Amount Of Reducing Agent Research Articles

A novel process for recovering aluminum and silicon from fly ash in cryolite molten salt

The recovery and utilization of by-product coal fly ash (CFA) in high-value-added thermal power plants is of great significance. This research focused on producing high-value-added Al–Si master alloy by aluminothermic reduction with coal fly ash as the raw material. The effects of reduction time and reducing agent amount on thermal reduction products were investigated using the single factor method. X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) results showed that Al, Si, and a small amount of Fe were the main components of the alloy. With an increase in reaction time, the mass fraction of Si in the product increased from 4.41% to 9.93%. Besides, the molten salt after thermal reduction was recovered by the electrochemical reduction process. The results showed that a longer electrolysis time is more conducive to improving the recovery of Si and Al. The results of cyclic voltammetry and electrodeposition showed that Si would be reduced in a multi-step process. Combined with thermal reduction and electrochemical secondary recovery process, the comprehensive recovery of Al and Si in fly ash could reach 87.33% and 84.02%, respectively.

High effective catalyst based on Ni doped TiO2 coated natural cotton fibers for catalytic reduction of organic pollutants

ABSTRACT A new type of nickel doped titanium oxide (Ni-TiO2) coated natural cotton fibers (CF) and Ni-TiO2 wrapped sodium alginate (Alg) hydrogel was developed for the efficient reduction of different contaminants. Ni-TiO2 was prepared by low-temperature method and coated on CF using Alg as a binder and entrapped inside Alg hydrogel. Ni-TiO2 coated CF (Ni-TiO2/CF) and Ni-TiO2 wrapped Alg (Ni-TiO2/Alg) were utilized for catalytic elimination of wastewater pollutants. Ni-TiO2/CF and Ni-TiO2/Alg were initially tested as nanocatalysts for reduction of potassium ferricyanide, 4-nitrophenol, congo red, and methylene blue (MB), and exhibited superior catalytic performance toward MB reduction. Different parameters such as catalyst amount, MB concentration, reducing agent amount, and recyclability were optimized. Comparatively, Ni-TiO2/CF revealed the best catalytic performance for MB reduction having the highest reaction rate constant (2.1564 min−1). Ultimately, the catalyst preserved superior activity in recyclability evaluation, confirming that Ni-TiO2/CF is a good catalyst for the efficient removal of MB up to four cycles. Ni-TiO2/CF can more easily be recovered compared to Ni-TiO2/Alg by easily pulling out the fibers from reaction medium, which is the main advantage of Ni-TiO2/CF. Moreover, Ni-TiO2/CF and Ni-TiO2/Alg were examined in real samples, providing the effective reduction of MB. The developed nanocatalyst offers a cost- and time-effective material for environmental safety purpose.

Eco-friendly, non-toxic and super adsorbent hydrogels based on graphene

This work aimed to develop three-dimensional materials based on graphene by a simple, low-cost, and environmentally friendly method, evaluating its toxicity and capacity for the cationic dye safranin removal from water. 3D-rGO materials were obtained by reducing graphene oxide (GO) in one step and through a sustainable route. The materials were obtained over 2 h, showing a self-supporting three-dimensional structure. The effect of ascorbic acid amount as a reducing agent for this material was evaluated. It was observed that variations in the reaction promoted significant morphological changes. The results showed that the greater the reducing agent amount used in the synthesis, the more compact the three-dimensional structure, the smaller the pores and specific surface area, and the lower the number of oxygenated sites. The pH of the zero charge point (pHZCP) ranged between 2 and 2.37, indicating that the material must efficiently adsorb cationic dyes at neutral pH. Adsorption studies for the cationic dye safranin showed materials capable of adsorbing the dye quickly, with a kinetic equilibrium time of only 10 min, and a high adsorption capacity (937,841 mg g−1), in the equilibrium isotherm studies. The changes in the surface area and the compaction of the structure directly influence intraparticle diffusion and adsorption mechanisms. In addition, the materials did not present significant toxicity in D. melanogaster fly, indicating the absence of immediate toxicological risk in a situation of possible contamination.

