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The goal of this research was to assess the efficiency of the liquid digestate treatment conducted with algal, environmental isolates illuminated entirely with sunlight. The photobioreactor was exposed to natural conditions and evaluated based on the reduction of chemical oxygen demand (COD), nitrogen compounds, and soluble phosphates. Microalgal and bacterial communities growing during the treatment process were studied. A high removal rate of soluble COD (= 91%) and nutrients (= 86%) was achieved. The average concentrations of nitrogen, phosphates, and COD in the reactor effluent were 95 mgN/L, 49 mg/L, and 735 mg O2/L, respectively. The overall algae-bacteria biomass productivity of 22 mg/L/d, calculated on the total suspended solids (TSS) basis, was recorded. The microbial analysis revealed the dominance of Tetradesmus obliquus followed by Microglena sp. in the first 14 weeks of the experiment. At the end of the experimental run, Chlorella sorokiniana cells appeared as a result of illumination intensity changes. The dominating bacteria belonged to Firmicutes (26.31%), Patescibacteria (17.38%), and Actinobacteriota (14.86%) and could have been responsible for the transformation of nitrogen and oxidation of organic contaminants. The research demonstrated that natural sunlight can successfully be used for efficient liquid digestate treatment with the algae-bacterial community. [ABSTRACT FROM AUTHOR]

The as-prepared and thermally treated Ni–P and Ni–Fe–P alloy powders obtained by chemical reduction were studied regarding the microstructure, as an important factor affecting the functional properties of the materials. Also, the influence of the microstructure and thermally induced transformations of the studied materials on the corrosion behavior in neutral, alkaline, and acidic media is presented. For a detailed study of the mentioned phenomena, different structural and electrochemical techniques were used, including XRD, TEM, DTA, potentiodynamic, and EIS measurements. The composition and microstructure of the studied alloy powders were shown to be dependent on the reactant ratio and thermal history of the material. Small amounts of crystalline phases present in the as-prepared powders, as well as crystalline phases formed during crystallization, included some or all of the following phases: Ni, Ni3P, and Ni12P5. It was shown that the addition of small amount of Fe into the Ni–P powder alloy considerably affects the microstructure and thermal stability of the material, having beneficial effect on the formation of protective oxide layers and thus on the corrosion resistance in chloride environments. [ABSTRACT FROM AUTHOR]

The present work deals with developing a method for revalorizing steel residues to create sunlight-active photocatalysts based on iron oxides. Commercial-grade steel leftovers are oxidized under different combinations of pH and temperature (50–90 °C and 3 ≥ pH ≤ 5) in a low energy-intensive setup. The material with the highest production efficiency (yield > 12%) and magnetic susceptibility (χm = 387 × 10−6 m3/kg) was further explored and modified by diffusion of M2+ (Zn and Co) ions within the structure of the oxide using a hydrothermal method to create ZnFe2O4, CoFe2O4 and combined Co–Zn ferrite. (Co–Zn)Fe2O4 displayed a bandgap of 2.02 eV and can be activated under sunlight irradiation. Electron microscopy studies show that (Co–Zn)Fe2O4 consists of particles with diameters between 400 and 700 nm, homogeneous size, even distribution, and good dispersibility. Application of the developed materials in the sunlight catalysis of black liquors from cellulose extraction resulted in a reduction of the Chemical Oxygen Demand (− 15% on average) and an enhancement in biodegradability (> 0.57 BOD/COD) after 180 min of reaction. Since the presented process employs direct solar light, it opens the possibility to large-scale water treatment and chemical upgrading applications. [ABSTRACT FROM AUTHOR]

Cu2O has been successfully synthesized in different morphologies/sizes (nanoparticles and octahedrons) via a low-temperature chemical reduction method. Trapping metal ions in an ice cube and letting them slowly melt in a reducing agent solution is the simplest way to control the nanostructure. Enhancement of charge transfer and transportation of ions by Cu2O nanoparticles was shown by cyclic voltammetry and electrochemical impedance spectroscopy measurements. In addition, nanoparticles exhibited higher current densities, the lowest onset potential, and the Tafel slope than others. The Cu2O electrocatalyst (nanoparticles) demonstrated the Faraday efficiencies (FEs) of CO, CH4, and C2H6 up to 11.90, 76.61, and 1.87%, respectively, at −0.30 V versus reference hydrogen electrode, which was relatively higher FEs than other morphologies/sizes. It is mainly attributed to nano-sized, more active sites and oxygen vacancy. In addition, it demonstrated stability over 11 h without any decay of current density. The mechanism related to morphology tuning and electrochemical CO2 reduction reaction was explained. This work provides a possible way to fabricate the different morphologies/sizes of Cu2O at low-temperature chemical reduction methods for obtaining the CO, CH4, and C2H6 products from CO2 [ABSTRACT FROM AUTHOR]

The environmental contaminant 1,3-Dinitrobenzene (1,3-DNB), which contains two nitro groups (-NO2), has a +III nitrogen atom oxidation state, and is susceptible to electron acceptance, and subsequent reductive degradation. In this study, carpet grass was investigated as a potential source of polyphenols for the reductive degradation of 1,3-DNB. A characterization of carpet grass revealed a rapid release of polyphenols from the grass in aqueous solution, and an increase in reduction capacity. The effects of the amount of grass in solution, and effects of the pH of the aqueous phase were examined. It was found that higher grass doses (e.g., 50 g L-1) in solution resulted in complete removal of 1,3-DNB in the aqueous phase after 7 d reaction, regardless of the pH level. Kinetic analysis of 1,3-DNB degradation and its reaction intermediates, 3-nitroaniline (3-NA) and 1,3-phenylenediamine, indicated that the overall observed degradation rates (2.51-3.17 × 10-2 h-1) were similar across different doses of carpet grass, but found that the dose did impact the formation and degradation of 3-NA. Based on the results, a potential soil mixing treatment for 1,3-DNB contaminated soils, consisting of the blending of carpet grasses with soils was proposed. Soil slurry experiments simulating field remediation application suggested that enhanced degradation of 1,3-DNB contaminated soils can be achieved under reaction conditions with an appropriate solution volume and sufficiently high grass doses. This research offers valuable insights into the utilization of carpet grass for potential soil remediation through its incorporation into soils contaminated with 1,3-DNB. [ABSTRACT FROM AUTHOR]

In this study, PtNi@SWCNT (Platinum Nickel @ Single Walled Carbon Nanotube) and PtNi@MWCNT (Platinum Nickel @ Multi Walled Carbon Nanotube) catalysts were obtained using carbon nanotubes (CNTs) produced by arc discharge method and used for ascorbic acid (AA) detection. SWCNT and MWCNT were used as support structures in PtNi nanostructures and synthesis was carried out by chemical reduction method. The nanostructure was analyzed by transmission electron microscopy (TEM), and X-ray diffraction (XRD). Electrochemical analyses were carried out on catalysts of appropriate size. According to the differential pulse voltammetry (DPV) results obtained; The calculated Limit of Detection (LOD) and Limit of Quantification (LOQ) values for PtNi@SWCNT and PtNi@MWCNT catalysts were 6.94 mM/ 21.05 mM and 5.03 mM /15.26 mM, respectively. With these results, it was seen that sensitive and selective sensor was created for AA detection. The results showed that both CNTs based materials are highly effective in AA detection. In addition, this study is important for the industrial scale production of SWCNT and MWCNT by arc discharge method and performance evaluation in different applications. [ABSTRACT FROM AUTHOR]

