scholarly journals Fast, Efficient and Environmentally Friendly Extraction of Cu(II) and Zn(II) by Hybrid Silicas Impregnated with Acidic Organic Extractants

2016 ◽  
Vol 12 (4) ◽  
pp. 4374-4386
Author(s):  
Hafida Miloudi ◽  
Zeina Mehyou ◽  
Anne Boos ◽  
Abdelkader Tayeb ◽  
Geneviève Goetz-Grandmont
Keyword(s):  
Phosphoric Acid ◽  
Silica Matrix ◽  
Acidic Ph ◽  
Extraction Capacity ◽  
Extraction Equilibrium ◽  
Equilibrium Time ◽  
Hybrid Silicas ◽  
Sulfate Medium ◽  
Organic Extractants ◽  
Very High

The extraction of copper and zinc by mesostructured silicas impregnated with organic acidic chelators, an acylisoxazolone 3-phenyl-4-benzoyl-5-isoxazolone (HPBI), an acylpyrazolone 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP) and an organophosphoric acid di-(2-ethylhexyl)-phosphoric acid (DEHPA) was performed in a sulfate medium. Various factors such as the pH of the aqueous phase, the chelators’ concentration in the silica matrix, the extraction equilibrium time and the extraction capacity of the two cations on silica were studied. The cations were extracted at very acidic pH with very high extraction rates. The stripping of cations was achieved at pH’s that were more acidic than those utilized for the extraction by maintaining the structure intact. Finally, their separation was successfully conducted in the cases of the three chelators.

Fast Proton Conductors from Inorganic-Organic Composites: I. Amorphous Phosphate-Nafion and Silicophosphate-PMA/PWA Hybrids

1999 ◽  
Vol 600 ◽  
Author(s):  
Yong-Il Park ◽  
Jae-Dong Kim ◽  
Masayuki Nagai
Keyword(s):  
Phosphoric Acid ◽  
Proton Conductivity ◽  
Proton Conductors ◽  
Phosphorus Concentration ◽  
High Proton ◽  
Proton Source ◽  
Drastic Increase ◽  
Amorphous Phosphate ◽  
Exchange Resins ◽  
Very High

AbstractA drastic increase of electrical conductivity was observed in the composite of amorphous phosphate and ion-exchange resins (Nafion) as phosphorus concentration increased. Incorporation of amorphous phosphate into Nafion caused a large increase of conductivity to about 4×10−1S/cm at 23°C. However, the fabricated composite showed very low chemical stability.A high proton conductivity was also observed in a new inorganic-organic hybrids through incorporating PMA(molibdo-phosphoric acid)/PWA(tungsto-phosphoric acid) as a proton source in amorphous silicophosphate gel structure. Obtained gels were homogeneous and chemically stable. Resulting proton conductivity is very high (up to 5.5×10−3S/cm) compared to those of silicophosphate gels.

scholarly journals Generation of ultrafast, transient, highly acidic pH spikes in the radiolysis of water at very high dose rates. Relevance for FLASH radiotherapy.

2021 ◽  
Author(s):  
Abida Sultana ◽  
Ahmed Alanazi ◽  
Jintana Meesungnoen ◽  
Jean-Paul Jay-Gerin
Keyword(s):  
High Dose ◽  
Acidic Ph ◽  
Cellular Functions ◽  
Spike Response ◽  
Dose Rates ◽  
Hydronium Ions ◽  
Circular Surface ◽  
Sparing Effect ◽  
Tissue Sparing ◽  
Very High

