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Published in J. van Eyk, Petroleum Bioventing, 1997
One possible approach to alleviate the demand for oxygen in the subsoil is the chemical approach followed by TRI mentioned earlier on. Although there is quite a variety of peroxides (like sodium peroxide, sodium superoxide, peroxysulfate and barium peroxide), hydrogen peroxide would probably indeed offer the best chances for success because of its low toxicity and the fact that it falls apart in two ubiquitous natural components, water and oxygen.
Separation of uranium(VI) and americium(III) by Extraction from Na2CO3–H2O2 solutions using methyltrioctylammonium carbonate in toluene
Published in Solvent Extraction and Ion Exchange, 2021
Alexander Valentinovich Boyarintsev, Galina Valerievna Kostikova, Sergey Illarionovich Stepanov, Andrei Аleksandrovich Shoustikov, Alexander Mihailovich Chekmarev, Aslan Yusupovich Tsivadze
Uranium in an amount of 13.2 g/L was added to the stock solutions containing 0.2 mol/L Na2CO3 in the form of Na4[UO2(О2)(CO3)2]. The addition of H2O2 to aqueous Na2CO3 solutions should be accompanied by neutralization of acid protons to form Na2O2. The peroxide group can act as a ligand in mixed peroxo-carbonate complexes, as an oxidant and decompose with oxygen release into the gas phase. Indeed, neutralization of the 0.2 mol/L solution Na2CO3 with an excess of weak acid H2O2 occurs with formation of NaHCO3 and partially Na2O2 (Table 3). Sodium peroxide in aqueous solution is hydrolyzed with formation of NaOH and an increase of the pH of the solution, decomposing to release oxygen. As a result of the equilibrium taking place in the Na2CO3–H2O2–H2O system, a 0.1–0.4 unit rise in pH was observed in the final solution. Changing the composition of the carbonate solution during the process of establishing an extraction equilibrium with increasing NaHCO3 concentration and decreasing pH reduces DU(VI) to a greater extent due to better coextraction of the single-charge bicarbonate anion and also leads to the formation of worse extracted hydrolyzed U(VI) compounds.