Co-B catalyst, W-modified Co-B (Co-W-B) catalyst, and Mo-modified Co-W-B (Co-W-Mo-B) catalyst powders were synthesized via chemical reduction of metal salt solutions at room temperature. The optimal hydrogen production rate was obtained when the ratio of the reducing agent (NaBH4) to the metal solution was 4:1. Among the ternary catalysts, the Co0.1-W0.9-B catalyst showed the optimal hydrogen production rate when the content of W doping was 0.9. Furthermore, the hydrogen production rate of the quaternary catalyst was enhanced when the content of Mo doping was 0.075, denoted as Co0.1-W0.9-Mo0.075-B. The catalyst powders were characterized by SEM, XRD, XPS, and BET. The hydrogen production rates of the Co-B catalyst, Co0.1-W0.9-B catalyst, and Co0.1-W0.9-Mo0.075-B catalyst were investigated for the decomposition of alkaline sodium borohydride (NaBH4) in a water–ethanol mixture solution. The Co0.1-W0.9-Mo0.075-B catalyst exhibited the highest hydrogen production rate compared to Co-B and Co0.1-W0.9-B catalyst powders. The optimal hydrogen production rate of the Co0.1-W0.9-Mo0.075-B catalyst is 4600 ml·min−1·g−1, which is nearly 1.9 times higher than that of the Co-B catalyst. Moreover, the Co0.1-W0.9-Mo0.075-B catalyst exhibited good stability, retaining 73% of its catalytic activity after five cycles, and had a low apparent activation energy of 41.51 kJ·mol−1. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites have been employed for various applications, including biocompatible biomedical devices, electronic devices, UV shielding, and thermal management. There is a pressing need to develop comprehensive characterization approaches that can assess the overall performance of these materials under irradiation conditions, encompassing a broader range of mechanical properties beyond those traditionally studied. In this context a hybrid polymer nanocomposite was developed using Polyvinyl Alcohol, glutaraldehyde, Silver, and Graphene Oxide nanoparticles through a straightforward in situ chemical reduction process. These prepared samples were subjected to varying doses of gamma radiation, ranging from 0 to 10 kGy, to investigate alterations in their structural and mechanical properties. To validate the elemental composition and functional groups present in both unirradiated and irradiated nanocomposites, EDX and FTIR spectra were employed. The investigation to the mechanical characteristics of these samples. In unirradiated samples, elongation at break (ϵf) was determined to be 134.67 ± 1.45%, while radiation exposure resulted in an increase in the ϵf to 175.33 ± 8.01%. Tensile strength (σult) initially declined for the 2 kGy exposure but increased at 5 kGy, only to decrease again with further dose increments. Remarkably, the material exhibited increased toughness as the dose reached 5 kGy, with a measured value of modulus of toughness (MT) at 55.30 ± 6.09 J/m3. These findings shed light on the impact of gamma radiation on the structural and mechanical properties of the polymer nanocomposite material. [ABSTRACT FROM AUTHOR]

In order to the yield maintenance along with environmental protection, the replacement or combination of chemical fertilizers with organic ones has received increasing attention recently. However, the yield and quality of production in aromatic plants differ from other plants. The present experiment was conducted for 2 years with the aim of evaluating the potential of vermicompost instead of nitrogen fertilizer for the production of geraniums without reducing its perfume quality. Regarded to the macronutrients, essential oil, and shoot yield, geranium treated with 20 ton ha−1 vermicompost and 16 ton ha−1 vermicompost + 40 kg ha−1 nitrogen had the best condition compared to other fertilizer regimes. Geranium is a perennial plant; hence the traits related to plant growth and yield were higher in the second harvest. Besides that, compared to treatments with a high amount of chemical nitrogen, the effects of vermicompost on the quality and quantity of geranium in the second yield were more effective and sustainable. Moreover, these findings suggested that an appropriate proportion of organic substitution not only provides uptake nutrients but also improves the essential oil yield and chemical composition. In fact, increasing the level of vermicompost resulted in improved oxygenated monoterpene content in geranium essential oil. According to the results of this study, cow manure-derived vermicompost could be a suited and sustained replacement for nitrogen inorganic fertilizer without any significant reduction in the quality and quantity of geranium products. Thus, it can be a practical step to reduce production costs, and environmental issues own to chemical fertilizers, particularly in aromatic plant cultivation. [ABSTRACT FROM AUTHOR]

In recent years, metal nanoparticles (MNPs) have gained significant research interest owing to their versatile characteristics in diversified applications ranging from catalysis to biomedical sciences. Due to their notable and improved properties such as higher flexibility, facile processability, thermal stability, mechanical strength, and exceptional optoelectrical and magnetic behavior as compared to pristine metal nanoparticles, the polymer mediated nanoparticles have recently drawn interest from both industry and academia. In this novel investigation, we report a sustainable synthesis of Ag, Fe, Cu, and Zn metal nanoparticles using a chemical reduction method using polyamide (PA) and polyhydrazide (PH) matrices. This work is innovative in that it makes use of these polymer matrices for improved MNP synthesis, offering a unique combination of thermal and structural features. The polymers-supported metal nanoparticles were characterized for structural, thermal, optical, chemical, and morphological characteristics using XRD, TGA, UV-Vis, IR spectroscopy, and SEM analysis, respectively. XRD measurements demonstrated a significant rise in the crystallinity index for the produced metal nanoparticles, indicating a significant increase in crystallinity quantitatively. The effective synthesis of nanoparticles with precise attributes was confirmed by UV-Vis spectroscopy, which showed a significant absorption peak in the UV region. The thermogravimetric study suggested an improvement in thermal stability of around 25%. This work offers a flexible and eco-friendly method for synthesizing metal nanoparticles, demonstrating the usefulness of polyamide and polyhydrazide matrices as platforms for the synthesis of nanomaterials for numerous applications including catalysis, electronics, sensors, and biomedical applications. Highlights: A facile synthesis of metal nanoparticles (Ag, Fe, Cu, and Zn) via chemical reduction approach. The nanoparticles of Ag, Fe, Cu, and Zn are formed utilizing polyamide (PA) and polyhydrazide (PH) matrices. The synthesized metal nanoparticles exhibited higher crystallinity, better thermal stability, high absorption in UV range. This work offers a potential for numerous applications including catalysis, electronics, sensors, and biomedical applications. [ABSTRACT FROM AUTHOR]

In this research, the generation of nanobubbles was carried out using a structure of vortex pump based on the relative blockage of flow (without the use of venturi and orifices, which consume a lot of energy to generate nanobubbles), which has made this process economical and commercial. In addition, the use of advanced synthesized nanoreactors with the Yolk@Shell structure, which forms a photoanode by coating the anode electrode and can operate in the visible light range, has highlighted this research work. An in-depth study of the synergistic effect of advanced photoelectrofenton oxidation methods in addition to the hydrodynamic reactor has shown that the intelligent selection of these three types of advanced oxidation methods together has improved the performance of each other and solved their negative aspects, including the use of hydrogen peroxide, divalent iron ion, and the removal of sludge generated by the electrofenton method. The use of hollow cylindrical electrodes allowed adequate loading of the advanced synthesized nanoreactors with Yolk@Shell structure. The investigation of the effects of micro (advanced synthesized nanoreactors with Yolk@Shell structure) and macro (vortex structure based on relative blockage of the flow) processes on the degradation of pharmaceutical pollutants, both separately and in combination, is a focus of this work. At the end, the energy consumption for each of these processes and this system in general was studied, which showed that the operating cost of this combined system according to the energy consumption requirements for the almost complete removal of the pollutant naproxen and the 90% reduction of its chemical oxygen demand is 6530 Rials/L.h (or 0.15525 USD/L.h), which presents this system as an economical method with industrialization capability. The degradability index (DI) of the introduced system under optimal operating conditions was 3.38, which shows that the development of the system based on the combination of advanced oxidation methods is a suitable method used in this research work due to its environmental friendliness, absence of side effluent production, efficiency and high degradation performance, ability to recover the nanocatalyst and consequently economic efficiency. [ABSTRACT FROM AUTHOR]

