Controlling the particle size and aggregation of nanosheet layers in layered double hydroxides (LDHs) is critical for their application. Herein, we report the preparation of Mg-Fe LDH through a co-precipitation method. The LDH was embedded using polyacrylamide (PAM) and polyvinyl alcohol (PVA; the LDH was designated as PAM/PVA-LDH) for As(III) and As(V) removal. We found that doping with 0.3 mL PVA (2 g L-1) and 0.4 mL (20 g L-1) PAM solution delaminated the nanosheet layers of 1 g of the LDH (PAM40/PVA30-LDH) and restructured the crystal phase from monoclinic to orthorhombic. This increased the surface area and pore volume. Furthermore, PAM40/PVA30-LDH exhibited higher affinity for As(III) and As(V) removal with maximum adsorption capacities of 14.1 and 22.8 mg g−1, respectively, compared to LDH alone with adsorption capacities of 7.1 and 7.9 mg g−1, respectively. It was found that the highest adsorption capacities of As(III) and As(V) using PAM40/PVA30-LDH occurred at pH ∼7 and pH 2.5, respectively. X-ray photoelectron spectroscopy analysis revealed that the removal of As(III) and As(V) on PAM40/PVA30-LDH was mainly attributable to ion exchange with intercalated SO42-, hydrogen bonding, and complexation mechanisms. These findings illustrate that PAM40/PVA30-LDH would be an excellent adsorbent for the remediation of arsenic-polluted wastewater.
- Ion exchange
- Layered double hydroxide