BACKGROUND: The global use of antibiotics has become a serious concern because of its variety of potential adverse effects when present in the environment. Acute and chronic toxicity, impact on aquatic organisms, disruption of microbial populations, and dissemination into antibiotic-resistant genes have reportedly been linked to pharmaceuticals. Therefore, the aim of this study was to investigate the mechanism of remediation of some selected pharmaceuticals in aqueous medium on ionic liquid modified biomass. RESULTS: The mechanism of sorption of pharmaceuticals on biomass and biomass modified with an ionic liquid (IL) was investigated. Kigelia pinnata (KP) was modified with IL to form modified biomass (KP-IL). The pharmaceuticals investigated were ibuprofen (IBU), ketoprofen (KET), ampicillin (AMP) and diclofenac (DCL). Optimum adsorption was at pH 2.5 for AMP and pH 5 for IBU, KET and DCL. Sorption data for all the pharmaceuticals were best described by pseudo-second-order kinetics and the Langmuir adsorption isotherm. Maximum sorption capacities of 251.2, 197.1, 276.8 and 73 mg g(-1) were obtained for KET, DCL, IBU and AMP, respectively. CONCLUSION: The study showed that KP-IL is a good material for the remediation of pharmaceuticals, and the adsorption capacity was far better than that of the unmodified KP and biomasses previously reported in literature. (c) 2016 Society of Chemical Industry