APPLICATION OF MODIFIED WHEAT STRAW FOR FLUORIDE REDUCTION FROM AQUEOUS SOLUTIONS: ISOTHERMS AND KINETICS

• Published in: Fluoride Vol. 45; no. 3; p. 195
• Main Authors: Rezaee, R, Mahvi, AH, Maleki, A, Jafari, A, Ashrafi, S D, Safari, M
• Format: Journal Article
• Language: English
• Published: 01.09.2012
• ISSN: 0015-4725

High levels of fluoride in drinking waters due to anthropogenic and natural sources are a major human health risk in some communities around the world. Different methods have been suggested for fluoride reduction in drinking water. Among them, adsorption methods have been widely applied with efficient results. Attempts to find more cost-effective and efficient adsorbents are continuing. The aim of this work was to determine the feasibility of modified wheat straw together with sodium bicarbonate for water defluoridation. In a batch-scale study in the laboratory, parameters including pH, contact time, initial fluoride concentrations, and adsorbent dosages were investigated. The kinetics and equilibrium isotherms were also examined. Adsorption was influenced by the initial fluoride concentration, adsorbent dosage, and pH. Among the models tested, the Langmuir and Freundlich models gave the best fit. Desorption experiments show that fluoride ions are strongly bound to the adsorbent and exhibit low rate of desorption. We conclude that adsorption by modified wheat straw is an efficient and reliable method for reduction of elevated fluoride levels in water.