The present energy demand of the world is increasing but the fossil fuels are gradually depleting. As a result, the need for alternative fuels and energy sources is growing. Fuel cells could be one alternative to address the challenge. The fuel cell can convert CO2 to value-added chemicals. The potential of bio-fuel cells, specifically enzymatic fuel cells and microbial fuel cells, and the importance of immobilization technology in bio-fuel cells are highlighted. The review paper also includes a detailed explanation of the microbial electrosynthesis system to reduce CO2 and the value-added products during microbial electrosynthesis. Future research in bio-electrochemical synthesis for CO2 conversion is expected to prioritize enhancing biocatalyst efficiency, refining reactor design, exploring novel electrode materials, understanding microbial interactions, integrating renewable energy sources, and investigating electrochemical processes for carbon capture and selective CO2 reduction. The challenges and perspectives of bio-electrochemical systems in the application of CO2 conversion are also discussed. Overall, this review paper provides valuable insights into the latest developments and criteria for effective research and implementation in bio-fuel cells, immobilization technology, and microbial electro-synthesis systems. [ABSTRACT FROM AUTHOR]

It has long been considered that compositional homogeneity would not be altered on the macro-scale by solute segregation during friction stir processing (FSP) without additives. Yet in this study, for the first time, macro-scale compositional inhomogeneity was found to be induced by FSP in AZ91. Using micro X-ray fluorescence spectrometry, three regions that different from conventional microstructural zones were clearly divided from the processed material, i.e., R1 with obvious enrichment of Al and Zn, R2 with significant depletion of Al and Zn, R3 with a similar composition to base material. R1 was found almost identical to the stir zone, while R2 occupied only a part of thermo-mechanically affected zone where grain structure was refined, and the evolution of R2 should have a strong correlation with grain refinement in thermo-mechanically affected zone. The underlying mechanisms of this newly discovered phenomenon could be attributed to dissolution of β-Mg17(Al, Zn)12 in R2 and accelerated segregation of Al and Zn from R2 to R1 driven by the reduction in their chemical potentials in R1 caused by higher temperature in this region during FSP. The local mechanical property in regions of different composition was evaluated by micro-hardness. Local softening was observed in R2, which can be mainly attributed to significantly reduced solid solution strengthening resulting from the depletion of Al and Zn. [ABSTRACT FROM AUTHOR]

In this study, a series of cobalt-based spinel ferrites catalysts, including nickel, cobalt, zinc, and copper ferrites, were synthesized using the sol–gel auto-combustion method followed by a chemical reduction process. These catalysts were employed for accelerating hydrogen generation via the sodium borohydride hydrolysis process. A continuous stirred tank reactor was used to perform catalytic reactor tests. All samples were subjected to analysis using XRD, FESEM, EDX, FTIR, and nitrogen adsorption–desorption techniques. The results revealed that the cobalt-based copper ferrite sample, Co/Cu-Ferrite, exhibited superior particle distribution, and porosity characteristics, as it achieved a high hydrogen generation rate of 2937 mL/min.gcat. In addition, the higher electrical donating property of Cu-Ferrite which leads to the increase in the electron density of the cobalt active sites can account for its superior performance towards hydrolysis of NaBH4. Using the Arrhenius equation and the zero-order reaction calculation, activation energy for the sodium borohydride hydrolysis reaction on the Co/Cu-Ferrite catalyst was determined to be 18.12 kJ/mol. This low activation energy compared to other cobalt-based spinel ferrite catalysts confirms the catalyst's superior performance as well. Additionally, the outcomes from the recycling experiments revealed a gradual decline in the catalyst's performance after each cycle during 4 repetitive cycles. The aforementioned properties render the Co/Cu-Ferrite catalyst an efficient catalyst for hydrogen generation through NaBH4 hydrolysis. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS) has shown a strong Raman enhancement with bimetallic nanoparticles. The combination of the different bimetallic nanoparticles is used in the field of SERS sensors. These sensors can resonate with the organic molecules adsorbed on their surfaces for SERS enhancement. Fabricating these bimetallic, cost-effective and ultrasensitive SERS sensors is a great challenge. To overcome this challenge, a rapid fabrication method of ultrasensitive noble SERS sensors that enable sub-femtomolar detection of molecular analytes, is reported here. SERS sensor is obtained by application of the silver nanorods (AgNRs) deposited on copper nanoflowers (CuNFs) fabricated by chemical reduction and chemical etching, respectively. Purity and structural characteristics of the SERS sensor are measured qualitatively by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, UV-visible spectroscopy, X-ray diffraction, Fourier transform infrared microscopy and Raman analysis. Rhodamine 6 g as an analyte analyses the sensitivity of the SERS sensor. The detection limit and enhancement factor are found to be 10−13 M and 109 respectively for AgNRs deposited CuNFs etched for 30 min. This study reveals that the AgNRs deposited CuNFs are practically found to be sensitive SERS sensors. [ABSTRACT FROM AUTHOR]

Using a seed–growth method, chemical reduction in aqueous solution was used to create gold nanoparticles (AuNPs). As seeds, AuNPs have been created and used as a nucleating agent with regard to the gold colloids' anisotropic growth. The various seed quantities were added to the gold chloride-containing growth solution, and NPs have started to grow as a result. Au seeds are typically 20 nm in spherical and size in shape, while gold is 25–30 nm in size and spherical in shape. Peak absorption from nanospheres was measured between 535 nm and 530 nm. The surface plasmon band's absorption peaks moved to the short wavelength region. AuNPs are doped with PMMA to create thin films that can be used as saturation absorbers (passive Q-switching) for Q-switching in visible region and green LEDs at various frequencies in the RhB fluorescence region. Those properties include the suitability of the resulting NPs for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Group 1 elements exhibit the lowest electronegativity values in the Periodic Table. The chemical reduction of Group 1 metal cations M+ to M(0) is extremely challenging. Common tetraaryl borates demonstrate limited redox properties and are prone to decomposition upon oxidation. In this study, by employing simple yet versatile bipyridines as ligands, we synthesized a series of redox-active borate anions characterized by NMR and X-ray single-crystal diffraction. Notably, the borate anion can realize the reduction of Li+, generating elemental lithium metal and boron radical, thereby demonstrating its potent reducing ability. Furthermore, it can serve as a powerful two-electron-reducing reagent and be readily applied in various reductive homo-coupling reactions and Birch reduction of acridine. Additionally, this borate anion demonstrates its catalytic ability in the selective two-electron reduction of CO2 into CO. Chemical reduction of alkali cations to their metals is extremely challenging. Here, the authors synthesized a series of redox-active borate anions stabilized by bipyridine ligands which can reduce lithium ions generating elemental lithium metal and borate radicals. [ABSTRACT FROM AUTHOR]

The scientific and industrial communities have shown considerable interest in the mass production of graphene in recent years. This heightened attention is attributed to graphene's promising applications across diverse fields such as electronics, energy storage, material science, biomedicine. While the potential benefits are substantial, large-scale graphene production poses significant challenges. Nonetheless, there have been noteworthy advances and dedicated efforts towards overcoming these challenges. This paper explores synthesis methods, structural distinctions, and a range of analytical techniques employed to compare properties among graphite, graphene oxide (GO), and reduced graphene oxide (rGO) samples subjected to varying reduction durations. The focus is on highlighting the efficacy of the chemical reduction method in successfully transforming GO into rGO. By extending the chemical reduction duration, the reduced graphene oxide exhibited reduced oxygen content and underwent a restoration of SP2 bonds, accompanied by the removal of oxygen functional groups. This process led to a reduction in the interplanar space between graphene layers and an increased number of exfoliated graphene layers. Notably, the resulting material demonstrated excellent stability with no coagulation in the dispersion medium and displayed improved electrical conductivity compared to graphene oxide (GO). The findings of this study suggest that optimizing the chemical reduction process, and varying reduction durations, can fine-tune the properties of reduced graphene oxide (rGO) to cater to diverse application needs. Furthermore, this approach holds promise for the scalable production of graphene. [ABSTRACT FROM AUTHOR]

