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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 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]

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 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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Nanomaterials possessing artificial, enzyme-like catalytic activity (nanozymes, NZs) have a great potential for application in research, immunological assays, biosensors, in vivo imaging, and as therapeutic agents. Despite the obvious advances in construction and understanding of functional properties of NZs, there is still no clear evidence of whether they can complement the loss of corresponding enzymatic activity in vivo. Herein, we report the first, to the best to our knowledge, example of successful substitution of natural enzyme activity by catalase-like platinum (nPt) and platinum-gold (nPtAu) nanoparticles transferred to the cells of methylotrophic yeast Ogataea polymorpha. The nPt NZs were synthesized by the chemical reduction method and used as a seed to produce the nPt(core)Au(shell) particles. The produced nPt NZs were 68.1 and 91.3 nm in size, while the hydrids were of 531.2 and 615.1 nm. Both nPt and nPtAu demonstrated catalase activity in vitro. The catalase-deficient strain Ogataea polymorpha C-105 was shown to be able to grow on methanol and a mixture of glucose and methanol in the presence although not in the absence of NZs, this correlating with the decrease in intracellular hydrogen peroxide production. The results provide the first example of complementation of the natural enzyme function by synthetic NZs, the phenomenon which can further be used in a screening for new catalase-like nanozymes and as a fruitful tool to modify living cells by nanoparticles possessing catalytic activity and to use such modified cells as sensitive elements in cell-based biosensors. [ABSTRACT FROM AUTHOR]

Core–shell structure Cu@Pd/C catalysts were prepared in two steps combining microwave-assisted glycol reduction and chemical impregnation method for the first time. Compared with the traditional one-step synthesis of PdCu/C alloy catalysts by microwave (marked as M-PdCu/C) and impregnation (denoted by I-PdCu/C) method, respectively. The Cu@Pd/C catalysts were prepared in two-step show better catalytic performance toward formic acid oxidation, due to its special core–shell structure and better dispersion. On this basis, different proportions of Cux@Pdy/C (x:y = 1:1, 1:2, 1:3, 1:4 and 1:5) catalysts were synthesized by the two-step strategy. The relationship between lattice strain, electron distribution and catalytic performance were explored by physical and chemical characterization. X-ray diffraction and X-ray photoelectron spectra analyses showed that the introduction of Cu lead to the lattice contraction and modified electronic structure of Pd. The electrochemical test showed that Cu@Pd3/C sample has the highest activity toward formic acid electro-oxidation. Its mass activity is about 3.3 times that of Pd/C catalyst that was synthesized by impregnation method (labelled as I-Pd/C). At the same time, the Cu@Pd3/C catalyst also demonstrated improved stability. The low-palladium catalyst with a Pd–Cu shell–core structure was synthesized by two-step method and has excellent catalytic activity and stability for formic acid electro-oxidation. [ABSTRACT FROM AUTHOR]

This work presents attempts to synthesize silver-doped copper nitride nanostructures using chemical solution methods. Copper(II) nitrate and silver(I) nitrate were used as precursors and the oleylamine as a reducing and capping agent. Homogeneous Cu3N/Ag nanostructures with a diameter of ~ 20 nm were obtained in a one-pot synthesis by the addition of the copper(II) salt precursor to the already-synthesized silver nanoparticles (Ag NPs). Synthesis in a two-pot procedure performed by adding Ag NPs to the reaction medium of the Cu3N synthesis resulted in the formation of a Cu3N@Ag nanocomposite, in which Ag NPs are uniformly distributed in the Cu3N matrix. The morphology, structure, and chemical composition of the obtained specimens were studied by TEM, XRD, XPS, and FT-IR methods, while optical properties using UV–Vis spectroscopy and spectrofluorimetry. The band gap energy decreased for Cu3N/Ag (Eg = 2.1 eV), in relation to pure Cu3N (Eg = 2.4. eV), suggesting the insertion of Ag atoms into the Cu3N crystal lattice. Additionally, Cu3N and Cu3N/Ag nanostructures were loaded on graphene (GNP) and tested as a catalyst in the oxygen reduction reaction (ORR) by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The Cu3N/Ag-modified GNP hybrid material revealed catalytic activity superior to that of Cu3N-based GNP hybrid material and pure GNP, comparable to that of a commercial Pt/C electrode. [ABSTRACT FROM AUTHOR]

