scholarly journals Isothermal models of Chromium (VI) adsorption by using Fe3O4 nanoparticles

10.30544/489 ◽  
2020 ◽  
Author(s):  
Dang Tan Hiep ◽  
Bui Thi Hoa ◽  
Ngo Thi My Thanh ◽  
Nguyen Viet Long ◽  
Le Hong Phuc ◽  
...  
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Contact Time ◽  
Ph Value ◽  
Average Particle Size ◽  
Adsorption Kinetic ◽  
Average Particle ◽  
Suitable Model ◽  
Isothermal Adsorption ◽  
Adsorption Models ◽  
Chromium Vi

The ferromagnetic Fe3O4 nanoparticles with the average particle size of about 10 nm were used to adsorb chromium (VI) in aqueous solution. The equilibrium of Cr(VI) adsorption can be achieved at the pH value of 2.5, in the contact time of 120 minutes. The mechanisms of Cr(VI) adsorption were evaluated by 4 isothermal adsorption models Langmuir, Freundlich, Redlich-Peterson, and Temkin. The results showed that all four models are satisfied; especially, Redlich-Peterson is the most suitable model to describe the adsorption kinetic of Cr(VI) on ferromagnetic Fe3O4 nanoparticles.

Photocatalytic Degradation of Diazinon in Aqueous Solutions Using Immobilized MgO Nanoparticles on Concrete

2019 ◽  
Vol 17 (9) ◽  
Author(s):  
Tayebeh Ahmadifard ◽  
Rouhollah Heydari ◽  
Mohammad Javad Tarrahi ◽  
Ghodratollah Shams Khorramabadi
Keyword(s):  
Photocatalytic Degradation ◽  
Contact Time ◽  
Ph Value ◽  
Uv Light ◽  
Degradation Products ◽  
Average Particle Size ◽  
Concrete Surface ◽  
Average Particle ◽  
Operational Parameters ◽  
Mgo Nanoparticles

Abstract Photocatalytic degradation of diazinon in the aqueous solution using UV light and MgO nanoparticle (NPs) immobilized on the concrete was investigated. Prepared catalyst was characterized using TEM, XRD, SEM, and EDX techniques. The results showed that the average particle size of immobilized MgO NPs was 38.3 nm and NPs appropriately was coated on the concrete surface. The performance of degradation and mineralization of diazinon was evaluated by HPLC and TOC techniques, respectively. The effect of operational parameters including pH value, initial pesticide concentration, and contact time were studied on the removal and mineralization of diazinon by a photocatalytic process. The results showed that the MgO NPs and UV light had little effect in removing pesticide when used individually. On the other hand, diazinon can be effectively degraded by immobilized MgO NPs in the presence of UV light. Degradation products of diazinon using the proposed photocatalytic technique were identified by the GC-MS analysis. The maximum diazinon removal (99.46 %) was obtained under the conditions; pH 7, diazinon concentration of 5 mg/L, and contact time of 120 minutes. Also, the lowest energy consumption conditions were as follow; pH 7, diazinon concentration of 5 mg/L, and contact time of 30 minutes.

scholarly journals Synthesis and characterization of Fe3O4 nanoparticles by electrodeposition and reduction methods

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Nurrulhidayah Salamun ◽  
How Xin Ni ◽  
Sugeng Triwahyono ◽  
Aishah Abdul Jalil ◽  
Ainul Hakimah Karim
Keyword(s):  
Surface Area ◽  
Ferric Oxide ◽  
Fe3o4 Nanoparticles ◽  
Average Particle Size ◽  
Hydrogen Atmosphere ◽  
Bet Surface Area ◽  
Average Particle ◽  
Chromium Vi ◽  
Removal Of Heavy Metals ◽  
Reduction Methods

Magnetite (Fe3O4) nanoparticles have been studied extensively due to their good magnetic, optic and electric properties which offer a great potential of applications in many field especially in removal of heavy metals such as the adsorption of poisonous Cr(VI) ion in water. In addition, Fe3O4 is the only material that has up to now been use in human because it is the only material which is known to be biocompatible, without relevant toxicity in the applied dosage. In this study Fe3O4 nanoparticles were prepared by reduction of ferric oxide (Fe2O3) precursor at 598 K for 10, 20, 30 and 40 min. While, ferric oxide (Fe2O3) precursor was prepared by electrodeposition of iron plate in the N,N-dimethylformamide solvent and tetraethylammonium perchlorate and naphthalene as mediators at 263 K. Reduction of Fe2O3 was carried out with an isothermal heating at 598 K under hydrogen atmosphere. Fe2O3 and Fe3O4 were characterized with XRD, BET Surface area, FTIR, FESEM-EDX and TEM. The surface area of both Fe2O3 and Fe3O4 was 38 - 45 m2/g with the average particle size was 40 - 60 nm. The XRD result showed that the crystallinity of Fe3O4 increased with reduction time. The activity of Fe2O3 and Fe3O4 nanoparticles were tested on the adsorption of chromium (VI) at room temperature in which 30-40 % of Cr(VI) ion was adsorbed on the Fe2O3 and Fe3O4 nanoparticles.

scholarly journals Reinforcement of Quaternary Ammonium Modified Silica (QAMS) with Magnetite and its Application by Solid Phase Adsorption (SPA) to Adsorb Chromate Ions

2020 ◽  
Vol 23 (10) ◽  
pp. 338-345
Author(s):  
Ngatijo Ngatijo ◽  
Restina Bemis ◽  
Abdul Aziz ◽  
Rahmat Basuki
Keyword(s):  
Solid Phase ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Average Particle ◽  
Modified Silica ◽  
Spherical Form ◽  
Chromate Ions ◽  
Chromium Vi ◽  
The Stability ◽  
Ph Range

Chromium (VI) in the form of chromate anions that have toxic properties needs to be overcome. This study aims to reinforce cationic sorbent quaternary amine-modified silica with magnetite (QAMS-Fe3O4) to adsorb chromate ions. QAMS prepared by reflux methylation ammine modified silica (AMS) obtained from destruction silicate from rice husk ash followed by the addition of 3-APTMS. Characterization QAMS-Fe3O4 by FT-IR showed successfully of methylation process indicated by disappearing absorbance at 1388 cm-1, and emerging absorbance at 2939 cm-1 in QAMS and QAMS-Fe3O4 indicated a transformation of N-H from -NH2 group to [-N+(CH3)3]. XRD analysis denotes 2θ = 30.15°, 35.53°, 43.12°, 57.22°, and 62.90° (JCPDS No. 00-033-0664) fathomed as a characteristic peak of magnetite. SEM-EDX reveals the homogenous topological spherical form with an average particle size 0.006 µm that is dominated by Si element (52.81%) with magnetic moment value = 34.1 emu/g. The stability test shows that this material stable in an acid condition. The adsorption of chromate ions was conducted by the SPA method. Optimal pH obtained by pH range 4-7 with more than 90% adsorbed chromate ions. Variation of increasing series flow rate from 0.05 to 1.5 mL min-1 resulted in decreased adsorbed chromate ions. The use of SPA methods offered simpler and easier handling than the batch method without overriding the adsorption process effectiveness.

scholarly journals Adsorption of methylene blue from aqueous solutions by pyrolusite ore

2018 ◽  
Vol 18 (44) ◽  
pp. 5-11 ◽  
Author(s):  
Nizamettin Demirkıran ◽  
G D Turhan Özdemir ◽  
M Saraç ◽  
M Dardağan
Keyword(s):  
Methylene Blue ◽  
Particle Size ◽  
Contact Time ◽  
Average Particle Size ◽  
Dye Adsorption ◽  
Blue Dye ◽  
Average Particle ◽  
Order Kinetic ◽  
Adsorbent Dosage ◽  
Initial Ph

In this study, the adsorption of methylene blue dye was examined by using pyrolusite ore as a low-cost alternative adsorbent source. Pyrolusite, which contains mainly MnO2, is a manganese ore. The effects of the initial concentration of dye, contact time, initial pH of solution, adsorbent dosage, stirring speed of solution, and average particle size of adsorbent on the adsorption of methylene blue were studied. It was found that the percentage of the adsorbed dye increased with increasing the amount of pyrolusite. While the initial dye concentration, initial pH, contact time, stirring speed, particle size, and adsorbent dosage were 25 ppm, 6, 90 min, 250 rpm, 63 µm, and 12 g/l, respectively, the efficiency of dye adsorption on pyrolusite ore was 99%. The isotherm and kinetic studies relating to this adsorption process were also made. It was found that the equilibrium data followed the Langmuir isotherm model while the kinetic of process could be described by the pseudo-second order kinetic model.

Selection of Polyanions as Complexation Agent in the Formation of Nanochitosan by Polyelectrolyte Complex Method

2019 ◽  
Vol 948 ◽  
pp. 140-145
Author(s):  
Al Dina N. Khoerunisa ◽  
Prihati Sih Nugraheni ◽  
Mohammad Fahrurrozi ◽  
Wiratni Budhijanto
Keyword(s):  
Particle Size ◽  
Polyelectrolyte Complex ◽  
Ph Value ◽  
Average Particle Size ◽  
Aqueous Dispersion ◽  
Complex Method ◽  
Average Particle ◽  
Arabic Gum ◽  
Mixing Ratios ◽  
The Stability

The aqueous dispersion of nanochitosan was prepared by polyelectrolyte complex (PEC) method with various mixing ratios of chitosan and polyanions, i.e., chitosan-glucomannan, chitosan-hyaluronic acid, and chitosan-Arabic gum. The formation of nanochitosan was carried out by adding the polyanion solution dropwise into the acid solution of chitosan. The study aimed to determine the best polyanion among the variations tested in this study, concerning the targeted particle size and the stability of the dispersion over time. Particle size distribution was observed by Particle Size Analyzer (PSA). The result indicated that Arabic gum gave the smallest average particle size, i.e. 192.5 nm, at a chitosan/polyanion mass ratio of 3:1 and pH value of 4.

scholarly journals Fabrication of Caseinate Stabilized Thymol Nanosuspensions via the pH-Driven Method: Enhancement in Water Solubility of Thymol

Foods ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1074
Author(s):  
Wei Zhou ◽  
Yun Zhang ◽  
Ruyi Li ◽  
Shengfeng Peng ◽  
Roger Ruan ◽  
...  
Keyword(s):  
Particle Size ◽  
Water Solubility ◽  
Ph Value ◽  
Average Particle Size ◽  
Amorphous State ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Commercial Products ◽  
Long Term Storage

Thymol has been applied as a spice and antibacterial agent in commercial products. However, the utilization of thymol in the food and pharmaceutical field has recently been limited by its poor water solubility and stability. In this work, a caseinate-stabilized thymol nanosuspension was fabricated by pH-driven methods to overcome those limitations. Firstly, the chemical stability of thymol at different pH value conditions was investigated. The physiochemical properties of thymol nanosuspensions were then characterized, such as average particle size, zeta potential, encapsulation efficiency, and loading capacity. Meanwhile, the X-ray diffraction results showed that thymol was present as an amorphous state in the nanosuspensions. The thermal stability of thymol was slightly enhanced by encapsulation through this process, and the thymol nanosuspensions were stable during the long-term storage, and the average particle size of nanosuspensions showed that there was no aggregation of nanosuspensions during storage and high temperature. Finally, the antimicrobial activity of thymol nanosuspensions was evaluated by investigating the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Salmomella enterca, Staphlococcus aureus, Escherichia coli, and Listeria monocytogenes. These results could provide useful information and implications for promoting the application of thymol in food, cosmetic, and pharmaceutical commercial products.

Ultrafine TiO2 Powders Prepared from Aqueous TiCl4 Solutions at Room Temperature

2007 ◽  
Vol 353-358 ◽  
pp. 2135-2138
Author(s):  
Hong Liang Yi ◽  
Jie Zhang ◽  
Ming Tu Ma ◽  
Hao Zhang ◽  
Bong Ho Lee ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Ph Value ◽  
Anatase Phase ◽  
Average Particle Size ◽  
Rutile Phase ◽  
Average Particle ◽  
Spectral Peaks ◽  
Scherrer Formula ◽  
Stock Solutions

Ultrafine TiO2 powders as rutile and anatase phase were simply precipitated at room temperature for only tens of hours by simply controlling the pH value and Ti4+ concentration via aqueous TiCl4 solution. Under the optimal pH value and Ti4+ concentration, the average particle size of powders with rutile phase was 3.7nm, while that of powders with anatase phase was 3.0nm. The average particle size was calculated from the broadening of corresponding X-ray spectral peaks by Scherrer formula. In addition, 3.0 mol.l-1 are suggested to be used as concentration of stock solutions instead of the current concentration 2.0 mol.l-1.

The Effect of the Malt Grinding Degree on the pH Value and Extract Content in Beer Mash

2018 ◽  
Vol 22 (4) ◽  
pp. 43-49
Author(s):  
Marcin Natoniewski ◽  
Leszek Rydzak ◽  
Agata Wyciszkiewicz ◽  
Tomasz Guz
Keyword(s):  
Particle Size ◽  
Food Production ◽  
Ph Value ◽  
Average Particle Size ◽  
Average Particle ◽  
Malt Extract ◽  
Chemical Changes ◽  
Extract Content ◽  
Physical And Chemical ◽  
Degree Of Fragmentation

AbstractIn recent years, a dynamic development of brewing has been observed. Increasingly, production of malt and beer takes place even in smaller industrial factories, breweries restaurants or at home. Extraction is a process applied in a variety of industries, including food production, as a way of extracting specific ingredients from their mixtures. As a result of this process, not only sugars, proteins, fats, enzymes, vitamins, colorants, fragrances and flavors, but also malt and hop extracts are being isolated. In the process of mashing, in which the malt ingredients are being extracted, many biochemical, physical and chemical changes take place. The aim of the study was to analyze the effect of the degree of fragmentation of pilsner type malt on the amount of extract obtained and the pH of the mash. It has been observed that the degree of malt fragmentation has a significant effect on the content of the extract in the mash: the more fragmented malt, the more malt extract in mash produced using the malt. It has also been found that the pH of the mash increases with the average particle size of malt.

Magnetic Fe3O4 nanoparticles for adsorptive removal of acid dye (new coccine) from aqueous solutions

2010 ◽  
Vol 62 (4) ◽  
pp. 844-851 ◽  
Author(s):  
Chih-Huang Weng ◽  
Yao-Tung Lin ◽  
Chia-Ling Yeh ◽  
Y. C. Sharma
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Fe3o4 Nanoparticles ◽  
Average Particle Size ◽  
Precipitation Method ◽  
Maximum Adsorption Capacity ◽  
Average Particle ◽  
Magnetic Fe3o4 Nanoparticles ◽  
Magnetic Fe3o4

The ability of magnetic Fe3O4 nanoparticles (MFN) to remove new coccine (NC), an acidic dye, from aqueous solutions was studied. Parameters including ionic strength, pH, and temperature were evaluated. MFN, prepared by precipitation method, exhibits an average particle size of 12.5 nm, specific surface area of 85.5 m2/g, and pHzpc of 5.9. Results of kinetic adsorption experiments indicated that the pseudo-second-order rate of adsorption increased with increasing initial NC concentration. Findings also revealed that the equilibrium data could be fitted into Langmuir adsorption isotherm. The adsorption is favored at low pH, high temperature, and low ionic strength, whereupon a maximum adsorption capacity of 1.11 × 10−4 mol/g was determined for NC. Thermodynamic functions indicated that the adsorption process is spontaneous and exothermic in nature. Tests of regeneration showed that after 5 regeneration cycles the adsorption capacity of NC decreased to 35% to its original capacity.

Preparation and Formation Mechanism of the Highly Dispersive Silver Powders Used for the Front Paste of the Solar Cell

2013 ◽  
Vol 448-453 ◽  
pp. 2963-2968
Author(s):  
Cui Yan Jiao ◽  
Tie Bing Xu ◽  
Gang Ren
Keyword(s):  
Ascorbic Acid ◽  
Solar Cell ◽  
Formation Mechanism ◽  
Growth Process ◽  
Ph Value ◽  
Average Particle Size ◽  
Average Particle ◽  
Silver Particles ◽  
Primary Particles ◽  
Three Stages

The preparation of highly dispersive silver particles of average particle size of 1~2μm used for the front paste of the solar cell were carried out by rapid addition of ascorbic acid solution into the aqueous AgNO3 solution at room temperature. The dispersive quasi-spherical silver particles were obtained with the AgNO3 concentration of 0.1M, AgNO3/Ascorbic acid mass ratio of 1:0.8 without controlling the pH value of the system. Elevating the concentrations of the AgNO3 solution resulted in the formation of flowerlike structures. The formation mechanism was investigated, it was concluded that the growth process of the highly dispersive silver particles include three stages, first, the formation of the precursor, followed by the nuclei burst and the diffusive growth process due to formation of H+ ions adsorbed on the negative charged Ag nuclei as well as the steric effect of the ascorbic acid molecule, finally, when the pH value decreased dramatically to approaching the isoelectric point, the adsorbed H+ was released and the resulting primary particles in turn aggregated to form secondary particles.

Sign in / Sign up

Export Citation Format

Share Document