The integrated electrocoagulation-assisted adsorption (ECA) system with a solar photovoltaic power supply has gained more attention as an effective approach for reduction chemical oxygen demand (COD) from pharmaceutical wastewater (PhWW). In this research, the ECA system was used for the treatment of PhWW. Several operating parameters were investigated, including electrode number, configuration, distance, operating time, current density, adsorption time, and temperature. A current density of 6.656 mA/cm2, six electrodes, a 20-min time, a 4 cm distance, an MP-P configuration, and a 45 °C temperature produced the maximum COD reductions, where the operating cost of conventional energy was 0.273 $/m3. The EC, adsorption, and combination of EC and adsorption processes achieved efficient COD reductions of 85.4, 69.1, and 95.5%, respectively. The pseudo-second-order kinetic model and the Freundlich isotherm fit the data of the endothermic adsorption process. Therefore, it was found that the combination processes were superior to the use of these processes in isolation to remove COD. [ABSTRACT FROM AUTHOR]

A reliable, rapid, and inexpensive nano-sized chemosensor is presented for methamidophos (MET) — an insecticide. Poly(lactic acid) (PLA)-stabilized gold nanoparticles (AuNPs) were synthesized by a simple one-pot, two-phase chemical reduction method. The synthesized PLA-AuNPs were subsequently employed for selective, efficient, and quantitative detection of MET. MET is one of the highly toxic pesticides used for eradication of agricultural and urban insects. Upon the addition of MET, the wine-red color of PLA-AuNPs swiftly transformed into greyish-blue, further corroborated by a significant bathochromic and hyperchromic shift in the SPR band. The presence of other interfering insecticides, metal salts, and drugs did not have any pronounced effect on quantitative MET detection. The detection limit, the quantification limit, and linear dynamic range of MET utilizing PLA-AuNPs were 0.0027 µM, 0.005 µM, and 0.005–1000 µM, respectively. The PLA-AuNP-based assay renders an efficient, rapid, accurate, and selective quantification of MET in food, biological, and environmental samples. The proposed sensor provides an appropriate platform for fast and on-the-spot determination of MET without requiring a well-equipped lab setup. [ABSTRACT FROM AUTHOR]

Sand storms and fine dust are known as the most important atmospheric problems in many windy regions around the world, especially in arid and semi-arid areas. Besides all the obvious negative effects of fine dust on human life, this phenomenon can extremely reduce the physical and chemical quality of output water from treatment plants into the distribution systems. In order to show and evaluate the impact of fine dust on the physico-chemical quality of the water, a long-term (three years: 2017–2020) experimental investigation was done in the Sistan region (Iran) which is one of the most popular regions in the world with high amount of annual fine dust level. The final results showed that the most physical and chemical quality indices of output water from the local treatment plants became progressively worse after the fine dust process. The total dissolved solids (TDS) and turbidity of the water, which could even obviously be seen in the samples, were increased so that the TDS level was raised to more than 850 ppm. The level of some metals such as Fe, Ca, Mg, Na, and K increased significantly but stood within the standard levels. pH level was increased to up to 8.3 in some water samples. In addition, high levels of NO3, SO4, F, EC, HCO3, Cl, CO3, and PO4 were observed in all water samples after fine dust processes. Also, the t-student analysis showed that there was a high correlation between wind speeds and the reduction of physical and chemical quality indices in most of the water samples. Finally, the experimental analysis showed that most of these chemical elements originated from the vast bed (5,660 km2) of the dried-up Hamun's Lake where the winds were blown over. [ABSTRACT FROM AUTHOR]

The hydrogenation of a number of carbonyl compounds with the formation of the corresponding alcohols was studied. The process was carried out in a flow-type reactor in the presence of nickel catalysts supported on γ-Al2O3 obtained by the deposition-precipitation method with chemical reduction of the active phase. The effect of the catalyst preparation method on the yield of the resulting alcohols was studied. It has been shown that the increase in the nickel content in the catalyst leads to complete substrates conversion even at 20–80°C and atmospheric hydrogen pressure. [ABSTRACT FROM AUTHOR]

This experimental study's main goal is to investigate the impact of various silver concentrations on the optical characteristics of Agshell/Aucore bimetallic nanoparticles. By using the pulsed laser ablation in liquid (PLAL) technique on the gold target at the bottom of the container full of silver colloids, the silver/gold nanoparticles are ablated. Colloidal silver nanoparticles, created through a chemical reduction process, are inside the container. The second harmonic of the pulsed Nd:YAG laser is used to irradiate the colloidal mixture of mixed nanoparticles at a wavelength of 532 nm. The Agshell/Aucore bimetallic nanoparticles are created by transferring laser energy to gold nanoparticles, which have a peak absorption of around 530 nm. The experimental variables are the volumetric ratio of nanoparticle solutions. X-ray diffraction pattern (XRD), spectroscopy in the UV–Vis-NIR and IR ranges, dynamic light scattering (DLS), energy-dispersive spectroscopy (EDS), photoluminescence spectrum (PL), and Fourier transform infrared spectroscopy (FT-IR) are used to identify bimetallic nanoparticles. Additionally, FE-SEM and TEM pictures are used to look at the size and morphology of nanoparticles. In order to test the reactivity of silver nanoparticles in the bimetallic system, one goal of this research is the production of stable bimetallic systems and the examination of optical properties. Additionally, a bimetallic structure with a variable silver concentration's shell thickness and catalytic qualities is examined. All samples in the visible range have dipole absorption observable. On the other hand, the first sample with a lower silver concentration exhibits quadrupole absorption. [ABSTRACT FROM AUTHOR]

A series of mesoporous nanoparticle P-CexZr1-xOy (PCZ) catalysts with abundant oxygen vacancies and high specific surface area were successfully prepared, exhibiting 100% formaldehyde conversion at room temperature (25 °C). The PCZ catalyst was investigated in depth utilizing TEM, BET, XRD, XPS, H2-TPR, and Raman characterization, it was found that the PCZ catalyst had an average particle size of 10 nm and a specific surface area of 108 m2/g; templating caused by P123 and effective doping of Zr atoms regulated the oxygen vacancies in the catalyst, altered the reduction characteristics and chemical state of cerium to formed the redox cyclic couple of Ce3+/Ce4+, which significantly enhanced the catalytic oxidation performance of the PCZ catalyst in the indoor environment. [ABSTRACT FROM AUTHOR]

Methanol is a renewable, low-carbon chemical that can be obtained from biomass. GeO2 is the main source for producing Ge, which is an important semiconductor. The current study aimed to investigate the reduction of GeO2 and chemical vapor deposition of Ge using gaseous species generated by methanol pyrolysis. Mass measurement, X-ray diffraction and scanning electron microscopy techniques were used to determine the extent of the oxide reduction, and to characterize the products. CO and H2 were predicted as the major reducing agents derived from the methanol pyrolysis at 1000 K to 1200 K, in agreement with the experimental measurement. It was found that the mass loss in GeO2 increased to 85.5 pct as the reaction time and temperature were raised to 10 minutes and to 1200 K. The GeO2 reduction was insignificant at 900 K, in contrast to the thermodynamic prediction, essentially owing to the sluggish reaction kinetics. At 1000 K, the significant reduction of GeO2 to Ge, close to the thermodynamic equilibrium, was attained. At 1100 K to 1200 K, the experimental mass loss was more than the thermodynamics prediction. The discrepancy was explained by a mass-transport theory involving boundary layer in the gas phase over the powder bed. Ge films were deposited from the gaseous species generated upstream at 1200 K for 10 minutes on a Si (400) substrate held downstream in the reaction tube at 723 K to 923 K. Polycrystalline rough Ge thin films with pillar-like crystals were obtained when the substrate temperatures were 723 K and 823 K. At 923 K, a denser polycrystalline Ge film was grown probably owing to the enhanced Ge diffusion on the substrate surface. [ABSTRACT FROM AUTHOR]

