Preparation and Photocatalytic Application of the Composites PMo12/AgNPs Based on Polyoxometalates

2021 ◽  
Vol 21 (12) ◽  
pp. 6135-6142
Author(s):  
Sai Zeng ◽  
Ce Liang ◽  
Hai-Hui Yu ◽  
Jun-Ping Wang ◽  
Chao-Bo Xue ◽  
...  
Keyword(s):  
Sodium Citrate ◽  
Catalytic Mechanism ◽  
Supported Catalysts ◽  
Test Methods ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Decolorization Rate ◽  
Silver Nanomaterials ◽  
Photocatalytic Application ◽  
Ft Ir

Supported catalysts, consisting of PMo12 immobilized on silver nanomaterials at different recombination time and the silver nanomaterials with different template sodium citrate amount characterized by FT-IR, XRD, SEM, UV-vis and other test methods. The results show that the AgNPs are relatively uniformed with sizes between 100–300 nm when the sodium citrate addition amount is 9.0 mL. As the reaction time of PMo12/AgNPs increases, the adhesion of AgNPs on the surface of PMo12 becomes more complete. Using PMo12 and PMo12/AgNPs composite materials as catalysts, methylene blue (MB) is photocatalytically degraded under simulated visible light conditions. The results show that PMo12 can catalyze MB effectively, and the decolorization rate reached 98.6% when the catalyst content is 2 g/L, the solution pH is 3 and the MB concentration is 5 mg/L. Under the same experimental conditions, photocatalytic performance of the PMo12/AgNPs system is better than that of the PMo12 further improved the photocatalytic degradation effect of the MB solution with a decolorization rate of 100%. The composite still keeps good photocatalytic activity and stability after three cycles of use. Finally, the catalytic mechanism of the POMs composite material is preliminarily discussed.

Effect of pH and NH4NO3 as a Spray Additive on Penetration of NAA Through Isolated Tomato Fruit Cuticle

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 550a-550 ◽  
Author(s):  
Royal G. Fader ◽  
Martin J. Bukovac
Keyword(s):  
Direct Measurement ◽  
Sodium Citrate ◽  
Tomato Fruit ◽  
Initial Slope ◽  
Control Effect ◽  
Solution Ph ◽  
Ph Change ◽  
Effect Of Ph ◽  
Spray Droplets ◽  
Partition Behavior

We have reported that NH4NO3 (AN, 8 mM, pH 4.2), applied as simulated spray droplets, enhanced penetration of 14C-NAA through isolated leaf and fruit cuticles. One explanation for this response is that AN depresses NAA (pKa= 4.2) dissociation, increasing the nondissociated moiety, which penetrates more readily than the anion (NAA'). Direct measurement of AN (concn. 0-800 mM) effect on NAA (215 μM) dissociation as indexed by change in solution pH revealed no significant effect, with a pH change from 4.19 to 4.05. This change is not sufficient to account for the observed enhancement. When 14C-NAA, buffered (20 mM sodium citrate) at pH 3.2, 4.2, 5.2, 6.2, was partitioned against chloroform, there was a marked increase in NAA partitioning into chloroform as pH was decreased. AN (8 mM) did not alter this partition behavior, also indicating no effect on NAA dissociation. However, in cuticle penetration studies, using a finite dose system with 14C-NAA buffered at pH 3.2, 4.2, 5.2, 6.2, and in the presence and absence of 8 mM AN, there was no marked or consistent pH or AN (-70 to + 232 % of no AN control) effect on penetration as indexed by initial slope (4-12 h) or penetration after 120 h. The possible effects of AN and buffer on penetration of 14C-NAA from the droplet deposit will be discussed.

scholarly journals Removal of Chromium(III) and Cadmium(II) Heavy Metal Ions from Aqueous Solutions Using Treated Date Seeds: An Eco-Friendly Method

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3718
Author(s):  
Mohammad Azam ◽  
Saikh Mohammad Wabaidur ◽  
Mohammad Rizwan Khan ◽  
Saud I. Al-Resayes ◽  
Mohammad Shahidul Islam
Keyword(s):  
Metal Ions ◽  
Adsorption Capacity ◽  
Low Cost ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Surface Analysis Techniques ◽  
Adsorption Processes ◽  
Ft Ir ◽  
Metal Elution ◽  
Date Pits

