Abstract

Antibiotics have been widely used in medical and agricultural fields, leading to the increasing problem of antibiotic pollution. Adsorption is one of the effective methods for removing antibiotics from water. In this paper, we review the current research status of adsorption technology for removing antibiotics. The types of adsorbents, including activated carbon, ion exchange resin, and nano-materials are discussed in detail. In addition, the application of adsorption combined with other technologies such as photocatalysis and microbial degradation is also summarized. Finally, we point out the future direction and challenges in this field.

Introduction

Antibiotics are important drugs for human health and animal husbandry, but their extensive use has led to serious environmental problems due to their persistence and toxicity [1]. Antibiotic residues can be found in surface waters, groundwater, soils, sediments, and even treated drinking water [2-4]. These residues not only pose a threat to human health but also lead to antibiotic resistance in bacteria [5]. Therefore, it is urgent to develop efficient methods for removing antibiotics from water.

Adsorption is a commonly used technique for removing antibiotics due to its simplicity, low cost, high efficiency, and wide applicability [6]. Adsorbents can selectively capture target substances through physical or chemical interactions between the adsorbate molecules and the surface of the adsorbent [7]. The aim of this paper is to review the current research status of adsorption technology for removing antibiotics.

Types of Adsorbents

Activated Carbon (AC)

Activated carbon is a highly porous material that has been extensively studied as an adsorbent for various pollutants removal due to its high specific surface area (>1000 m2/g), excellent adsorption capacity, thermal stability and low cost [8]. It can effectively remove different classes of antibiotics such as tetracyclines (TCs), sulfonamides (SAs), fluoroquinolones (FQs), and macrolides (MLs) [9,10]. The adsorption mechanism involves the physical interaction between antibiotic molecules and the surface of activated carbon, including van der Waals forces, hydrogen bonding, and π-π interactions [11].

Ion Exchange Resin (IER)

Ion exchange resin is a type of polymer that contains functional groups with ion-exchange capacity. It can selectively capture charged molecules based on electrostatic attraction or repulsion [12]. IER has been widely used for removing positively charged antibiotics such as quaternary ammonium compounds (QACs) and cationic surfactants [13]. However, it is less effective in removing neutral or negatively charged antibiotics.

Nano-materials

Nano-materials have recently attracted attention as an adsorbent due to their unique properties such as high specific surface area, small particle size, tunable morphology and chemical composition [14]. Various nano-materials have been reported for removing antibiotics such as graphene oxide (GO), magnetic nanoparticles (MNPs), mesoporous silica nanoparticles (MSNs), etc. For instance, GO can effectively remove TCs through hydrophobic interactions and π-π stacking interactions [15], while MNPs can capture tetracycline through coordination with iron ions on the surface of MNPs [16].

Combination with Other Technologies

Adsorption can be combined with other technologies to improve its removal efficiency. For example, photocatalysis technology can enhance the adsorption performance by generating reactive oxygen species that oxidize antibiotics into harmless substances [17]. Microbial degradation technology can also be coupled with adsorption to achieve complete mineralization of antibiotics. The adsorbed antibiotics serve as a substrate for microorganisms to grow and degrade [18].

Future Direction and Challenges

Although significant progress has been made in the research on adsorption for removing antibiotics, there are still some challenges that need to be addressed in the future. Firstly, the adsorption mechanism of different antibiotics on various adsorbents needs to be further elucidated. Secondly, the development of new types of adsorbents with high selectivity and capacity for specific antibiotics is required. Thirdly, the application of adsorption technology in real wastewater treatment needs to be optimized to achieve higher removal efficiency and lower cost.

Conclusion

Adsorption is a promising technology for removing antibiotics from water due to its simplicity, low cost, high efficiency and wide applicability. Activated carbon, ion exchange resin, and nano-materials are the commonly used adsorbents. Combining with other technologies such as photocatalysis and microbial degradation can improve the removal efficiency. However, more efforts are needed to address the challenges and improve its practical application in water treatment.

References

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