Aqueous Boron Removal by Using Electrospun Poly(vinyl alcohol) (PVA) Mats: A Combined Study of IR/Raman Spectroscopy and Computational Chemistry

We report the use of a novel and efficient method to remove aqueous boron by using electrospun, water-resistant poly­(vinyl alcohol) (PVA) mats stabilized in methanol. The removal of the primary aqueous boron species as (B­(OH)3), was accomplished by chemical adsorption in reactions with −OH (hydroxyl) groups on the PVA mat surface. The chemical adsorption of B­(OH)3 was qualitatively confirmed by the analysis of IR and Raman spectra. The bands, corresponding to the molecular vibration modes of chemically bonded boron in PVA, were identified by using the frequency calculation from the computational chemistry for the first time. The adsorption capacities of PVA mats for aqueous boron were then quantitated at a low boron concentration (range: 0.0010 to 0.0025 g of aqueous boron per g of PVA mats) by the Carmine method. The PVA mats were prepared by a well-established electrospinning technique, which make these substrates promising potential candidates for use as boron-selective sorbent media in applications such as reverse osmosis desalination processes.