The black TiO2 material was prepared by chemical reduction method, and the difference in structure and performance between black TiO2 and white TiO2 was discussed. At the same time, the effects of hydrogenation temperature and mass ratio factors on the formation and structure of black TiO2 were investigated. The results show that black TiO2 has a special structure: the existence of oxygen vacancies shortens the Ti–O bond, and the lattice shrinks. In addition, defects such as Ti3+ and Ti–OH are formed in the TiO2 crystal, which cause a disordered layer on the surface of the black TiO2 crystal. At the same time, the existence of defects such as oxygen vacancies and Ti3+ will make the valence and conduction bands of TiO2 appear tail bands. This greatly reduces the band gap and improves absorption. Considering the absorption effect and preparation cost comprehensively, the optimum conditions for the preparation of black TiO2 are that the hydrogenation temperature is 400 °C and the mass ratio of white TiO2 and NaBH4 is 2:1. [ABSTRACT FROM AUTHOR]

Nanozymes are nanomaterials that possess intrinsic enzyme mimicking activity. In this study, the application of silver nanoparticles coated filter paper (AgNPs/FP) that exhibits a peroxidase-like catalytic activity as a potential sensor is reported. A simple chemical reduction method was used to produce AgNPs/FP. The formation of the particles on filter paper were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and surface-enhanced Raman spectroscopy (SERS). In the presence of hydrogen peroxide, AgNPs/FP oxidized the colorless o-phenylenediamine (OPD) and 3,3′,5,5′-tetramethylbenzidine (TMB) solutions to a yellow colored 2,3-diaminophenazine (DAP) and deep blue colored oxidized TMB (oxTMB), respectively. In the presence of thiocyanate, however, the peroxidase-like activity was inhibited in a concentration dependent manner. This makes the AgNPs/FP a promising catalyst and employed for colorimetric detection of thiocyanate via inhibition of the peroxidase-like activity. The application can be further extended to other environmentally and biologically important analytes. [ABSTRACT FROM AUTHOR]

The article presents data on the synthesis and antimicrobial properties of guanidine-containing carboxymethylcellulose derivatives with different physical and chemical characteristics. The regularities of the reaction of nucleophilic substitution of the aldehyde groups of modified Na-carboxymethylcellulose (Na-CMC) by guanidine under different conditions have been studied. It has been found that the maximal replacement of reactive electrophilic groups by nucleophilic reagent depends on the pH value of the medium, molar ratio of guanidine, and the degree of oxidation of cellulose ester. The azomethine derivatives with different content of nitrogen-containing fragments in the polymer chain have been synthesized by varying the reaction conditions and the number of aldehyde groups in oxidized Na-CMC. Chemical reduction of labile azomethine bonds has led to water-soluble derivatives that contain strong amino-bound guanidine groups. The study shows and substantiates the influence of structural parameters (degree of substitution, quantitative guanidine content, pKα values, and nature of counterions) of macromolecular systems on antibacterial and antifungal properties. The developed approach to the synthesis opens up prospects for the creation of antimicrobial derivatives with regulated physical and chemical characteristics and specified biologically active properties. [ABSTRACT FROM AUTHOR]

Chemical reduction in an aqueous solution of a polymer is a relatively available method of synthesizing composites based on Cu/CuOx nanoparticles. The microstructure and composition of composites based on bimetallic Cu–Ni nanoparticles, obtained by chemical reduction in an aqueous solution of a polymer, have been studied by transmission electron microscopy, scanning transmission electron microscopy, and energy-dispersive X-ray microanalysis, in combination with X-ray diffraction (XRD) analysis. The investigations have been carried out for sol and dried powder; it is shown that the sol contains dendritic structures, composed of rounded polycrystalline nanoparticles 20–80 nm in size, which, in turn, consist of copper oxide crystallites. The powder, obtained after centrifugation and drying, consists of relatively large nanoparticle conglomerates more than 200 nm in size, which are composed of fcc-Cu and Cu2O crystallites, monoclinic CuO, and fcc-NiO. Cu2O and CuO particles generally occupy the inner and outer parts of nanoparticles, respectively. The obtained composites can be used as catalysts. The range of their application is wider than that of copper-based catalysts. [ABSTRACT FROM AUTHOR]

