Fluoride Removal from Aqueous Solution Using Custard Apple (Annona Squamosa) Leaves

Abstract

Fluoride contamination in groundwater and wastewater due to geological and anthropogenic causes was a major problem in many parts of the world. The presence of fluoride in low concentration causes dental caries and higher concentration causes dental, skeletal fluorosis. Researchers conducted experiments and developed many technologies to remove fluoride from water, among them, Adsorption proved to be one of the best feasible methods for fluoride removal. Custard Apple (Annona squamosa) leaves and pyrolyzed leaves of Custard Apple at 8000C were used as an adsorbent material. Effect on adsorption of fluorine on Annona squamosa as the adsorbent by varying parameters such as particle size, agitation speed, pH, contact time, adsorbent dosage, initial fluoride concentration, and temperature are studied. At optimum parameters of pH 7, contact time 30 min, agitation speed 500 rpm, and adsorbent dosage 1.5g per 50 mL of fluoride water, a fluoride removal efficiency of 95% was achieved. Adsorption isotherm modeling studies show that the adsorption onto Dry leaf powder followed Dubinin-Raudskevitch isotherm model and Pyrolysed leaf powder followed Langmuir isotherm model respectively. FTIR and XRD patterns of the adsorbent were recorded to get a better insight into the mechanism of the adsorption process.