Formation of Platinum and Palladium Bimetallic Superfine Particles by Ultrasonic Irradiation

1997 ◽  
Vol 497 ◽  
Author(s):  
Toshiyuki Fujimoto ◽  
Shinya Terauchi ◽  
Hiroyuki Umehara ◽  
Isao Kojima ◽  
William Henderson
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Size Distribution ◽  
Ultrasonic Irradiation ◽  
Bimetallic Nanoparticles ◽  
Average Diameter ◽  
Narrow Size Distribution ◽  
Bimetallic Particles

ABSTRACTPt/Pd bimetallic nanoparticles were prepared by ultrasonic irradiation of aqueous solutions containing salts of both metal ions. Uniform bimetallic particles were found to have a 2.8 nm average diameter and a narrow size distribution. The size was similar to Pt monometallic particles, and the shape was similar to Pd monometallic particles, both prepared by ultrasound in the same way.

Colloidal synthesis of monodisperse trimetallic IrNiFe nanoparticles as highly active bifunctional electrocatalysts for acidic overall water splitting

2017 ◽  
Vol 5 (47) ◽  
pp. 24836-24841 ◽  
Author(s):  
Luhong Fu ◽  
Gongzhen Cheng ◽  
Wei Luo
Keyword(s):  
Synergistic Effect ◽  
Size Distribution ◽  
Water Splitting ◽  
Average Diameter ◽  
Colloidal Synthesis ◽  
Synthetic Method ◽  
Alloy Nanoparticles ◽  
Narrow Size Distribution ◽  
Acidic Media ◽  
Highly Active

Monodisperse IrNiFe alloy nanoparticles with an average diameter of 2.2 nm have been synthesized by a colloidal synthetic method. By taking advantage of the synergistic effect between Ir, Ni and Fe and the ultrasmall NPs with narrow size distribution, the as-synthesized IrNiFe catalyst exhibits superior HER/OER performances in acidic media.

Macrostructure and microphysics of Saturn's E-ring

1984 ◽  
Vol 75 ◽  
pp. 607-613 ◽  
Author(s):  
Kevin D. Pang ◽  
Charles C. Voge ◽  
Jack W. Rhoads
Keyword(s):  
Size Distribution ◽  
Spherical Shape ◽  
Mie Scattering ◽  
Narrow Size Distribution ◽  
Electrostatic Levitation ◽  
Volcanic Origin ◽  
Micron Diameter

Abstract.All observed optical and infrared properties of Saturn's E-ring can be explained in terms of Mie scattering by a narrow size distribution of ice spheres of 2 - 2.5 micron diameter. The spherical shape of the ring particles and their narrow size distribution imply a molten (possibly volcanic) origin on Enceladus. The E-ring consists of many layers, possibly stratified by electrostatic levitation.

Chitosan-based Magnetic Composites - Efficient Adsorbents for Removal of Pb(II) and Cu(II) from Aqueous Mono and Bicomponent Solutions

2018 ◽  
Vol 69 (9) ◽  
pp. 2323-2330 ◽  
Author(s):  
Daniela C. Culita ◽  
Claudia Maria Simonescu ◽  
Rodica Elena Patescu ◽  
Nicolae Stanica
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Chemical Properties ◽  
Order Kinetic ◽  
Mass Ratio ◽  
Magnetic Adsorbent ◽  
Magnetic Composites ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Physical And Chemical

A series of three chitosan-based magnetic composites was prepared through a simple coprecipitation method. It was investigated the influence of mass ratio between chitosan and magnetite on the physical and chemical properties of the composites in order to establish the optimum conditions for obtaining a composite with good adsorption capacity for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions. It was found that the microspheres prepared using mass ratio chitosan / magnetite 1.25/1, having a saturation magnetization of 15 emu g--1, are the best to be used as adsorbent for the metal ions. The influence of different parameters such as initial pH values, contact time, initial concentration of metal ions, on the adsorption of Pb(II) and Cu(II) onto the chitosan-based magnetic adsorbent was investigated in details. The adsorption process fits the pseudo-second-order kinetic model in both mono and bicomponent systems, and the maximum adsorption capacities calculated on the basis of the Langmuir model were 79.4 mg g--1 for Pb(II) and 48.5 mg g--1 for Cu(II) in monocomponent systems, while in bicomponent systems were 88.3 and 49.5 mg g--1, respectively. The results revealed that the as prepared chitosan-based magnetic adsorbent can be an effective and promising adsorbent for Pb(II) and Cu(II) from mono and bicomponent aqueous solutions.

