Removal of antibiotic residues from water using lignocellulosic materials

Abstract

Adsorption is an efficient method for the removal of antibiotics from water; however, the cost of activated carbon can be prohibitive for some applications in wastewater treatment. Lignocellulosic materials may offer a cheaper alternative, but have not been tested as widely. This study investigated the potential of sawdust to remove beta-lactams meropenem (MER), penicillin G (PEN-G) and fluoroquinolones ciprofloxacin (CIP) and ofloxacin (OFL) from water. It also examined factors that impact adsorption. HPLC methods were developed for the antibiotics’ quantitative determination in water. Batch adsorption tests were conducted with Raw Sitka spruce sawdust (RSD) and its sulphuric acid treated modification (TSD) to evaluate the sorbents’ efficiency for antibiotic removal. Both forms of sawdust successfully removed the antibiotics from water, with TSD performing better for the removal of the beta-lactams, probably due to increased hydrophobic interaction. The removal efficiency of RSD for MER, PEN-G, CIP, OFL was 40%, 48%, 90%, 96% and efficiency of TSD was 52%, 68%, 94%, 99%, respectively. Molecular size of the antibiotics did not account for observed differences in sorption; however, a higher charge density and the difference between an exothermic and endothermic adsorption were likely explanations for the higher removal efficiency of fluoroquinolones in comparison to beta-lactams. Data on sorption of all examined antibiotics to both types of sawdust were described well by the Freundlich isotherm which indicates multi-layer adsorption on the heterogeneous sawdust surface. The most applicable kinetic model was the Elovich equation as a description of a heterogeneous distribution of different adsorption sites on an irregular surface. This study showed that sawdust can be an alternative adsorbent for the removal of antibiotics from water.

Date of Award	Jan 2022
Original language	English
Sponsors	Vice Chanchellor's Research Scholarship
Supervisor	Joerg Arnscheidt (Supervisor), Heather Coleman (Supervisor) & Svetlana Tretsiakova (Supervisor)