No abstract

Electrocoagulation (EC) has been evaluated as a treatment technology for arsenic (As) removal. Experiments were developed in an electrochemical reactor with three parallel iron plates. Current densities of 15, 30, and 45 A m −2 were used to treat model water and 45 A m −2 to treat underground water (GW). For both types of water, the EC process was able to decrease the residual arsenic concentration to less than 10μg L −1 . However, the treatment time for As removal from GW was higher. This phenomenon was attributed to the competition of dissolved species present in GW such as silica and calcium with arsenic for the adsorption sites on the ferric oxyhydroxides flocs generated during the EC process. A procedure is proposed to reduce such interference by the addition of a silica adsorption inhibitor compound into the GW achieving a reduction in the process time. The adsorption of arsenic species over adsorbent was found to follow Lagergren adsorption model.

No abstract

Arsenic (As) was removed electrochemically from underground water (GW) by electrocoagulation (EC) process employing a bipolar cell configuration with continuous flow using iron electrodes. A kinetic model derived from the Lagergren equation was applied to specify the kinetics of the arsenic removal reaction. Elucidation of the effect of the liquid flow rate on the treatment time and on the simulation results of the model was achieved. The results showed that treatment times decreased from 10.50 min to 0.75 min as the flow rate decreased from 3.500 to 0.875 L min(-1) and the current density varied from 15 to 45 A m(-2) respectively. The used sorption kinetic model successfully describes the arsenic removal by this process. The coefficients of determination were found to be very high in all cases (R(2)>0.99) indicating a good fit of the experimental data to Lagergren model.