The aim of the research was to prepare low-cost adsorbents, including raw date pits and chemically treated date pits, and to apply these materials to investigate the adsorption behavior of Cr(III) and Cd(II) ions from wastewater. The prepared materials were characterized using SEM, FT-IR and BET surface analysis techniques for investigating the surface morphology, particle size, pore size and surface functionalities of the materials. A series of adsorption processes was conducted in a batch system and optimized by investigating various parameters such as solution pH, contact time, initial metal concentrations and adsorbent dosage. The optimum pH for achieving maximum adsorption capacity was found to be approximately 7.8. The determination of metal ions was conducted using atomic adsorption spectrometry. The experimental results were fitted using isotherm Langmuir and Freundlich equations, and maximum monolayer adsorption capacities for Cr(III) and Cd(II) at 323 K were 1428.5 and 1302.0 mg/g (treated majdool date pits adsorbent) and 1228.5 and 1182.0 mg/g (treated sagai date pits adsorbent), respectively. It was found that the adsorption capacity of H2O2-treated date pits was higher than that of untreated DP. Recovery studies showed maximal metal elution with 0.1 M HCl for all the adsorbents. An 83.3–88.2% and 81.8–86.8% drop in Cr(III) and Cd(II) adsorption, respectively, were found after the five regeneration cycles. The results showed that the Langmuir model gave slightly better results than the Freundlich model for the untreated and treated date pits. Hence, the results demonstrated that the prepared materials could be a low-cost and eco-friendly choice for the remediation of Cr(III) and Cd(II) contaminants from an aqueous solution.

scholarly journals Novel Preparation of Cu and Fe Zirconia Supported Catalysts for Selective Catalytic Reduction of NO with NH3

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 55
Author(s):  
Katarzyna Świrk ◽  
Ye Wang ◽  
Changwei Hu ◽  
Li Li ◽  
Patrick Da Costa ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Supported Catalysts ◽  
Catalytic Performance ◽  
Experimental Conditions ◽  
One Pot ◽  
Nh3 Scr ◽  
Scr Of No ◽  
Temperature Programmed ◽  
Stationary Sources

Copper and iron promoted ZrO2 catalysts were prepared by one-pot synthesis using urea. The studied catalysts were characterized by XRD, N2 physisorption, XPS, temperature-programmed desorption of NH3 (NH3-TPD), and tested by the selective catalytic reduction by ammonia (NH3-SCR) of NO in the absence and presence of water vapor, under the experimental conditions representative of exhaust gases from stationary sources. The influence of SO2 on catalytic performance was also investigated. Among the studied catalysts, the Fe-Zr sample showed the most promising results in NH3-SCR, being active and highly selective to N2. The addition of SO2 markedly improved NO and NH3 conversions during NH3-SCR in the presence of H2O. The improvement in acidic surface properties is believed to be the cause.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste

2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen
Keyword(s):  
Granular Material ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Precipitation Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

scholarly journals Characterization of Manganese Oxide/Alumina Catalysts

1995 ◽  
Vol 12 (3) ◽  
pp. 221-229 ◽  
Author(s):  
S.A. El-Hakam
Keyword(s):  
Manganese Oxide ◽  
Calcination Temperature ◽  
Manganese Content ◽  
Textural Properties ◽  
Catalytic Decomposition ◽  
Experimental Conditions ◽  
Surface Areas ◽  
Ft Ir ◽  
Mn Content ◽  
Alumina Catalysts

The effect of heat treatment of manganese oxide/alumina catalysts of various manganese content on the structural and textural properties and the catalytic decomposition of hydrogen peroxide were investigated. The FT-IR results have shown that depending on the calcination temperature and metal loading MnO2 and MnO3 are formed on the investigated samples. No spinel structure was detected under the experimental conditions. The surface areas were found to decrease with increasing calcination temperature and metal content up to 30 wt.% Mn. The mean pore radius increased with both calcination temperature and Mn content. The rate of catalytic decomposition of H2O2 was found to depend on the pH, the calcination temperature and the state of Mn on the catalyst surface.

