars. Full article

The unicellular ciliate Paramecium caudatum undergoes a developmental transition from asexual binary fission to sexual reproduction during its mature stage. This transition is triggered by mating interactions between cells of complementary mating types, leading to aggregate formation, mating pairs, and the meiotic division of micronuclei. Although calcium-driven EF-hand kinases have been implicated as mating type proteins, the spatiotemporal dynamics of calcium signaling during conjugation have not been comprehensively characterized. In this study, we established a behavioral assay to isolate committed cells from aggregates immediately after mating onset, and developed an experimental system to monitor intracellular calcium fluctuations specifically expressed in these cells. By combining Ca²⁺/EGTA buffering and microinjection approaches, we manipulated extracellular and intracellular calcium levels and confirmed the continuous requirement of calcium ions for conjugation-specific functions. Two significant findings emerged. First, we identified, for the first time, a calcium atlas covering the entire cell, with ascending centers localized in the anterior, oral apparatus, and posterior regions. The calcium/Indo-1-AM fluorescence peaked at 6 h after mating initiation and declined gradually, but persisted until conjugation was completed at ~48 h. Second, we demonstrated that distinct intracellular calcium thresholds are required for each stage of mating, including maintenance of mating activity, commitment of micronuclei to meiosis, and two-stepwise formation of mating pairs. These thresholds function as regulatory checkpoints that coordinate subcellular localization and stage synchronization. Collectively, our findings highlight calcium ions as pivotal regulators of conjugation in Paramecium and propose a novel framework, the Paramecium calcium atlas, for understanding the cellular and molecular mechanisms underlying sexual reproduction in ciliates. Full article

Intrinsic optical bi-stability in dense two-level systems is developed for the bad cavity limit where electromagnetic modes are adiabatically eliminated. Each atom interacts via dipole–dipole forces with its nearby spatial distribution of atoms. The theory is developed into two parts, corresponding to the short sample, with dimensions shorter than the wavelength, and the long sample. In both cases, the local field corrections modify the Maxwell–Bloch equations, so that cubic or quartic equations are obtained for the inversion of population as a function of the external light intensity, thus leading to intrinsic bi-stability. The effects of noise sources on intrinsic bi-stability were treated, and I found that while the observability of bi-stability was not obtained experimentally for a simple two-level system, there were many observations of bi-stability obtained through the ‘up-conversion’ of rare earth excited crystals. I show the differences between these two systems. Full article

Polyampholytes combine cationic and anionic groups in one macromolecular platform and are emerging as versatile components for energy storage and conversion. This review synthesizes how their charge balance, hydration, and architecture can be engineered to address ionic transport, interfacial stability, and safety across batteries, supercapacitors, solar cells, and fuel cells. We classify annealed, quenched, and zwitterionic systems, outline molecular design strategies that tune charge ratio, distribution, and crosslinking, and compare device roles as gel or solid electrolytes, eutectogels, ionogels, binders, separator coatings, and interlayers. Comparative tables summarize ionic conductivity, cation transference number, electrochemical window, mechanical robustness, and temperature tolerance. Across Li and Zn batteries, polyampholytes promote ion dissociation, homogenize interfacial fields, suppress dendrites, and stabilize interphases. In supercapacitors, antifreeze hydrogels and poly(ionic liquid) networks maintain conductivity and elasticity under strain and at subzero temperature. In solar cells, zwitterionic interlayers improve work function alignment and charge extraction, while ordered networks in fuel cell membranes enable selective ion transport with reduced crossover. Design rules emerge that couple charge neutrality with controlled hydration and dynamic crosslinking to balance conductivity and mechanics. Key gaps include brittleness, ion pairing with multivalent salts, and scale-up. Opportunities include soft segment copolymerization, ionic liquid and DES plasticization, side-chain engineering, and operando studies to guide translation. Full article

This study investigated the efficiency of biochar in eliminating Cd(II) and Pb(II) ions from slurries generated from construction-derived waste materials. The construction waste slurry samples consisted of genuinely contaminated sludge sediments. To improve the adsorption capacity of biochar for metal ions, coconut shell-derived biochar was subjected to hydrochloric acid treatment. The modified biochar demonstrated an improved porous structure and showed a higher concentration of oxygen-containing functional groups compared to the untreated biochar. After a 48 h contact with the contaminated slurry, the treated biochar attained removal efficiencies of 21.15% for Cd(II) and 19.43% for Pb(II). The kinetic study of the adsorption process conformed to a pseudo-second-order model. Density functional theory (DFT) computations clarified the adsorption mechanism of Cd(II) and Pb(II) by carboxyl (-COOH) and hydroxyl (-OH) functional groups. The findings demonstrated that functional groups contribute lone-pair electrons for the adsorption of heavy metal ions. The carboxyl (-COOH) functional group exhibited a greater affinity for binding Cd(II) and Pb(II) ions than the hydroxyl (-OH) group, which explains the improved adsorption efficiency seen in biochar treated with hydrochloric acid. These findings offer theoretical validation for the use of hydrochloric acid-modified biochar as an efficient adsorbent for the remediation of sludge contaminated with Cd(II) and Pb(II). Full article

