Ultrasound‐Activated Modified Starch Microgranules for Removal of Ibuprofen from Aqueous Media

Abstract

Ultrasound activated (U‐CCS) and non‐activated microgranular cross‐linked cationic starch sorbents (CCS) of different degree of substitution (DS) of quaternary ammonium groups are developed and used for binding of ibuprofen (IB) via adsorption and removal from aqueous solution. Ultrasonic treatment results in the formation of some fissures and cracks on the exterior of the modified starch granules as observed by a scanning electron microscopy studies. The equilibrium adsorption of IB onto both types of granules is investigated. The parameters of the Langmuir, Freundlich, and Dubinin‐Radushkevich adsorption models are calculated and showed that driving forces of adsorption are electrostatic interaction between quaternary ammonium groups of modified starches and carboxylic groups of IB. The sorption capacities of CCS with DS of quaternary ammonium groups equal to 0.21 and 0.42 are 232 and 345 mg g−1, respectively. The ultrasound activation increases the sorption capacities of U‐CCS to 574 and 579 mg g−1, accordingly. Therefore, the ultrasound activation allows to achieve high‐level binding of IB by using low amounts of chemical agent to modify starch granules. The ultrasound activation method presents a great potential to improve the CCS sorption properties and generating a promising sorbent for the removal of IB from aqueous media.

Cross-Linked Cationic Starch Microgranules for Removal of Diclofenac from Aqueous Systems

“…As the native starch cannot directly act as an adsorbent, potato starch was cross-linked and cationized to increase the firmness of the granules and to provide the binding ability of the contaminant, respectively. Similar sorbents have already been tested for ibuprofen adsorption from water in our previous studies [49][50][51] and showed high sorption capacities. Therefore, we propose the removal of diclofenac from the effluents through the adsorption process and before sludge formation in order to not contaminate sewage sludge with micropollutants during wastewater treatment.…”

“…Cross-linked cationic starches (CLCSs) were prepared by a two-stage modification reaction which was described in detail in our previous paper [49]. The molecular mass of an anhydroglucopyranose unit (AGP) was assumed as a mole of starch.…”

“…In this study, native potato starch was chemically modified to obtain cross-linked cationic starch (CLCS) which was used for removal of diclofenac from an aqueous medium. The two modification reactions of potato starch, such as cross-linking and etherification, were used for adsorbent granule preparation as described in our previous paper [49]. The cross-linked starch derivatives can swell in an aqueous medium without dissolution due to a three-dimensional structure.…”

“…The significant advantage of using such adsorbents is that CLCS is active in a wide pH range [59]. For instance, it was revealed in our previous studies that ibuprofen containing carboxylate groups interacts with the cationic moieties of CLCS [49,50]. Therefore, diclofenac possessing carboxylate groups should also interact with CLCS.…”