Abstract
In most countries, arsenic (As) and antimony (Sb) are regulated pollutants, due to their significant impacts on the environment and human health. Iron-based (Fe) coagulants play a fundamental role in the removal of both elements from aqueous media. This study aims to investigate the competitive removal of As and Sb in relation to Fe solubility. Coagulation experiments were conducted in synthetic water under various pH and contaminant loading, using ferric chloride (FC) as a coagulant. In the single system, the pentavalent species significantly reduced the Fe solubility and thereby enhanced the mobility of As and Sb under these environmental conditions. The coexistence of pentavalent and trivalent species in the binary system considerably decreases the Fe solubility at acidic conditions while enhancing the dissolution under alkaline conditions, thus affecting the overall removal of both species. The presence of four redox species in the quaternary system decreases the Fe solubility remarkably over a wide pH range, with better Sb removal, as compared to As under similar conditions. The adsorption study of the single system showed a decrease in As(V) adsorption capacity at higher concentration, while in the binary system, the Sb(III) showed strong adsorption potential, compared to other species. In the quaternary system, the presence of all four redox species has a synergistic effect on total Sb adsorption, in comparison to the total As. Furthermore, the results of Fourier transform infrared (FT-IR) analysis of FC composite contaminant flocs confirm that the combined effect of charge neutralization and inner sphere complexation might be a possible removal mechanism. These findings may facilitate the fate, transport and comparative removal of redox species in the heterogeneous aquatic environment.
Highlights
Arsenic (As) and antimony (Sb) have numerous applications, including the manufacture of plastics, batteries, flame retardants and semiconductor materials [1,2,3]
The results indicate that the adsorption affinity of Sb species rivals the adsorption capacity of As species on ferric chloride (FC) precipitates in coexisting environments at neutral pH
We systematically investigated the influence of pH and contaminant loading of four redox species on Fe solubility, as well as their adsorptive removal behavior, in the single, binary and quaternary system
Summary
Arsenic (As) and antimony (Sb) have numerous applications, including the manufacture of plastics, batteries, flame retardants and semiconductor materials [1,2,3]. Indicated that the global annual consumption of Sb was 188,000 tons, about fivefold more than that of As. As a result, anthropogenic emission causes As and Sb concentrations in soils and waters that greatly exceed their baseline concentrations [5]. The high levels of co-occurring As and Sb in soils and waters are mostly found in the vicinity of mining and smelting areas [7,8]. The groundwater near abandoned Sb mines in Slovakia presented high Sb levels of up to 1 mg/L [9]. A recent study [10,11] reported the concentration of Sb (6 mg/L) in underground well water and high contamination of Sb (5045 mg/Kg) and As (205 mg/Kg) in the soils near Xikuangshan Sb mine, China. The release of these toxic elements from different sources into the environment has raised global concerns regarding their potential risk of exposure to human, as well as the aquatic environment
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
