Adsorptive Removal of Famotidine Drug from Aqueous Medium by Ocimum Basilicum

Abstract

The present study investigated the potential of basil seeds as adsorbent in order to remove famotidine drug from aqueous media. The optimum conditions for the adsorption of famotidine on the basil seeds were found to be 50 min contact time, 50 °C temperature, pH 1, 100 ppm concentration of famotidine, 0.03 g adsorbent mass and 50 rpm agitation rate. Pseudo 2nd order kinetics with a higher correlation coefficient (R2=0.9942) suggested chemisorption as preferable mechanism of adsorption. However, the enthalpy of adsorption (ΔH=+33.67 KJ/mol) was less than that of chemisorption but higher than that of physisorption which was attributed to strong hydrogen bonding between famotidine molecules and basil seed surface. The Langmuir isotherm with higher R2 (0.9960) than Freundlich isotherm (R2=0.8798) predicted maximum adsorption capacity (qm) of 99 mg/g while suggesting monolayer and favourable adsorption. The adsorption was endothermic (+ΔH) and spontaneous (−ΔG) in nature. The FT‐IR spectroscopy confirmed that famotidine was adsorbed on basil seed via strong hydrogen bonding. The study proposed that the simultaneous intake of famotidine and basil seeds should be strictly avoided as the drug readily adsorbs on basil seeds in acidic environment (gastric pH) thereby reducing its curing effect.