Showing papers on "Ammonium hydroxide published in 2015"
TL;DR: An innovative quantitative synthetic method for preparing magnetite nanoparticles was achieved by co-precipitation in aqueous solution using only one single iron(III) salt as a precursor.
156 citations
TL;DR: The aqueous solution growth process of ZnO rods, starting from zinc hydroxide formed during the ultrasonic precipitation of zinc acetate and ammonium hydroxides has been demonstrated in this article.
Abstract: The aqueous solution growth process of ZnO rods, starting from zinc hydroxide formed during the ultrasonic precipitation of zinc acetate and ammonium hydroxide has been demonstrated here. A dispersion consisting of 0.3 (w/v) % zinc hydroxide in water on heating at 80 ± 5 °C for 6 h has resulted in the formation of ZnO rods having an aspect ratio between 8 and 12. We have monitored the growth of ZnO rods as a function of different reaction parameters. The as-prepared rods have also been characterized by optical and Raman spectroscopic methods in addition to other techniques. Further, we also investigated the photocatalytic degradation of methyl violet, which is a well known textile pollutant by using the as-prepared ZnO rods and found that the degradation was more effective using a 365 nm light source than using a 254 nm light source. This result confirms that the as-processed ZnO rods could be used directly under sunlight for the degradation of methyl violet present in polluted water. Our experimental results, confirmed that the sample with more oxygen defects shows better photocatalytic degradation of the dye molecule due to the involvement of oxygen vacancy defects and oxygen interstitials in the charge recombination process and helps in better catalytic reaction under a UV lamp.
102 citations
TL;DR: In this paper, a D-labeled epoxide and an optically active epoxide were used to study the reaction mechanism, which invoked three plausible pathways, among which path A seemed to be the predominant; the bicarbonate ion of TBABC attacks the less hindered C atom of the epoxide to generate a ring-opened alkoxide intermediate, which adds to CO2 to give a carbonate ion, and the subsequent cyclization yields a cyclic carbonate.
95 citations
TL;DR: In this paper, a self-crosslinked anion exchange membrane (AEM) without the need for any crosslinkers or catalysts was synthesized via the Menshutkin reaction.
82 citations
TL;DR: In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation, and the α-Ga2O3 and β-Ga 2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.
Abstract: Gallium oxide (Ga2O3) nanorods were facilely prepared by a simple hydrothermal synthesis, and their morphology and photocatalytic property were studied. The gallium oxide hydroxide (GaOOH) nanorods were formed in aqueous growth solution containing gallium nitrate and ammonium hydroxide at 95 °C of growth temperature. Through the calcination treatment at 500 and 1000 °C for 3 h, the GaOOH nanorods were converted into single crystalline α-Ga2O3 and β-Ga2O3 phases. From X-ray diffraction analysis, it could be confirmed that a high crystalline quality of β-Ga2O3 nanorods was achieved by calcinating at 1000 °C. The thermal behavior of the Ga2O3 nanorods was also investigated by differential thermal analysis, and their vibrational bands were identified by Fourier transform infrared spectroscopy. In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation. As a result, the α-Ga2O3 and β-Ga2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.
75 citations
TL;DR: In this article, high-silica H-ZSM-5 catalysts were successfully synthesized using the conventional hydrothermal method under a static condition in the presence of tetrapropyl ammonium hydroxide (TPAOH), TPABr, n-butyl amine (NBA), and morpholine (MOR) as the structuredirecting agents.
65 citations
TL;DR: This simple and versatile synthetic method to produce high amine content CNC can be used for further conjugation as required for various applications.
58 citations
TL;DR: In this paper, a co-precipitation of manganese and ammonium hydroxide precursors in a continuous stirred tank reactor was studied with a two-step precipitation mechanism, and the two-stage precipitation mechanism was experimentally confirmed.
54 citations
TL;DR: A facile wet chemical method was adopted for preparing highly photoactive nitrogen doped TiO2 (N-TiO2) powders with visible responsive capability, which could be achieved by the hydrolysis of titanium isopropoxide (TTIP) in the ammonium hydroxide precursor solution in various concentrations and then calcined at different temperatures as discussed by the authors.
