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A systematic analysis of antibacterial activity of individual nanoderivatives, e.g. GO nanosheets, Ag and Cu nanoparticles (NPs), as well as combinations of Cu-Ag NPs, and GO-Cu-Ag nanocomposites against Escherichia coli , Pseudomonas aeruginosa , Staphylococcus aureus , Klebsiella pneumoniae and Methicillin-resistant Staphylococcus aureus (MRSA) was performed. Chemical properties of the GO, Cu and Ag NPs were determined employing X-ray photoelectron spectroscopy and X-Ray-excited Auger electron spectroscopy. Morphology of corresponding nanoderivatives was studied employing transmission electron microscopy and scanning electron microscopy. It was shown that combination of Cu and Ag NPs, as well as GO-Cu-Ag nanocomposite material possess enhanced antibacterial activity through a possible synergy between multiple toxicity mechanisms. MRSA showed highest resistance in all cases. [ABSTRACT FROM AUTHOR]

This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162±1°) SiO2 nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO2 nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, water droplets on SiO2 nanocomposite film surface are subjected to a series of icing and deicing cycles in a humid (~70% relative humidity) atmosphere and the resulting morphological changes are monitored and characterized using atomic force microscopy (AFM) and contact angle measurements. Our data show that the formation of the frozen or thawed water droplet, with no further shape change, on superhydrophobic SiO2 nanocomposite film, is obtained faster within each cycle as the number of the icing/deicing cycles increases. After 10 icing and deicing cycles, the superhydrophobic SiO2 nanocomposite film had a water contact angle value of 146±2° which is effectively non-superhydrophobic. AFM analysis showed that the superhydrophobic SiO2 nanocomposite film surface area under the water droplet undergoes gradual mechanical damage during the repetitive icing/deicing cycles. We propose a possible mechanism of the morphological changes to the film surface that take place during the consecutive icing/deicing experiments. [ABSTRACT FROM AUTHOR]

Abstract: In this study SiOx containing amorphous hydrogenated carbon (a-C:H/SiOx) and nitrogen-doped a-C:H/SiOx (a-C:H:N/SiOx) films were deposited on polyvinylpyrrolidone (PVP) templates of variable thickness using a Hall-type closed drift ion beam source with constant irradiation parameters. A detailed surface characterization was followed using atomic force microscopy (AFM) topography images, surface morphology parameters, height distribution histograms and bearing ratio curves with hybrid parameters. The AFM analysis directly showed that the a-C:H/SiOx/PVP and a-C:H:N/SiOx/PVP composite films represent different morphologies with characteristic surface textures. Surface adhesive properties were evaluated by measuring the force required to separate the AFM tip from the surface by means of AFM force-distance curves. The variance in adhesion force detected was lower for a-C:H/SiOx/PVP composite films due to lower structural homogeneity of the surfaces. Fourier transform infrared spectroscopy analysis was performed to study the blend behavior of PVP upon a-C:H/SiOx and a-C:H:N/SiOx direct ion beam deposition. It was determined that interfacial interactions of PVP with the direct ion beam induced changes in the carbonyl group of the PVP and are dependent on the carrier gas used for the synthesis of the amorphous hydrogenated carbon films. [Copyright &y& Elsevier]

