Boron isotope fractionation accompanying formation of potassium, sodium and lithium borates from boron-bearing solutions

Abstract

A series of experiments was conducted in which boron minerals were precipitated by water evaporation from solutions containing boron and potassium, sodium or lithium at 25°C, and boron isotope fractionation accompanying such mineral precipitation was investigated. In the boron-potassium ion system, K Computer simulations for modeling boron mineral formations, in which polyborates were decomposed into three coordinated BO 3 unit and four coordinated BO 4 unit for the purpose of calculation of their boron isotopic reduced partition function ratios, were attempted to estimate the equilibrium constant, K B , of the boron isotope exchange between the boric acid molecule (B(OH) 3 ) and the monoborate anion (B(OH) 4 -). As a result, the K B value of 1.015 to 1.029 was obtained. The simulations indicated that the K B value might be dependent on the kind of boron minerals, which qualitatively agreed with molecular orbital calculations independently carried out.

Removal of Hazardous Oxyanions from the Environment Using Metal-Oxide-Based Materials

“…Except for small amount in meteoroids, uncombined boron is never found in the elemental form in nature. Boron is a naturally found mainly as oxygen compounds (e.g., borate minerals) in oceans, sedimentary rocks, coal, shale, and some soils [95,96]. Its formation in aquatic environments is highly dependent on the hydrogen ion concentration—in pH above 8 it exists mainly as boric acid H 3 BO 3 , and below as a borate oxyanion B(OH) 4 − [97].…”

The effect of different boron compounds on nutrient digestibility, intestinal nutrient transporters, and liver lipid metabolism

“…Likely, the positive impact of SPP on nutrient digestibility seems to be related to cell proliferative activity [ 30 ], as does BA [ 13 , 14 ]. Also, the water solution of BA [ 31 ] and SPP [ 32 ] has a low buffering capacity and almost the same pH values as the intestinal tract; thus, due to these boron compounds did not decompose to borate anions at physiological pH [ 33 ], they may have exerted the same effect on nutrient digestibility. However, the lack of assessment of the histopathological alterations and luminal pH measurements is the limitation of our study.…”

Advances in Boron Isotope Separation by Ion Exchange Chromatography

“…The formation of polyborate anions in the resin phase accounts for the reduced S value. The concentrations of the polyborate anions depend on, among others, the concentration of boric acid and pH of the solution 29 . A higher boric acid concentration results in more polyborate anions.…”