A review of the antibiotic ofloxacin: Current status of ecotoxicology and scientific advances in its removal from aqueous systems by adsorption technology

It is estimated that the growth of the population, the augmented expectancy of life, and the emergence of new pandemics will significantly increase the consumption of phar-maceutical drugs in the coming years. Due to its high efficiency, the group of fluor-oquinolones, where the antibiotic ofloxacin hydrochloride (OFL) is found, is widely used to combat bacterial infections in humans and animals. The big problem is concentrated in the effluents generated by industries and hospitals. Additionally, most of the drug is not absorbed by the body and is released directly into domestic effluents. On the other hand, treatment stations have removal limitations for small concentrations. This review ana-lyzed all adsorbents developed and used in OFL removal, listing the main parameters influencing the process. In the end, the other existing technologies in the literature and the gaps and future prospects were described. OFL adsorption in most studies occurs under basic conditions (pH between 6.5 and 8). The increase in concentration provides an increase in adsorption capacity. The adsorbents analyzed showed moderate kinetics, reaching equilibrium before 250 min for most studies. The pseudo-second-order model showed the best statistical fit. In most of the studies, the increase in temperature (313, 315, and 328 K) favored the adsorption of OFL. The Langmuir monolayer model represented most of the isothermal studies. The adsorption capacity varied from 3702 to 0.3986 mg g-1. In this aspect, factors such as OFL concentration and textural characteristics of the ad-sorbent exerted great influence. The thermodynamic parameters were compatible with the isothermal data, where the endothermic nature of the studies was confirmed. Physical interactions (pi-pi stacking, H bonding, hydrophobic and electrostatic interactions) gov-erned the main adsorption mechanism. Although some studies stated that chemosorp-tion occurred, thermodynamic parameters cannot validate the same. Coexisting ions in the solution can positively and negatively influence OFL adsorption. The listed studies are all applied to batch processes, where fixed bed studies should be better explored. From this review, it can be concluded that adsorption is a promising technique for OFL removal. However, it is extremely necessary to break the laboratory scale barrier and analyze possible conditions for applying these materials in treating real effluents together with combining technologies.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Automated summary

It is estimated that the consumption of pharmaceutical drugs will increase due to population growth, longer life expectancy, and new pandemics. The fluorquinolone group, specifically ofloxacin hydrochloride, is widely used to treat bacterial infections. However, the release of this antibiotic into industrial and domestic wastewater poses a significant challenge. This review evaluates the adsorbents used for ofloxacin hydrochloride removal and discusses other potential technologies and future prospects.