Boron Removal from Aqueous Solutions by Electrocoagulation at Low Concentrations

Boron can cause gastrointestinal dysfunction, blood circulation disorder, and reproductive problems.
In this research, the effect of some parameters on the efficiency of treatment system is studied in
detail. These parameters include pH, distance between electrodes, current density, reaction time,
initial concentration of boron, and interference effect of common anions in water including carbonate,
sulfate, and chloride. The boron concentration in the samples is determined by standard method. The
efficiency of electrocoagulation for boron removal at a concentration of 100 mg/L and under optimal
condition (pH: 8, distance between electrodes: 10 mm, reaction time: 60 min, concentration of 100
mg/L and current density: 5.5 mA/Cm2) is good (about 70%). Boron adsorption isotherm on produced
aluminum according to Faraday's law corresponds to isotherms of Langmuir (R2 = 0.77) and
Freundlich (R2 = 0.79). Boron adsorption kinetics on produced aluminum corresponds to the pseudosecond-order model (R2 = 0.99). Interfering effect of carbonate ions is more than other anions in water
such as chloride and sulfate. The addition of two moles of carbonate ions can reduce the efficiency of
the process by 15%. Therefore, unlike the chemical coagulation process, using pre-treatment
processes for the initial adjustment of pH in water using limewater due to an increase of carbonate in
water can decrease the efficiency of electrocoagulation. Electrocoagulation process can be used for
treatment of boron- polluted water and wastewaters containing boron at initial concentrations of more
than 50 mg/