A mathematical relationship for the explanation of ion exchange for boron adsorption

Characteristic Sorption of H₃BO₃/B(OH)₄^− on Magnesium Oxide

“…This suggests that molecular H 3 BO 3 (pK a 9.23) was a trigger for reaction with the MgO surface. However, for C e above 25 mM, it was stereochemically difficult for the H 3 BO 3 trimer to approach the MgO surface to form surface complexes through triboric acid, and the equilibrium pH was lower at an initial pH of 6.0 than at 9.0, leading to an insufficient increase in saturation index for Mg(OH) 2 and lower Q values. At an initial pH of 11.0, the predominant species were B(OH) 4 ¹ and/or B 3 O 3 (OH) 4 ¹ , which are less reactive with MgO than H 3 BO 3 , resulting in far smaller Q values compared with those observed at initial pH of 6 and 9.…”

“…The molar ratio of [4] B/ [3] B was estimated based on the 11 B-NMR spectra of Na 2 [4] B) in all residues, and that the molar ratio of [4] B/ [3] B gradually increased with initial B concentration. This suggests that the molecular form of H 3 BO 3 is preferentially inserted between Mg(OH) 2 layers, and that co-precipitation of B(OH) 4 ¹ with Mg(OH) 2 follows after H 3 BO 3 integration when excess amounts of B are present. This is a novel insight explaining the reaction mechanism of H 3 BO 3 /B(OH) 4 ¹ with MgO.…”

“…11 B-NMR results indicated that the predominant B species in solid residues after sorption at an initial pH of 9.0 was trigonal [3] 2 , with production of some B(OH) 4 ¹ by co-precipitation, based on 11 B-NMR and XRD results. XRD patterns for the solid residues demonstrated more significant broadening, except for hk0 plane reflections, with increasing B content.…”

“…The Mg 2+ ions were stabilized in solution as a chelate complex with EDTA, which inhibited the precipitation of Mg(OH) 2 and led to no immobilization of B species. Thus, it was confirmed that formation of Mg(OH) 2 is principle for immobilization of H 3 BO 3 /B(OH) 4 ¹ .…”

Preparation, characterization, and boron adsorption behavior of gluconate‐intercalated hydrotalcite

“…It was reported that the adsorption of boron with the boron adsorbents was due to the complexation of boron with the adjacent dihydroxyl [8][9][10]. On the basis of the adsorption principle described above, the gluconate having multiple hydroxyl groups was selected to synthesize the gluconate anion intercalated LDHs to obtain an adsorbent with high boron adsorption capacity.…”