Alginate biopolymer as a reactor container for copper oxide-tin oxide: Efficient nanocatalyst for reduction of different pollutants

The need of clean water demands to design an efficient catalytic system with high effective and selective reduction of water pollutants. Here, we successfully prepared copper oxide-tin oxide (CuO–SnO2) nanomaterial and further wrapped in Na-alginate hydrogel (Alg/CuO–SnO2). CuO–SnO2 and Alg/CuO–SnO2 were characterized by FESEM, EDS, FTIR-ATR, and XRD and tested for the reduction of water pollutants. The catalytic ability of CuO–SnO2 and Alg/CuO–SnO2 was examined for numerous pollutants like 4-nitrophenol (4-NP), methyl orange (MO), congo red (CR), methylene blue (MB) and potassium ferricyanide (K3[Fe(CN)6]) where the designed CuO–SnO2 and Alg/CuO–SnO2 nanocatalysts were most selective toward MB reduction. Further on optimization of catalyst amount, stability, and reducing agent amount, it was found that the increase of nanocatalyst amount and NaBH4 concentration increase the rate of MB reduction. CuO–SnO2 and Alg/CuO–SnO2 nanocatalysts reduced MB in 3.0 min with reaction rate constants (kapp) of 1.2944 min−1 and 1.2715 min−1, respectively. Additionally, Alg/CuO–SnO2 nanocatalyst was easily recovered by simply pulling hydrogel after completion of reaction and reused four times with no loss in efficiency. Besides, Alg/CuO–SnO2 nanocatalyst was further investigated in real samples like sea water, irrigation water, well water, university wastewater and found effective for MB reduction even in real samples.

Sodium alginate nanocomposite based efficient system for the removal of organic and inorganic pollutants from wastewater

An effective and selective catalytic system based on cerium oxide-stannous oxide (CeO2-SnO) wrapped Na-alginate hydrogel was developed for the selective reduction of potassium ferricyanide (K3[Fe(CN)6]). Na-alginate hydrogel was used as a reacting container for CeO2-SnO nanoparticles. Na-alginate wrapped CeO2-SnO (Alg/CeO2-SnO) was applied as a catalyst and examined toward the reduction of several hazardous pollutants, such as nitrophenols, dyes and K3[Fe(CN)6]. Alg/CeO2-SnO nanocatalyst was mostly selective toward K3[Fe(CN)6] since it was more effective and economical for reduction of K3[Fe(CN)6]. Further different parameters like catalyst amount, reducing agent amount, K3[Fe(CN)6] concentration and recyclability were optimized. The increase in both nanocatalyst amount and NaBH4 concentration resulted in increasing the rate of the catalytic reduction of K3[Fe(CN)6]. Alg/CeO2-SnO nanocatalyst reduced K3[Fe(CN)6] in 4.0 min with a reaction rate constant of 0.9114 min−1. The nanocatalyst can be easily recovered by pulling the hydrogel from the reaction medium up to four cycles. Alg/CeO2-SnO nanocatalyst was also examined in real samples like irrigation water, sea water, well water, university water, which was effective for K3[Fe(CN)6] reduction by 95.16%–96.54%. This novel approach provides a new catalyst for efficient removal of K3[Fe(CN)6] from real samples and can be a time and cost alternative tool for environmental safety.

Novelty Au Nanoparticles with Different Nano Sizes as an Acidity Sensor

The amazing wide range, applications of gold nanoparticles corresponding to excellent optical and electronic properties enhance utilization of Au NP as PH sensor. Gold nanoparticles were synthesized in simple and rapid Turkevich method to accomplish optical sensing technologies covalent or non-covalent, bonds formation causes, aggregation of the nanoparticles in the target substance. Au nanoparticles characterization was studied using XRD, UV-spectroscopy and SEM. XRD indicate polycrystalline. Nanoparticles with two different sizes according to reducing agent amount to obtain 20 30 nm. Optical energy gap was calculated for both particle size to find it (2.13) eV for 30nm particle size and (2.33) eV for 20nm.Scanning Electron Microscope showed spherical shape particles. PH test were performed to investigate efficiency of Au Np’s for PH sensor and that is found to be excellent results for both sizes with more efficiency for 30 nm due to its rough surface. Which is a fantastic tool and measurement device to test the pH of soil, food, and other puncture-worthy applications.

