Liquid Phase Chemical Reduction Method Research Articles

Synthesis of an innovative SF/NZVI catalyst and investigation of its effectiveness on bio-oil production in liquefaction process alongside other parameters

Today, new energy sources alternative to fossil fuels are needed to meet the increasing energy demand. It is becoming increasingly important to constitute new energy sources from waste biomass through the liquefaction process. In this study, walnut shells (WS) were liquefied catalytically and non-catalytically under different parameters using the liquefaction method. In this process, the effect of silica fume/nano zero-valent iron (SF/NZVI) catalysts on the conversion rates was investigated. The catalyst was synthesized by reducing NZVI using a liquid phase chemical reduction method on SF. The SF/NZVI catalyst was characterized by scanning electron microscopy- energy dispersive X-ray (SEM–EDX), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. The effect of various process parameters on the liquefaction process was investigated. In this context, the reaction temperature ranged from 300 to 400 °C, the solid/solvent ratio ranged from 1/1 to 1/3, the reaction time ranged from 30 to 90 min, and the catalyst concentration ranged from 1 to 6%. According to the results obtained, the most suitable operating conditions for non-catalytic experiments in liquefaction of WS were found to be temperature of 400 °C, reaction time of 60 min, and solid/solvent of 1/3. In catalytic conditions, the optimum values were obtained as temperature of 375 °C, reaction time of 60 min, solid/solvent ratio of 1/3, and catalyst concentration of 6%. The highest total conversion and (oil + gas) % conversion were 90.4% and 46.7% under non-catalytic conditions and 90.7% and 62.3% under catalytic conditions, respectively. Gas chromatography/mass spectrometry (GC/MS) analysis revealed the bio-oil was mainly composed of aromatic compounds (benzene, butyl-, indane and their derivatives,) and polyaromatic compounds (naphthalene, decahydro-, cis-, naphthalene, 1-methyl-.). The aim of increasing the quantity and quality of the light liquid product in the study has been achieved.

TEMPO oxidized cellulose nanocrystal (TOCNC) scaffolded nanoscale zero-valent iron (nZVI) for enhanced chromium removal

The conventional carboxymethyl cellulose (CMC) stabilization hampered available active sites of adsorption and reduction, due to irregular shape of nanoscale zero-valent iron (nZVI) particles with augmented average size and passivated surface, leading to insufficient removal and poor resistance against complex environmental conditions. Herein, we presented (2,2,6,6-Tetramethylpiperidine-1-oxyl)-mediated (TEMPO-mediated) oxidation of cellulose nanocrystal (TOCNC) scaffolded nZVI (nZVI@TOCNC) with enhanced efficiency for chromium removal in comparison with CMC stabilized nZVI (nZVI@CMC). The anchoring of nZVI at the functional sites of TOCNC was initiated by liquid-phase chemical reduction method. The nZVI@TOCNC showed improved nZVI distribution with uniform particle size and thinner shell (∼1 nm). Characterizations using FT-IR, XPS and XRD demonstrated that bindings between TOCNC and nZVI were through hydrogen bonds, electrostatic attractions, coordination-covalent bonds and bidentate chelation. TOCNC with shorter branch-chain (–COC–) surrounding the nZVI could potentially form a porous and compact “mesh” to rigidly encapsulate nZVI, while CMC wrapped around nZVI in the way of traditional polymeric stabilizers. Thus, 0.5 g/L nZVI@TOCNC achieved 99.96% Cr (Ⅵ) removal efficiency (20 mg/L) at pH = 7 and the removal capacity were up to 55.86 mg/g. The nZVI@TOCNC consistently presented higher removal efficiency than nZVI@CMC under wide pH range (3–7). Cr (Ⅵ) was reduced to Cr (Ⅲ) by nZVI@TOCNC with deposition of CrxFe1-x (OH)3 and Cr2O3. The predominant mechanisms of removal probably consisted of electrostatic attractions, reduction, co-precipitation and surface complexation. The pseudo-second-order kinetic model well-fitted the sorption kinetic, indicating TOCNC scaffold stabilized nZVI for efficient reduction of Cr (Ⅵ) through multi-layer adsorption. As a template and delivery carrier, TOCNC shows promising potential to further improve the capability and practice of nZVI for in situ treatment of industrial waste water with heavy metal pollution.

