Simultaneous Arsenic and Fluoride Removal from Contaminated Water Using Powder Reagents of CaO, Ca(OH)2, and CaCO3 as Calcium-Based Adsorbents

As and F contamination are a global problem, and their simultaneous contamination in groundwater is a frequent occurrence, necessitating strategies for their concurrent removal. This study evaluated the performance and potential applicability of Ca-based adsorbents (CaO, Ca(OH)2, and CaCO3) for simultaneous As–F removal. Removal tests were performed using synthetic contaminated water with an initial As concentration of 1 mg/L and initial F concentrations of 15–60 mg/L. The results showed that CaCO3 had difficulty removing As and F in contaminated water; in contrast, CaO and Ca(OH)2 achieved simultaneous As–F removal under certain conditions. Regardless of the presence or absence of F, the water purified using CaO and Ca(OH)2 met the As environmental standard (0.01 mg/L) for As(V) and As effluent standard (0.1 mg/L) for As(III). Meanwhile, with or without As, CaO- and Ca(OH)2-treated water met the F environmental standard (0.8 mg/L) at a concentration of 15 mg/L and F effluent standard (8 mg/L for non-marine areas) at 30 and 60 mg/L. In this study, where the initial As concentration was set to a constant value, the degree of mutual effects on As and F adsorption behavior differed depending on the combination of adsorbent addition and initial F concentrations.