scholarly journals Kinetic Study on the Hydrolysis of p-nitrophenyl picolinate Catalyzed by g-C3N4/LaNiO3-Perovskite-type Oxides

2020 ◽  
Author(s):  
Changyu Ye ◽  
Rui Wang ◽  
Haoyu Wang ◽  
Huixing Zhang ◽  
Fubin Jiang
Keyword(s):  
Sol Gel ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
X Ray ◽  
First Order ◽  
Ph Values ◽  
Calcination Method ◽  
Hydrolysis Of ◽  
Perovskite Type

Abstract LaNiO 3 -Perovskite-type oxides, as a novel hydrolytic catalyst, were synthesized using a sol-gel-calcination method, and were characterized by employing x-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Brunauer–Emmett–Teller (BET). It was revealed that LaNiO 3 and 2% g-C 3 N 4 /LaNiO 3 -Perovskite-type oxides are nanoparticles about 12 nm and 10nm easily agglomerated in large amounts, and the specific surface area of LaNiO 3 is 21.277 m 2 /g and 2% g-C 3 N 4 /LaNiO 3 is 26.645 m 2 /g, respectively. The results also indicate that there are irregular microporoes in the material. In the catalytic activity test, the absorption spectra were collected when hydrolysis of p-nitrophenyl picolinate (PNPP) (C PNPP =1-5×10 -5 mol/L) was catalyzed by LaNiO 3 (0.5g/L) and 2% g-C 3 N 4 /LaNiO 3 (0.5g/L) in buffer solution at different pH values (6.5-7.8), respectively. Based on the absorption spectrum data, the pseudo first-order rate constant is estimated to be 0.59min -1 and 1.14min -1 , respectively. In addition, the proposed kinetics model of this reaction was confirmed by the results of the spectrum and the calculations.

Oxidation of Nickel(II) and Manganese(II) by Peroxodisulfate in Aqueous Solution in the Presence of Molybdate. Crystal Structure of the (NH4)6[NiMo9O32].6H2O Product

1992 ◽  
Vol 45 (12) ◽  
pp. 1943 ◽  
Author(s):  
SJ Dunne ◽  
RC Burns ◽  
GA Lawrance
Keyword(s):  
Rate Constant ◽  
Linear Dependence ◽  
Ph Dependence ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Oxidant Concentration ◽  
Ph Range ◽  
Kinetics Of

Oxidation of Ni2+,aq, by S2O82- to nickel(IV) in the presence of molybdate ion, as in the analogous manganese system, involves the formation of the soluble heteropolymolybdate anion [MMogO32]2- (M = Ni, Mn ). The nickel(IV) product crystallized as (NH4)6 [NiMogO32].6H2O from the reaction mixture in the rhombohedra1 space group R3, a 15.922(1), c 12.406(1) � ; the structure was determined by X-ray diffraction methods, and refined to a residual of 0.025 for 1741 independent 'observed' reflections. The kinetics of the oxidation were examined at 80 C over the pH range 3.0-5.2; a linear dependence on [S2O82-] and a non-linear dependence on l/[H+] were observed. The influence of variation of the Ni/Mo ratio between 1:10 and 1:25 on the observed rate constant was very small at pH 4.5, a result supporting the view that the precursor exists as the known [NiMo6O24H6]4- or a close analogue in solution. The pH dependence of the observed rate constant at a fixed oxidant concentration (0.025 mol dm-3) fits dequately to the expression kobs = kH [H+]/(Ka+[H+]) where kH = 0.0013 dm3 mol-1 s-1 and Ka = 4-0x10-5. The first-order dependence on peroxodisulfate subsequently yields a second-order rate constant of 0.042 dm3 mol-1 s-1. Under analogous conditions, oxidation of manganese(II) occurs eightfold more slowly than oxidation of nickel(II), whereas oxidation of manganese(II) by peroxomonosulfuric acid is 16-fold faster than oxidation by peroxodisulfate under similar conditions.

