Boron and fluoride ions may present in wastewaters simultaneously in a form of tetrafluoroborate ions (BF4–) from various industrial processes. This research aims to remove BF4– (10 – 100 mg-B/L) by electrocoagulation (EC) using metallic aluminum as the sacrificial anode. The experimental parameters included the initial BF4– concentration, reaction pH, current density, types and concentration of electrolytes (NaCl, Na2SO4, NaClO4 and NaNO3). During electrocoagulation, the dissolved aluminum would effectively decompose BF4– as boric acid and fluoride ions, which were coagulated by aluminum hydroxide (Al(OH)3) created in an EC process. A portion of the released fluoride ions converted to fluoroaluminate ions due to the presence of dissolved aluminum ions. The sludge from EC was characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM). Under the optimal conditions: pHr 8, current density = 5 mA/cm2, NaCl = 10 mM, 98.24 % of BF4–, 98.20 % of total fluorine and 74.12 % of boron removal were achieved for an initial 100 mg-B/L.

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