Sawdust of Artocarpus hirsutus impregnated with ferric hydroxide and activated alumina (SFAA) has been studied for defluoridation of water. This paper presents a detailed surface characterization of the adsorbent by studying pore size distribution and surface morphology. By combining the constituents in the right proportion, an adsorbent with a well-developed pore size distribution could be synthesized. The effects of various parameters on fluoride adsorption by SFAA are investigated. The adsorption capacity of SFAA is considerably higher than that of many adsorbents including activated alumina. More importantly, the adsorption capacity remains unchanged for the pH range of 1 to 9, which also makes it attractive for wastewater treatment. Besides a higher efficiency supported by the results of column studies, this adsorbent is economic as the sawdust constitutes 40% by weight of the total adsorbent. Kinetic studies indicate that fluoride adsorption on SFAA follows pseudo second-order model. Breakthrough adsorption capacity of SFAA is 1.21 mg/g, as compared with 0.41 mg/g for activated alumina.
- First received 21 September 2015.
- Accepted in revised form 22 February 2016.
- © IWA Publishing 2016