The main problem associated with the use of polylactides (PLAs) in various fields is the requirement for their controlled degradation in the composition of waste. However, the possibilities of biodegradation of PLAs have not been sufficiently studied. It is assumed that microorganisms can decompose a polymer only after its preliminary chemical hydrolysis and reduction of its molecular weight to 10 000 and less. This review examines the influence of various factors on the abiotic and biotic stages of the degradation of PLAs. Special attention is paid to the peculiarities of polymer biodegradation in the conditions of industrial composting as the most promising method of its processing as part of food waste. The microorganisms involved in the degradation of PLAs, as well as their enzymes, are shown. [ABSTRACT FROM AUTHOR]

The fine particles generated by the foundry industry are present in the atmosphere; they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics (CFD) software. In CFD, the Reynolds stress model was applied for simulation. The pressure magnitudes and velocity magnitudes are obtained by this simulation. The volume fraction of the dust was evaluated through the DPM approach. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow. [ABSTRACT FROM AUTHOR]

Flexible surface-enhanced Raman spectroscopy (SERS) substrates were produced by in situ chemical reduction of Ag+ on poly(vinyl alcohol)/chitosan (PVA/CS) nanofibers. PVA/CS nanofibers (which have a large number of amino and hydroxyl functional groups) were prepared by electrospinning, which can provide more sites for adsorbing Ag+ than pure PVA. The Ag nanoparticles were evenly distributed on the PVA/CS nanofibers. The SERS substrate also exhibited excellent water stability, sensitivity, and uniformity. The detection limit of probe molecule rhodamine 6G was 10−7 M and the relative standard deviation was 5%. In addition, the Ag–PVA/CS nanofibers substrate was effective for recognition and detection of norfloxacin, a well-known antibiotic that is pertinent to food safety and animal/human health. [ABSTRACT FROM AUTHOR]

New facile way for production of antimicrobial wound healing dress was achieved using freshly fabricated bacterial cellulose (BNC) decorated with in situ formed silver nanoparticles (AgNPs). Herein, BNC was fabricated by using a domestic isolated strain Komagataeibacter hansenii SA1.1. BNC/AgNPs nanocomposites were in situ synthesized by introducing AgNO3 to alkaline BNC at 60 °C for 30 min to attain full chemical reduction of Ag ions which manifested visually by color change. Results signified the successful fabrication of nanofibrillated BC with network structure. Also, AgNPs were successfully assembled on the surface of BNC in spherical shape with distribution uniformity consists of narrow size particles lied in range of 10–40 nm. The hybrid BNC/AgNPs manifested a strong antibacterial activity against Gram negative and Gram positive as well as unicellular fungus. The results from in vitro study demonstrated, undoubtedly, that BNC/AgNPs can be able to promote the wound healing affinity of chronic ulcers through reducing microbial infection besides accelerating the healing by their inflammatory. While, the antioxidant affirmed the potential protection of BNC/AgNPs from oxidative stressors, it was displayed a vital role in the improvement cell propagation and cell proliferation. [ABSTRACT FROM AUTHOR]

Metal/N-doped carbon (M/C–N) composites were prepared using the melamine-formaldehyde polymer (MFP) as a source of C–N carbon and a metal salt (Cu2+, Ni2+, Co2+) by two synthesis methods: (1) introduction of a metal salt by in situ polycondensation of melamine with formaldehyde followed by thermal treatment at 400, 500, and 700°C and (2) chemical reduction of metal cations in the presence of carbonized MFP. The phase compositions and morphology of the resulting composites were analyzed by X-ray diffractometry and electron microscopy. Their electrocatalytic properties were studied in the electrohydrogenation of acetophenone. The Cu/C–N composites prepared by method 2 showed higher electrocatalytic activity due to the additional reduction of copper cations in the electrochemical system. The synthesis of composites by method 1 and their thermal treatment led to the formation of metal oxides and their reduced forms, lying mostly inside the carbon matrix of the carbonized MFP. [ABSTRACT FROM AUTHOR]

Gold nanomaterials have received much attention in sensing due to their unique optical and electronic properties. This article briefly summarized the synthesis, property of gold nanomaterials before focusing on their application to sensing. The synthesis of three major types of gold nanomaterials is discussed: gold nanoclusters, which are synthesized by templated method, and gold nanoparticles, which are synthesized by chemical reduction methods, and gold nanorods, which are synthesized by the seed-mediated method. More methods affecting nano properties are discussed. Properties of these gold nanomaterials are usually connected to their application. Their fluorescent, photoluminescent, chemiluminescent, electrochemiluminescent, and catalytic properties are what give them potential in sensing. For the further application of gold-based nanomaterials in sense, the author suggests that more research needs to be done on understanding their properties and surface functionalization which provide greater selectivity and sensitivity in sense. Moreover, new detection techniques need to be developed to improve detection accuracy and reduce operational complexity. [ABSTRACT FROM AUTHOR]

In this study, the Cu–Mo–B catalyst in nanostructure was successfully synthesized with the chemical reduction method of sodium borohydride (NaBH4). The categorization of the attained Cu–Mo–B nano-catalyst was examined with XRD, BET, SEM, and EDS analytical methods. As a result of the ammonium borane hydrolysis of this attained catalyst, the most convenient Mo/Co ratio, NaOH impact, the impact of different catalyst amounts, and the impact of different ammonium borane concentrations on ammonium boron hydride hydrolysis were examined. In addition, hydrolysis was examined at different temperatures, and the degree and activation energy of the reaction were determined. At 333 K with the ammonium borane (AB) hydrolysis of Cu–Mo–B nanoparticles, the maximum hydrogen production rate and activation energy were found to be 4075 mL min−1gcat−1 and 21.37 kJ mol–1, respectively. In this context, Cu–Mo–B catalyst can be used in practical fuel cells since it is obtained economically and easily. [ABSTRACT FROM AUTHOR]

The supported Ni-B/KIT-6 amorphous alloy catalyst was prepared by chemical reduction method for the hydrogenation reaction of α-pinene. The catalyst was characterized by XRD, BET, SEM–EDS, TEM, XPS, ICP and DLS, the influences of single factor of catalyst on its structure, morphology and performance were investigated and analyzed. It was found that the amount of Ni loading, preparation pH and B/Ni molar ratio had great effects on the reduction amount, dispersion and specific surface area of the catalyst, resulted in affecting the catalytic performance of the catalyst. The optimum synthesis conditions were at m(Ni2+)/m(KIT-6) = 1:3, pH 13 and n(B)/n(Ni) = 1.5, obtaining a 90.62% conversion of α-pinene and 97.67% selectivity of cis-pinane. In addition, the catalysts also exhibited better repeatability and stability. [ABSTRACT FROM AUTHOR]

A facile in-situ chemical reduction and self-assembly method was developed to prepare graphene fibers with silver nanoparticles (GFs@Ag). Inside the prepared composite fibers, Ag nanoparticles with sizes of about 50 nm homogeneously dispersed on the graphene sheets through scanning electron microscope (SEM) characterization. The obtained GFs@Ag exhibited excellent tensile mechanical performance with high mechanical strength, which was up to 83.7 MPa. [ABSTRACT FROM AUTHOR]

In this study, TiO2-supported Ni-Mo-Ru–B (TiO2@Ni-Mo-Ru–B) catalyst was synthesized by chemical reduction method for hydrogen production from the hydrolysis of potassium borohydride (KBH4) solution. The characterizations of the synthesized catalysts were carried out with BET, XRD, and SEM. In hydrolysis experiments, the effects of parameters such as KOH concentration, KBH4 concentration, catalyst amount, metal/TiO2 ratio, and temperature on hydrogen production rate were investigated. The optimum metal/TiO2 ratio was determined as 10% and the hydrogen production rate of the catalyst at 30 °C was calculated as 2410.28 mL/min.gcat. In addition, the reaction rate order was found to be 0.8 (nth order); accordingly, the value of the activation energy was obtained from the Arrhenius equation as 51.807 kJ/mol. [ABSTRACT FROM AUTHOR]

Chemical aspects of reduction of natural topaz Al2SiO4[F1,3(OH)0,7] are studied. It is shown that with a weight ratio of Al:topaz = 0.24 corundum synthesis is completed in one stage (780 – 1200°C) without formation of intermediate mullite. Production parameters of topaz aluminothermal processing are selected that make it possible to convert up to 84% of aluminum from a charge into fused corundum with 98.6 wt.% Al2O3 and up to 24% of silicon into high-purity product. [ABSTRACT FROM AUTHOR]

