Hydroxyl‐assisted nitrogen‐containing group modified persimmon tannin with enhanced recovery capacity for Mo(VI) in aqueous solution

Abstract

BACKGROUND: Persimmon tannin, extracted from young astringent persimmons, is a cheap waste biomass material. The abundant phenolic hydroxyl groups in persimmon tannin are known to display excellent affinity to Mo(VI). In addition, ligands containing N donor atoms, as brilliant adsorption groups, can strongly interact with Mo(VI) when the groups are protonated under acidic conditions. Therefore, the introduction of nitrogen-containing groups in persimmon tannin may be an effective method to improve the recovery capacity of biosorbent for Mo(VI) in aqueous solution. In this work, a series of adsorbents were prepared by immobilizing ethylenediamine or methylamine on the surface of persimmon tannin. RESULTS: Due to the abundant nitrogen-containing groups and hydroxyl groups, the ethylenediamine modified persimmon tannin exhibited excellent maximum uptake capacity to Mo(VI) (478.02 mg•g −1), which was superior to that of methylamine modified persimmon tannin. Further, the results of XPS and FT-IR confirmed that Mo(VI) was adsorbed on the hydroxyl-assisted nitrogen-containing group modified persimmon tannin via coordination and electrostatic interaction. CONCLUSION: Furthermore, 99% of Mo(VI) was selectively recovered from coexisting ions by en-CPT under appropriate acidic conditions (pH 1). Pseudo-second-order kinetic model best represented the adsorption process of Mo(VI) onto the en-CPT. The adsorption equilibrium was achieved in a relatively short time (no more than 1 h). High recovery efficiency and excellent selective adsorption made the en-CPT an ideal candidate for Mo(VI) recovery in practical applications.

Synergistic Effect of WN/Mo2C Embedded in Bioderived Carbon Nanofibers: A Rational Design of a Shuttle Inhibitor and an Electrocatalyst for Lithium–Sulfur Batteries

“…) were adopted as a natural structural template to simultaneously graft two metallic sources, which realized bimetallic compound-modified carbon nanofibers (CNFs) through self-nitridation and carbonization during heat treatment. Bayberry tannin (BT) was immobilized onto CFs in advance to introduce phenolic hydroxyl (PhOH) groups (BT@CFs), which could graft metal anion species of WO 4 2– /MoO 4 2– through chelation . When calcined under an inert atmosphere, the aggregated metal ions on BT@CFs reacted with the supermolecule to form nanograins of the corresponding metallic compounds of tungsten nitride and molybdenum carbide (WN/Mo 2 C) according to the reactive peculiarities of different metal sources.…”