Aluminum hydroxide supported on zeolites for fluoride removal from drinking water

Abstract

BACKGROUND Problems of fluorosis are still affecting millions of people around the world including Ethiopia. Hence the need to find sustainable solutions is still worth investigating. In this study, commercial zeolite Y (ZY) and natural stilbite (STI) from Ethiopia are evaluated as support for aluminum hydroxide (AO) and studied for fluoride removal from aqueous solution. The composites (STI‐AO) and (ZY‐AO) are synthesized at different zeolite to AO ratios by modifying the procedure used for synthesizing AO, reported earlier. RESULTS The X‐ray diffraction profiles show that zeolite structures are stable during modification processes. The Si/Al ratio of composites decreases as the amount of AO is increased due to increase in Al content. The PZC of STI, initially at 2.5, increased to 9.2 in STI‐AO. Textural properties of ZY and ZY‐AO proved to block certain microporosity by the AO. Optimum conditions to reduce an initial fluoride concentration of 10 mg L−1 to below the WHO guideline value of 1.5 mg L−1 were 2 g L−1 for the 2:1 systems and 4 g L−1 for the 6:1 systems. CONCLUSION Zeolite‐AO composites have very good equilibrium fluoride adsorption capacity compared with most reported materials. Hence these materials can be considered alternative adsorbents for the removal of fluoride from drinking water. © 2016 Society of Chemical Industry

Environmental uses of zeolites in Ethiopia

“…Zeolites are cationic exchangers thus their activity in raw is rather low [27]. Attempts to form composites based on zeolites require a compromise in the efficiency of the mechanical strength of the composite while maintaining good fluoride removal capacity [28]. The most pure zeolitic phase obtain in the geological screening in the north of Ethiopia was found to be Stilbite, a mineral belonging to the STI family, which contains a mixture of Na and Ca as extra-framework cations.…”

Low-Calcium, Porous, Alkali-Activated Materials as Novel pH Stabilizers for Water Media

“…It is well known that zeolites and zeolite-like materials are used as pH stabilizers and unwelcomed chemical compound absorbents in water treatment systems [17][18][19]. It is proven that AAM can contain a certain amount of zeolite, depending on the chemical composition of the precursors and activation solution used as well as from the curing conditions.…”

Selective separation and recovery of fluoride ion from ammonia‐based flue gas desulfurization slurry using electrodialysis

“…15 Therefore it is essential to develop effective, eco-friendly and cost-effective methods for the removal of F − from desulfurization slurry. The traditional defluoridation methods include precipitation, adsorption, [16][17][18][19] ion exchange, 20 membrane methods, 21 electrocoagulation, 22 biological methods 11 and so on. Precipitation and adsorption are the most used owing to their low treatment cost and efficiency.…”