Comparison of the fixation of several metal ions onto a low-cost biopolymer

2002 ◽  
Vol 2 (5-6) ◽  
pp. 217-224 ◽  
Author(s):  
Z. Reddad ◽  
C. Gérente ◽  
Y. Andrès ◽  
P. Le Cloirec
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Low Cost ◽  
Operating Conditions ◽  
Order Kinetic ◽  
Adsorption Mechanisms ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Beet Pulp ◽  
Removal Of Metal Ions

In the present work, sugar beet pulp, a common waste from the sugar refining industry, was studied in the removal of metal ions from aqueous solutions. The ability of this cheap biopolymer to sorb several metals namely Pb2+, Cu2+, Zn2+, Cd2+ and Ni2+ in aqueous solutions was investigated. The metal fixation capacities of the sorbent were determined according to operating conditions and the fixation mechanisms were identified. The biopolymer has shown high elimination rates and interesting metal fixation capacities. A pseudo-second-order kinetic model was tested to investigate the adsorption mechanisms. The kinetic parameters of the model were calculated and discussed. For 8 × 10-4 M initial metal concentration, the initial sorption rates (v0) ranged from 0.063 mmol.g-1.min-1 for Pb2+ to 0.275 mmol.g-1.min-1 for Ni2+ ions, with the order: Ni2+ > Cd2+ > Zn2+ > Cu2+ > Pb2+. The equilibrium data fitted well with the Langmuir model and showed the following affinity order of the material: Pb2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+. Then, the kinetic and equilibrium parameters calculated qm and v0 were tentatively correlated to the properties of the metals. Finally, equilibrium experiments in multimetallic systems were performed to study the competition of the fixation of Pb2+, Zn2+ and Ni2+ cations. In all cases, the metal fixation onto the biopolymer was found to be favourable in multicomponent systems. Based on these results, it is demonstrated that this biosorbent represents a low-cost solution for the treatment of metal-polluted wastewaters.

scholarly journals An Investigation on Design and Characterization of a Highly Selective LED Optical Sensor for Copper Ions in Aqueous Solutions

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1099
Author(s):  
Sheng-Chun Hung ◽  
Chih-Cheng Lu ◽  
Yu-Ting Wu
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Copper Ions ◽  
Incident Light ◽  
Copper Ion ◽  
Intensity Change ◽  
Optical Absorbance ◽  
Sensing System ◽  
Optic Sensor ◽  
Cu Ions

The optical characteristics of copper ion detection, such as the photometric absorbance of specific wavelengths, exhibit significant intensity change upon incident light into the aqueous solutions with different concentrations of metal ions due to the electron transition in the orbit. In this study, we developed a low-cost, small-size and fast-response photoelectric sensing prototype as an optic sensor for copper (Cu) ions detection by utilizing the principle of optical absorption. We quantified the change of optical absorbance from infra-red (IR) light emitting diodes (LEDs) upon different concentrations of copper ions and the transmitted optical signals were transferred to the corresponding output voltage through a phototransistor and circuit integrated in the photoelectric sensing system. The optic sensor for copper (Cu) ions demonstrated not only excellent specificity with other metal ions such as cadmium (Cd), nickel (Ni), iron (Fe) and chloride (Cl) ions in the same aqueous solution but also satisfactory linearity and reproducibility. The sensitivity of the preliminary sensing system for copper ions was 29 mV/ppm from 0 to 1000 ppm. In addition, significant ion-selective characteristics and anti-interference capability were also observed in the experiments by the proposed approach.

scholarly journals Porous BMTTPA–CS–GO nanocomposite for the efficient removal of heavy metal ions from aqueous solutions

RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3725-3731
Author(s):  
Juan Huang ◽  
Weirong Cui ◽  
Ruping Liang ◽  
Li Zhang ◽  
Jianding Qiu
Keyword(s):  
Heavy Metal ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Polluted Water ◽  
Efficient Removal

Novel porous BMTTPA–CS–GO nanocomposites are prepared by covalently grafting BMTTPA–CS onto GO surfaces, and used for efficient removal of heavy metal ions from polluted water.

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