Magnetically recoverable carbon-coated iron carbide with arsenic adsorptive removal properties

Abstract

Magnetic particles, generally nanostructured and magnetite-based, have been studied extensively to remove drinking water contaminants. Compositions beyond Fe 3 O 4 could address long-standing issues of magnetic recoverability and materials integrity in drinking waters. Herein carbon-coated iron carbide (Fe 3 C@C) were studied for the first time for their stability, magnetic characteristics, magnetic separability, and arsenic adsorptive properties. Experimental results show that (i) Fe 3 C@C with a 9-nm thick graphitic shell is chemically stable in simulated drinking water; (ii) is ferromagnetic with small magnetic remanence and a magnetic saturation that is ~ 2 × greater than Fe 3 O 4 ; (iii) can be separated from water magnetically under continuous-flow conditions with greater than 99% recovery; and (iv) has a surface area-normalized adsorption capacity for arsenic (6.75 µg/m 2) of the same order of magnitude as that of Fe 3 O 4 (9.62 µg/m 2). Fe 3 C@C can be a viable alternative to Fe 3 O 4 with further development, for the magnetic removal of arsenic and other contaminants from drinking water sources. Graphic abstract A comparative look at the chemical stability, adsorptive prowess, and magnetic capturability of nanostructured carbon-coated iron carbide for arsenic removal from simulated drinking water.

Adsorption methods for arsenic removal in water bodies: a critical evaluation of effectiveness and limitations

“…In another study (Sunil et al, 2018), more than 96% of As was removed with Al-Ti 2 O 6 nanoparticles. In another study (Powell et al, 2020), carboncoated iron carbide (Fe 3 C@C) was used to remove arsenic (As) from groundwater. The maximum adsorption capacity was 168 micrograms per gram (µg/g).…”