en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:1;"><b><span style="color:black">Background:</span></b><span style="color:black"> Fluoride in drinking water at high concentrations causes dental and skeletal fluorosis. Ion exchange resins are effective for fluoride removal, but require improved efficiency. This study aimed to modify the surface of an anion exchange resin with alginate and evaluate its fluoride removal performance.</span><br> <b><span style="color:black">Methods:</span></b><span style="color:black"> The resin was surface-modified using alginate via calcium crosslinking. XRD, FTIR, and SEM analyzed adsorbent characteristics. Batch experiments were optimized using Box-Behnken design. Kinetics and isotherms were evaluated using pseudo-first/second-order and Langmuir/Freundlich models. Regenerability was tested over five cycles.</span><br> <b><span style="color:black">Results:</span></b><span style="color:black"> Analyses confirmed the successful immobilization of alginate nanoparticles (average size 24.5 nm) onto the resin surface. The optimal conditions were pH 5.0, initial fluoride 7.0 mg/L, and contact time 68 min, resulting in 94.9% removal efficiency and 13.7 mg/g adsorption capacity. Fluoride adsorption followed pseudo-second-order kinetics (R&sup2; = 0.9997) and the Langmuir isotherm model (R&sup2; = 0.999), with a theoretical maximum adsorption capacity of 36 mg/g. The modified resin showed an approximately 13% loss in efficiency after five cycles.</span><br> <b><span style="color:black">Conclusion:</span></b><span style="color:black"> Surface modification of the ion exchange resin with alginate is an effective, biocompatible, and cost-efficient method to enhance fluoride removal from water, with suitable stability over consecutive cycles.</span></span></span></span></div> Ion exchange resin, Surface modification, Alginate, Fluoride removal, Adsorption, Optimization, 0 0 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-650-7&slc_lang=en&sid=1 Narges Khalili khalili.n1380@gmail.com 100319475328460016919 0009000647124061 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Esrafil Asgari sasgary@gmail.com 100319475328460016920 0000000343725936 Yes Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Mohammad Reza Mehrasbi zmehr@zums.ac.ir 100319475328460016921 0000000292514513 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran. Ali Assadi assadi@zums.ac.ir 100319475328460016922 0000000299633267 No Department of Environmental Health, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran.