Arsenic adsorbent derived from the ferromanganese slag.

Abstract

Arsenic-contaminated groundwater has a severe negative impact on the health of living beings. Groundwater majorly contains arsenite (As(III)) as well as arsenate (As(V)). Among these two, the arsenite species are more carcinogenic, mobile, and lethal. Hence, it is more difficult to remove by conventional water treatment methods. Ferromanganese slag, waste generated from steel industries, has been utilized in this study for the development of arsenic adsorbent. A chemical treatment method is applied to the ferromanganese slag to prepare efficient arsenic adsorbent, and it is easy to scale up. An adsorbent with the capacity for simultaneous oxidation of As(III) and adsorption of total arsenic species can be efficient for arsenic decontamination. X-ray photoelectron spectroscopy and X-ray absorption near edge spectra techniques prove the As(III) oxidation capability of the developed material is about 70 ± 5% based on initial As(III) concentration. The adsorbent not only oxidizes the As(III) species but also adsorbs both the arsenic species. The Langmuir isotherm model estimates the maximum adsorption capacities at the equilibrium concentration of 10 μg/L are 1.010 ± 0.004 mg/g and 1.614 ± 0.006 mg/g for As(III) and As(V), respectively. The rate of adsorption of As(III) was higher compared to the As(V), which was confirmed by the pseudo-second-order kinetic model. Therefore, the treated water quality meets the World Health Organization and Indian drinking water standards.