Objective:

The pollution of water bodies, a product of effluent discharges contaminated with Chromium (VI), is a widely studied environmental problem due to the toxic effects of this pollutant on human health and the environment. The aim of this work is to study the elimination of hexavalent chromium by means of the electrocoagulation method with iron and aluminum electrodes in a monopolar configuration. The effect of residence time, voltage, and the number of electrodes over removal efficiency was evaluated.

Methodology:

The experiments were conducted in a 3 L batch electrocoagulation cell, using 10 and 6 aluminum and stainless-steel plates, respectively, as electrodes connected at a distance of 1,5 cm in a monopolar configuration and parallel to the power source. A contaminated solution with Cr(VI) was treated at a concentration of 50 mg/L, evaluating two levels of residence time (20 and 30 min), voltage (20 and 30 V), and number of electrodes (6 and 10).

Results:

Removal percentages between 60,15 and 92,9% were obtained. It was found that the most positively influential variable in the process is the increase in residence time. It can be inferred that electrocoagulation performs better at lower voltages and longer residence times, and the joint effect of the increase in the number of electrodes and the contact time increases the performance of the process, thus achieving greater removal.

Conclusions:

The Cr(IV) reduction process by electrocoagulation has the potential to be used for the removal of heavy metals from water in a cost-effective way.