Production of sodium metaborate tetrahydrate (NaB(OH)4·2H2O) using ultrasonic irradiation

Sodium metaborate, a derivative of the borax compound, has a wide range of industrial applications. Recently, it is used as a source of boron in the production of sodium borohydride (NaBH4), which is a medium for hydrogen storage. In the present study, sodium metaborate tetrahydrate (SMT, NaB(OH)4·2H2O) was produced by the reaction of borax (B) with the sodium hydroxide (SH) solution under ultrasonic irradiation. The effect of the reaction parameters (amount of water, temperature, particle size, and time) on the production of sodium metaborate tetrahydrate was investigated in the present study. It was shown that the reaction parameters (amount of water, temperature, and time) played a significant role in the synthesis of sodium metaborate tetrahydrate. In addition, the concentration of characteristic B–O group in the reaction solution was quantitatively determined by Fourier Transform Infrared Spectroscopy (FTIR). The optimum condition for the production process included 26% water by weight, borax particles of size −250+150 μm and irradiation time of 60 min at 80 °C.

The results of the analyses indicate that the amount of water played a crucial role in the production of SMT. The comparison of the XRD pattern of the product synthesized in 16 and 26 wt.% water indicated that the intensity of NaB(OH)4 peaks decreased when the amount of water was increased. The optimal water content was found as 26 wt.%.Figure optionsDownload as PowerPoint slideHighlights
► NaB(OH)4·2H2O was produced under ultrasonic irradiation for the first time.
► The amount of water, temperature, and time played a significant role in the production.
► Ultrasonic irradiation decreased the time temperature by 60% and 11%, respectively.
► Unknown concentration of the characteristics B-O group in the solution was determined.