Optimization of Ni-B coating bath and effect of DMAB concentration on hardness and wear

In this study, reducing agent amount, stabilizer amount, coating bath temperature and stirring speed parameters were examined for optimization of electroless Ni-B coatings, and the effect of reducing agent amount on hardness and wear of the coating was investigated. The pH of the electroless Ni-B coatings made for 1 h was set to 6, nickel chloride (NiCl2.6H2O) as the nickel source, sodium acetate (C2H3NaO2) as the complexing agent, thiourea as the stabilizer (CH4N2S) and DMAB ((CH3)2NBH2) as the reducing agent was used in the coatings. The bath parameters were varied as; the amount of reducing agent (2 g/L, 3 g/L and 4 g/L), coating bath temperature (65°C, 70°C and 75°C), stabilizer amount (0.5 mg/L, 1 mg/L, and 2 mg/L) and stirring speed (250, 300 and 350 rpm). After determining the optimum conditions, the effects of the amount of reducing agent on the coating were examined. Scanning Electron Microscopy (SEM), X-ray diffractometer (XRD), Vickers nano-hardness test and tribometer were used for characterization of coatings. In the optimization studies, it was observed that the coating morphology was in the form of cauliflower and columnar structures were formed in the cross-section images. According to optimization results on the morphologies, the samples which compact and free-crack have been investigated phase structure, hardness and tribology properties. In XRD analysis, coatings produced with different amounts of reducing (DMAB) are amorphous as-deposited, after annealed at 400°C for 2 h, nickel borides (Ni2B and Ni3B) phases are formed and increased the preferential orientation (111) of the nickel crystal plane. The effect of DMAB concentration on coating was examined in as-deposited condition and post annealing. The formation of nickel borides after annealing increases the hardness. The effect of DMAB concentration on the coating after annealed was examined and it was observed that the wear resistance of the dense and homogeneously dispersed sample in the coating matrix was more perfect than other samples. Consequently, hardness (850 HV), coefficient of friction (0.37) and wear rate (2.92 × 10−7 mm3/Nm) of B2 sample which free-crack and compact was obtained. These results indicate a high strengthen B2 sample produced with 3 g/L DMAB concentration and 70°C bath temperature could utilize in a harsh medium.

One pot synthesis of zwitteronic 99mTc doped ultrasmall iron oxide nanoparticles for SPECT/T1-weighted MR dual-modality tumor imaging

In this study, we have synthesized 99mTc intrinsically labeled ultrasmall magnetic iron oxide nanoparticles with zwitterionic surface coating (99mTc-ZW-USIONPs) via one pot synthesis using sulfobetains functionalized poly (acrylic acid) as stabilizer and Na99mTcO4 and SnCl2 as additives. The commercialization of single photon emission computed tomography (SPECT)/magnetic resonance imaging (MRI) scanner made the combination use of 99mTc and iron oxide nanoparticles attracting much attention. Direct doping radioisotope into nanoparticles has the advantages of excellent radiochemical stability and no restriction on the surface functionalization. The complex Technetium chemistry made it challenging to direct dope 99mTc into IONPs, especially those ultrasmall ones without precipitation. We proved that it is possible to prepare 99mTc doped USIONPs with excellent water solubility and favorable T1 signal by controlling the radioactivity and reducing agent amount. With no need of chelator, the zwitterionic surface resists the protein corona formation, resulting in a reduced RES uptake and higher tumor contrast. The 99mTc-ZW-USIONPs demonstrated excellent performance of tumor SPECT and T1-weighted MR imaging capability in 4T1 tumor bearing mice. Together with their ease of preparation and superior biocompatibility, we believe these 99mTc-ZW-USIONPs represent a type of promising dual contrast agent for SPECT/T1 MRI.

A novel 99m Tc-diester complex as tumor targeting agent: Synthesis, radiolabeling, and biological distribution study.

The target of this study is the synthesis of a new diester derivative and radiolabeling with one of the most effective diagnostic radioisotopes to be investigated as a novel targeting radiotracer for tumor imaging. 10-[2-(9-Carboxynonanoyloxy)propoxy]-10-oxodecanoic acid was synthesized in excellent yield and characterized by Fourier-transform infrared spectroscopy, mass, 1 H-NMR, and 13 C-NMR spectra. The diester was technetium-99m (99m Tc) radiolabeled by direct technique using sodium dithionite as a reducing agent. The labeling parameters such as diester amount, reducing agent amount, pH of the medium, and reaction time were optimized. High radiochemical yield of 95.10 ± 0.41% and in vitro stability in serum up to 12 h have been obtained on complexation of the synthesized diester with Tc-99m. Evaluation of the diester anticancer activity against breast cancer cell line (MCF-7) showed high percent of inhibition about 61.5% at 100 μg/ml. The rhenium complex of the diester was synthesized and characterized by liquid chromatography-mass spectrometry (ESI) and elemental analysis depending on the strong chemical resemblance between Tc and Re. Biodistribution studies of 99m Tc-diester complex showed high target to nontarget ratio (T/NT) equals 6.24 ± 0.09 in tumor-bearing mice at 30-min postinjection, suggesting this complex could be used as hopeful solid tumor-imaging agent.