Impurity-driven simultaneous size and crystallinity control of metal nanoparticles

Both the size and crystallinity should be optimized for practical applications utilizing metallic nanoparticles because they strongly influence the nanoparticles property. Herein a liquid phase chemical reduction method controls the defects (crystallinity) in metallic Cu nanoparticles simply and easily. Although the addition of an impurity substance, which cannot be thermodynamically alloyed with Cu, reduces the crystallinity of synthesized Cu nanoparticles, it also affects the deposition behavior, and consequently, the nanoparticle size changes unexpectedly. Therefore, a precise control of the synthesis condition is required to synthesize the nanoparticles having optimal size and crystallinity. To clarify the nanoparticle formation mechanism in an impurity-containing solution, the catalytic activity of the reductant and the redox potential change due to the metastable product are electrochemically evaluated to reveal the correlation between nanoparticle formation behavior and synthesis condition. Finally, the synthesis of two types of Cu nanoparticles, which have similar sizes but different crystallinities is demonstrated. This simple nanomaterial design approach to control the crystallinity and the interpretation of the deposition process in an impurity-containing condition should be widely applicable to metallic nanoparticle syntheses.

Light Weight, Flexible and Ultrathin PTFE@Ag and Ni@PVDF Composite Film for High-Efficient Electromagnetic Interference Shielding.

Dopamine was used to modify polytetrafluoroethylene (PTFE) in order to obtain functional polydopamine (PDA) surface-modified PTFE microporous film (PTFE@PDA). Ag was deposited on the surface of PTFE@PDA using electroless plating in order to obtain Ag-wrapped PTFE@PDA film (PTFE@Ag). A liquid-phase chemical reduction method was employed to prepare nickel nanochains. A Ni@PVDF cast film was obtained by mechanically blended nickel nanochains and polyimide (PVDF). The above two films were hot pressed to give a flexible, ultra-thin, and highly effective electromagnetic shielding composite film with a "3+2" layered structure. IR, XRD, and TEM results showed the PTFE@PDA film surface was coated by a tight plating layer of Ag particles with a particle size of 100~200 nm. PTFE@Ag+Ni@PVDF composite film exhibited excellent electromagnetic shielding effectiveness, with the conductivity of 7507.5 S/cm and the shielding effectiveness of 69.03 dB in the X-band range. After a 2000-cycle bending, this value still remained at 51.90 dB. Furthermore, the composite film presented excellent tensile strength of 62.1 MPa. It has great potential for applications in flexible and wearable intelligent devices.

Platinum-Tellurium Alloy Metallene Toward Formic Acid Oxidation Reaction

Open AccessRenewablesRESEARCH ARTICLES14 Jan 2023Platinum-tellurium alloy metallene towards formic acid oxidation reaction Ya-Nan Li, Qing-Ling Hong, Bo-Qiang Miao, Tian-Jiao Wang, Yu Ding and Yu Chen Ya-Nan Li Google Scholar More articles by this author , Qing-Ling Hong Google Scholar More articles by this author , Bo-Qiang Miao Google Scholar More articles by this author , Tian-Jiao Wang Google Scholar More articles by this author , Yu Ding Google Scholar More articles by this author and Yu Chen Google Scholar More articles by this author https://doi.org/10.31635/renewables.022.202200005 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Engineering the composition and/or morphology is highly effective strategy for enhancing the electrocatalytic performance of noble metal nanocrystals. Recently, metallenes with specific chemical and physical properties have attracted increasing attention in electrocatalysis field. In this work, two-dimensional ultrathin platinum-tellurium alloy metallene (PtTe A-ML) is synthesized by using a conventional liquid-phase chemical reduction method. The high atom utilization as well as alloy effect endow PtTe A-ML with preeminent electrocatalytic activity for the formic acid oxidation reaction (FAOR). Specifically, the direct oxidation pathway of FAOR can be completely achieved at PtTe A-ML, which suppresses the production of toxic carbon monoxide (CO) intermediates and improves the reaction kinetics of FAOR. Accordingly, the FAOR activity of PtTe A-ML in acidic media is 43 and 5.6 times higher than that of commercial Pt and Pd nanocrystals, respectively. Meanwhile, PtTe A-ML exhibits also excellent electrocatalytic activity for CO oxidation reaction because of the introduction of oxygenophilic Te atoms and electron transfer between Pt and Te, which elevates the durability of PtTe A-ML for FAOR. The study provides a simple synthesis strategy of PtTe A-ML and shows PtTe A-ML has a promising practical prospect in direct formic acid fuel cells. Download figure Download PowerPoint Next article FiguresReferencesRelatedDetails Issue AssignmentNot Yet AssignedSupporting Information Copyright & Permissions© 2023 Chinese Chemical Society Downloaded 4 times PDF downloadLoading ...

