Various techniques for water defluoridation by alumina: Development, challenges and future prospects

Abstract

The contamination of the fluoride in ground water due to natural or anthropogenic sources has become serious problem worldwide and seems to be major threat to the environment. The fluoride guards our teeth from cavities but its excess concentration loses cluster of enamel and imparts fluorosis. This paper critically reviews the recent progress on the synthesis and applications of alumina based materials being used for defluoridation of ground water. Although there are many adsorbent techniques like clay, bio-adsorbent, carbon based compounds, natural and chemical materials but alumina is most widely used material due to its low cost, non-toxic and porous nature. This alumina can be used in various forms and can be impregnated with other material which may enhance defluoridation capacity of alumina. However there are still challenges and questions for these techniques that need to be addressed in future researches such as optimization of the investment cost by introducing new fabrication technologies, selectivity, permeability and packing densities improvement, fouling minimisation and proposing scale up based on experimental research results. This paper may provide an insight for the development of various alumina based materials for ground water purification in future.