Applying radiolabeled novel recombinant insulin via 99mTc for ensuring native like action by in vivo biodistribution in mice.

In order to study functionality and pharmacodynamics of any important biological molecule such hormones and enzymes, it takes alot of time and complexed stratigies to do that. Here we study the incidence of new recombinant human insulin prevalence in body tissues in real time with aid of radiotracing technique. A new designed model of recombinant-human insulin and produced in E.coli suggested to be functional without post translational modification, has been radiolabeled with Technetium-99m, then tracing its biodistribution with 99mTc in mice. The new construct of human recombinant Insulin protein subjected to the formation of 99mTc-complex using sodium dithionite(Na2S2O4) as a reducing agent, whole reaction conditions subject to optimization of the pH, tempature, substrate amount and a reducing agent amount. Then 99mTc-Insulin complex has been intravenously administrated for biodistribution study invivo in Albino Swiss mice. The optimized conditions for preparing the 99mTc–insulin complex with the highest radiochemical yield(93.3%) disclosed that using 100 μg of insulin in the presence of 20μg of a reducing agent sodium dithionite(Na2S2O4) at pH 8 and within 30 minutes reaction time. The radioactive complex of 99mTc-Insulin gives a much better result after IV injection, where no accumulation in distinect organ. And due to aqueous nature of Insulin, it show clearance from both renal and hepatic route, Also prevalance of Insulin in body according every organs mass or size, have a great impact of functionality of recombinant-insulin molecule. Consequently, this method seems to be much rapid and effective for evaluation of biological molecule invivo via radioactive tracing technique.

Tailoring the Performance of Graphene Aerogels for Oil/Organic Solvent Separation by 1-Step Solvothermal Approach

Ultra-light eco-friendly graphene oxide (GO)-based aerogels are reported by simple one-step solvothermal self-assembly. The effect of varying parameters such as C/O ratio of GO; reducing agent amount; temperature; and duration on the properties of the aerogels was studied. The structural and vibrational features and hydrophobic surface properties of the obtained aerogels were obtained by XRD; FTIR; XPS; Raman; SEM; and contact angle measurements. The effect of synthesis conditions on the engine oil and organic solvent absorption properties was assessed. The results indicated that the lower the C/O ratio of GO, the better the absorption properties, with the best performance for oil uptake reaching 86 g g−1. The obtained results indicate the approach based on ice-templating and the tailoring of oxygen content in GO make the resulting aerogels potential candidates for use in oil spill and organic solvent treatments.

Phase transitions during reducing roasting of a leucoxene concentrate with carbon

The phase transitions during the reducing roasting of a leucoxene concentrate with carbon are studied to obtain an anosovite product. Thermodynamic modeling of the reducing roasting is performed, and the influence of the temperature and the amount of a reducing agent on the reduction of rutile to Ti3O5-based anosovite is studied. Almost complete reduction of rutile to anosovite occurs in a temperature range of 1350–1400°C in the presence of 2.5–5.0% carbon. The Magneli phases of various compositions are predominantly formed at lower temperatures and smaller amounts of the reducing agent. At temperatures higher than 1400°C and a reducing agent amount >2.5%, rutile reduction results in the formation of anosovite along with an undesirable titanium carbide phase.

Preliminary Assessment of Tc-Salmeterol Xinafoate as a Potential Bone Imaging Agent

Sameterol xinafoate is a selective β2-adrenoceptor agonist used in the treatment of some lung diseases and play a vital role in the regulation of bone mass and bone turnover. 99mTc-salmeterol was formulated for the development of a novel potential diagnostic bone imaging agent with excellent biological properties. Factors influencing the labeling yield such as salmeterol xinafoate amount, pH of the reaction medium, reducing agent amount and the reaction time were studied in details. 99mTc-salmeterol was obtained with a high radiochemical yield of 94.6±0.5% and in vitro stability of 6 h when 0.5 mg of salmeterol was mixed with 10 mg NaBH4 at pH 9 and a reaction time 30 min. The biological distribution showed that 99mTc-salmeterol was highly concentrated in the bone (36.5 ± 2%ID/organ) at 30 min post injection. The bone uptake of 99mTc-salmeterol was remained high (29.3 ± 2ID/organ) for a time up to 2h post injection. The results revealed that 99mTc-salmeterol could solve the 99mTc-phosphonate drawbacks and could be used as a bone imaging agent.