In this study, the anaerobic sludge withdrawn from thickener in a sewage treatment plant served as the precursor for sludge-based biochar fabrication, which was further modified via sulfur (S) heteroatom doping (i.e., S-BC). The S atom doping resulted in the adjustment of the physicochemical properties towards the carbon material, endowment of abundant functional groups on biochar surface, and increasing the binding sites between biochar and Cr(VI). Compared to the primary biochar (i.e., biochar without heteroatomic doping, named BC), S-BC exhibited a rough surface and possessed remarkable advantages in ash content, specific surface area, and pore volume. The existence of graphene carbon crystal structure for S-BC was confirmed through S-BC by XRD and FTIR analysis. The studies of adsorption kinetics and isotherms showed that pseudo-second-order kinetics and the Langmuir model more fitted the Cr(VI) removal behavior in the presence of S-BC. Therefore, the chemisorption and monolayer adsorption were the primary mechanisms involved in the Cr(VI) removal process. Additionally, XPS analysis results illustrated the aqueous Cr(VI) was efficiently eliminated through the synergistic effect of chemisorption and reduction to Cr(III) in the presence of S-BC. Moreover, S-BC could still achieve the Cr(VI) eliminating efficiency of 85.31% undergoing five cycles with unchanged functional group and crystal structure via FTIR and XRD analysis. Thus, the results of this study may shed light on a new approach for simultaneous economical sludge disposal and the sustainable remediation of the Cr(VI)-contaminated wastewater. [ABSTRACT FROM AUTHOR]

Conjugated polymers are promising tools to differentiate various types of semiconducting single-walled carbon nanotubes (s-SWCNTs). However, their synthesis is challenging. Insufficient control over molecular weights, and unpredictive/unrepeatable batches hinder possible applications and scale-up. Furthermore, commercial homogeneous catalysts often require inert conditions and are almost impossible to recycle. To overcome these problems, we present a nanocatalyst consisting of magnetic nickel nanowires decorated with highly active palladium nanoparticles. A two-step wet chemical reduction protocol with the assistance of sonochemistry was employed to obtain a heterogeneous catalyst capable of conducting step-growth Suzuki polycondensation of a fluorene-based monomer. Additionally, we enhanced the performance of our catalytic system via controlled microwave irradiation, which significantly shortened the reaction time from 3 d to only 1 h. We studied the influence of the main process parameters on the yield and polymer chain length to gain insight into phenomena occurring in the presence of metallic species under microwave irradiation. Finally, the produced polymers were used to extract specific s-SWCNTs by conjugated polymer extraction to validate their utility. [ABSTRACT FROM AUTHOR]

In agriculture, there is a constant search for increased productivity, which leads to increased use of fungicides, insecticides, and inoculants, among other products to perform seed treatment before planting. After treatment, the machines and equipment are sanitized, generating a liquid residue with potentially negative environmental impacts. This study aimed to characterize and evaluate the toxicity of the effluent generated from washing soybean seed treatment machines and suggest treatment methods for this residue. The applied treatment was a combined process of coagulation followed by heterogeneous photocatalysis and ozonization. The treatments caused a significant decrease in the concentration of sedimentable solids (95.22%), total solids (25.26%), and total dissolved solids (9.14%). The chemical oxygen demand and the active ingredient thiamethoxam were also reduced by 31.55% and 40.98%, respectively. Despite the reduction of the physical and chemical parameters of the effluent, it still presented acute toxicity to the bioindicators Artemia salina L. and Eisenia fetida since these showed mortality in the tests. The results confirm the risk that this effluent presents to the environment and highlights the importance of continuing the search for new treatment technologies to promote the reduction of the physicochemical parameters and the final toxicity. [ABSTRACT FROM AUTHOR]

An aerobic microbial fuel cell (MFC) was designed to produce bio-electricity using cow manure-pretreated slurry (CM) and sewage sludge (SS). A comparative study of parametric effects on power generation for various parameters like feed ratio of wastes, pH of anode media, and electrode depth was conducted. This experiment aimed to identify the most important system parameters and optimize them to develop a suitable controller for a stable output. Power production reached its maximum at an electrode depth of 7 cm, a pH of 6, and a feed ratio of 2:1 in the CM + SS system before applying the controller. Response surface methodology (RSM) was practiced to explore the relationships between various parameters and the response using MINITAB software. The regression equation of the most productive system deduced from the RSM result has an R2 value of 85.3%. The results show that an ON/OFF controller works satisfactorily in this study. The highest energy-generating setup has a chemical oxygen demand (COD) removal efficiency of 45%. The morphology and content of the used wastes indicate that they can be recycled in other applications. [ABSTRACT FROM AUTHOR]

The application of zero-valent iron nanoparticles (nZVI) is an area of growing interest, especially in the remediation processes of waters of different origin. The standard synthetic procedure for nZVI involves the chemical reduction of Fe2+ or Fe3+ with the solution of a strong reducing agent. This type of synthetic route leads to the formation of new toxic species. The green synthesis of nZVI using plant extracts is, therefore, an excellent alternative to the above-mentioned conventional methods. Within the scope of this work, the amorphous nZVI was synthesized by green tea mediated single-step method from Fe3+ as precursors, denoting an eco-friendly approach. Additionally, the physico–chemical characterization (TEM, SEM/EDS, size of particles/aggregates, XRD, BET) of nZVI was performed. The catalytic activity of the obtained nZVI was tested in a Fenton-like reaction of the removal/degradation of three representative industrial textile dyes (methylene blue, methyl orange and bromothymol blue) from water. In order to optimize the process parameters, the effect of homogenization treatment, nZVI and H2O2 concentration on catalytic performance were also done followed by degradation kinetic study using four different models. The results of this work have shown the exceptionally high efficiency of the green nZVI which is reflected in almost complete degradation of all tested dyes within very short period of time, despite their amorphous nature, aggregates arrangement and very low specific surface area. Furthermore, the examined degradation kinetics has excellently followed the BMG model, indicating that the degradation process of the investigated dyes proceeds via two stages (two-stage pattern)—a fast one and a much slower one, regardless of the used reaction conditions. Based on all gained results, particular degradation mechanisms were proposed. [ABSTRACT FROM AUTHOR]

Anthropogenic carbon dioxide (CO2) levels are rising to alarming concentrations in earth's atmosphere, causing adverse effects and global climate changes. In the last century, innovative research on CO2 reduction using chemical, photochemical, electrochemical and enzymatic approaches has been addressed. In particular, natural CO2 conversion serves as a model for many processes and extensive studies on microbes and enzymes regarding redox reactions involving CO2 have already been conducted. In this review we focus on the enzymatic conversion of CO2 to carbon monoxide (CO) as the chemical conversion downstream of CO production render CO particularly attractive as a key intermediate. We briefly discuss the different currently known natural autotrophic CO2 fixation pathways, focusing on the reversible reaction of CO2, two electrons and protons to CO and water, catalyzed by carbon monoxide dehydrogenases (CODHs). We then move on to classify the different type of CODHs, involved catalyzed chemical reactions and coupled metabolisms. Finally, we discuss applications of CODH enzymes in photochemical and electrochemical cells to harness CO2 from the environment transforming it into commodity chemicals. [ABSTRACT FROM AUTHOR]

