Simultaneous Arsenic and Fluoride Removal from Contaminated Water Using Powder Reagents of CaO, Ca(OH) 2 , and CaCO 3 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 CaCO 3 ) 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 CaCO 3 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.