Solid-liquid extraction was investigated to obtain selected major plant nutrients (P, K, Ca, Mg) from biofuel ash using weak organic acids like salicylic acid, citric acid, and oxalic acid as sacrificial leaching agents. In this study, three organic acids were compared to determine the most effective leaching agent for maximizing the P, K, Ca, and Mg extraction from biofuel ash. The findings indicated that 0.1 M citric acid was the most efficient for plant nutrient recovery, with 81.9% of P recovered after 30 min, 82.4% of Ca, 76.8% of Mg, and 47.3% of K. after 120 min. The highest amount of K, with 59.3% was recovered after 180 min of extraction with 0.1 M oxalic acid. However, recovery of P-80.7% was lower, and much lower recovery of Ca-2.3%, and Mg-68.6% after 180 min of extraction with 0.1 M oxalic acid. The leachates were not contaminated with heavy metals, just 0.47 mg/L of Zn, 7.67 mg/L of Al, and 1.99 mg/L of Fe were detected after 180 min of extraction with 0.1 M oxalic acid. The formation of calcium oxalates after extraction with 0.1 M oxalic acid was seen by SEM-EDS. The findings indicated that to achieve the highest recovery of all beneficial nutrients (P, K, Ca, Mg) different extraction times and different extraction agents are required., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Interest in energy-to-X and X-to-energy (where X represents green hydrogen, carbon-based fuels, or ammonia) technologies has expanded the field of electrochemical conversion and storage. Solid oxide electrochemical cells (SOCs) are among the most promising technologies for these processes. Their unmatched conversion efficiencies result from favorable thermodynamics and kinetics at elevated operating temperatures (400-900 °C). These solid-state electrochemical systems exhibit flexibility in reversible operation between fuel cell and electrolysis modes and can efficiently utilize a variety of fuels. However, electrocatalytic materials at SOC electrodes remain nonoptimal for facilitating reversible operation and fuel flexibility. In this Review, we explore the diverse range of electrocatalytic materials utilized in oxygen-ion-conducting SOCs (O-SOCs) and proton-conducting SOCs (H-SOCs). We examine their electrochemical activity as a function of composition and structure across different electrochemical reactions to highlight characteristics that lead to optimal catalytic performance. Catalyst deactivation mechanisms under different operating conditions are discussed to assess the bottlenecks in performance. We conclude by providing guidelines for evaluating the electrochemical performance of electrode catalysts in SOCs and for designing effective catalysts to achieve flexibility in fuel usage and mode of operation.

Phosphorus (P) and Ammonium Nitrogen (N) are essential nutrients for plants and environmental stability. However, their excess in water causes eutrophication, damaging aquatic ecosystems. While adsorption is a promising solution, finding affordable and efficient adsorbents remains a challenge. In this study, magnesium (Mg), iron (Fe), and Mg/Fe doped biochars (BC) adsorbents were synthesized, and evaluated for adsorption of individual P and N and a P + N mixture from a solution and wastewater from a wastewater treatment plant. Compared to other adsorbents, Mg/BC showed excellent performance in adsorbing phosphorus (P) and ammonium nitrogen (N) from aqueous solutions. It demonstrated a large adsorption capacity of 64.65 mg/g and 62.50 mg/g from individual P and N solutions, and 30.3 mg/g and 27.67 mg/g from the P and N mixture solution, respectively. In addition, Mg/BC efficiently removed P and N from real-life wastewater. In the real wastewater, P and N removal efficiencies reached 88.30% and 59.36%, respectively. Kinetics analysis revealed that the pseudo-second-order model accurately described the adsorption of phosphorus (P) and ammonium nitrogen (N) in all solutions. The adsorbent followed the monolayer-Langmuir isotherm for N ions and the multilayer-Freundlich isotherm for P, indicating efficient adsorption processes. Thermodynamic experiments indicated that the adsorption of P and N was not only feasible but also occurred spontaneously in a natural manner. This study revealed that the strategic modification of biochar plays a crucial role in advancing effective wastewater treatment technologies designed for nutrient removal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Boroxine- and borazine-cage analogs to C 20 , C 60 , and C 70 were calculated and compared in terms of structure, strain indicators, and physical properties relevant to nanoscale applications. The results show C 60 and C 70 type cages are less strained than the smaller congener, primarily due to minimized bending in the B-arylene-B segments. The smallest cage calculated has a diameter of 2.4 nm, which increases up to 4.9 nm by either variation of the polyhedron (C 20 < C 60 < C 70 -type cage) or organic spacer elongation between boron centers. All calculated cages are porous (apertures ranging from 0.6 to 1.9 nm). Molecular electrostatic potential and Hirshfeld population analysis revealed both nucleophilic and electrophilic sites in the interior and exterior cage surfaces. HOMO-LUMO gaps range from 3.98 to 4.89 eV and 5.10-5.18 eV for the boroxine- and borazine-cages, respectively. Our findings provide insights into the design and properties of highly porous boroxine and borazine cages for nanoscience.

