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 calcium carbonate (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).

Adsorption of Heavy Metals Ions from Mining Metallurgical Tailings Leachate Using a Shell-Based Adsorbent: Characterization, Kinetics and Isotherm Studies

“…Wang and Zhu 2019 [ 42 ] studied the removal of As(V) ions from aqueous solutions using CaO, CaF 2 and CaCO 3 ; they found that the main mechanism for the removal of As(V) ions by calcium-bearing materials was the formation of insoluble calcium arsenate salt generated by arsenate anions and calcium ions. Ayala and Fernandez 2020 [ 43 ] studied the capacity of four industrial waste materials originating from steelmaking processes (slags) and from gas treatment at a thermal power plant (fly ash and gypsum) to remove As ions from a leachate from the spoil heap of an abandoned mercury mine.…”

Adsorption performance and its mechanism of aqueous As(III) on polyporous calcined oyster shell‐supported Fe–Mn binary oxide

“…Besides, many researchers have found that the presence of Ca 2+ promotes the removal of arsenic through the formation of Ca-As sediments (Zama et al, 2022). The mechanism of arsenic removal by lime (CaO) and hydrated lime (Ca (OH) 2 ) has been proved to be through the precipitation of different types of calcium arsenate salts (Yang et al, 2021;Zama et al, 2022) and CaO, which may form calcium arsenate precipitation in the process of As(III) removal, thus improving the As(III) adsorption efficiency of FMBO/OS (Mollah et al, 2004;Wang & Zhu, 2019). The FMBO/OS after As(III) adsorption was analyzed by XRD, as shown in Figure 7, which confirmed that Ca-As sediments, CaHAsO 4 Á3H 2 O (d = 4.96, 2.95, 2.63, and 2.51 Å), Ca(H 2 AsO 4 ) 2 (d = 3.04, 1.79 and 1.48 Å), and CaAs 2 O 6 (d = 2.94 and 2.96 Å) had formed (Mollah et al, 2004).…”