Abstract: A facile wet chemical method was adopted for preparing highly photoactive nitrogen doped TiO2 (N-TiO2) powders with visible responsive capability, which could be achieved by the hydrolysis of titanium isopropoxide (TTIP) in the ammonium hydroxide precursor solution in various concentrations and then calcined at different temperatures. The N-TiO2 powders were characterized, and the photocatalytic activity was evaluated for the photocatalytic oxidation of ethylene gas under visible light irradiation to optimize the synthesizing conditions of N-TiO2 catalyst. The N-TiO2 photocatalytic powders were calcined in a range of temperatures from 300 to 600°C and obviously found to have greater photocatalytic activities than commercial TiO2 P25. The strong absorption in the visible light region could be ascribed to good crystallization and adapted sinter temperature of as prepared sample. XPS test demonstrated that the N was doped into TiO2 lattice and made an interstitial formation (Ti-O-N), and N doping also retarded the phase transformation from anatase to rutile as well. The N-TiO2 catalyst prepared with 150 mL ammonium hydroxide added and calcined at 500°C showed the best photocatalytic activity. The experimental results also proved the enhanced photoactivity of N-TiO2 material depends on the synthesizing conditions.
38 citations
TL;DR: In this paper, the authors demonstrate the synthesis of poly(sulfobetain methacrylate) (p(SBMA)) hydrogels of micro dimensions by inverse suspension polymerization of a zwitterionic monomer 2-(methacryloyloxy) ethyl] dimethyl (3-sulfopropyl) ammonium hydroxide (SBMA).
33 citations
TL;DR: The chromatographic behaviour of eleven synthetic cathinones and four phenylethylamines under supercritical/subcritical fluid conditions was investigated and efficient separations of four isomeric pairs (R>1), and most of the remaining analytes, were achieved in less than 3.3min.
TL;DR: In this article, the effect of ammonia in syngas on the Fischer-Tropsch synthesis (FTS) reaction over 100Fe/5.1Si/2.0K catalyst was studied at 220-270°C and 1.3-MPa using a 1-L slurry phase reactor.
TL;DR: In this paper, a series of hydroxyl functionalized ionic liquids such as dialkyl (or alkyl) di-(tri-) hydroxyethyl ammonium hydroxide, tetrahydroxyethyl amyridine hydroxides, and dihydroxyethyl immidazolium hydoxide were synthesized and characterized by FT-IR and 1H NMR.
Abstract: A series of hydroxyl-functionalized ionic liquids such as dialkyl (or alkyl) di-(tri-) hydroxyethyl ammonium hydroxide, tetrahydroxyethyl ammonium hydroxide and alkylhydroxyethyl or dihydroxyethyl immidazolium hydroxide were synthesized and characterized by FT-IR and 1H NMR. These ionic liquids containing hydroxyls were used as catalysts for direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide. The results showed that benzylmethyldihydroxyethyl ammonium hydroxide (BzMDH) is an effect catalyst with raised catalytic activity and high selectivity to DMC. The effect of hydroxyl groups on the activation of methanol and CO2 were explored. Furthermore, the reaction mechanism of this synthetic reaction was discussed.
TL;DR: In this paper, a remarkably improved dissolution of cellulose in 40 wt% tetra-n-butylammonium hydroxide has been realized with a decrease in temperature to 16 °C.
Abstract: A remarkably improved dissolution of cellulose in 40 wt% tetra-n-butylammonium hydroxide has been realized with a decrease in temperature to 16 °C.
TL;DR: In this paper, several aerobic growth tests were performed with K. marxianus DSM 5422 as a potent producer of ethyl acetate in whey-borne media supplemented with various N sources.