The utilization of lignin, an abundant and renewable bio-aromatic source, is of significant importance. In this study, lignin oxidation was examined at different temperatures with zirconium oxide (ZrO 2 )-supported nickel (Ni), cobalt (Co) and bimetallic Ni-Co metal catalysts under different solvents and oxygen pressure. Non-catalytic oxidation reaction produced maximum bio-oil (35.3 wt%), while catalytic oxidation significantly increased the bio-oil yield. The bimetallic catalyst Ni-Co/ZrO 2 produced the highest bio-oil yield (67.4 wt%) compared to the monometallic catalyst Ni/ZrO 2 (59.3 wt%) and Co/ZrO 2 (54.0 wt%). The selectively higher percentage of vanillin, 2-methoxy phenol, acetovanillone, acetosyringone and vanillic acid compounds are found in the catalytic bio-oil. Moreover, it has been observed that the bimetallic Co-Ni/ZrO 2 produced a higher amount of vanillin (43.7% and 13.30 wt%) compound. These results demonstrate that the bimetallic Ni-Co/ZrO 2 catalyst promotes the selective cleavage of the ether β-O-4 bond in lignin, leading to a higher yield of phenolic monomer compounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Plasma-catalytic bireforming of methane was studied and actively optimized using a La 0.7 Ce 0.3 NiO 3 perovskite catalyst via experimentation in tandem with response surface modeling. Plasma power, inlet flow rate, temperature, CO 2 /CH 4 ratio, and steam concentration were tuned to maximize a variety of process- and sustainability-based metrics. Analysis of the optimal conditions (with respect to different metrics) with and without the catalyst reveals that dry reforming is driven largely via noncatalytic reactions, while steam reforming and water gas shift reactions require the catalyst. The experimental outcome demonstrated that under optimum reaction conditions using the La 0.7 Ce 0.3 NiO 3 catalyst it is possible to minimize global warming potential (GWP), in terms of inferred CO 2 footprint normalized to hydrogen throughput, resulting in maximizing hydrogen yield through steam reforming (and water gas shift reactions) at an SEI of ≈12 eV/molecule. Furthermore, the highest CH 4 conversion reached was 87% while the catalyst showed good activity stability in DBD plasma experiments.The actively learned iterative optimization procedure developed in this work allows for a direct juxtaposition of thermal (heat needed to make steam and heat the plasma reactor) and electrical (power requirement for plasma generation) carbon footprints in a highly nonlinear multivariate process. Furthermore, the corresponding GWP was calculated using a conventional electricity mix, wind electricity, and solar electricity, allowing a direct sustainability assessment in catalyst-assisted plasma conversion of carbonaceous feedstock to H 2 and CO., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

A parabolic trough collector solar field was designed to supply the heat needed to regenerate the CO 2 -rich monoethanolamine in a solar-assisted carbon capture system. Process design modeling was performed for 90% of the CO 2 removal from 1% of the flue gas produced by a 255 MWe natural gas combined cycle power plant. Calculations with and without 24 h of thermal energy storage by increasing the solar collector size needed and providing a buffer vessel to store hot heat transfer fluid were performed. A dynamic analysis of the solar field using the hourly solar forecast was performed to investigate how heat transfer fluid mass flow changes during January and June to maintain the desired parabolic solar field outlet temperature needed for CO 2 reboiler operation. The calculations provided here present an explicit method to calculate relevant solar field design parameters that can be scaled up and used in solar energy-assisted gas capture processes., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

A capacitive micromachined ultrasound transducer (CMUT) was engineered and functionalized with zeolitic imidazolate framework-8 (ZIF-8) dispersed in a photoresist AZ1512HS (AZ) matrix to function as a gravimetric gas sensor. The sensor response was recorded in the presence of nitrogen, argon, carbon dioxide, and methane gases as well as water, acetylene, a propane/butane mixture, n-hexane, gasoline, and diesel vapors. The photoresist matrix alone was found to have a negligible response to all the gases and vapors, except for water vapor. No visible difference in sensor response was detected when switching from nitrogen to methane gas. However, a strong shift in the sensor resonance frequency was observed when exposed to higher hydrocarbons, ranging from 1 kHz for acetylene to 7.5 kHz for gasoline. Even longer-chain hydrocarbons, specifically kerosene and more so diesel, had a significantly reduced sensor frequency shift compared with gasoline. Sensors functionalized with a thin film of AZ+ZIF-8 demonstrated higher sensitivity in their response to a hydrocarbon molecular mass than without functionalization.

