Boric acid binding studies with diol containing polyethylenimines as determined by ¹¹B NMR spectroscopy

Abstract

Three water-soluble polymers incorporating increasing levels of 2,3-dihydroxy propyl attached to polyethylenimine (PEI) backbone were synthesized, characterized by NMR, and investigated for their ability to bind boric acid (BA).11 B NMR spectroscopy showed that BA interacted with the polymeric 2,3-dihydroxy propyls by forming borate monoester and borate diesters in the boron concentration range of 100-1000 ppm and at 0.0775M polymer. Borate monoester species predominated for low functionalization levels (33% of the PEI amines functionalized), whereas borate diester species dominated for the higher functionalized polymers (66-100% of the PEI amines functionalized). All three polymers showed that 100% of the BA was bound as a mixture of borate mono-and diesters at 100-ppm boron. The overall best performer based on total borate ester formation was the 2/3-PEI, with a binding K d of 631 at 200 ppm boron. Borate ion concentration was measured from the 11 B NMR chemical shift of the BA/borate peak and it decreased as 1/3-PEI > 2/3-PEI > 3/3-PEI. Variable temperature 11 B NMR showed drastic reduction of borate ester species at 658C. Thus, PEI polymers, as the ones investigated in this work, are reasonable candidates for the selective recovery and recycle of BA.

A novel hyperbranched polyborazine and its reactive blend with benzoxazine thermosets

“…13 C‐NMR spectrum (Fig. 2b) also verified the presence of the above residue with signals around 55.8 and 18.2 ppm [31], and the representative sp 2 carbons around 172.7 and 166.2 ppm [32]. The other peaks centered around 136.3 and 121.4 ppm are due to the aromatic carbon atoms of various functionalities.…”

Boron adsorption mechanism on polyvinyl alcohol

“…The reason for this difference can be explained as follows. We believe that the adsorption was mainly caused by the affinity between tetrahydroxyboric acid anions and hydroxyl groups (Labouriau et al 2006; del Mar de la Fuente Garcia-Soto and Camacho 2005). Boron species exist mainly as tetrahydroxyboric acid anions under basic conditions and as boric acid under acidic conditions.…”

“…Many adsorbents for the selective removal of boron contain many hydroxyl groups in their molecules and remove boron by utilizing the strong affinity between boron and hydroxyl groups (Labouriau et al 2006;del Mar de la Fuente Garcia-Soto and Camacho 2005). For the development of boron adsorbents, it might be one of the quickest ways of introducing more hydroxyl groups to increase the amount of adsorbed boron.…”

Facile in Situ Synthesis of Multiple-Heteroatom-Doped Carbons Derived from Polyimide Precursors for Flexible All-Solid-State Supercapacitors

“…As shown in Figure S3, the cycling variation could not be observed in NFCPs. It is known that B atoms have strong affinity properties with hydroxyl groups in PVA. − It is obvious that further studies are needed to understand the detailed mechanism of the full cell cycle variations with the B-doped carbon materials under the PVA–1 M H 2 SO 4 solid electrolyte.…”