Immobilization of K7PW11O39 on ZrO2 Nanofiber: Ultra-deep Desulfurization Based in Extraction Catalytic Oxidation Desulfurization System

2021 ◽  
Vol 72 (3) ◽  
pp. 89-101
Author(s):  
Guowei Zeng ◽  
Guihong Wu ◽  
Zhihui Wang ◽  
Xiaonan Li ◽  
Jie Yang ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Catalytic Mechanism ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
Transmission Electron ◽  
Deep Desulfurization ◽  
Thermo Gravimetric Analyzer ◽  
Ft Ir ◽  
Model Oil

In this work, K7PW11O39 (abbreviated as PW11) was immobilized on ZrO2 nanofibers and used as an efficient recyclable catalyst in extraction catalytic oxidation desulfurization system (ECODS).The 500 ppm DBT model oil(5mL) can desulphurize completely within 20 min with the catalytic conditions of 50��, 0.010 g 50 wt%- CTAB�C PW11�CZrO2 nanofibers and O/S molar ratio H2O2/DBT molar ratio�� was 2:1. The synthesized catalyst was characterized by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and thermo gravimetric analyzer (TGA). The results indicated the PW11�CZrO2 nanofibers were synthesized successfully and the possible catalytic mechanism is also revealed.

scholarly journals Green synthesis of the innovative super paramagnetic nanoparticles from the leaves extract of Fraxinus chinensis Roxb and their application for the decolourisation of toxic dyes

2019 ◽  
Vol 8 (1) ◽  
pp. 256-271 ◽  
Author(s):  
Imran Ali ◽  
Changsheng Peng ◽  
Dichu Lin ◽  
Iffat Naz
Keyword(s):  
Environmental Remediation ◽  
Degradation Mechanism ◽  
Pseudo First Order Reaction ◽  
Solution Ph ◽  
Factors Affecting ◽  
Toxic Dyes ◽  
Degradation Of Dyes ◽  
Stability Structure ◽  
Ft Ir ◽  
Fraxinus Chinensis

Abstract The leaves extract of Fraxinus chinensis Roxb was used for the synthesis of the innovative phytogenic magnetic nanoparticles (PMNPs) without adding toxic surfactants. The formation, morphology, elemental composition, size, thermal stability, structure and magnetic properties of these PMNPs were examined by UV-visible spectrophotometry, FT-IR, XRD, SEM, EDX, TEM, VSM, XPS, BET and TGA. The reactivity of the obtained PMNPs against decolourising toxic dyes, namely, malachite green (MG), crystal violet (CV) and methylene blue (MB), were investigated by UV-vis spectrophotometry. Further, the factors affecting the removal of dyes, including solution pH, adsorbent dosages, initial concentration of dyes, reaction temperature and contact time, were also investigated. The results revealed the decolourisation of 99.12% of MG and 98.23% of CV within 60 min, and 97.52% of MB within 200 min by the PMNPs using dyes concentration of 25 mg/l at pH 6.5 and 298.15 K. The kinetics outcome indicated that the degradation of dyes matched well to the pseudo first-order reaction kinetics model. Furthermore, the probable degradation mechanism of dyes by the PMNPs, including the adsorption of cationic dye molecules onto the negatively charged surface of adsorbent and the oxidation of the Fe° in the solution, were discussed. Thus, the PMNPs can be produced by the bulk and have great potential to be employed for biomedical/environmental remediation.

Preparation and application of magnetite nanoparticles immobilized on cellulose acetate nanofibers for lead removal from polluted water

2016 ◽  
Vol 17 (1) ◽  
pp. 176-187 ◽  
Author(s):  
Thanaa I. Shalaby ◽  
Marwa F. El-Kady ◽  
Abd El Halem M. Zaki ◽  
Soheir M. El-Kholy
Keyword(s):  
Iron Oxide ◽  
Cellulose Acetate ◽  
Iron Oxide Nanoparticles ◽  
Composite Nanofibers ◽  
Polluted Water ◽  
Oxide Nanoparticles ◽  
Lead Removal ◽  
Order Model ◽  
Solution Ph ◽  
Ft Ir