Many polar compounds of biochemical and pharmaceutical relevance exhibit low retention in reversed-phase liquid chromatography (RPLC), making their separation challenging. While hydrophilic interaction liquid chromatography (HILIC) columns are commonly used for such analyses, they require mobile phases with high organic solvent content. This work explores an alternative approach using RPLC with conventional C18 columns and mobile phases containing low percentages of acetonitrile, along with small amounts of the surfactant sodium dodecyl sulfate (SDS). This combination significantly enhances the retention of highly polar compounds. When the SDS concentration is sufficiently low, below the critical micellar concentration in water (8 mM), the retention increase follows a linear pattern. The retention behavior of polar compounds with different properties (nucleosides, methylxanthines, sulfonamides, and the diuretic hydrochlorothiazide) is examined using mobile phases in the submicellar region, with SDS concentrations ranging from 0 to 0.3 mM, acetonitrile contents between 10 and 20% (v/v), and temperatures varying from 25 to 55 °C. Changes in peak half-widths are also analyzed. Since SDS adsorbs onto the stationary phase, modifying its surface, the equilibration time has been investigated as a critical factor affecting retention reproducibility, influenced by the SDS concentration, acetonitrile content, and temperature. The results emphasize the need for complete equilibration to ensure reliable and consistent results. Full article

A novel and facile route for intercalating alkali-metal ions and ammonium ions into the layered mixed-ion compound tungsten oxychloride (WO₂Cl₂) has been developed using the iodide–triiodide redox couple as a mild redox-active reagent. Unlike traditional intercalation techniques employing highly reducing and air-sensitive reagents such as n-butyllithium, alkali triethylborohydride, and naphthalenide, the I⁻/I₃⁻ redox system operates at a moderate potential (0.536 V vs. SHE), enabling safer handling under ambient conditions without stringent inert-atmosphere requirements. This redox pair promotes the reduction of W⁶⁺ to W⁵⁺, thereby facilitating cation insertion into the van der Waal (vdW) gaps of WO₂Cl₂. This method uniquely enables ammonium ion intercalation into WO₂Cl₂, a first for this system. Intercalation was confirmed by X-ray diffraction, scanning electron microscopy (SEM/EDS), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), with measured lattice expansion correlating well with Shannon ionic radii and coordinating environments. Electrical transport measurements reveal a transition from insulating WO₂Cl₂ to a semiconducting phase for K_0.5WO₂Cl₂, exhibiting a resistance drop of over four orders of magnitude. This work demonstrates the I⁻/I₃⁻ couple as a general, safe, and versatile method for layered mixed-anion materials, broadening the chemical toolkit for low-temperature, solution-based tuning of structures and properties. Full article

Organic electrochemical transistors (OECTs) are compelling artificial synapses because mixed ionic–electronic coupling and transport enables low-voltage, analog weight updates that mirror biological plasticity. Here, we engineered solid-state, polymer electrolyte-gated vertical OECTs (vOECTs) and elucidate how electrolyte molecular weight influences synaptic dynamics. Using Pg2T-T as the redox-active channel and pDADMAC polymer electrolytes spanning low- (~100 k), medium- (~300 k), and high- (~500 k) molecular weights, cyclic voltammetry reveals reversible Pg2T-T redox, while peak separation and current density systematically track ion transport kinetics. Increasing electrolyte molecular weight enlarges the transfer curve hysteresis (memory window ΔV_mem from ~0.15 V to ~0.50 V) but suppresses on-current, consistent with slower, more confining ion motion and stabilized partially doped states. Devices exhibit rich short- and long-term plasticity: paired-pulse facilitation (A₂/A₁ ≈ 1.75 at Δt = 50 ms), frequency-dependent EPSCs (low-pass accumulation), cumulative potentiation, and reversible LTP/LTD. A device-aware CrossSim framework built from continuous write/erase cycles (probabilistic LUT) supports Fashion-MNIST inference with high accuracy and bounded update errors (mean −0.02; asymmetry 0.198), validating that measured nonidealities remain algorithm-compatible. These results provide a materials-level handle on polymer–ion coupling to deterministically tailor temporal learning in compact, robust neuromorphic hardware. Full article

