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Removal of Fluoride from Water by a Continuous Electrocoagulation Process

Graça, Nuno S., Ribeiro, Ana M., Rodrigues, Alírio E.
Industrial & engineering chemistry process design and development 2019 v.58 no.13 pp. 5314-5321
aluminum, electric potential difference, electrical resistance, electrocoagulation, electrodes, fluorides, models, process design, statistical analysis
The present work proposes a continuous electrocoagulation experimental setup for the removal of fluoride from water using aluminum electrodes. The experimental results showed that the proposed process can remove 97% of fluoride from 5 L of water with a concentration of 15 mg F–/L. Additionally, was verified that the applied voltage during the operation remains almost constant, indicating that this experimental setup overcomes the increase of the electrical resistance due to the electrode passivation. The statistical analysis of the results showed that for the fluoride removal all the operating variables have significant effects whereas for the applied voltage only the current intensity and electrodes configuration are significant. A quadratic model showed to be suitable to relate the responses with the operating variables. The experimental setup was tested for the treatment of 20 L of water. The results showed that for 20 L of water the total removal of fluoride could be achieved with an energy consumption of 506 kWh m–³.