Novel magnetic cellulose acetate (CA) nanofibers were fabricated using an electrospinning process. Co-precipitated magnetite iron oxide nanoparticles were immobilized onto CA nanofibers at different weight ratios (0.2–2.5% wt/v) with a CA concentration of 15% (wt %), applied electric voltage of 20 kV, feeding rate of 1.5 ml/h and 7 cm distance between needle tip and collector. The prepared iron oxide nanoparticles were characterized using X-ray diffraction, a transmission electron microscope, a Fourier transform infrared spectrophotometer (FT-IR) and a vibrating sample magnetometer (VSM). The magnetic nanofibers were characterized by scanning electron microscopy, FT-IR, thermogravimetric analysis and VSM. The fabricated composite nanofibers were evaluated as a sorbent matrix for lead decontamination from aqueous solution using a batch technique. The influence of solution pH, contact time and adsorbent concentration on the removal efficiency was investigated. Adsorption kinetics models and isotherms were applied to the lead decontamination process onto the fabricated composite nanofibers. The kinetics of the sorption process revealed that the pseudo-second-order model fitted relatively better than the pseudo-first-order model. On the other hand, both the Langmuir and Freundlich isotherms gave a comparable fit to the adsorption data, with a high coefficient of regression of 0.999.

Effect of Grinding Aids on the Fracture Energy of Mica

2011 ◽  
Vol 402 ◽  
pp. 503-509
Author(s):  
Ze Hong Wang ◽  
Fu Jia Yu ◽  
Shan Cai ◽  
Shan Zhi Deng ◽  
Roger Horn
Keyword(s):  
Sodium Chloride ◽  
Fracture Energy ◽  
Sodium Citrate ◽  
Ph Value ◽  
Sodium Tripolyphosphate ◽  
Experimental System ◽  
Ammonium Bromide ◽  
Solution Ph ◽  
Grinding Aids ◽  
Slurry Rheology

An extension of the classical Obriemoff experiments has been set up to measure the fracture energy of mica. This experimental system will be entirely independent of slurry rheology. CTAB (Cetyl Trimethyl Ammonium Bromide), sodium tripolyphosphate, sodium hexametaphosphate, and tri-sodium citrate are used as grinding aids in this study and the fracture energy has been measured for mica in air, water, and water with the addition of various concentrations of these grinding aids. The results show that the fracture energy of mica in water is about half of what it is in air. Grinding aids are shown to reduce the fracture energy of mica, but not dramatically. Addition of grinding aids reduces the fracture energy by a further 10-20%, with tri-sodium citrate appearing to be the most effective. For each grinding aid there appears to be an optimal concentration, typically around 10 mmol. An experiment is also done with sodium chloride at a range of concentrations to investigate the mechanism of these grinding aids, but no reduction in fracture energy (compared to water) was observed, hence the molecular-level mechanism of action of these grinding aids remains unclear. The effect of solution pH values on the fracture energy are also investigated using tri-sodium citrate and sodium chloride. The results show that the solution pH value may effect on the fracture energy of mica. So, in practice, both concentration and pH value of solution are important for getting better grinding results.

scholarly journals Removal of anionic surfactants by sorption onto Aminated Mesoporous Carbon

2013 ◽  
Vol 19 (3) ◽  
pp. 347-357 ◽  
Author(s):  
S.E. Moradi ◽  
J. Khodaveisy ◽  
R. Dashti
Keyword(s):  
Contact Time ◽  
Mesoporous Carbon ◽  
Anionic Surfactants ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Langmuir Model ◽  
Carbon Adsorbents ◽  
Solution Ph ◽  
Batch Mode ◽  
Ft Ir

Direct and indirect releases of large quantities of surfactants to the environment may result in serious health and environmental problems. Therefore, surfactants should be removed from water before release to the environment or delivery for public use. In the present work, the removal of anionic surfactants, benzene sulfonate (BS), p-toluene sulfonate (TS) and 4-octylbenzene sulfonate (OBS) from water by adsorption onto Amino modified mesoporous carbon (AMC) were studied. The AMC surface chemistry and textural properties was characterized by nitrogen adsorption, XRD and FT-IR analyses. Experiments were conducted in batch mode with the variables such as amount of contact time, solution pH, dose of adsorbent and temperature. Finally, the adsorption isotherms of anionic surfactants on mesoporous carbon adsorbents were in agreement with a Langmuir model. AMC has shown higher anionic surfactants adsorption capacity than the untreated mesoporous carbon, which can explain by strong interaction between anionic surfactant and cationic surface of adsorbent.

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