Selenium, an essential micronutrient for plants and animals, can cause selenium toxicity as an oxyanion or at elevated doses. However, the toxic selenite (SeO32−) oxyanion, can be converted into less harmful elemental nano-selenium (Se0), with various practical applications. This research aimed to investigate two methods for reducing SeO32−: abiotic reduction using cell-free extract from Enterococcus spp. (abiotic-SeNPs) and chemical reduction involving L-ascorbic acid (chemical-SeNPs). Analysis with XPS confirmed the presence of Se0, while FTIR analysis identified surface functional groups on all SeNPs. The study evaluated the effects of SeO32−, abiotic-SeNPs, and chemical-SeNPs at different concentrations on the growth and germination of Pisum sativum L. seeds. SeO32− demonstrated detrimental effects on germination at concentrations of 1 ppm (germination index (GI) = 0.3). Conversely, both abiotic- and chemical-SeNPs had positive impacts on germination, with GI > 120 at 10 ppm. Through the DPPH assay, it was discovered that SeNPs exhibited superior antioxidant capabilities at 80 ppm, achieving over 70% inhibition, compared to SeO32− (less than 20% inhibition), therefore evidencing significant antioxidant properties. This demonstrates that SeNPs have the potential to be utilized as an agricultural fertilizer additive, benefiting seedling germination and development, while also protecting against oxidative stress. [ABSTRACT FROM AUTHOR]

Peatland vegetation takes up mercury (Hg) from the atmosphere, typically contributing to net production and export of neurotoxic methyl-Hg to downstream ecosystems. Chemical reduction processes can slow down methyl-Hg production by releasing Hg from peat back to the atmosphere. The extent of these processes remains, however, unclear. Here we present results from a comprehensive study covering concentrations and isotopic signatures of Hg in an open boreal peatland system to identify post-depositional Hg redox transformation processes. Isotope mass balances suggest photoreduction of HgII is the predominant process by which 30% of annually deposited Hg is emitted back to the atmosphere. Isotopic analyses indicate that above the water table, dark abiotic oxidation decreases peat soil gaseous Hg0 concentrations. Below the water table, supersaturation of gaseous Hg is likely created more by direct photoreduction of rainfall rather than by reduction and release of Hg from the peat soil. Identification and quantification of these light-driven and dark redox processes advance our understanding of the fate of Hg in peatlands, including the potential for mobilization and methylation of HgII. Mercury isotope signatures in groundwater, soil gas, solid peat, and atmosphere suggest that dark abiotic reduction of peat soil HgII to volatile Hg0 does not play a significant role in mobilizing Hg during peat mass loss [ABSTRACT FROM AUTHOR]

The reduction of nitric oxide (NO) emissions to atmosphere has been recently addressed using biological technologies. However, NO removal through bioprocesses is quite challenging due to the low solubility of NO in water. Therefore, the abatement of NO emissions might be improved by adding a chelating agent or a mass transfer vector (MTV) to increase the solubility of this pollutant into the aqueous phase where the bioprocess takes place. This research seeks to assess the performance of different non-aqueous phase liquids (NAPs): n-hexadecane (HEX), diethyl sebacate (DSE), 1,1,1,3,5,5,5-heptamethyl-trisiloxane (HTX), 2,2,4,4,6,8,8-heptamethylnonane (HNO), and high temperature silicone oil (SO) in chemical absorption–biological reduction (CABR) integrated systems. The results showed that HNO and HTX had the maximum gas-liquid mass transfer capacity, being 0.32 mol NO/kmol NAP and 0.29 mol NO/kmol NAP, respectively. When an aqueous phase was added to the system, the mass transfer gas–liquid of NO was increased, with HTX reaching a removal efficiency of 82 ± 3% NO with water, and 88 ± 6% with a phosphate buffer solution. All NAPs were tested for short-term toxicity assessment and resulted neither toxic nor inhibitory for the biological activity (denitrification). DSE was found to be biodegradable, which could limit its applicability in biological processes for gas treatment. Finally, in the CABR system tests, it was shown that NO elimination improved in a short time (30 min) when the three mass transfer vectors (HEX, HTX, HNO) were added to enriched denitrifying bacteria. [ABSTRACT FROM AUTHOR]

It is still challenging to avoid polyaniline agglomeration and fabricate polyaniline-based adsorbents with stable structure, excellent adsorption performance. Herein, we synthesized montmorillonite/humic acid/polyvinyl alcohol@polyaniline (MMT/HA/PVA@PANI) composite porous hydrogel adsorbent by Pickering emulsion template-in situ chemical oxidative polymerization, and the enhancement effect of this design idea on the adsorption performance of PANI was studied with heavy metal ion hexavalent chromium Cr(VI) as the target adsorbate. The in-situ polymerization of aniline at the Pickering emulsion interface and the unique three-dimensional network structure of the hydrogel act as an effective "confinement" for the growth of the polyaniline. The porous structure of hydrogel can be used as water channel, which can accelerate the combination of adsorbate and adsorption site, and significantly improve the adsorption capacity and adsorption rate. Compared with the pure PANI (43.48 mg g−1 PANI), MMT/HA/PVA@PANI (1753.60 mg g−1 PANI) obviously had significantly higher removal efficiency, which increased the removal efficiency of Cr(VI) by about 40 times. Adsorption experiments suggest that solution pH, adsorbent dosage, contact time and initial concentration all have certain effects on adsorption performance. According to the FESEM, EDX, FTIR and XPS analysis of the materials before and after adsorption, the removal of Cr(VI) is mainly enhanced by ion exchange, electrostatic attraction and chemical reduction. In conclusion, MMT/HA/PVA@PANI adsorbent has novel design, good adsorption performance and strong stability, and it has great development prospects in removing heavy metal ions from wastewater. [ABSTRACT FROM AUTHOR]

Background The bleach-boosting capability of xylanases is well-known. The use of xylanase pre-treatment before the application of chemical bleach has multiple advantages including (i) lesser use of polluting chemicals of the traditional bleaching process; (ii) less damage to the cellulosic fbers, therefore better recyclability; and (iii) better brightness of chemical bleach. The major impediment in the application is the availability of commercial enzymes that are active at the elevated temperature and pH that exist during the industrial pulping process. In the present paper, xylanase having suitability for application in deinking is reported. Results The xylanase used showed high deinking potential. Optimal deinking was obtained at the xylanase dosing of 20U/g of the dried pulp at 60°C for a treatment time of 1h. It could bring about a 50% reduction in the usage of chemical bleach that was applied after xylanase pre-treatment. The comparison of FTIR spectra showed changes in intensity without signifcant changes in the functional group signatures implying that there is negligible damage to the fber strength in the xylanase pre-treatment process as compared to the chemical bleach process. Conclusion The xylanase used in this study was efective in deinking paper pulp and can be used for bio-bleaching of recycled paper. [ABSTRACT FROM AUTHOR]

This study evaluated the spatial variability of magnetic minerals and the potential of mass-specific magnetic susceptibility (χlf) to recognize minimum areas of phosphorus adsorbed (Pads). In an area of 443 ha cultivated with sugar cane in the state of São Paulo, 84 soil samples were collected at a depth range of 0.0–0.20 m. Analysis of mass-specific magnetic susceptibility at low (χlf) and high (χhf) frequencies was performed in all soil samples. Characterization of ferrimagnetic minerals was carried out by X-ray diffraction (XRD) and the chemical distinction between lithogenic (magnetite-Mt) and pedogenic (maghemite-Mh) ferrimagnetic minerals was determined by χlf before and after chemical reduction by citrate-bicarbonate-dithionite (CBD), with subsequent determination of Pads. The analytical results were evaluated by descriptive analysis and the spatial pattern was assessed by applying the geostatistical technique. χlf differentiated soils from their respective parent material even under conditions of high weathering and lithologic complexity. Positive linear correlations between Pads and clay (R2 = 0.77; p < 0.01), Pads and χlf (R2 = 0.86; p < 0.01), and Pads and Mh (R2 = 0.84; p < 0.01) indicated the use of χlf as a component of pedotransfer functions (PTF) for indirect quantification of Pads in the soil. Quantification of Mh and Mt by χlf was more sensitive than by XRD. The spatial pattern of ferrimagnetic minerals indicated that Mh originated from the direct oxidation of Mt. Soil χlf was sensitive to the spatial variability of Pads and might have assisted with the identification of minimum areas of phosphate fertilization in soils under lithologic complexes. [ABSTRACT FROM AUTHOR]

