11B-MAS NMR approach to the boron adsorption mechanism on a glucose-functionalised mesoporous silica matrix

Abstract

et al.. 11 B-MAS NMR approach to the boron adsorption mechanism on a glucose-functionalised mesoporous silica matrix. Microporous and Mesoporous Materials, Elsevier, 2018, 266, pp.ABSTRACT: Boron chemistry has raised much interest because, despite the difference between necessities and toxicity being very narrow, it is still widely used in industrial processes. In a previous work we reported an adsorbent for boron extraction from water by the functionalisation of a UVM-7 mesoporous silica matrix with gluconamide moieties. The ability of this material to adsorb boron is based on its well-known affinity for coordinating the cis-diols present in attached saccharide. Although much research on the formation of boron esters with sugars and sugar derivatives in solution has been done, very few reports have dealt with the adsorption mechanism of boron onto functionalised materials in the solid state. Hence an in-depth study of the adsorption process was conducted in this paper. For this purpose, several solids with increasing boron contents were prepared from the gluconamide-functionalised UVM-7 material and an isothermal boron adsorption curve was obtained. The 11 B and 13 C MAS NMR techniques were used to characterise the obtained solids, and the simulation of the boron NMR and isothermal adsorption combined data was accomplished to enlighten the boron adsorption process. A model with three different coordination environments, two possible adsorption sites and the presence of oligomeric boron species allowed us to reproduce not only the isothermal boron adsorption curve, but also the evolution of the integrated areas for the signals in the 11 B MAS NMR spectra obtained for the different boron-containing gluconamide-functionalised UVM-7 materials.

Application of feed-forward and recurrent neural network in modelling the adsorption of boron by amidoxime-modified poly(Acrylonitrile-co-Acrylic Acid)

“…As compared with other adsorbent report in boron adsorption [46][47][48][49][50][51][52], the maximum adsorption capacity in current study at 15.23 ± 1.050 mg boron/g adsorbent has moderate performance among all. Nevertheless, this shows amidoxime-functionalized polymer as a potential alternative polymer to remove boron while the chemical structure can be further modified and improved in the future research to enhance the adsorption capacity.…”

Effective Removal of Boron from Aqueous Solutions by Inorganic Adsorbents: A Review

“…The incorporation of alumina particles in the new alginate-based composite improves mechanical strength and slightly improves boron removal. Sanfeliu et al [ 89 ] studied the removal of boron using nanosized mesoporous silica that had been crosslinked in successive steps with 3-aminopropyltriethoxysilane (APTES) and polyhydroxy compounds (gluconolactone), respectively. The maximum adsorption capacity obtained was 20.0 mg/g.…”

Boron Adsorption Kinetics of Microcrystalline Cellulose and Polymer Resin

“…Nevertheless, X-ray diffraction (XRD) and Fourier transform (FT) Raman spectroscopy has been employed to gain insight into the degree of order and crystallinity in cellulose . As a local probe, solid-state nuclear magnetic resonance (ssNMR) spectroscopy has previously been applied to gain insight into the local structures of cellulose and cellulose–lignin interactions in neat cellulose and biomass-derived lignocellulose compounds. − Recently, surface-enhanced dynamic nuclear polarization (DNP) NMR spectroscopy has been used to characterize functional groups on the surface of cellulose fibers in paper materials, drug-functionalized TEMPO-oxidized cellulose nanofibrils, and cellulose ethers …”