Insight into the fate of 8-hydroxyquinoline and o-aminophenol in the treatment of antibiotic production wastewater by adsorption method: Synergistic or competitive adsorption

Abstract

The extensive use of antibiotics leads to a surge in antibiotic production and the generation of substantial volumes of antibiotic production wastewater in China. This wastewater posed a significant threat to ecological environments due to its high pollutant concentrations, biological toxicity, and limited biodegradability. To address the presence of toxic substances, including 8-hydroxyquinoline (8-HQ) and o-aminophenol (OAP) within cephalosporin antibiotic production wastewater, the study selected hypercrosslinked resin NDA-150 with substantial surface area and porosity as adsorbent. Batch experiments demonstrated that NDA-150 exhibited favorable adsorption capabilities for both 8-HQ and OAP, and would be influenced by pH conditions. Adsorption isotherms and kinetics followed Langmuir and pseudo-second-order models, respectively. Coexisting organic compounds like methanol and glycerol weakened the adsorption process, whereas inorganic salts had minimal impact. Significantly, competitive and synergistic adsorption effects were observed in binary systems. Specifically, synergistic adsorption occurred at a mass ratio of 1:0.1 for 8-HQ and OAP, leading to an increase in the total adsorption capacity. As the concentration of OAP excessively rose, competitive adsorption was dominant, with the resin demonstrating a preference for 8-HQ, and the total adsorption capacity of NDA-150 decreased. The adsorption mechanisms were investigated through introducing competitive substances, SEM, FT-IR and XPS, and the adsorption of two substances primarily relied on hydrophobic interactions, with additional π-π interactions for 8-HQ. Desorption experiments confirmed the effectiveness of a 1:1 volumetric mixture of ethanol and 2 mol/L NaOH. This study offered a comprehensive theoretical investigation into the adsorption behavior of 8-HQ and OAP in a mixed system, and it provided practical guidance for antibiotic production wastewater treatment by adsorption method.