Chlorpheniramine (CHP) is an antihistamine used to treat symptoms of allergic diseases. Ibuprofen (IBU) is used in the management of pain, fever and inflammation while Glipizide (GLI) enhances release of body’s natural insulin and hence used in the management of hyperglycemia. Chlorpherinamine, Ibuprofen and glipizide are some commonly produced drugs by pharmaceutical industries whose unguarded discharge into the environment can be harmful to man, animals and plants. Therefore, it is crucial to adsorb these drugs from pharmaceutical effluents using surface functionalized activated carbon so as to avert the harmful effects of the drug residues in the environment. Thus, study investigated the thermodynamic parameters for adsorption of CHP, IBU and GLI using OAC, HAC and BAC of mango kernel seed. Activated carbons (ACs) were prepared from mango kernel seed (MKSAC) through KOH activation. The ACs were oxidized with HNO₃ to produce oxidized activated carbons (OACs) that were surface functionalized using ethylene diamine to produce basic surfaces (BACs) and ethylamine to produce hydrophobic surfaces (HACs). Thermodynamic parameters for adsorption were then determined using standard methods. Drug adsorption depends mainly on solution pH and the adsorbent surface nature, and initial pH 7 was found optimal for the removal of the three drugs. Equilibrium adsorption was reached faster on HAC and OAC than on BAC with kinetic adsorption data following well pseudo second order model much better than pseudo first order and intra-particle diffusion. Equilibrium adsorption data follow well the Langmuir model than the Freundlich model. The Chlorpheniramine uptake followed the order: HAC > OAC > BAC for mango kernel seed, whereas the adsorption of Ibuprofen and Glipizide followed the order: OAC > HAC > BAC. Thermodynamic parameters showed that drug adsorption is spontaneous and endothermic, with values less than 40kJmol^-1 indicating physisorption processes domination. From the result of this study, OAC, HAC, BAC prepared from mango kernel seed (MKSAC) has demonstrated drug adsorption that is spontaneous, endothermic and hence thermodynamically favorable.

Keywords: Chlorpherinamine, Glipizide, Ibuprofen, functionalization, activated carbons, adsorption.

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