The debate between ontological reductionists and emergentists in chemistry has revolved around quantum mechanics. What Franklin and Seifert (BJPS 2020) add to the long-running dispute is an attention to the measurement problem. They contend that all three realist interpretations of the quantum formalism capable of resolving the measurement problem also obviate any need for chemical emergence. I push their argument further, arguing that the realist interpretations of quantum mechanics actually subvert the basis for reduction as well, by undercutting the idea that fundamental physical particles are actual parts of molecules. With both reduction and traditional synchronic emergence pictures ruled out, the only option for realists about quantum chemistry is strong Thomistic emergence. [ABSTRACT FROM AUTHOR]

Cytochrome c oxidase (CcO) is an essential enzyme in mitochondrial and bacterial respiration. It catalyzes the four-electron reduction of molecular oxygen to water and harnesses the chemical energy to translocate four protons across biological membranes. The turnover of the CcO reaction involves an oxidative phase, in which the reduced enzyme (R) is oxidized to the metastable OH state, and a reductive phase, in which OH is reduced back to the R state. During each phase, two protons are translocated across the membrane. However, if OH is allowed to relax to the resting oxidized state (O), a redox equivalent to OH, its subsequent reduction to R is incapable of driving proton translocation. Here, with resonance Raman spectroscopy and serial femtosecond X-ray crystallography (SFX), we show that the heme a3 iron and CuB in the active site of the O state, like those in the OH state, are coordinated by a hydroxide ion and a water molecule, respectively. However, Y244, critical for the oxygen reduction chemistry, is in the neutral protonated form, which distinguishes O from OH, where Y244 is in the deprotonated tyrosinate form. These structural characteristics of O provide insights into the proton translocation mechanism of CcO. Using resonance Raman spectroscopy and serial femtosecond X-ray crystallography, the authors show the heme a3 iron and CuB in the resting oxidized form of Cytochrome c Oxidase are coordinated by a hydroxide ion and a water molecule, respectively. [ABSTRACT FROM AUTHOR]

In the study, we have fabricated Ag@Li dual shell hallow nanosphere (Ag@Li DSHN) by chemical reduction method for the dual non-enzymatic detection of glucose and phosphorus. TEM image of Ag@Li DSHN confirms the dual shell hallow nanosphere with Li core and Ag shell. The XRD spectrum of Ag@Li DSHN shows the particle was crystalline in nature. The dual detection of glucose and phosphorus by Ag@Li DSHN showed high sensitivity, and selectivity as a potential sensing probe. Zeta potential and average particle size of Ag@Li DSNH was found to be − 32.9 mV ± 2.1 mV and 12 ± 1.3 nm respectively. The limit of detection of glucose and phosphorus by Ag@Li DSHN was 2.8 and 2.9 nM respectively. Furthermore, the environmental parameter (pH, temperature and saline concentration) on the detection of glucose and phosphorus by Ag@Li DSHN was studied. Additionally, the real sample detection by Ag@Li DSHN towards the detection of glucose and phosphorus was studied and the recovery % was from 97 to 99%. Hence, Ag@Li DSHN can be used for the effective detection of glucose and phosphorus form environmental sample. [ABSTRACT FROM AUTHOR]

We have developed a biological macromolecule stabilized method for the preparation of cobalt sulfide nanoparticles using carboxymethyl cellouse (CMC) as a stabilizing agent. We investigated the formation of cobalt sulfide nanoparticles as a function of different amounts of CMC. At 0.05% w/v amount of CMC, the high percentage of cube shaped cobalt sulfide nanoparticles is obtained. The samples obtained from 0.01% w/v and 0.1% w/v amounts of CMC shows random shaped cobalt sulfide nanoparticles and aggregated cobalt sulfide nanostructures, respectively. The obtained cobalt sulfide nanoparticles are stabilized through the interactions of hydroxyl (–OH) and carboxylate (–COO–) functional groups in CMC. The CMC encapsulated cobalt sulfide nanoparticles were shown to have good catalytic activity for chemical reduction of p-nitroaniline in the presence of sodium borohydride. [ABSTRACT FROM AUTHOR]

Silver (Ag) nanocrystals are appealing due to their excellent antimicrobial properties. Synthesis of harmless Ag nanocrystals by low toxic reagents remains significant. Herein, an environmentally benign solvothermal process was applied to synthesize Ag nanocrystals in ethylene glycol (EG) dissolving silver nitrate and sodium oleate. Silver ions were reduced by EG to zero-valent Ag atoms that underwent nucleation and growth to form oleate-stabilized Ag nanocrystals. Multiple experimental parameters including the reaction time, temperature, concentration of Ag precursor, and the molar ratio of sodium oleate and silver nitrate were investigated to probe their effects on morphological structures and surface plasmon resonance (SPR) properties of resulting Ag nanocrystals. Results from UV–Vis absorption spectra and TEM images show that structural and SPR features of Ag nanocrystals are extremely sensitive to the reaction temperature as well as the molar ratio of sodium oleate and silver nitrate. Especially, two absorption bands appeared. The short wavelength (~ 450 nm) represents the characteristic SPR of Ag nanospheres. While, the plasmon absorption at long wavelength (500–700 nm depending on reaction conditions) indicates the anisotropic or heterogeneous structures of Ag nanocrystals that maybe pave their potential applications in asymmetric catalysis, selective growth of coating materials, nanomedicine and optoelectronics. [ABSTRACT FROM AUTHOR]

One of the development directions in the nanotechnology field is the synthesis of nanoparticles in the direction of green synthesis. In this study, Ag@AgCl nanoparticles were synthesized via the chemical reduction method using purple Cam leaf extract as reducing and capping/stability agents. The products were characterized by X-ray diffraction (XRD), Raman, field emission scanning electron microscope and UV–Vis techniques. The results XRD contributed to the Ag@AgCl nanoparticles were successfully synthesized with an average diameter of 15 nm. The ratio of Ag and AgCl depends on the volume of AgNO3 used. Raman spectroscopy indicates different group functions responsible for reducing agents and stabilizers in the reaction. The analysis by UV–vis spectra confirmed the formation of Ag@AgCl nanoparticles following the Lambert–Beer theorem and stabilize after 20 days. The Ag@AgCl nanoparticles exhibited the catalysis activity of decomposing red Congo, which is 6–31 times that of reaction without using catalysis. [ABSTRACT FROM AUTHOR]

In this study, the spent bleaching earth carbon (SBE@C) was modified with iron to obtain the iron-modified spent bleaching earth carbon (defined as FexOy-SBE@C) to remove bromate. The pseudo-second-order kinetic model and Langmuir model could well fit the bromate removal process. When the temperature was increased from 25 to 45 °C, bromate removal efficiency increased, and FexOy-SBE@C exhibited the highest bromate removal capacity of 521.82 mg/g at 45 °C. The effect of coexisting anions was investigated, and their adverse effects decreased in the order of PO43->NO3->SO42-. The higher the concentration of coexisting ions, the greater their inhibitory effect on bromate removal. By studying the effect of pH, it was found that the bromate removal was the highest at pH = 3. Characterization analysis confirmed that the iron was successfully loaded on the surface of SBE@C. The main mechanism for bromate removal by FexOy-SBE@C was the reduction of zero-valent iron and divalent iron with bromate to form the bromide ion. Overall, FexOy-SBE@C is a high-performance material for bromate removal. [ABSTRACT FROM AUTHOR]

