A novel magnesium ascorbyl phosphate graphene-based monolith and its superior adsorption capability for bisphenol A

Abstract

In this study, a non-shell graphene-based monolith (GBM) with huge surface area was synthesized by chemical reduction of Graphene oxide (GO) using magnesium ascorbyl phosphate (MAP), and tested as an adsorbent for trace Bisphenol A (BPA) removal. The properties of MAP-GBM was characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller N2 specific surface area (BET), X-ray powder diffraction, Fourier transform-infrared (FTIR), Raman, and X-ray photoelectron spectroscopies. BPA adsorption was investigated in batch and column adsorption experiments. The data showed that MAP-GBM was a three-dimensional (3D) graphene material with macrostructure and most CC double bonds were recovered. Adsorption isotherms and kinetics of BPA on MAP-GBM followed the Langmuir model and fitted well with a pseudo-second-order kinetic model, respectively, and the adsorption process was endothermic. The saturated adsorption capacity of MAP-GBM was 324 mg/g for BPA, which was 2.43 times of that of ascorbic acid-GBM. A MAP-GBM adsorption column completely removed BPA from solution at low concentration (50 μg/L) for ∼450 mL.This efficiency is much higher than traditional adsorbents such as activated carbon, which could be ascribed to the unique 3D porous structure, hydrogen bonding, and π-π interaction characteristics of this MAP-GBM. The material can be easily regenerated by simply immersing in methanol for 24 h, and the adsorption efficiency remain as high as 88% after five regenerations. These findings demonstrated that MAP-GBM is a promising adsorbent for the effective and cost-efficient removal of low concentration endocrine-disrupting chemicals.