Processing of NaBH4 from NaBO2 with MgH2 by ball milling and usage as hydrogen carrier

In this paper, NaBH4 is synthesized from NaBO2 and MgH2 under inert gas via ball milling, without applying high temperature or pressure. Developments in the recycling of NaBO2 will make NaBH4 usage more feasible. To obtain the optimum recycling conditions of NaBO2 with MgH2 via solid phase reaction under inert atmosphere, 3 sets of experiments were performed. With additives such as Al, Na and Na2CO3, the effect of additives on the hydrogenation reaction was carried out. The results indicate that additives are not helpful in the process, so reaction time and stochiometric ratio experiments were performed with pure NaBO2 and MgH2. The reaction time varied from 400 to 800 min and MgH2 added in excess amount of 5, 27, 50 and 70%. Products were qualified by FT-IR and quantified by iodimetric method and dehydrogenation tests. Compiled results show that 73% NaBH4 yield can be accomplished if reactant is operated by ball milling for 11 h with 30% excess MgH2 addition. Furthermore, yield can be increased to 92.33% if the product is purified by ethylene diamine. (C) 2010 Elsevier Ltd. All rights reserved.