Abstract: Whey is just turning from a waste of milk processing to a renewable raw material in biotechnology for producing single-cell protein, bio-ethanol, or ethyl acetate as an economic alternative. Conversion of whey-borne sugar into ethyl acetate requires yeast biomass as a biocatalyst. A high cell concentration results in a quick ester synthesis, but biomass growth means consumption of sugar at the expense of ester production. Efficient and cost-saving biomass production is thus a practical requirement. Whey is poor in nitrogen and has therefore to be supplemented with a bioavailable N source. Several aerobic growth tests were performed with Kluyveromyces marxianus DSM 5422 as a potent producer of ethyl acetate in whey-borne media supplemented with various N sources. Preliminary tests were done in shake flasks while detailed studies were performed in a stirred bioreactor. Ammonium sulfate resulted in strong acidification due to remaining sulfate, but costly pH control increases the salt load, being inhibitory to yeasts and causing environmental impacts. Ammonium carbonate lessened acidification, but its supplement increased the initial pH to 7.5 and delayed growth. Urea as an alternative N source was easily assimilated by the studied yeast and avoided strong acidification (much less base was required for pH control). Urea was assimilated intracellularly rather than hydrolyzed extracellularly by urease. Conversion of urea to ammonium and usage of formed ammonium for biomass production occurred with a similar rate so that the amount of excreted ammonium was small. Ammonium hydroxide as another N source was successfully added by the pH controller during the growth of K. marxianus DSM 5422, but the medium had to be supplemented with some ammonium sulfate to avoid sulfur limitation and to initiate acidification. Non-limited growth resulted in 82 mg N per g of biomass, but N-limited growth diminished the N content. K. marxianus could be efficiently produced by supplementing the whey with nitrogen. Urea and ammonia were the favored N sources due to the proton neutrality at assimilation which lessened the salt load and reduced the supply of alkali for pH control or made this even needless.
TL;DR: In this paper, a carbonate co-precipitation method was used to synthesize ultra-fine, well dispersed Yb: (Lu x Sc 1−x ) 2 O 3 nanopowders by using ammonium hydrogen carbonate (NH 4 HCO 3 ) as precipitant and ammonium sulfate ((NH 4 ) 2 SO 4 ) as dispersing agent.
Patent•
30 Dec 2015
TL;DR: In this article, a method for separating tungsten and molybdenum is proposed, which comprises the following steps: (1) adding acid into a tengsten-molybde-denum mixed solution and adjusting pH value to obtain mixed sediment of tengstion acid and mizeebdenum acid; (2) adding hydrogen peroxide and acid into the mixed sediment to form peroxide tngsten acid and peroxide molybenum acid, and (3) heating an obtained mixed solution, adding Tungsten powder, reacting
Abstract: The invention relates to a method for separating tungsten and molybdenum The method comprises the following steps: (1) adding acid into a tungsten-molybdenum mixed solution and adjusting pH value to obtain mixed sediment of tungsten acid and molybdenum acid; (2) adding hydrogen peroxide and acid into the mixed sediment to form peroxide tungsten acid and peroxide molybdenum acid; (3) heating an obtained mixed solution, adding tungsten powder, reacting and filtering to obtain tungsten acid sediment and a molybdenum-containing acid solution; (4) calcining the prepared tungsten acid to prepare tungsten trioxide or dissolving by using ammonium hydroxide to obtain an ammonium tungstate solution and then evaporating and crystallizing to prepare APT; (5) extracting the molybdenum in the obtained molybdenum-containing acid solution by using an extraction agent/ion exchange resin; and (6) reversely extracting molybdenum-containing organic phase/resin by using ammonium hydroxide to obtain the ammonium molybdate solution, and carrying out acid precipitation to obtain ammonium tetramolybdate The production process of tungsten-molybdenum products is taken into account in the method, so that the separated tungsten acid or molybdenum can be directly used for preparing the products thereof; the separation effect is excellent; the operation process is simple and is liable to control; the industrial popularization and application are liable to implement
TL;DR: In this article, the authors used one-step sol-gel process to prepare the hydrophobic silica films on the glass substrate from the ethyltriethoxysilane (ETES) as a precursor and iso-octyltrimethoxymethylsilicon (Iso-OTMS) as an agent, and the results revealed that different sizes of silica nanoparticles from 41.24 to 86.16 µm were obtained.
TL;DR: In this paper, a light-violet pigment of neodymium disilicate (Nd 2 Si 2 O 7 ) was prepared by a co-precipitation method with alcohol-water as a solvent.
TL;DR: The developed method offered satisfactory recoveries in the 91-99% range and good precisions (<5%) and good agreement between the determined values by the proposed CE method and the HPLC-ICP-MS method proved its great potential in routine analysis of iodine speciation in environmental, food and biological samples.
TL;DR: In this paper, the synthesis of cobalt hydroxide on ∼40nm zeolite crystallites by treatment of Co2+-exchanged Zeolite (Co-NZ) with either NaOH treated with either Co-NZ-OH or tetramethyl ammonium hydroxides (TMA-NH) was reported.
