Investigation of performances and mechanism of fluoride removal by Fe(III)-loaded ligand exchange cotton cellulose adsorbent

Novel adsorbent, Fe(III)-loaded ligand exchange cotton cellulose adsorbent [Fe(III)LECCA], was used to investigate the adsorption performances and mechanism of fluoride removal from aqueous solutions. The adsorbent was found to adsorb fluoride rapidly and effectively. The fluoride removal was influenced by pH. Adsorption mode followed first-order reaction at different temperature, theapparent adsorption activated energy E_a was 6.37 kJ · mol^-1, and adsorption enthalpy ΔH was 5.35 kJ · mol^-1. The adsorption capacity of fluoride on adsorbent was 3.2 mmol · g^-1 (dry weight). The maximal integer coordination ratio of fluoride with Fe (III) LECCA was 3:1. The ligand exchange mechanism of adsorption was elucidated through chemical methods and IR spectral analysis.