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Sodium metaborate

About: Sodium metaborate is a(n) research topic. Over the lifetime, 366 publication(s) have been published within this topic receiving 4361 citation(s). The topic is also known as: NaBO2 & Sodium borate.
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Journal ArticleDOI
Yoshitsugu Kojima1, Tetsuya Haga1
Abstract: Sodium borohydride ( NaBH 4 ) was synthesized by reacting sodium metaborate ( NaBO 2 ) with magnesium hydride ( MgH 2 ) or magnesium silicide ( Mg 2 Si ) by annealing (350– 750° C ) under high H 2 pressure (0.1– 7 MPa ) for 2– 4 h . As the temperature and the pressure increased, the yield increased to have a maximum value (97–98%) at 550° C under 7 MPa , but the value was independent of time. A concept for converting NaBO 2 back to NaBH 4 using coke or methane is described.

229 citations

Journal ArticleDOI
Abstract: Sodium borohydride (NaBH4) is regarded as an excellent hydrogen-generated material, but its irreversibility of hydrolysis and high cost of regeneration restrict its large-scale application. In this study a convenient and economical method for NaBH4 regeneration is developed for the first time without hydrides used as starting materials for the reduction process. The real hydrolysis by-products (NaBO2·2H2O and NaBO2·4H2O), instead of dehydrated sodium metaborate (NaBO2), are applied for the regeneration of NaBH4 with Mg at room temperature and atmospheric pressure. Therefore, the troublesome heat-wasting process to obtain NaBO2 using a drying procedure at over 350 °C from NaBO2·xH2O is omitted. Moreover, the highest regeneration yields of NaBH4 are achieved to date with 68.55% and 64.06% from reaction with NaBO2·2H2O and NaBO2·4H2O, respectively. The cost of NaBH4 regeneration shows a 34-fold reduction compared to the previous study that uses MgH2 as the reduction agent, where H2 is obtained from a separate process. Furthermore, the regeneration mechanism of NaBH4 is clarified and the intermediate compound, NaBH3(OH), is successfully observed for the first time during the regeneration process.

221 citations

Journal ArticleDOI
Abstract: Surfactant flooding is one of the most promising method of enhanced oil recovery (EOR) used after the conventional water flooding. The addition of alkali improves the performance of surfactant flooding due to synergistic effect between alkali and surfactant on reduction of interfacial tension (IFT), wettability alteration and emulsification. In the present study the interfacial tension, contact angle, emulsification and emulsion properties of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and polysorbate 80 (Tween 80) surfactants against crude oil have been investigated in presence of sodium chloride (NaCl) and alkalis viz . sodium hydroxide (NaOH), sodium carbonate (Na 2 CO 3 ) , ammonium hydroxide (NH 4 OH), sodium metaborate (SMB) and diethanolamine (DEA). All three surfactants significantly reduce the IFT values, which are further reduced to ultra-low value (∼10 −4 mN/m) by addition of alkalis and salt. It has been found experimentally that alkali-surfactant systems change the wettability of an intermediate-wet quartz rock to water-wet. Emulsification of crude oil by surfactant and alkali has also been investigated in terms of the phase volume and stability of emulsion. A comparative FTIR analysis of crude oil and different emulsions were performed to investigate the interactions between crude oil and displacing water in presence of surfactant and alkali.

184 citations

Journal ArticleDOI
Abstract: We have developed a hydrogen generator that generates high purity hydrogen gas from the aqueous solution of sodium borohydride, NaBH 4 . This paper discussed the performance testing of the hydrogen generator using a Pt-LiCoO 2 -coated honeycomb monolith. The NaBH 4 solution hydrolyzed to generate H 2 and sodium metaborate when it contacted the monolith. The gravimetric and the volumetric H 2 densities of the system were 2 wt.% and 1.5 kg H 2 /100 l, respectively. The volumetric density was similar to that of the compressed H 2 at 25 MPa. The hydrogen generator successfully provided a maximum H 2 generation rate of 120 nl/min. Assuming a standard PEM (polymer electrolyte fuel cell, PEFC) fuel cell operated at 0.7 V, generating 120 nl/min was equivalent to12 kW.

154 citations

Journal ArticleDOI
Abstract: Sodium borohydride (NaBH4) hydrolysis is a promising approach for hydrogen generation, but it is limited by high costs, low efficiency of recycling the by-product, and a lack of effective gravimetric storage methods Here we demonstrate the regeneration of NaBH4 by ball milling the by-product, NaBO2·2H2O or NaBO2·4H2O, with MgH2 at room temperature and atmospheric pressure without any further post-treatment Record yields of NaBH4 at 900% for NaBO2·2H2O and 883% for NaBO2·4H2O are achieved This process also produces hydrogen from the splitting of coordinate water in hydrated sodium metaborate This compensates the need for extra hydrogen for generating MgH2 Accordingly, we conclude that our unique approach realizes an efficient and cost-effective closed loop system for hydrogen production and storage

122 citations

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Topic's top 5 most impactful authors

Tonghua Sun

5 papers, 79 citations

Biljana Bujanovic

3 papers, 20 citations

Stanley H. Kravitz

3 papers, 103 citations

John Cameron

3 papers, 29 citations

Nelson S. Bell

3 papers, 103 citations