Rapid effectual entrapment of arsenic pollutant by FeO supported on bimodal meso-macroporous silica for cleaning up aquatic system.

Arsenic (As) contamination in aqueous media is a major concern due to its adverse impacts on humans and the ecosystem more broadly because of its non-biodegradability. Consequently, an effective and selective sorbent is needed urgently to scavenge As pollutant. Herein, the adsorption behaviors of As(V) by FeO and FeO supported on different silica materials, consisting of unimodal mesoporous silica (FeO/U-SiO) and dual meso-macroporous silica (FeO/B-SiO), were compared to examine their structure-efficiency relationships in the elimination of As(V). FeO/B-SiO was much faster at As(V) removal and had an impressively higher uptake capability, reaching nearly 50% and 2.5 mg g within 5 min compared to bare FeO (6% and 0.3 mg g) and FeO/U-SiO (11.9% and 0.59 mg g). These better results were because of the highly dispersed FeO nanoparticles on the B-SiO support that provided abundant reactive sites as well as a macropore structure facilitating As(V) diffusion into adsorptive sites. The maximum adsorptive capacity of FeO/B-SiO (4.7 mg As per 1 g adsorbent) was 1.3- and 1.7-fold greater than for FeO/U-SiO and FeO, respectively. The outstanding performance and reusability of FeO/B-SiO with its ease of production, economical and environmentally friendly features made it even more attractive for As(V) remediation. The explored relationship between the structure of SiO-supported FeO sorbents and their performance in removing As(V) could be informative for the future design of highly efficient adsorbents for the decontamination of water.