Simultaneous fluorescence sensing of vitamin B2 and sulfur ions based on fluorescent copper nanoparticles

In this study, the F-CuNPs were synthesized by a modified liquid-phase chemical reduction method. Throughout the preparation process, anhydrous copper sulfate was used as the copper source, and ascorbic acid in the NaOH solution served as the reducing and protective agent. Förster resonance energy transfer (FRET) may exist between F-CuNPs and vitamin B2 due to the large spectral overlap between the fluorescence emission spectra of F-CuNPs and the UV–vis absorption spectra of vitamin B2. Therefore, the detection of vitamin B2 was designed based on a FRET system between F-CuNPs and vitamin B2. With S2− into the F-CuNPs&VB2 system, the fluorescence intensity of vitamin B2 was quenched, while the fluorescence intensity of F-CuNPs was almost unchanged. There may be a specific reaction between S2− and vitamin B2. Therefore, the research system can be further used to detect S2− based on ratiometric fluorescent probe. The research findings show that the linear range of vitamin B2 was 0.51 nM–34.64 nM with a detection limit of 0.25 nM (S/N = 3), the linear range of S2− was 0.64 μM–60.00 μM with a detection limit of 0.32 μM (S/N = 3). Furthermore, the simultaneous fluorescent sensing system has high sensitivity and selectivity. Therefore, this system was designed and successfully used to detect the content of vitamin B2 and S2− in actual samples to find a new effective method to detect analytes.

Characterization of silver nanoparticles loaded chitosan/polyvinyl alcohol antibacterial films for food packaging

Sliver nanoparticles (AgNPs) were loaded on chitosan (CS) and incorporated into polyvinyl alcohol (PVA) to develop novel active food packaging films. AgNPs were fabricated by liquid phase chemical reduction method using CS and sodium citrate friendly reductant of AgNO3. The silver we prepared was found to be nanoscale by transmission electron microscopy (TEM) and AgNPs were homogeneously dispersed in the matrix by scanning electron microscopy (SEM). The composite film exhibited excellence mechanical properties with tensile strength of 49.97 MPa and elongation at break of 275.90%. When the concentration of AgNPs was 0.019% (w/w), the diameter of filter paper was 5.00 mm and the inhibition zone against Escherichia coli reached 16.07 mm at 37 °C for 8 h. The water vapor permeability and water solubility of the Ag@CS/PVA films decreased with the incorporation of AgNPs, and this was beneficial for food preservation. Especially, Ag@CS/PVA films could reduce the weight loss of strawberries and avoid microbial infection at 25 ± 1 °C and 50 ± 5% RH. Benefiting for good mechanical properties, antibacterial property, flexibility and high transparency, Ag@CS/PVA films showed its great potential in fruit storage and transportation application.

Reduced graphene oxide-supported ruthenium nanocatalysts for highly efficient electrocatalytic hydrogen evolution reaction

Hydrogen energy has received great attention because of its advantages such as large energy density and not producing carbon dioxide, and it is currently considered to be one of the most valuable green energy sources. Therefore, the development of efficiently hydrogen production is of great importance. Hydrogen production from water electrolysis has large application prospects due to its cleanliness and no pollution. However, how to prepare an efficient, stable and low-cost electrocatalyst for this process is still challenging. Here, we develop a reduced graphene oxide-supported ruthenium (Ru) nanoparticle electrocatalyst synthesized by a simple method. The ruthenium precursors are encapsulated and isolated with N,N-dimethylformamide (DMF) (Ru3+-DMF), which effectively inhibits the further agglomeration growth of ruthenium. After Ru3+-DMF being loaded on graphene oxide, Ru is supported on reduced graphene oxide (Ru/rGO) by the liquid phase chemical reduction method and the remaining organic solvent could be removed by calcination to form a well-dispersed Ru-based electrocatalyst. Ru/rGO shows excellent electrocatalytic activity and long-term stability for hydrogen evolution reaction (HER). In a solution of 1.0 M KOH, the overpotential of 3.0 wt%Ru/rGO for the HER at 100 mA cm−2 is only 111.7 mV, and the Tafel slope is 31.5 mV dec−1. It exhibits better HER performance compared to commercial Pt/C and other Ru/rGO catalysts with different Ru loadings. The work could give a new strategy for the synthesis of efficient electrocatalysts.

