Polyaniline – rare earth metal chloride composites are synthesized and used to remove fluoride ions from drinking water as part of a "prospective strategy to sustainable waste management". The influence of variables such as the effect of initial fluoride concentrations, pH, contact time, effects of co-ions, and temperature on the removal of fluoride ions have been examined. The thermodynamic studies showed that the reaction is endothermic, and the reaction is favoured at an elevated temperature. The reaction mechanism is explored with an analysis of Fourier Transform–Infrared spectroscopy, X-Ray diffraction technique, Scanning electron microscopy, Energy Dispersive X-Ray Analysis and X-ray photoelectron spectroscopy during the adsorption of fluoride ions. The solid waste material generated after defluoridation is utilized as an electrode material for supercapacitor performance study through "Waste utilization for technology."