Ultrafast and deep removal of arsenic in high-concentration wastewater: A superior bulk adsorbent of porous Fe2O3 nanocubes-impregnated graphene aerogel

Abstract

Bulk adsorbents for fast and deep removal of arsenic in water is highly demanded for practical treatment process, especially fixed-bed column process. In this study, a superior bulk adsorbent of porous Fe2O3 nanocubes-impregnated porous graphene aerogel (PGA/PFe2O3) is prepared using a simple template engineering. The maximum capacity for As(III) and As(V) reaches as high as 172.27 and 217.34 mg g−1 of Fe2O3, respectively. The adsorption equilibrium times of As(III) and As(V) on PGA/PFe2O3 are only 30 and 5 min, respectively (m/V = 0.5 g L−1, C0 = 5 mg L−1). Significantly, the high concentrations of As(III) and As(V) can be reduced below 10 μg L−1 within only 60 and 5 min, respectively. The aerogel is conducive to fast diffusion of arsenic and porous Fe2O3 nanocubes provide abundant adsorption sites. Moreover, the adsorbent exhibits an outstanding reusability. The adsorbent also shows a strong anti-interference to aquatic environment. A real realgar tailing wastewater (C0 = 3.076 mg L−1 for As(III) and 3.225 mg L−1 for As(V)) can be deep treated (below 10 μg L−1) within 4 h (m/V = 0.6 g L−1). The bulk adsorbent of PGA/PFe2O3 presents a high column treatment capacity of arsenic-containing groundwater (4750 BV for As(III), 5730 BV for As(V)), producing only 12 BV eluent. This work develops a superior bulk adsorbent for large-scale treatment of arsenic-containing wastewater.