Abstract

GONZALEZ-CHAVEZ, José Luz; CHIKEN SORIANO, Anaí; ROMERO, Francisco Martín  and  CENICEROS-GOMEZ, Agueda Elena. Elucidation of the arsenic removal mechanism in aqueous solution with metallurgical waste. Rev. Int. Contam. Ambient [online]. 2023, vol.39, 54399.  Epub June 05, 2023. ISSN 0188-4999.  https://doi.org/10.20937/rica.54399.

We present the elucidation mechanism of arsenite removal with slags through the evaluation of five materials: A1, C1, N1 (steel industry), M1 (lead industry), and M2 (iron industry), all of them with different surface areas pore diameter, and chemical and mineralogical composition. The slags were physically characterized, determining surface area (1.6 to 10 m2/g) and zero charge point (5.5); chemically by X ray fluorescence (XRF) mainly identifying Si, Ca and Fe, and the release of potentially toxic elements by leaching at different pH´s (5, 7 and 9) was ruled out. The mineralogy determined by X ray difraction (XRD) showed iron compounds. The removal of arsenite was evaluated at laboratory level by means of a 2k experimental design in synthetically contaminated samples. Agitation time, amount of slag and initial concentration of arsenite were evaluated. The optimal removal conditions were: 250 mg of slag, 10 mg/L of arsenite, and agitation time of 60 min. The C1 slag removed more than 90 % of the initial arsenite, and the proposed fixation mechanism could be a chemisorption at heterogeneous sites, as well as through intraparticle diffusion. XRD and infrarred (IR) spectroscopy analyses of the slag after arsenic fixation showed that there is a direct interaction of arsenite with iron.

Keywords : arsenite; slags; adsorption; chemisorption; remotion.