Patent•
25 Mar 2015
TL;DR: In this article, a method for resourceful treatment of ammonia chloride wastewaters is proposed, which comprises the following steps: (1) respectively carrying out pretreatment on ammonia chloride wastewater with different concentrations for removing impurities; (2) carrying out reverse osmosis treatment on a clear liquor of the ammonia chloride, which is obtained in the step (1), with the concentration being lower than 05%; (3) mixing obtained reverse Osmosis concentrated water with a clear liquid of the ammonium hydroxide, which was obtained in step (2), and (4
Abstract: The invention relates to a method for resourceful treatment of ammonia chloride wastewaters The method comprises the following steps: (1) respectively carrying out pretreatment on ammonia chloride wastewater with different concentrations for removing impurities; (2) carrying out reverse osmosis treatment on a clear liquor of the ammonia chloride wastewater, which is obtained in the step (1), with the concentration being lower than 05%; (3) mixing obtained reverse osmosis concentrated water with a clear liquid of the ammonia chloride wastewater, which is obtained in the step (2), with the concentration being higher than 05% so as to obtain ammonia chloride mixed wastewater; (4) carrying out conventional electrodialysis treatment on the obtained ammonia chloride mixed wastewater so as to obtain electrodialysis fresh water; (5) returning the obtained electrodialysis fresh water, carrying out reverse osmosis treatment the obtained electrodialysis fresh water to obtain electrodialysis concentrated water, and carrying out acid-alkali regeneration on the electrodialysis concentrated water by adopting bipolar membrane electrodialysis; and (6) converting ammonia chloride in the wastewater into hydrochloric acid and ammonium hydroxide by adopting the bipolar membrane electrodialysis to obtain low-concentration ammonia chloride wastewater, simultaneously returning the obtained low-concentration ammonia chloride wastewater and carrying out the conventional electrodialysis treatment on the obtained low-concentration ammonia chloride wastewater According to the method, the resourceful treatment and the zero emission of the ammonia chloride wastewater can be really achieved
01 Jan 2015
TL;DR: This chapter discusses the different types of alkali used in the pretreatment of biomass, their mode of action, conditions of alkaline pretreatment, prospects and consequences, and commercialization aspects.
Abstract: Pretreatment plays an important role in lignocellulosic biomass conversion process. It is required to alter the structure of lignocellulosic biomass and to make it accessible for enzymatic saccharification. Alkali pretreatment is one among the different chemical pretreatment technologies that has been investigated extensively. The common agents used for alkaline pretreatment are sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide, and aqueous ammonia. Alkali pretreatment plays an important role in delignification. The effectiveness of alkaline pretreatment depends on the composition of the biomass as well as the pretreatment conditions. This chapter discusses the different types of alkali used in the pretreatment of biomass, their mode of action, conditions of alkali pretreatment, prospects and consequences, and commercialization aspects.
TL;DR: In this paper, two approaches were considered to reduce treatment costs by selectively separating the ammonium and sulphate from the remaining organics in the wastewater, using ultrafiltration and electrodialysis.
Abstract: Ethanol production from cellulose is technically feasible. However, treatment of the resultant wastewater can account for 20–33% of the total process cost and thus potentially hold back commercialisation. Wastewater from dilute acid processes has high levels of organic material, colour, sulphate and ammonium. Two approaches were considered to reduce treatment costs by selectively separating the ammonium and sulphate from the remaining organics in the wastewater. Using ultrafiltration, ammonium and sulphate retentions (68 and 57%, respectively) were similar to COD retention (67%). The second approach used was electrodialysis. This proved far more selective and was able to regenerate solutions of sulphuric acid and ammonium hydroxide with little evidence of sugar, COD or colour migrating across the ion-exchange membranes. These preliminary results thus confirm previous findings that sulphuric acid can be recovered from aqueous streams containing high concentrations of sugars with little sugar loss—r...
TL;DR: In this article, the effect of the aluminosilicate structure and the nature and concentration of modifying agent on the adsorption and surface characteristics of mineral sorbents was determined.
