Degradation of fluoride in groundwater by electrochemical fixed bed system with bauxite: performance and synergistic catalytic mechanism

Abstract

Fluoride pollution in water has garnered significant attention worldwide. The issue of fluoride removal remains challenging in areas not covered by municipal water systems. The industrial aluminum electrode and natural bauxite coordinated defluorination system (IE–BA) have been employed for fluoride removal. The experiment investigated the effects of pH, current density, and inter-electrode mineral layer thickness on the defluorination process of IE–BA. Additionally, the study examined the treatment efficiency of IE–BA for simulated water with varying F⁻ concentrations and assessed its long-term performance. The results demonstrate that the defluorination efficiency can reach 98.4% after optimization. Moreover, irrespective of different fluoride concentrations, the defluorination rate exceeds 95.2%. After 72 hours of continuous operation, the defluorination rate reached 91.9%. The effluent exhibited weak alkalinity with a pH of around 8.0, and the voltage increased by 2.0 V compared to the initial moment. By analyzing the characterization properties of minerals and flocs, this study puts forward the possible defluorination mechanism of the IE–BA system. The efficacy of the IE–BA system in fluoride removal from water was ultimately confirmed, demonstrating its advantages in terms of defluorination ability under different initial conditions and resistance to complex interference. This study demonstrates that the IE–BA technology is a promising approach for defluorination.