Nanomaterials in Sports Training and Its Biological Safety

Nanomaterials have many special functions. Sports field provides a platform for nanomaterials to show their excellent performance. At the same time, nanomaterials in the body may also have negative effects on cells, lung tissue, liver and kidney tissue, and brain tissue; there are certain biological safety risks. Based on the above background, this article studies the application and biological safety of nanomaterials in sports training. In this article, silver nanoparticles were prepared by improved liquid-phase chemical reduction method and photochemical reduction method. The antibacterial properties of silver nanoparticles with different concentrations and sizes were tested and characterized, and the possible antibacterial mechanism was speculated. Nanosilver refers to the metallic silver element with the particle size to the nanoscale. The acute toxicity test and hemolytic test were carried out on the safety of silver nanoparticles. In the acute toxicity test, when 100 μL nanosilver solution was added, the visceral weight, body weight, and tissue sections of mice were almost not affected; in terms of biochemical indexes, all biochemical indexes returned to normal when the injection volume was 0.1 μL. The results show that nanosilver still has certain influence on biochemical indexes at high dose. How to reduce the influence will be one of the key work in the future. In addition, hemolysis test showed that no hemolysis occurred when nanosilver solution was injected at 2.77 μL. This will lay a foundation for the use of nanosilver sportswear in direct contact with human blood in the future.

Fabrication of Silver Electrical Circuits on Textile Substrates by Reactive Inkjet Printing

Delivery of electronic functionality such as sense and response to the human body using smart textiles is important for developing wearable electronics. As the key component of connecting various devices in smart textiles, electrical circuit with excellent electrical performance is an essential effort for ongoing research in textronics. In this work, a new liquid phase chemical reduction method combined with inkjet printing technology for fabricating electrical circuits on textile substrates is adopted. The aqueous silver nitrate is ejected spot by spot onto textiles that are wetted with ascorbic acid solution and placed on the copper foil. After redox and replacement reactions, silver particles are deposited to form conductive layer for electrical circuits. Deposited layers of silver with high conductivity up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${0.86201}\times {10}^{{6}}$ </tex-math></inline-formula> S/m and the sheet resistance in the range 0.0116- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.06913~\Omega $ </tex-math></inline-formula> /sq. Based on these findings, we realized the textile capacitive sensor with good response time, and stability for 1500 cycles of repeated loading. The fabricated textile electrocardiogram (ECG) electrode attached to braces could be effective for human heart rate and ECG signal monitoring.

The synthesis of biochar-supported nano zero-valent iron composite and its adsorption performance in removal of malachite green

The new composite material was synthesised bonding nano zero-valent iron (NZVI) with liquid-phase chemical reduction method on the support material obtained by carbonising the organic waste mandarin peel, and the surface characteristics of it were determined by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and zero point of charge (pHzpc). The effectiveness of the composite as an adsorbent in the removal of malachite green (MG) was investigated with different parameters. Equilibrium data were employed to different adsorption isotherms used in aqueous solutions, and the most suitable isotherm was found as Freundlich isotherm with the highest R2 =0.999 and the lowest chi-square (χ2) and residual root-mean-square error (RMSE) values. The maximum adsorption capacity was 909.09 mg/g according to Langmuir isotherm. When the kinetic data were analysed, the most appropriate kinetic model was determined as pseudo-second-order with the lowest χ2 and RMSE and the highest R2 (≥0.987) values. The adsorption process was carried out as endothermic (∆H°=145.79 kJ/mol) and spontaneously (∆G°≤−2.89kJ/mol) according to thermodynamic parameters. Also, it was possible to say that the irregularity at the adsorbent-adsorbate interface increased due to positive entropy. NZVI/carbonised mandarin peel (CMP) with high adsorption capacity could be used effectively to remove many industrial wastes.

Preparation of nanoscale zero-valent iron and its application in coking wastewater treatment

Nanoscale zero-valent iron (NZVI) was prepared by liquid phase chemical reduction method. The nanoparticles were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of prepared three nanoscale materials was evaluated by degrading coking wastewater. Optimal experiments involved the effects of water sample initial pH and Fe/C of NZVI on COD removal efficiencies were also investigated. It indicated that NZVI showed more excellent COD removal efficiencies. Under the optimal condition of dosage 1 g in 300 mL wastewater, Fe/C 1:1, pH 4, 120-min reaction time, the COD removal rate by NZVI could reach 67%.