Nickel nanoparticles are an attractive ingredient for preparing metal-based conductive pastes. In particular, using a mixture of nanoparticles containing two different particle sizes as the paste fillers is an effective way to improve the microstructure as well as the electrical conductivity of the printed films after sintering. This study presents a facile solvent-directed chemical reduction method for the synthesis of nickel nanoparticles with bimodal size distribution in one-pot. Through simply adjusting the volume ratio of alcohol (methanol, ethanol or n-propanol) to water and nickel precursor concentration in a mixed solvent system (alcohol and water), the size and size distribution of the synthesized nickel nanoparticles could be controlled. The bimodal nickel nanoparticles obtained at a volume ratio of methanol to water of 2 were used as fillers for a screen-printing paste. After sintering at a temperature of 600 ℃, the printed film exhibited a compact structure with a relatively low volume resistivity of 167.3 µΩ∙cm. [ABSTRACT FROM AUTHOR]

The fine particles generated by the foundry industry are present in the atmosphere; they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics (CFD) software. In CFD, the Reynolds stress model was applied for simulation. The pressure magnitudes and velocity magnitudes are obtained by this simulation. The volume fraction of the dust was evaluated through the DPM approach. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow. [ABSTRACT FROM AUTHOR]

The water pollution currently constitutes a severe threat to our living life, and MOF (metal–organic framework)-based photocatalysts offer an efficient route to clean various water pollutants in an eco-friendly manner. Integration of metal nanoparticles (MNPs) with photoactive MOFs has proven an effective way to further boost the photocatalytic performance. In this work, Ag/UiO-66-NH2 composites (UiO = University of Oslo) have been facilely assembled in two steps involving first wet impregnation of AgNO3 into UiO-66-NH2 followed by chemical reduction with NaBH4. Benefited from the built-in heterostructure that can promote both the electron–hole separation, and the absorption of the visible-light, Ag/UiO-66-NH2 composites exhibited an enhanced photocatalytic performance than the pristine UiO-66-NH2 towards photodegradation of RhB (Rhodamine B) dye under the irradiation of UV–Visible light. About 96% of RhB can be degraded by Ag/UiO-66-NH2 in a period of 40 min. Besides, Ag/UiO-66-NH2 demonstrated a good recycling stability which showed an only slight drop in the dye photodegradation efficiency after three consecutive runs. The current work suggests that Ag/UiO-66-NH2 composites have a great potential in practical application toward water remediation. [ABSTRACT FROM AUTHOR]

The synthesis process of reduced graphene oxide (rGO) sheets generally requires the printing of graphene oxide (GO) as a first step and later its reduction through a chemical or thermal route to get the required rGO in the second step. The present work demonstrates the printing of rGO using 0.1% w/v dispersion of GO in water in a single-step process. The method uses the nascent electrochemical additive manufacturing, which allows for non-template-based deposition of microscopically patterned systems. The samples are deposited at 1, 3, and 5 V at 0.1 mm s−1 printing speed. Deposited rGO is characterized using XRD, Raman, and FTIR for various qualitative and quantitative aspects. The surface morphology and topographical studies are performed using SEM and AFM techniques. The RMS roughness calculated using the AFM results, ranging from 5.7 nm to 15.3 nm for 1 to 5 V, indicates the trend of increasing roughness with the deposition potential. The XAS spectroscopy data show that the sample printed at 5 V has the highest purity rGO. The capacitive behaviour of the as-deposited rGO has also been discussed and contrasted with the rGO deposited using other prevalent methods. The specific capacitance of the micro capacitor was found up to 10.84 F g−1 with coulombic efficiencies for 500 cycles at 0.2 A g−1. [ABSTRACT FROM AUTHOR]

