scholarly journals Size- and Surface-Dependent Solubility of Cadmium Telluride in Aqueous Solutions

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 398 ◽  
Author(s):  
Renate Zapf-Gottwick ◽  
Matthias Zorn ◽  
Jessica Nover ◽  
Michael Koch ◽  
Carolin Feifel ◽  
...  
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Diffusion Coefficients ◽  
Room Temperature ◽  
Ph Value ◽  
Leaching Behavior ◽  
Photovoltaic Modules ◽  
Chemical Treatments ◽  
Temperature Diffusion ◽  
The Stability

Due to the toxicity of cadmium (Cd) and the scarcity of telluride (Te), CdTe-based photovoltaic modules have been under discussion during the last few years. In particular, the stability of CdTe in aqueous solutions is under debate. Here we show that the stability of CdTe depends not only on the pH of water-based solutions but also on size and surface treatment of CdTe particles. We compare milled module pieces with CdTe powders of different particle size. The leaching of CdTe is conditioned by the outdiffusion of Cd and Te at the interface between CdTe particles and the aqueous solution. The smaller the particle size, the faster the leaching. Therefore, milled module pieces decompose faster than CdTe powders with relatively large grains. We observe a dependence on time t according to t0.43. The room temperature diffusion coefficients are calculated as DCd ≈ 3 × 10−17 cm2/s for Cd, and DTe ≈ 1.5 × 10−17 cm2/s for Te in pH4. The chemical instability in aqueous solutions follows thermodynamic considerations. The solution behavior of Cd and Te depends on the pH value and the redox potential of the aqueous solutions. Chemical treatments such as those used in solar cell production modify the surface of the CdTe particles and their leaching behavior.

Electrosynthesis of Organic Amalgam from Tetraethylammonium Tetrafluoroborate in Aqueous Medium

1994 ◽  
Vol 59 (11) ◽  
pp. 2375-2382 ◽  
Author(s):  
Simon Krásenský ◽  
Marie Studničková
Keyword(s):  
Aqueous Solutions ◽  
Aqueous Medium ◽  
Anodic Oxidation ◽  
Room Temperature ◽  
Ph Value ◽  
Binary Compound ◽  
Black Precipitate ◽  
Mercury Cathode ◽  
Simultaneous Evolution

The electroreduction of neutral aqueous solutions of 0.1 - 0.5 M Et4NBF4 on a mercury cathode at room temperature at -2.8 - -2.4 V produces a black precipitate of Et4N . Hgx with simultaneous evolution of hydrogen (the pH value increases to 12). No anodic oxidation of the amalgam has been observed in the interval of 0 - 2.8 V. The composition of the precipitate, collected by filtration under nitrogen, has been determined from the decrease of Et4N+ in the solution after electrolysis and from analysis of mercury in the binary compound Et4N . Hgx. The value x = 2.9 ± 0.8 has been found.

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.

Stability of nano-sized titanium dioxide in an aqueous environment: effects of pH, dissolved organic matter and divalent cations

2013 ◽  
Vol 68 (2) ◽  
pp. 276-282 ◽  
Author(s):  
X. N. Yang ◽  
F. Y. Cui
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Organic Matter ◽  
Zeta Potential ◽  
Dissolved Organic Matter ◽  
Ph Value ◽  
Divalent Cations ◽  
Aqueous Environment ◽  
Nano Tio2 ◽  
The Stability

Nano-sized titanium dioxide in the aquatic environment has a potential impact on the environment and human health. In this study, the impact of pH value, dissolved organic matter (DOM) and divalent cations (Ca2+) on the stability of titanium dioxide nanoparticles (nano-TiO2) in an aqueous environment was investigated in batch tests. The results showed that the particle size of nano-TiO2 was not sensitive to pH value but was inversely proportional to zeta potential. The nano-TiO2 becomes more stable with surface zeta potential, accompanied by small particle size and high dispersion. In the presence of DOM, the particle size was smaller and the stability of nano-TiO2 could be enhanced. This might be a synergistic effect of the ligand exchange and electrostatic force. Particle size increased with the addition of Ca2+ and the stability decreased.