Characteristics and Photocatalytic Activity of Sm Doped ZnO Nanoparticles

2019 ◽  
Vol 799 ◽  
pp. 179-184 ◽  
Author(s):  
Pavels Rodionovs ◽  
Dzidra Jankovica ◽  
Jānis Grabis
Keyword(s):  
Photocatalytic Activity ◽  
Calcination Temperature ◽  
Zno Nanoparticles ◽  
Sol Gel ◽  
Spherical Shape ◽  
Order Rate Constant ◽  
X Ray Diffraction ◽  
First Order ◽  
Microwave Assisted ◽  
Gel Combustion

Sm2O3/ZnO nanoparticles were prepared via microwave-assisted hydrothermal and sol-gel combustion synthesis. Characteristics of obtained samples were compared in dependence of Sm2O3 content and calcination temperature. Prepared nanostructures were characterized with scanning electron microscopy and X-ray diffraction. Nanoparticles prepared via microwave-assisted hydrothermal and sol-gel method have flower-like and spherical shape respectively. The photocatalytic activity of samples under solar light simulated illumination was found to be affected by content of Sm2O3, calcination temperature and preparation method. The first-order rate constant of MB solution degradation of samples prepared via microwave-assisted hydrothermal method approximately three times exceeds that of sol-gel samples.

Synthesis and Characterization of Nano-Calcium Titanate-Based Coated Aluminum Oxide and its Application in Water Analysis of Cr(III) and Cr(VI) Concentration

2010 ◽  
Vol 44-47 ◽  
pp. 2136-2139
Author(s):  
Dong Zhang
Keyword(s):  
Aluminum Oxide ◽  
Sol Gel ◽  
Calcium Titanate ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Composite Adsorbent ◽  
X Ray ◽  
Ph Values ◽  
Adsorption Capability

Nano-calcium titanate-based coated aluminum oxide (ACCTO) was successfully prepared by the citrate acid sol-gel method and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Its application in speciation of Cr(III) and Cr(VI) from water was studied. The conditions of adsorption and elution were investigated. The results show that nanometer calcium titanate could be immobilized on the aluminum oxide firmly, becoming a composite adsorbent. Two forms of chromium showed different adsorption capability at different pH values, Cr (III) selectively retained at pH 8-14, whereas Cr (VI) retained at pH≤2. So separation of the Cr(III) and Cr(VI) is possible. Retained species were eluted with 5mL of 1 mol•L-1 HCl and NaOH. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The adsorption agent has a promising prospect in removal or enriching and separation of Cr(III) and Cr(VI) in water.

Effects of Calcination Parameters on the Microstructure and Morphology of PZT Nanoparticles Prepared by Modified Sol–Gel Method

2012 ◽  
Vol 576 ◽  
pp. 326-329 ◽  
Author(s):  
Amid Shakeri ◽  
Hossein Abdizadeh ◽  
Mohammad Reza Golobostanfard
Keyword(s):  
Lead Zirconate Titanate ◽  
Sol Gel ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Treatment Conditions ◽  
Perovskite Type ◽  
Perovskite Type Structure

Lead zirconate titanate nanopowder Pb(Zr0.53Ti0.47)O3 (PZT) was prepared by modified sol-gel method with 1-propanol as solvent and acetylacetone as stabilizer. The microstructure and particle size measurements at different heat treatment conditions were characterized by field emission scanning electron microscopy and x-ray diffraction analysis. It was found that the PZT nanoparticles calcinated at 600 °C showed mean diameter of 75-125 nm with high crystallinity of perovskite-type structure.

