Experience in Implementation of Systems Applied for Drainage Water Ion-Selective Purification from Radionuclides at Units 1,2 of Novovoronezh-2 NPP

The article is dedicated to the assessment of the experience in drainage water purification from radionuclides using ion-selective purification method on Units 1,2 Novovoronezh-2 NPP. Application of an ion-selective sorbent based on nickel ferrocyanide, as well as the preliminary oxidation of corrosive origin radiongjuclides, allow to achieve a satisfactory quality of purification from Cs-134, Cs-137, Co-60, Co 58, Mn-54, Cr-51. However, this method turned out to be ineffective for drainage water purification from Be-7, Sb-124, Sb-125. The article presents a possible method for drainage water purification from Be-7, Sb-124, Sb-125 using an iron-based coagulant, prospects for the modernization of the ion-selective drainage water purification plant, as well as plans to improve methods for drainage water purification at Novovoronezh-2 NPP

Nickel Ferrocyanide as High-Performance Next Generation Electrocatalyst for Urea Oxidation

Urea oxidation, a key process in energy and environmental science, faces challenges because of the insufficient understanding of its mechanism and the lack of efficient catalysts. Here we demonstrate that nickel ferrocyanide (Ni2Fe(CN)6) molecular catalyst supported on Ni form can drive urea oxidation reaction (UOR) with the record electrochemical activity and stability among all supported catalysts reported so far. A combination of kinetics data, in-situ spectroscopic measurements and energy computations suggests a new UOR pathway that delivers such outstanding performance. Different from most studied Ni-based catalysts with NiOOH derivative as a real catalytically active site for UOR, Ni2Fe(CN)6 appears to be a next-generation catalyst able to directly facilitate a two-step reaction pathway involving a critical reaction of intermediate ammonia’s production (on Ni site) and oxidation (on Fe site). Due to the alternative rate-determining step with a more favorable thermal energetics, Ni2Fe(CN)6 broke the limiting activity of the reported so far UOR catalysts. As a result, the UOR process on Ni2Fe(CN)6 can replace conventional water oxidation process in various energy-saving systems for hydrogen and hydrogen peroxide production.

Carbon Nanotube-Prussian Blue Spongiform Adsorbent for Selective Capture of Cesium and Strontium

Prussian blue analogue nickel ferrocyanide (NiPB) decorated carbon nanotube sponge (CNT sponge) was prepared as a newly designed spongiform adsorbent. This composite material was characterized by scanning electron microscopy (SEM), inductively coupled plasma (ICP) and tested in adsorption experiments. Results show that the CNT-NiPB sponge was equipped with large holes and porous structure, a large number of MWNTs and NiPB particles uniformly deposited on the surface and internal cavities. This adsorbent CNT-NiPB sponge showed a good adsorption selectivity of cesium and strontium in mixed aqueous solution, which is mainly induced by the ion exchange reaction of NiPB and metal ions. The novel spongiform adsorbent might have a promise prospect in radioactive wastewater treatment applications.