The homeostatic control of Sodium (Na+) ion in the human body assumes paramount relevance owing to its physiological importance. Any deviation from the normal level causes serious health problems like hypernatremia, hyponatremia, stroke, kidney problems etc. Therefore, quantification of Na+ levels in body fluids has significant diagnostic and prognostic importance. However, interfering ions like Potassium ion (K+) is the major hurdle in sodium detection. In this work, we synthesized the clusters of 3–9 nm-sized highly stable and pure Copper nanoparticles surface functionalised with curcumin, through chemical reduction method. Each cluster of particles is encapsulated in a curcumin layer which is clearly visible in TEM images. The results show that these curcumin functionalized Cu NPs (CuC) are highly selective to the colorimetric detection of Na+. The ions like K+, Mg2+ and Zn2+ did not interfere with the Na+ in this sensing technique. Low-cost paper-based sensor strips are fabricated and calibrated for the sensing of sodium in the physiological range and shade cards were developed as a calorimetric guide for estimation of Na+ which makes them ideal point of care diagnostic platform. We demonstrate that the proposed CuC paper strip can be used for detecting Na+ concentration within the whole physiological range in both blood serum and urine. [ABSTRACT FROM AUTHOR]

This study focused on the reduction of chemical oxygen demand (COD) from gas refinery wastewater via copper oxide nanoparticles which loaded on activated carbon supplied from Terminalia catappa (CuO-NPs-TCW-AC), while accordingly understudy process was accelerated by decomposition of organic pollutants in the presence of H2O2 as oxidant. CuO-NPs-TCW-AC as heterogeneous catalyst in the combination of H2O2 lead to generating OH radical as most efficient species degradation of organic pollutants (it is expected that copper ions also exhibited somewhat Fenton-like behaviors). TCW-AC prepared by carbonization at 850 °C for 90 min and subsequently was activated with CO2 at 900 °C for 90 min and TCW-AC as the final product was oxidizing with nitric acid and hydrochloric acid solution. Characterization of adsorbent and investigation of mechanism process were undertaken by FT-IR (before and after COD removal), pHZPC, Boehm's titration method, SEM, XRD, BET, and BJH. Conduction of preliminary experiments reveals that setting experimental condition at their optimum values including 0.06 g of the CuO-NPs-TCW-AC, pH of 4 and 0.1 mol L−1 of H2O2 at 75 °C following 5 min agitation at speed of 400 rpm leads to 61.5% reduction of initial COD (320 ppm) from gas refinery wastewaters. According to the coefficients of determination (R2) for Langmuir (0.985), Freundlich (0.993) and Temkin isotherm (0.981) reveal cooperative mechanism on whole adsorption/decomposition process, while its experimental and calculating maximum adsorbent capacity were 250.1, 263.2 (mg g−1), respectively. Judgment based on correlation coefficients represents an agreement among experimental and predicted adsorption capacity and confirms that understudy COD reduction using CuO-NPs-TCW-AC follows the second-order kinetics. The negative Gibbs free energy strongly support the high tendency of present material for COD through spontaneous while, higher adsorption rate by temperature rising confirm the endothermic nature of the process. As a result, the application of CuO-NPs-TCW-AC in the combination of H2O2 is suggested as a powerful tool for COD reduction from gas refinery wastewater. [ABSTRACT FROM AUTHOR]

Aggregatively stable, positively charged (~45 mV) chitosan-Ag nanocomposites with a spherical shape and size up to 60.0 nm were synthesized by the "green chemistry" method via the chemical reduction of silver nitrate with chitosan. Chitosan-Ag/ceftriaxone and chitosan-Ag/cefotaxime complexes containing up to 1.06 ± 0.01 and 1.29 ± 0.03 mg antibiotic/mg chitosan-Ag respectively were obtained. It was found that an increase in the ceftriaxone : chitosan-Ag weight ratio in the reaction mixture from 0.5 to 1.25 leads to an increase in the efficiency of antibiotic binding to nanoparticles from 7.2 ± 0.2 to 71.7 ± 0.2%. With an increase in the cefotaxime : chitosan-Ag ratio in the reaction mixture from 0.5 to 10, the antibiotic binding efficiency decreases from 66.2 ± 1.5 to 13.0 ± 0.7%. The formation of chitosan-Ag/antibiotic complexes was confirmed by infrared (IR) spectroscopy. The effectiveness of the use of the chitosan-Ag/cefotaxime complexes against antibiotic-resistant strains of Escherichia coli and Staphylococcus aureus was established. [ABSTRACT FROM AUTHOR]