The role of novel lignosulfonate-based sorbent in a sorption mechanism of active pharmaceutical ingredient: batch adsorption tests and interaction study

The aim of presented research concerned synthesis of a novel lignosulfonate-based sorbent and its application in batch adsorption tests related to removal of an active pharmaceutical ingredient (ibuprofen). Obtained hybrid material was thoroughly characterized with respect to morphology, porosity (BET method and BJH algorithm), electrokinetic stability, and characteristic functional groups. As a result of the proposed synthesis route, an active MgO–SiO2/lignosulfonate hybrid was obtained as confirmed by significant amount of functional groups present in its structure and relative good parameters of the porous structure (ABET = 71 m2/g, Vp = 0.2 mL/g and Sp = 11.8 nm). Next stage concerned typical batch adsorption tests with respect to active pharmaceutical ingredient (API)—ibuprofen. It was proved that efficiency of removal of ibuprofen was mostly determined by its structure as well as variable process parameters. Affinity of sorption material towards model organic impurity was established based on equilibrium and kinetics study of adsorption process performed. A key element of the investigations was an interaction and mechanism study resulted from interpretation how the parameters of the adsorption affect the nature of the adsorbent/adsorbate interactions. Experimental data collected, supplemented with regeneration tests, proved significant affinity of ibuprofen to the hybrid sorbent and enabled determination of nature of the adsorbent/adsorbate interactions. Moreover, suggested mechanism of ibuprofen sorption was proposed.