Efficient treatment of nutrient-rich wastewater is of paramount importance for protecting the ecosystem. In this work, an efficient, abundant, and eco-friendly adsorbent was derived from biochar and employed for phosphorus (P) adsorption. The key factors influencing the P removal efficiency of the activated biochar, including P concentration, pH, dosage, temperature, adsorption time, and influence of co-existing ion type, were investigated. Maximum P adsorption percentage (100%) was obtained with 10 mg/L and zinc chloride activated biochar (BC-Zn) compared to the other activated biochars. Results show that by increasing the P concentration from 5 to 200 mg/L, the phosphorus adsorption capacity increases from 0.13 to 10.4 mg/g biochar. Isotherms and kinetic studies further show that the P adsorption follows the Langmuir and quasi-second-order kinetic models. The mechanistic investigation demonstrated that P adsorption occurred by precipitation reaction. Furthermore, P desorption has been studied at different time intervals to understand the P release rate after adsorption., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Single atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metal-support interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.6 wt % Co SAC) in a pyridinic N-rich graphenic network. The highly porous carbon network (surface area of ∼186 m 2 g -1 ) with increased conjugation and vicinal Co site decoration in Co SACs significantly enhanced the electrocatalytic oxygen evolution reaction (OER) in 1 M KOH (η 10 at 351 mV; mass activity of 2209 mA mg Co -1 at 1.65 V) with more than 300 h stability. Operando X-ray absorption near-edge structure demonstrates the formation of electron-deficient Co-O coordination intermediates, accelerating OER kinetics. Density functional theory (DFT) calculations reveal the facile electron transfer from cobalt to oxygen species-accelerated OER.

This article presents the synthesis, property characterization and catalytic application of CuO-supported disodium titanium phosphate, (CuO@Na 2 Ti(PO 4 ) 2 ⋅H 2 O) for the reduction of industrial pollutant 4-nitrophenol (4-NP). A simple hydrothermal route was developed to synthesize CuO@Na 2 Ti(PO 4 ) 2 ⋅H 2 O catalyst (CuO@Na 2 TiP) from beach sand ilmenite. The prepared CuO@Na 2 TiP was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption isotherms. The catalyst 12 wt.% CuO@Na 2 TiP showed the fastest reduction kinetics for 4-NP.

The experimentally validated computational models developed herein, for the first time, show that Mn-promotion does not enhance the activity of the surface Na 2 WO 4 catalytic active sites for CH 4 heterolytic dissociation during OCM. Contrary to previous understanding, it is demonstrated that Mn-promotion poisons the surface WO 4 catalytic active sites resulting in surface WO 5 sites with retarded kinetics for C-H scission. On the other hand, dimeric Mn 2 O 5 surface sites, identified and studied via ab initio molecular dynamics and thermodynamics, were found to be more efficient in activating CH 4 than the poisoned surface WO 5 sites or the original WO 4 sites. However, the surface reaction intermediates formed from CH 4 activation over the Mn 2 O 5 surface sites are more stable than those formed over the Na 2 WO 4 surface sites. The higher stability of the surface intermediates makes their desorption unfavorable, increasing the likelihood of over-oxidation to CO x , in agreement with the experimental findings in the literature on Mn-promoted catalysts. Consequently, the Mn-promoter does not appear to have an essential positive role in synergistically tuning the structure of the Na 2 WO 4 surface sites towards CH 4 activation but can yield MnO x surface sites that activate CH 4 faster than Na 2 WO 4 surface sites, but unselectively., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)