A study of fluoride removal by granular iron-lanthanum complex hydroxide adsorbent

The fluoride removal performance of a prepared granular iron-lanthanum complex hydroxide adsorbent is evaluated.Results show that it has a maximum adsorption capacity of 12.1 mg/g,and can reach equilibrium within 24 hours.The adsorption kinetics is in accordance with first order reaction rate equation and the adsorption isotherm is in accordance with Langmuir model.The optimal adsorption,in terms of pH is at the range of 5-7,and the main interfering ions' affecting sequences are HCO-3HPO2-4SO2-4NO-3Cl-.The comparison between continuous adsorption experiments of the granular iron-lanthanum complex hydroxide and granular activated alumina shows that the breakthrough time of the former one is much longer than that of the latter,with the dynamic adsorption capacity of 3 times as that of the latter.