Preparation and Characterization of Nanosized Barium-Strontium Titanate Immobilized on Aluminum Oxide and its Application in Separation of Cr(III) and Cr(VI)

2010 ◽  
Vol 152-153 ◽  
pp. 1013-1016
Author(s):  
Hong Wang ◽  
Jing Yang
Keyword(s):  
Aluminum Oxide ◽  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Sol Gel ◽  
Complete Separation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Barium Strontium

Nanometer barium-strontium titanate based coated aluminum oxide (ABST) was prepared by the sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Its application in speciation of Cr(III) and Cr(VI) from water were studied. The results showed that the nanometer barium-strontium titanate was immobilized on aluminum oxide firmly, becoming a new adsorbent. Two forms of chromium showed different exchange capacities at different pH values, viz. Cr (III) selectively retained at pH 10–13, whereas Cr (VI) retained at pH 1. Hence complete separation of the two forms of chromium is possible. Retained species were eluted with 5mL of 1 mol•L−1 HCl and 1 mol•L−1 NaOH. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The adsorbent had a promising prospect in the separation of Cr(III) and Cr(VI) in environment water.

scholarly journals ENHANCED FERROELECTRICITY AND FERROMAGNETISM OF (Y, Ni) CO-DOPED BiFeO3 MATERIALS

2018 ◽  
Vol 56 (1A) ◽  
pp. 219
Author(s):  
Dao Viet Thang
Keyword(s):  
Ferroelectric Properties ◽  
Sol Gel ◽  
Rhombohedral Structure ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co Doping ◽  
Saturation Polarization ◽  
Perovskite Type ◽  
Co Doped

In this study, multiferroicMultiferroic Bi1-xYxFe0.975Ni0.025O3 (x = 0.00, 0.05, 0.10, and 0.15) called as (Y, Ni)                co-doped BiFeO3 materials were synthesized by a sol-gel method.  and characterized by X-ray diffraction diagrams and(XRD), energy-dispersive X-ray (EDX) and vibrating sample magnetization (VSM) measurements demonstrated. The result showed that Bi1-xYxFe0.975Ni0.025O3all investigated materials waspresent a single phase of the perovskite-type rhombohedral structure. Ferromagnetism and ferroelectricity of the Bi1-xYxFe0.975Ni0.025O3 materials have been investigated. Results showed that the co-doping by (Y, Ni) for (Bi, Fe)  have affected in enhancing by the (Y, Ni) co-doping, as a result the ferroelectric polarization and magnetization of BiFeO3. The magnetic characterization indicated that the ferromagnetic behavior wasthe initial BiFeO3 materialwere enhanced with increasing concentration of Y3+ for (Y, Ni) co-substituted of BiFeO3. Which could beion. It is attributed to the defferentdifference of the magnetic momentmoments of Ni2+ and Fe3+, and+ ions, as well as the Y3+-Fe3+,+ and Y3+-Ni2+ super-exchange interaction. Theinteractions. The characteristics of the investigated materials, such as remanent magnetization (Mr), saturation magnetization (Ms), remanent polarization (2Pr) and saturation polarization (2Ps) continuously increase upon increasing in the range of x from 0.00 to 0.15. When x = 0.15, the values of Mr and Ms are 0.078 and 0.794 emu/g, respectively. The values of 2Pr and 2Ps are 16.58 and 27.99 µC/cm2, respectively. Origin of ferromagnetic and ferroelectric properties of Bi1-xYxFe0.975Ni0.025O3 materials will be discussed in this paper.

Synthesis of Nano-Sized SrTiO3 Photocatalyst by Sol-Gel Method

2012 ◽  
Vol 512-515 ◽  
pp. 1673-1676 ◽  
Author(s):  
Wei Zhao ◽  
Jian Jun Yao ◽  
Jing Ya ◽  
Lei E ◽  
Zhi Feng Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Complexing Agent ◽  
Strontium Nitrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Gel Processing

A sol-gel processing technology was employed to synthesize fine SrTiO3 powder by using strontium nitrate (Sr(NO3)2) , butyl titanate (Ti(OC4H9)4) as precursors, citric acid (C6H8O6) as complexing agent and (ethylene) glycol (C2H6O2) as stabilizer. Prepared the precursors in liquid phase and then calcined the precursors to achieve nano-sized SrTiO3 powders. The microstructure and composition of the as-synthesized samples were characterized by X-ray diffraction (XRD), Scan Electron Microscopy (SEM), and the photocatalytic activity was studied. The results showed that all the SrTiO3 particles were identified as perovskite phase. The pH values, the content of the acetic acid, the heat treat temperature play important roles on the synthesis of the SrTiO3 photocatalyst. When the pH=1, n(Sr(NO3)2 ) : n(Ti(OC4H9)4) = 1 : 1, n(Sr(NO3)2 ) : n(C6H8O6)=1:1.7, the product has better rate of photodegradation for the Methylene Blue under the ultraviolet condition.

Preparation and Characterization of TiO2 Nanoparticle with SiO2 Shell

2011 ◽  
Vol 233-235 ◽  
pp. 1188-1191
Author(s):  
Hong Cai ◽  
Yan Chen ◽  
Yun Ying Wu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Chemical Components ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Bonding Phase ◽  
Hydrolysis Of

Nano-TiO2 particles were prepared by sol-gel method, of which the surfaces were coated by SiO2. The coating was achieved by the hydrolysis of sodium silicate (Na2SiO3) in ammonium chloride (NH4Cl). The surface bonding, phase constitution and chemical components of the samples were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy (XPS). The mechanism of the SiO2 coating process onto TiO2 surface was analyzed. Results show that SiO2 particles were immobilized on the TiO2 surface via Ti—O—Si bondings, which formed at the interface. The SiO2 layer on TiO2 surface was amorphous, the photocatalytic performance was decreased of the TiO2 while its stability was enhanced after surface modification.

Effect of pH Values on Conversion of Calcite Crystals into Calcium Phosphate Phases in Buffer Solutions

2007 ◽  
Vol 353-358 ◽  
pp. 2183-2186 ◽  
Author(s):  
Ya Ping Guo ◽  
Bao Qiang Li ◽  
Yu Zhou ◽  
De Chang Jia
Keyword(s):  
Calcium Phosphate ◽  
Ph Value ◽  
Octacalcium Phosphate ◽  
Precipitation Reaction ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
Effect Of Ph ◽  
X Ray ◽  
Buffer Solutions ◽  
Ph Values

Calcium phosphate phases with laminar-plate structure were converted from calcite powders after soaking in phosphate buffer solutions of pH’s 6.0-8.0 at 37 °C for 9 days. The effect of pH values on the conversion of calcite crystals was investigated by X-ray diffraction, scanning electron microscopy and Fourier-transform infrared spectroscopy. If the pH value of a buffer solution is kept at 6.0, calcite powders are converted mainly to dicalcium phosphate dehydrate (DCPD) or octacalcium phosphate (OCP). If the pH value is kept at 6.4 or 7.0, calcite powders are converted mainly to OCP. Hydroxyapatite (HAP) with poorly crystalline can be obtained from calcite powders both by treatment of a basic buffer solution, and by treatment of an acid buffer solution without regulating its pH value during the reaction. The conversion mechanism of calcite crystals is a dissolution-precipitation reaction.

Photocatalytic Degradation of Reactive Brilliant Blue KN-R by N, Fe- TiO2/FFA

2011 ◽  
Vol 183-185 ◽  
pp. 2028-2031
Author(s):  
Gui Rong Wang
Keyword(s):  
Ph Value ◽  
Sol Gel ◽  
Dip Coating ◽  
Brilliant Blue ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Operation Conditions ◽  
First Order Kinetics ◽  
Fe Ions

TiO2 photocatalyst modified by N and Fe ions was loaded on self-made fly ash forming adsorbent (FFA) using the sol-gel dip-coating process. The crystal structure and photoadsorption ability was characterized by X-ray diffraction (XRD) and UV-Vis spectrophotometer, respectively. The photo catalytic degradation of Reactive Brilliant Blue KN-R using N, Fe-TiO2/FFA was examined. Effects of initial dye concentration, pH value and hydrogen peroxide dosage on degradation were studied. The degradation of the organic molecule followed a pseudo-first-order kinetics according to the Langmuir model. Under the optimum operation conditions, 30 mg/L KN-R could be decolorized over 97.47% within 75 min.

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