Abstract: The possibility of regulating the sorption processes on clinoptilolite and nontronite by acidic and basic modifications was found. The effect of the aluminosilicate structure and the nature and concentration of modifying agent on the adsorption and surface characteristics of mineral sorbents was determined. An increase in the sorption capacity of natural minerals as a result of preadsorption treatment with solutions of sulfuric, hydrochloric, and nitric acids, as well as sodium hydroxide and ammonium hydroxide, was shown. An ambiguous effect of the nature and concentration of various modifiers on the formaldehyde adsorption was found. An increase in the specific surface and pore volume of minerals occurs during acidic treatment. The action of sodium hydroxide results in a decrease in the nontronite specific surface and an increase in the pore volume. Treatment with ammonium hydroxide does not affect the surface characteristics of the sorbents. The most effective modifiers for clinoptilolite in the formaldehyde adsorption are 0.5 M hydrochloric acid and 1.5 M ammonium hydroxide; for nontronite, 1.0 M sulfuric acid is most effective.
TL;DR: In this article, high concentrated silver colloidal solutions were synthesized via alcohol reduction process by adding ammonium hydroxide (NH 4 OH), which played a role of enhancing the conversion of silver ions to silver atoms by accelerating oxidation reaction of alcohol.
TL;DR: In this paper, the effects of template type, template amount and ammonium hydroxide (NH 4 OH) solution concentration on the pore structure of the prepared porous silica were comprehensively studied.
Patent•
14 Jan 2015
TL;DR: In this paper, a three-compartment bipolar membrane electrodialysis device was used to produce high-purity tetrabutyl ammonium hydroxide by continuous electrolysis.
Abstract: The invention relates to a method for preparing high-purity tetrabutyl ammonium hydroxide by continuous electrolysis, particularly relates to a method for preparing high-purity tetrabutyl ammonium hydroxide by using tetrabutyl ammonium bromide as a raw material and adopting a three-compartment bipolar membrane electrodialysis device, and belongs to the field of organic chemistry. The method is characterized by comprising the following step: by adopting the three-compartment bipolar membrane electrodialysis device, continuously preparing 5-20% tetrabutyl ammonium hydroxide by using a 15-35% tetrabutyl ammonium bromide aqueous solution as a raw material under the condition that the reaction temperature is 30-60 DEG C, the current density is 200-600A/m and the flow rate of the raw materials is 500-2000L/h, wherein the concentration of bromine ions in the prepared tetrabutyl ammonium hydroxide is less than 100ppm. According to the method provided by the invention, the materials in the compartments are relatively constant in concentration, the temperature is relatively constant, an ionic membrane is not easy to swell or shrink, the membrane cost is saved, the current efficiency and the product conversion ratio are improved and the energy consumption is reduced, and moreover, the product quality is further improved. The method is suitable for industrial safe production on a large scale, clean in production process and free of discharge of wastewater and solid wastes.
TL;DR: In this paper, a co-precipitation method was used to synthesize cobalt ferrite nanoparticles using three different precipitating agents, viz. ammonium hydroxide, sodium hyroxide and monoethanolamine.
Abstract: Cobalt ferrite nanoparticles have been synthesized by co-precipitation method using three different precipitating agents, viz. ammonium hydroxide, sodium hydroxide and monoethanolamine. The average particle size of the nanoparticles varied in the range 17-70 nm by varying the precipitating agents. The phase formation of the synthesized nanoparticles was performed via X-ray diffraction. Fourier infrared spectroscopy also confirmed the product formation. The microstructure and elemental composition were characterized by scanning electron microscopy and energy dispersive X-ray spectroscopy respectively. The precipitating agents were varied to vary the size and to study the effect of size on the morphology and antibacterial properties. The effect of precipitating agents and particle size on the antibacterial activity was carried out against the microorganism Staphylococcus aureus (gram positive bacteria) quantitatively by spread plate method.
TL;DR: In this article, single-layer graphene films were prepared through mechanical exfoliation of Kish graphite and chemical vapor deposition techniques, and these samples were treated in nitric acid, sulfuric acid, sodium hydroxide and ammonium hyroxide solutions to induce doping, and they used Micro Raman Spectroscopy before and after chemical functionalization to monitor differences in the Raman spectrum.
Abstract: We prepared single-layer graphene films through mechanical exfoliation of Kish graphite and chemical vapor deposition techniques. These samples were treated in nitric acid, sulfuric acid, sodium hydroxide and ammonium hydroxide solutions to induce doping. We used Micro Raman Spectroscopy before and after the chemical functionalization to monitor differences in the Raman spectrum. We found shifting for both G and 2D peaks of graphene and a significant upshifting in samples treated with sulfuric acid, similar to those reported for nitric acid.