Room-temperature diffusion coefficients for oxygen and water in UO2 matrices: a SIMS study

2012 ◽  
Vol 45 (1) ◽  
pp. 360-363 ◽  
Author(s):  
I. Marchetti ◽  
P. Carbol ◽  
J. Himbert ◽  
F. Belloni ◽  
T. Fanghänel
Keyword(s):  
Diffusion Coefficients ◽  
Room Temperature ◽  
Temperature Diffusion

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.

Stability Analysis of Nano-Sized Titanium Dioxide in Aqueous Environment

2011 ◽  
Vol 374-377 ◽  
pp. 869-874 ◽  
Author(s):  
Xiao Nan Yang ◽  
Fu Yi Cui ◽  
Xiao Ying Mu ◽  
Zhi Wei Zhao
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Zeta Potential ◽  
Ph Value ◽  
Electrostatic Force ◽  
High Dispersion ◽  
Aqueous Environment ◽  
Tio2 Nps ◽  
The Stability ◽  
The Impact

Nano-sized titanium dioxide in aquatic environment poses potential impact on environment and human health. In this research, the impact of pH value, humic acid (HA) and divalent cations (Ca2+) on the stability of titanium dioxide nanoparticles(NPs) in the aqueous enviorment was investigated using a batch test. The results showed that the particle size of TiO2 NPs was not sensitive to the pH value but presented inversely proportional to zeta potential. The TiO2 NPs become more stable along with surface zeta potential, accompany with small particle size and high dispersion. In the presence of HA, the particle size was smaller and TiO2 NPs could be stabilized. This might be synergistic effect of the ligand exchange and electrostatic force. Meanwhile, NPs particle size increased with the addition of Ca2+ and the stability of TiO2 NPs became decreased.

Co-Sorption Characteristics of Zn(II) and As(V) on Mixed Fe/Al-PILCs

2013 ◽  
Vol 681 ◽  
pp. 26-30
Author(s):  
Su Yuan Wu ◽  
Hong Zheng ◽  
Peter G. Weidler ◽  
Peng Cai
Keyword(s):  
Aqueous Solutions ◽  
Langmuir Isotherm ◽  
Contact Time ◽  
Room Temperature ◽  
Ph Value ◽  
Freundlich Isotherm ◽  
Single System ◽  
Batch System ◽  
Maximum Sorption ◽  
Sorption Characteristics

Co-sorption characteristics of Zn(II) and As(V) on the mixed Fe/Al-PILCs was investigated in a batch system at room temperature. The effects of relevant parameters, such as pH value of solution, adsorbent dosage, initial Zn(II) and As(V) concentrations and contact time were examined, respectively. The results show that co-sorption capacities and co-sorption rates of Zn(II) and As(V) by Fe/Al-PILC are higher and faster than those of single Zn(II) or single As(V) by Fe/Al-PILC. Co-sorption isotherm data of Zn(II) and As(V) by Fe-Al-PILC were fitted well to Langmuir isotherm and the maximum sorption capacities of Zn(II) and As(V) on mixed Fe-Al-PILCs (Q0) are 16.98 mg/g and 16.29 mg/g, respectively, which are higher than those in single system. n>1 from Freundlich isotherm indicate that the sorption of Zn(II) and As(V) by Fe-Al-PILC is favorable. E values from D-R model indicate that the type of sorption of Zn(II) and As(V) by Fe-Al-PILC is physical. The results indicate that there is significant potential for Fe/Al-PILCs as an adsorbent material for Zn(II) and As(V) removal from aqueous solutions.

scholarly journals FORMULATION AND EVALUATION OF RED PALM OLEIN NANOEMULSION

2018 ◽  
Vol 11 (9) ◽  
pp. 237
Author(s):  
Febia Sari ◽  
Kasmirul Ramlan Sinaga ◽  
Donald Siahaan
Keyword(s):  
Particle Size ◽  
Phase Separation ◽  
Room Temperature ◽  
Palm Olein ◽  
Tween 80 ◽  
Size Measurement ◽  
Spontaneous Emulsification ◽  
Particle Size Measurement ◽  
The Stability ◽  
Red Palm Olein

Objective: The objective of this study is to formulate and evaluate the red palm olein (RPO) nanoemulsion using spontaneous emulsification method.Methods: Nanoemulsion formulated by spontaneous emulsification method using the comparison of surfactant (tween 80) and cosurfactant (sorbitol) concentration with the variation of RPO concentration. Evaluation of the stability of the nanoemulsion preparation includes centrifugation test, viscosity, pH, organoleptic observation (odor, color, clarity, and phase separation), and particle size measurement during 12 weeks storage at room temperature.Result: The results showed that all nanoemulsion preparations were transparent yellow, characteristic odor, type weights 1.0166–1.0641 g/ml, and stable for 12 weeks storage at room temperature. The smallest particle size was produced by the nanoemulsion preparation in a formula of the concentration of 5%, which was 67, 64 nm.Conclusion: RPO can be formulated as a nanoemulsion by spontaneous emulsification method. RPO with a 5% concentration is very stable for 12 weeks storage.

Effect of pH Value of the Broth on the Gelled Microspheres Containing Zirconium Prepared by Internal Gelation Process

2014 ◽  
Vol 602-603 ◽  
pp. 155-158 ◽  
Author(s):  
Yong Gao ◽  
Jing Tao Ma ◽  
Xing Yu Zhao ◽  
Shao Chang Hao ◽  
Chang Sheng Deng
Keyword(s):  
Room Temperature ◽  
Ph Value ◽  
Internal Gelation ◽  
Uniform Size ◽  
Effect Of Ph ◽  
Gelation Process ◽  
The Stability

The internal gelation process was used to produce gel microspheres containing Zr. The effect of the broth composition particularly pH value on the stability of the broth and morphology of the dried spheres was investigated. The results indicated that the stability of the broth at room temperature increased with the decrease of the pH of the broth. When the pH of the broth was in the range of 1 to 2 the spheres obtained had good sphericity and uniform size and at pH of 1.35 the spheres were transparent.

Preparation and Characterization of Cationic Emulsion of Styrene and Acrylate

2011 ◽  
Vol 55-57 ◽  
pp. 1886-1891
Author(s):  
Xian Mei Zhu ◽  
Gang Hu Cheng ◽  
Hong Zhao Liu
Keyword(s):  
Particle Size ◽  
Charge Density ◽  
Emulsion Polymerization ◽  
Dimethyl Sulphate ◽  
Particle Distribution ◽  
Ph Value ◽  
Reactivity Ratio ◽  
Water Soluble ◽  
Glass Temperature ◽  
The Stability

The control of particle size and its distribution has become more and more important both in theory and in practice of emulsion polymerization field. In this study, cationic styrene-acrylate copolymer containing functional monomer was converted into water-soluble polymers by reaction with quaternising agents and acids with the free-soap emulsion polymerization method. The latex was obtained at the existence of nitrogen by the copolymerization of hydrophobic monomer styrene and 2-ethylhexyl acrylate, hydrophilic monomer dimethylaminoethyl methacrylate, modified PVA-0588 as the emulsifiers. The influences of the amount of azoisobutyronitrile initiator, the amount of dimethyl sulphate quaternising agent, reactivity ratio between monomers, charge density and pH value on the preparation process were discussed. The particle size and particle distribution was strongly affected by these factors. The results showed that the latex with narrow particle distribution and mean particle size about 100nm was obtained under redox system by adjusting 33% monomer to become precursor and dropping the rest of 67% monomer, after polymerization, N,N-dimethylamino groups were fully quaternised with dimethyl sulphate to improve the stability of the solutions. The glass temperature of polymer was 58.1°C, as pH values range of solution was 3~5, the stability and charge density of polymer emulsion could improve.

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