There are 880 studies focused on trivalent chrome baths, and several studies suggest the formation of ${\left[Cr\left(III\right)L(H_{2}O{)}_5\right]}^{2+}$, where $L$ is an additive such as oxalate. The literature suggests that this compound decreases the energy needed in the electrodeposition process. We call this approach the inner-sphere complex hypothesis because these complexes are suggested, such as principal intermediate compounds. There are several disadvantages of this postulate, which are numbered in our study. This hypothesis was tested via Fourier transform infrared spectroscopy performed in attenuated total reflectance (ATR) mode. In addition, the potassium bis(oxalato) diaqua chromate (III) dihydrate ($K\left[Cr{\left(C_2{O}_4\right)}_2{\left(O{H}_2\right)}_2\right]·2H_{2}O$) compound was selected as a probe molecule because it contains bridging $C-O-Cr$ bonds, which are supposedly the largest number of bonds in the inner-sphere complexes in bath solutions. There is strong evidence of numerous bridging $C-O-Cr$ bonds in the solid sample; conversely, in solution, $Cr\left(III\right)$ prefers to form terminal bonds ($Cr-O$). These results suggest that the concentration of the inner-sphere complex is lower in solution. In solutions containing chromium (III) sulfate and oxalate anions, the concentrations of these complexes are much lower. Although some inner-sphere complexes are formed, their concentration does not seem to be relevant to the electrodeposition process. Otherwise, at high ionic strengths, the formation of ion pairs and hydrogen bonds between $Cr\left(III\right)$ and additives is probable. Our research highlights the importance of vibrational spectroscopy in resolving the mechanics of the trivalent chrome electrodeposition process. This is the first study reporting a band of $Cr-O$ bonds in trivalent chrome baths. Full article

This work reports on novel acid–base conjugate pairs of monocationic allyldiamidinium and dicationic diamidinium salts, some of which are ionic liquids (ILs) at ambient temperatures. A series of allyldiamidinium salts of the general formula [C₃H(NRMe)₄]X (R = Me, Et, Pr, allyl, CH₂CH₂OMe; X = Cl, bistriflimide, dicyanamide) were prepared from C₃Cl₄ or C₃Cl₅H and the appropriate secondary amine, RNMeH. Alkylated ethylenediamines similarly yield bicyclic allyldiamidinium salts, whereas longer diamines (H₂N(CH₂)_nNH₂ (n = 3, 4, 5)) were isolated as their conjugate acids, the diamidinium dicationic salts [C₃H₂(HN(CH₂)_nNH)₂]X₂. The salts were characterized by NMR, ES-MS, DSC, TGA, and miscibility or solubility studies. Additionally, the ILs were characterized by their viscosities. The conductivities of the diamidinium ILs were also measured, and this allowed for an investigation of their Walden parameters. In contrast to expectations, since the ion pairing and clustering were expected to be significant, this showed them to be “superionic”. Previous reports of Walden plots of dicationic ILs were found to be erroneous, and a reanalysis of the literature data found that all reported dicationic and even tetracationic ILs can be classified as superionic. The salts [C₃H(NMe₂)₄]Cl, [C₃H(EtN(CH₂)₂NEt)₂]OTf, and [C₃H₂(HN(CH₂)_nNH)₂]Cl₂ (n = 3, 4, 5) were also characterized by single-crystal X-ray diffraction. Full article

Doping lead-free halide perovskite nanocrystals with trivalent lanthanide ions has emerged as a promising strategy for engineering their optical properties in various photonic applications. Here, we report the design and synthesis of a series of lead-free double halide perovskite (Cs₂Na(In/Y/Gd)Cl₆) nanocrystals co-doped with a pair of different lanthanides (e.g., Tb³⁺, Dy³⁺, and Eu³⁺) as emission centers, and ns² ions (Sb³⁺ or Bi³⁺) as sensitizers. The tunability of the delayed photoluminescence spectral density was achieved through the selective excitation of lanthanide dopants either via ligand-to-metal charge transfer (e.g., Eu³⁺) or via ns² ion s-p transitions (e.g., Dy³⁺ or Tb³⁺). The intensities of the narrow lanthanide f-f emission bands can, therefore, be tuned by modulating the excitation wavelength and/or dopant ratio, allowing for the accurate engineering of the emission color coordinates and spectral density. We also demonstrated time-resolved tuning of the photoluminescence spectral density for the investigated nanocrystal host lattices co-doped with transition-metal (Mn²⁺) and lanthanide ions, owing to a large difference between the decay dynamics for Mn²⁺ d-d and lanthanide f-f transitions. The rational co-doping of double halide perovskite nanocrystals reported in this work provides a new strategy for generating pre-designed multilevel luminescent signatures for protection against counterfeiting. Full article