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

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 FeO nanocubes-impregnated porous graphene aerogel (PGA/PFeO) 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 of FeO, respectively. The adsorption equilibrium times of As(III) and As(V) on PGA/PFeO are only 30 and 5 min, respectively (m/V = 0.5 g L, C = 5 mg L). Significantly, the high concentrations of As(III) and As(V) can be reduced below 10 μg L within only 60 and 5 min, respectively. The aerogel is conducive to fast diffusion of arsenic and porous FeO 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 (C = 3.076 mg L for As(III) and 3.225 mg L for As(V)) can be deep treated (below 10 μg L) within 4 h (m/V = 0.6 g L). The bulk adsorbent of PGA/PFeO 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.