The zirconium QDs have been synthesized using the chemical reduction method by using sodium borohydride as a reducing agent. The purity of the synthesized QDs was determined using EDS and EDX techniques. The XRD data indicate that the Zr QDs exist in both cubic and hexagonal lattice forms. The morphology of the Zr QDs is characterized by HRTEM and FESEM as homogeneous, small, spherical QDs of 5 nm to 6 nm diameter. The QDs exhibit chemiluminescence. The H2O2 sensitivities of Zr QDs have been studied. The changes in the intensity of emission spectra of Zr QDs at different wavelengths (406 nm, 430 nm, and 413 nm) satisfy the Stern–Volmer equation, thus proving to be promising candidates for their applications in biological science and as energy materials. [ABSTRACT FROM AUTHOR]

FeNi3 nanoparticles were synthesized using chemical reduction, with FeCl2.4H2O and NiCl2.6H2O as starting materials, and N2H4.H2O as the reduction agent. FeNi3-C60 core shells were subsequently prepared through hydrothermal process on a mixture of C60 and FeNi3 nanoparticles. The mean crystallite sizes of both FeNi3 and FeNi3-C60, calculated from Scherrer's formula, were 17 and 29 nm, respectively with most of the relatively spherical formed FeNi3-C60 grains ranging in size from 200 to 350 nm. The vibrating sample magnetometry confirmed ferromagnetism in both produced nanoparticles, with saturation magnetizations (MS) and coercive force (HC), 110.1 emu g−1, 79.3 Oe and 95.2 emu g−1, 70.0 Oe for FeNi3 and FeNi3-C60, respectively. The lowest reflection losses (RL) were achieved − 47.9 dB at peak frequency (f m) 4.1 GHz with a matching thickness ( d m ) of 3.7 mm for FeNi3 and − 39.7 dB at peak frequency (f m) 2.2 GHz with a matching thickness ( d m ) of 6 mm for FeNi3-C60. Due to their small specimen thicknesses and wide effective absorption bandwidth (below − 10 dB) in the Ku (12.4–18.0 GHz) band, both samples are excellent for designing lightweight EM wave absorbers with broadband capabilities. Additionally, these nanoparticles, especially FeNi3-C60, can filter specific localized frequencies in the L (1.0–2.0 GHz) and S (2.0–4.0 GHz) bands. [ABSTRACT FROM AUTHOR]

Chemical reduction in oxides plays a crucial role in engineering the material properties through structural transformation and electron filling. Controlling the reduction at nanoscale forms a promising pathway to harvest functionalities, which however is of great challenge for conventional methods (e.g., thermal treatment and chemical reaction). Here, we demonstrate a convenient pathway to achieve nanoscale chemical reduction for vanadium dioxide through the electron-beam illumination. The electron beam induces both surface oxygen desorption through radiolytic process and positively charged background through secondary electrons, which contribute cooperatively to facilitate the vacancy migration from the surface toward the sample bulk. Consequently, the VO2 transforms into a reduced V2O3 phase, which is associated with a distinct insulator to metal transition at room temperature. Furthermore, this process shows an interesting facet-dependence with the pronounced transformation observed for the c-facet VO2 as compared with the a-facet, which is attributed to the intrinsically different oxygen vacancy formation energy between these facets. Remarkably, we readily achieve a lateral resolution of tens nanometer for the controlled structural transformation with a commercial scanning electron microscope. This work provides a feasible strategy to manipulate the nanoscale chemical reduction in complex oxides for exploiting functionalities. The authors demonstrate a nanoscale chemical reduction for VO2 into V2O3 through electron-beam illumination, showcasing potential for nanoscale manipulation of oxygen ionic evolution for advanced harvesting functionalities. [ABSTRACT FROM AUTHOR]

Compared to their native range, non-native plants often experience reduced levels of herbivory in the introduced range. This may result in reduced pressure to produce chemical defences that act against herbivores. We measured the most abundant secondary metabolites found in Rumex spp., namely oxalates, phenols and tannins. To test this hypothesis, we compared native (UK) and introduced (NZ) provenances of three different Rumex species (R. obtusifolius, R. crispus and R. conglomeratus, Polygonaceae) to assess whether any significant differences existed in their levels of chemical defences in either leaves and roots. All three species have previously been shown to support a lower diversity of insect herbivores and experience less herbivory in the introduced range. We further examined leaf herbivory on plants from both provenances when grown together in a common garden experiment in New Zealand to test whether any differences in damage might be consistent with variation in the quantity of chemical defences. We found that two Rumex species (R. obtusifolius and R. crispus) showed no evidence for a reduction in chemical defences, while a third (R. conglomeratus) showed only limited evidence. The common garden experiment revealed that the leaves analysed had low levels of herbivory (~ 0.5%) with no differences in damage between provenances for any of the three study species. Roots tended to have a higher concentration of tannins than shoots, but again showed no difference between the provenances. As such, the findings of this study provide no evidence for lower plant investments in chemical defences, suggesting that other factors explain the success of Rumex spp. in New Zealand. [ABSTRACT FROM AUTHOR]

The surface plasmon resonance property of silver nanoparticles (AgNPs) makes them a top-notch material for developing sensors, especially in surface-enhanced Raman scattering (SERS). The multi-shape silver nanoparticles decorated on cellulose fiber of paper provide flexible paper-based SERS substrates with different sensitivity. The isotropic and anisotropic morphology of AgNPs on filter paper has been controlled by weak and strong reducing agents: sodium borohydride (NaBH4), ascorbic acid (L-AA), glucose, formaldehyde (HCHO). The capping agent's chitosan and the reaction conditions like the ratio of precursors and stirring speed also influence the shape, size, stability, and dispersity of AgNPs on filter paper. Multi-shape AgNPs on paper are obtained as spherical shapes (about 50–100 nm), rods (size 100–500 nm in length, 50-nm wide), or thin wings. Depending on the reduction condition, these AgNPs can be single-dispersed or stuck together to form corals on paper. The fabricated paper-based SERS substrates were investigated the optical characterization and used to detect melamine in an aqueous solution with detection limits as low as 10−8 M with the EF = 2.3 × 109. [ABSTRACT FROM AUTHOR]

The use of gaseous and air-captured CO2 for technical biosynthesis is highly desired, but elusive so far due to several obstacles including high energy (ATP, NADPH) demand, low thermodynamic driving force and limited biosynthesis rate. Here, we present an ATP and NAD(P)H-free chemoenzymatic system for amino acid and pyruvate biosynthesis by coupling methanol with CO2. It relies on a re-engineered glycine cleavage system with the NAD(P)H-dependent L protein replaced by biocompatible chemical reduction of protein H with dithiothreitol. The latter provides a higher thermodynamic driving force, determines the reaction direction, and avoids protein polymerization of the rate-limiting enzyme carboxylase. Engineering of H protein to effectively release the lipoamide arm from a protected state further enhanced the system performance, achieving the synthesis of glycine, serine and pyruvate at g/L level from methanol and air-captured CO2. This work opens up the door for biosynthesis of amino acids and derived products from air. The use of gaseous and air-captured CO2 for technical biosynthesis is highly desired but challenging due to high energy demands. Here, the authors present an ATP and NAD(P)H-free chemoenzymatic system for glycine, serine, and pyruvate biosynthesis by coupling methanol with gaseous and air-captured CO2. [ABSTRACT FROM AUTHOR]