Monte Carlo multi-track chemistry simulations were carried out to study the effects of high dose rates on the transient yields of hydronium ions (H<sub>3</sub>O<sup>+</sup>) formed during low linear energy transfer (LET) radiolysis of both pure, deaerated and aerated liquid water at 25 °C, in the interval ~1 ps–10 μs. Our simulation model consisted of randomly irradiating water with <i>N</i> interactive tracks of 300-MeV incident protons (LET ~ 0.3 keV/μm), which simultaneously impact perpendicularly on the water within a circular surface. The effect of the dose rate was studied by varying <i>N</i>. Our calculations showed that the radiolytic formation of H<sub>3</sub>O<sup>+</sup> causes the entire irradiated volume to temporarily become very acidic. The magnitude and duration of this abrupt “acid-spike” response depend on the value of <i>N</i>. It is most intense at times less than ~10–100 ns, equal to ~3.4 and 2.8 for <i>N</i> = 500 and 2000 (<i>i.e.</i>, for dose rates of ~1.9 × 10<sup>9</sup> and 8.7 × 10<sup>9</sup> Gy/s, respectively). At longer times, the pH gradually increases for all <i>N</i> values and eventually returns to the neutral value of seven, which corresponds to the non-radiolytic, pre-irradiation concentration of H<sub>3</sub>O<sup>+</sup>. It is worth noting that these early acidic pH responses are very little dependent on the presence or absence of oxygen. Finally, given the importance of pH for many cellular functions, this study suggests that these acidic pH spikes may contribute to the normal tissue-sparing effect of FLASH radiotherapy.

scholarly journals New Trident Molecule with Phosphoric Acid Functionality for Trivalent Rare Earth Extraction

2017 ◽  
Vol 17 (3) ◽  
pp. 491 ◽  
Author(s):  
Keisuke Ohto ◽  
Hiromasa Murashima ◽  
Hiroshi Murakami ◽  
Shintaro Morisada ◽  
Hidetaka Kawakita ◽  
...  
Keyword(s):  
Rare Earth ◽  
Phosphoric Acid ◽  
Rare Earths ◽  
Equilibrium Constants ◽  
Extraction Equilibrium ◽  
Ph Values ◽  
Extraction Behavior ◽  
Separation Factors ◽  
Trivalent Rare Earth ◽  
Rare Earth Extraction

Tripodal extraction reagent with three phosphoric acid groups, together with the corresponding monopodal molecule has been prepared to investigate some metals extraction behavior, in particular, trivalent rare earth elements (REEs). The tripodal reagent exhibited extremely high selectivity for metals with high valency such as Zr(IV), In(III), Lu(III), and Fe(III). Tripodal reagent also exhibited exceptionally high extraction ability compared with the corresponding monopodal one in the extraction of trivalent rare earths. The result for the stoichiometry of tripodal reagent to heavy rare earths showed the inflection point between Er (2:1 for a ligand with ion) and Tm (1:1). The extraction reactions were determined for all rare earths with both reagents. The extraction equilibrium constants (Kex), the separation factors (β), half pH values (pH1/2), difference half pH values (ΔpH1/2) for extraction of REEs with both reagents are estimated.

Solvent extraction of Nd(III) in a Y type microchannel with 2-ethylhexyl phosphoric acid-2-ethylhexyl ester

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Libo Zhang ◽  
Feng Xie ◽  
Shiwei Li ◽  
Shaohua Yin ◽  
Jinhui Peng ◽  
...  
Keyword(s):  
Solvent Extraction ◽  
Phosphoric Acid ◽  
Mixing Time ◽  
Volumetric Flow Rate ◽  
Narrow Channel ◽  
Mechanical Mixing ◽  
Experimental Conditions ◽  
Extraction Equilibrium ◽  
Solvent Extraction System ◽  
Area Occupation

AbstractConventional extraction equipment has many problems like a long mixing time, a large factory area occupation, a large amount of organic solvent consumption and so on. In this paper, a micro solvent extraction system for the extraction of Nd(III) was investigated to solve the above issues. The initial aqueous pH 4.0 and saponification rate 40% of 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) were selected as the optimal experimental conditions. The extraction equilibrium was quickly achieved within 1.5 s, without any mechanical mixing in a narrow channel (100 μm in width and 120 μm in depth) at a volumetric flow rate from 5.55×10

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