A novel nitrogen-deficient g-C3N4 photocatalyst fabricated via liquid phase reduction route and its high photocatalytic performance for hydrogen production and Cr(VI) reduction

A facile liquid phase chemical reduction method was developed to synthesize nitrogen-deficient graphitic carbon nitride (FH-g-C3N4) by application of the weak reducibility of formaldehyde in weak acidic solution. The nitrogen defects in g-C3N4 were confirmed by EA, EPR, XPS and EDS. The extra electrons in nitrogen-deficient sites can easily capture photogenerated holes and reduce the recombination of photogenerated electrons and holes. With appropriate amount of nitrogen defects, FH-g-C3N4 possesses the best photocatalytic activity which is 58% higher than that of H-g-C3N4 (without nitrogen defects) and P25 (TiO2) for Cr(VI) reduction, and its hydrogen production rate is twice of the H-g-C3N4. Compared with H-g-C3N4, FH-g-C3N4 has a stronger light absorption capacity, a more negative potential of conduction band, and a stronger reduction capacity. This work could provide significant information for the simple synthesis of nitrogen-deficient g-C3N4 photocatalyst with distinct reduction performance.

Green synthesis of silver nanoparticles from Lonicera japonica leaf extract and their anti‐inflammatory and antibacterial effects

A green synthesis of silver nanoparticles (AgNPs) using aqueous Lonicera japonica leaf extract (AgNPs-LLJ) was reported and their anti-inflammatory and antibacterial effects were investigated. In comparison, AgNPs were also synthesised using the liquid phase chemical reduction method (AgNPs-N2H4·H2O). The synthesised AgNPs were identified using multiple analytical techniques. The results showed that both AgNPs were spherical particles with an average particle size of 20–30 nm for AgNPs-LLJ and 10–20 nm for AgNPs-N2H4·H2O. The anti-inflammatory ability of AgNPs was shown by the effective inhibition against 5-lipoxygenase with IC50 values of 5.08 μg/mL for AgNPs-LLJ and 59.12 μg/mL for AgNPs-N2H4·H2O, indicating that AgNPs-LLJ had much more obvious anti-inflammatory effect. Furthermore, the cytotoxicity research on RAW264.7 mouse macrophages showed that AgNPs-LLJ had no cytotoxicity at the concentration of 40 μg/mL compared with control. Their antibacterial effects on Escherichia coli (EC) and Staphlococcus aureus (SA) were studied by agar well diffusion method. The maximum antibacterial circles of AgNPs-N2H4·H2O on EC and SA were 15 and 14 mm, respectively, whereas it was 5.0 and 5.0 mm for AgNPs-LLJ, respectively. The authors conclude that AgNPs-LLJs have a potential to be a nanomedicine for nanobiomedical applications.

Polyaniline/attapulgite-supported nanoscale zero-valent iron for the rival removal of azo dyes in aqueous solution

In this paper, polyaniline/attapulgite (PANI/APT)-supported nanoscale zero-valent iron (nZVI) composites were synthesized by liquid-phase chemical reduction method and used for the removal of two kinds of dyes. The structure of as-prepared nZVI/PANI/APT was characterized by various test methods. The removal property and degradation mechanism for azo (alizarin yellow R, methyl red, chrome black T, methyl orange) and non-azo (methylene blue, rhodamine B) dyes in aqueous solution were investigated. The presence of PANI/APT can decrease the aggregation of nZVI particles with maintenance of reactivity and improving adsorption capacity for degradation azo dye. The experiment results showed that the removal property of the composite materials on azo dyes is obviously better than that on non-azo dyes. The varying removal efficiencies of dyes depend on the different degradation mechanisms. Azo dyes removal by nZVI/PANI/APT was mainly due to the reductive cleavage of the N = N of nZVI, while non-azo dyes removal mainly contributes to the adsorption of PANI/APT. The study demonstrated that nZVI/PANI/APT has potential applications for the removal of azo dyes from wastewaters.

SiO2-stabilized Bi nanoparticles: A high active and stable visible light photocatalyst

A SiO2-coated Bi nanoparticle structure in 40–60 nm with high activity and stability was designed by a liquid phase chemical reduction method. The effect of SiO2 layer on high active Bi nanoparticles was studied by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and thermo-gravimetric and differential thermal analysis characterizations. The SiO2 layer effectively enhanced the stability of Bi core without having negative effect on its activity. The as-prepared Bi@SiO2 nanoparticles showed high activity and recycling stability both in photocatalytic degradation of pollutant (rhodamine B and bisphenol A, respectively) and hydrogen exhalation reaction (HER). The photocatalytic degradation mechanism of Bi@SiO2 nanoparticles under visible light irradiation was discussed. The porous structure of SiO2 layer performed transport channel for electrons and active species, and enhanced the plasmonic photocatalytic effect of Bi.

