ABSTRACT

The contamination of drinking water has been a major issue due to the presence of various organic, inorganic, and pathogenic ingredients. Fluoride contamination is a serious problem in several parts of India, as well as in different parts of the world, causing serious damage to health. Different techniques like adsorption, precipitation, membrane separation, ion exchange, and various hybrid techniques have been reported for the removal of fluoride from drinking water. This chapter deals with the effective removal of fluoride from drinking water using electrocoagulation (EC) followed by the microfiltration (MF) technique. During EC, several parameters such as the initial fluoride concentration, current density, electrode connection (monopolar and bipolar), pH level, and interelectrode distance affect the removal of fluoride contaminants from drinking water. An aluminum electrode is considered for the batch mode of the EC operation. The corrosion of electrodes, as well as the sludge formed during the process, is estimated. By-products obtained from the EC bath are analyzed using scanning electron microscopy (SEM), elemental analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) and explained. A comparative cost estimation for both electrode connections is also presented. It is found that drinking water contamination caused by the significant presence of fluoride is successfully monitored by bipolar EC for 45 min at a current density of 625 A m−2 and an interelectrode distance of 0.005 m. EC performance is estimated in terms of percentage removal of fluoride, and up to 93.2% of fluoride removal can be achieved. However, the electrocoagulated solution is not suitable for drinking purposes as

2.3.7.1 Scanning Electron Microscopy and Elemental Analysis (SEM and EDAX) ...36 2.3.7.2 X-Ray Diffraction (XRD) ............................................................................ 37 2.3.7.3 Fourier Transform Infrared Spectroscopy (FTIR) ...................................... 37

2.4 Electrocoagulation: Results and Discussion ........................................................................... 37 2.4.1 Effect of Initial Fluoride Concentration ..................................................................... 38 2.4.2 Effect of Bipolar Connection of Electrodes ................................................................ 39 2.4.3 Effect of Interelectrode Distance ................................................................................ 39 2.4.4 Fluoride Removal with Varying Current Density ......................................................40