Equilibrium Studies of Fluoride Adsorption onto a Ferric Poly−mineral from Kenya

Journal of Applied Sciences and Environmental Management

Onindo, Charles O.¹  Wambu, Enos W.¹  Muthakia, Gerald K.¹  Ambusso, Willis¹ 

关键词: Adsorption isotherms;    Equilibrium analysis;    Ferric poly−;    mineral;    Fluoride adsorption;    Water fluoride;   

DOI  :  

学科分类：环境科学（综合）

来源: University of Port Harcourt * Department of Pure and Industrial Chemistry

【 摘 要 】

African countries along the Great Rift Valley are among areas of the world where excessfluoride in water sources is a major public health problem. In this work, the removal of fluoride (F) from watersolutions using a ferric poly-mineral (FPM) from Kenya was therefore studied using batch adsorptionexperiments. The effect of change in solution pH, temperature, initial concentration of F, mass of FPM, contacttime and presence of various competing ions on F adsorption onto FPM was evaluated. Adsorption isothermswere then applied to the adsorption data to characterize and establish the adsorption capacity of the mineral. Theadsorption of F onto FPM was found to be a fast process and, at 1000 mg/L initial F concentration at pH 3.32and 293 K and using 0.2 g/mL adsorbent dosage, over 90% F removal from solution could be achieved in 30min. Based on Giles system of classification of adsorption isotherms, F adsorption isotherm conformed to L4Langmuir-type isotherms. This indicated that FPM is composed of a heterogeneous surface consisting of siteswhich, during adsorption, filled-up with F ions in succession. The adsorption data also correlated to Langmuirand Freundlich models indicating that F adsorption onto FPM was a mixed process involving chemisorptiononto surface sites followed by gradual intra-particle penetration of F into mesoporous structure of the mineral.High mean Langmuir adsorption capacity of 10.8 mg/g, indicate that the mineral could be of use as aninexpensive substrate for the removal of F from aqueous streams.

【 授权许可】

Unknown