An experimental study of magnesite precipitation rates at neutral to alkaline conditions and 100–200°C as a function of pH, aqueous solution composition and chemical affinity

2012 ◽  
Vol 83 ◽  
pp. 93-109 ◽  
Author(s):  
Giuseppe D. Saldi ◽  
Jacques Schott ◽  
Oleg S. Pokrovsky ◽  
Quentin Gautier ◽  
Eric H. Oelkers
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Chemical Affinity ◽  
Solution Composition ◽  
Alkaline Conditions

Multi-Pathway Excited State Relaxation of Adenine Oligomers in Aqueous Solution: A Joint Theoretical and Experimental Study

2013 ◽  
Vol 19 (11) ◽  
pp. 3762-3774 ◽  
Author(s):  
Akos Banyasz ◽  
Thomas Gustavsson ◽  
Delphine Onidas ◽  
Pascale Changenet-Barret ◽  
Dimitra Markovitsi ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Excited State

Experimental Study of Adsorption of Ammonia Nitrogen from Wastewater onto the Bagasse Adsorbent

2014 ◽  
Vol 529 ◽  
pp. 22-25 ◽  
Author(s):  
Li Wei Xie ◽  
Ze Long Xu ◽  
Yan Hua Huang ◽  
Shuang Cao ◽  
Zong Qiang Zhu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Adsorption Capacity ◽  
Ammonia Nitrogen ◽  
Alkaline Condition ◽  
Maximum Adsorption Capacity ◽  
Initial Concentration ◽  
Adsorption Capacities ◽  
Neutrality Condition ◽  
Adsorbent Dose

Adsorption of ammonia nitrogen from aqueous solution onto the bagasse adsorbent has been investigated to evaluate the effects of Adsorbent dose, initial NH4+-N concentration, and pH on the removal systematically. With increasing initial concentration, the amount of ammonia nitrogen sorbed onto the adsorbent increased until it gradually decreased due to the initial concentration exceed 50 mg·L-1, and the maximum adsorption capacity was observed for the sample to be 1.31 mg·g-1 at the initial concentration of 30 mg·L-1, and the corresponding removal rates decreased from 94.01 to 3.89%, with increase in initial concentration from 5 to 100 mg·L-1. Adsorption capacities decreased from 6.04 to 0.49 mg·g-1 with increasing adsorbent dose from 0.1 to 1.5g. What’s more, under alkaline condition, the removal efficiency of ammonia nitrogen from aqueous solution onto the samples were superior to that under acidity and neutrality condition.

Dissolution of spent nuclear fuel fragments at high alkaline conditions under H2 overpressure

MRS Advances ◽  
2016 ◽  
Vol 1 (62) ◽  
pp. 4163-4168
Author(s):  
E. González-Robles ◽  
M. Herm ◽  
V. Montoya ◽  
N. Müller ◽  
B. Kienzler ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Partial Pressure ◽  
Nuclear Fuel ◽  
Alkaline Solution ◽  
Spent Nuclear Fuel ◽  
Dissolution Tests ◽  
The Matrix ◽  
Alkaline Conditions ◽  
Long Term Behavior

ABSTRACTThe long-term behavior of the UO2 fuel matrix under conditions of the Belgian “Supercontainer design” was investigated by dissolution tests of high burn-up spent nuclear fuel (SNF) in high alkaline solution under 40 bar of (Ar + 8%H2) atmosphere. Four fragments of SNF, obtained from a pellet previously leached during two years, were exposed to young cement water with Ca (YCWCa) under 3.2 bar H2 partial pressure in four single/independent autoclave experiments for a period of 59, 182, 252 and 341 days, respectively. After a decrease of the concentration of dissolved 238U, which is associated with a reduction of U(VI) to U(IV), the concentration of 238U in solution is constant in the experiments running for 252 and 341 days. These observations indicate an inhibition of the matrix dissolution due to the presence of H2. A slight increase in the concentration of 90Sr and 137Cs in the aqueous solution indicates that there is still dissolution of the grain boundaries. These findings are similar to those reported for spent nuclear fuel corrosion in synthetic near neutral pH solutions.

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