Efficient Synthesis of Furfuryl Alcohol from H2-Hydrogenation/Transfer Hydrogenation of Furfural Using Sulfonate Group Modified Cu Catalyst

A copper-based catalyst, which was supported by sulfonate group (−SO3H) grafted active carbon (AC), was prepared and activated simultaneously by liquid phase chemical reduction method. The modified copper catalyst, Cu/AC–SO3H, displayed an enhanced catalytic performance for selective hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) in liquid phase, in which almost 100% FOL yield was obtained at 378 K and 0.4 MPa of hydrogen pressure after 120 min reaction. The effect of −SO3H was evaluated and illustrated by the combination of reaction performance and physicochemical characterizations, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectrometer (XPS) measurements. Through grafting sulfonate group on the support, better dispersion of nanoparticles, higher reduction degree of Cu, and stronger adsorption of FAL can be attained to contribute high hydrogenation performance. In addition, the effects of reaction conditions (such as reaction temp...

Kinetics of Solvent Blue and Reactive Yellow removal using microwave radiation in combination with nanoscale zero-valent iron

We investigated the efficiency and kinetics of the degradation of soluble dyes over the pH range 5.0–9.0 using a method employing microwave radiation in combination with nanoscale zero-valent iron (MW–nZVI). The nZVI particles (40–70nm in diameter) were prepared by a liquid-phase chemical reduction method employing starch as a dispersant. Compared to the removal of Solvent Blue 36 and Reactive Yellow K-RN using only nZVI, more rapid and efficient dye removal and total organic carbon removal were achieved using MW–nZVI. The dye removal efficiency increased significantly with decreasing pH, but was negligibly affected by variation in the microwave power. The kinetics of dye removal by MW–nZVI followed both an empirical equation and the pseudo first-order model, while the kinetics of dye removal using nZVI could only be described by an empirical equation. It was also concluded that microwave heating of the dye solutions as well as acceleration of corrosion of nZVI and consumption of Fe(II) were possible reasons behind the enhanced dye degradation.

Preparation and Characterization of Silver Liquid Thin Films for Magnetic Fluid Deformable Mirror

Silver liquid thin film, formed by silver nanoparticles stacking and spreading on the surface of the liquid, is one of the important parts of magnetic fluid deformable mirror. First, silver nanoparticles were prepared by liquid phase chemical reduction method using sodium citrate as reducing agent and stabilizer and silver nitrate as precursor. Characterization of silver nanoparticles was studied using X-ray diffractometer, UV-vis spectrophotometer, and transmission electron microscope (TEM). The results showed that silver nanoparticles are spherical and have a good monodispersity. Additionally, the effect of the reaction conditions on the particle size of silver is obvious. And then silver liquid thin films were prepared by oil-water two-phase interface technology using as-synthesized silver nanoparticles. Properties of the film were investigated using different technology. The results showed that the film has good reflectivity and the particle size has a great influence on the reflectivity of the films. SEM photos showed that the liquid film is composed of multilayer silver nanoparticles. In addition, stability of the film was studied. The results showed that after being stored for 8 days under natural conditions, the gloss and reflectivity of the film start to decrease.

Enhanced Cr(vi) removal from aqueous solutions using Ni/Fe bimetallic nanoparticles: characterization, kinetics and mechanism

In this study, Ni/Fe bimetallic nanoparticles were prepared by a liquid-phase chemical reduction method and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS) with image mapping, transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The as-prepared Ni/Fe material was applied to remove Cr(VI) via a coupled adsorption/reduction process. It was found that Cr(VI) removal followed pseudo-second-order reaction kinetics. Acidic pH favored the efficient removal of Cr(VI) due to the abundance of reactive H˙ species that were mediated by the Ni catalyst. XPS studies demonstrated that Cr(VI) removal on the surface of the bimetallic nanoparticles was a synergistic adsorption and reduction process. The introduction of nickel to nZVI not only controls iron passivation but also facilitates the efficient flow of electron transfer between iron and Cr(VI), and thus the efficient reduction of Cr(VI) to Cr(III). Hydroxylated Cr(OH)3 and co-precipitation of CrxFe1−x(OH)3 were the final products of Cr(VI) removal by the Ni/Fe material.