A comparison study on the arsenate adsorption behavior of calcium-bearing materials

Abstract

The calcium-bearing adsorbents are widely used in the treatment of arsenic-containing wastewater due to their excellent treatment effect and economy. In order to obtain high-efficient adsorbents for arsenate (As(V)) removal, the adsorption behavior of calcium oxide (CaO), calcium fluoride (CaF2) and calciumcarbonate (CaCO3) on As(V) in aqueous solution at different concentrations were explored. The adsorption mechanism was also explored based on surface characteristics: morphology, specific surface area, as well as their effective calcium content. Not only that, the chemical stability of these materials was further studied. Results exhibited that the As(V) removal capability of these materials is in the following order, CaO > CaF2 > CaCO3. When CaO served as an absorbent, As(V) with initial concentration of 0.2 mg/L can be reduced to 0.383 × 10-3 mg/L in 10 min. Moreover, the capabilities of CaO, CaF2 and CaCO3 for removing As(V) are positively correlated with their effective calcium content in aqueous solution, which provide the basis for selecting calcium-bearing materials with excellently comprehensive properties for the field of As(V) removal in aqueous solution. What's more, all three materials exhibit great chemical stability after adsorption of As(V).