Influence of nickel recovery efficiency on crystallinity and microhardness of electroless Ni–P coatings and optimisation using Taguchi technique

This research paper reports on the improvement of nickel recovery efficiency (NRE) and microhardness of the electroless Ni–P coating process. At present, in the electroless nickel coating process, the NRE is very low. Owing to this reason, the coating cost of electroless nickel is very high. Earlier researchers have tried to recover the nickel from the used bath after coating is completed and some achieved success in their attempt by further improving the nickel recovery from 25 to 35%. To overcome the above problem, the excess amount of reducing agent (RA) is supplied to the bath during the coating process to compensate for the consumed amount of electrons. The influence of adding excess amount of RA on NRE and other properties of the deposit have been investigated in this study. The NRE was significantly increased from 35 to 61%.The various coatings parameters used in the electroless bath were optimised to get the high NRE using a Taguchi optimisation technique.

Investigation of Graphene/Ag Nanocomposites Synthesis Parameters for Two Different Synthesis Methods

Graphene/Ag nanocomposites were prepared with two different approaches; (i) sequential reduction of graphene oxide and silver nitrate (AgNO3), (ii) simultaneous reduction of graphene oxide and AgNO3 with hydrazine hydrate. The effect of synthesis parameters such as AgNO3 amount, concentration of AgNO3 solution, reducing agent amount, concentration of reducing agent solution, on the mean size and particle size distribution of Ag nanoparticles deposited on graphene nanosheets were examined. The structure and morphology of the prepared nanocomposites were characterized with Fourier transform infrared spectrophotometer (FTIR), UV-visible spectra, scanning electron microscope (SEM), transmission electron microscope (TEM), and Raman spectra. Based on experimental data shown in this work Ag nanoparticles with smaller sizes (3.04 ± 0.64 nm) and narrower size range (2–6 nm, approximately % 90) that homogenously deposited on graphene nanosheets were obtained by simultaneous reduction method, compared to sequential reduction method.

Development of a hydrothermal method to synthesize spherical ZnSe nanoparticles: Appropriate templates for hollow nanostructures

Hydrothermal method was used to synthesize pure ZnSe nanosphere materials. The effects of the reducing agent amount, the reaction time and temperature were investigated on the purity of ZnSe. Also, the effects of surfactants such as sodium dodecyl sulfate (SDS) (anionic) and cetyl trimethylammonium bromide (CTAB) (cationic) were studied on the morphology of ZnSe. The prepared nanospheres were characterized using XRD, SEM, TEM and UV-Vis spectroscopy. Through these techniques, it was found that the pure ZnSe nanoparticles have a zinc blend structure and in a spherical form with average diameter of 30 nm. KEY WORDS: ZnSe, Nanosphere, Hydrothermal, Surfactant Bull. Chem. Soc. Ethiop. 2014, 28(1), 37-44.DOI: http://dx.doi.org/10.4314/bcse.v28i1.5

Optimization of Dyeing Wool Fibers Procedure with Isatis tinctoria by Response Surface Methodology

The response surface method (RMS) was used to optimize the color strength (K/S) of the wool fibers dyed with Isatis tinctoria. The eight independent variable terms, in which two of them are categorical and the other six numerical, were selected at two levels (low and high). The ANOVA test results of the linear model showed that the model terms, including reducing agent amount, dyeing temperature, dyeing time, and dyestuff percentage, have a significant effect on K/S. The actual values agreed with the predicted values and the suggested equation model was satisfactory and accurate.

인디고를 이용한 아스킨 섬유의 염착특성

Recently, polyester is widely used in textile fabrics due to its application potentials in various fields. It is known that askin fabric is prepared with mainly polyester and is enjoyed with various end uses such as marine clothing, underwear, shirts, swimming suits and so on. For this purpose, color fastness should be considered with great importance during its wet processing step. In this context, vat dyes were very much attracted due to the advantage of superior fastness property. Thus, we have used indigo dye towards askin fabric dyeings and investigated corresponding properties namely, dyeing temperature, concentration of dye, reducing agent amount and alkali amount. The results showed that higher color strengths of indigo dyeing on askin fabric were obtained at , 8% o.w.f, 3g/l, 5g/l, respectively. The color fastness to washing was considerable generally.