Enhancing fluoride removal in nanofiltration: a Box-Behnken design approach

This study explores the removal of fluoride from groundwater using nano-filtration (NF) with three different membrane types: TR60, NF270, and NF90. A response surface methodology (RSM) based on the Box-Behnken design (BBD) was employed to assess the influence of key operational parameters, including initial fluoride concentration (IC), transmembrane pressure (TMP), and conversion rate (CR), on permeate concentration (PC), permeate flux (PF), and energy consumption (EC). The findings indicated that IC had the most significant impact on PC, while TMP was the dominant factor affecting PF. CR showed a limited effect on both PC and PF. However, regarding EC, CR and TMP had notable influences, while IC played only a minor role. Among the membranes tested, NF270 demonstrated the highest efficiency, achieving a high PF and low EC. The optimal conditions for this membrane were determined to be a TMP of 15 bar, a CR of 0.9, and an IC of 5.31 mg/L. Additionally, the second-order regression model effectively captured the relationships between the operational parameters and the measured outcomes, with a high coefficient of determination (R-2 > 0.97) for all three membranes. This research supports SDGs 3 (Good Health and Well-Being) and 6 (Clean Water and Sanitation) by providing a framework for optimizing water treatment processes. By tackling fluoride contamination, it contributes to global efforts to reduce water-related health risks and improve public health. The study also highlights the potential of advanced NF techniques to enhance water purification systems, particularly in areas facing serious fluoride contamination issues.