The Study Of Removal And Mechanism Onto Two Kinds Of Common Antibiotics By Carbon-based Composites

With the improvement of human quality of life,the dependence on drugs and personal care products（PPCPs）is increasing.More and more residues of difficult-to-degrade PPCPs were detected in water and soil environments.Most of them exist in trace amounts in the environment and have a stable structure,which could not be satisfactorily removed by conventional sewage treatment processes.And it could be discharged through human or animal waste,and finally migrated into the environment through sewage treatment plants,soil drenching,etc.The residues of new organic micro-pollutants may exist in soil,surface and groundwater.Therefore,it is urgent to explore more effective pollutant treatment technologies.In this article,two kinds of antibiotics（chloramphenicol antibiotics and tetracycline hydrochloride）was investigated.The details are summarized as follows:（1）The appearance and contamination of chloramphenicol antibiotics（CAPs）,such as chloramphenicol（CAP）,florfenicol（FF）and thiamphenicol（TAP）,in aqueous solutions has aroused public concerns in recent years due to its negative impact on human health and ecological system.In this study,a 3D porous-structured biochar aerogel（3D-PBA）with large BET surface area（2607 m²/g）was synthesized,and applied on CAPs removal.Notably,to the best of our knowledge,among all the reported carbon-based adsorbents,3D-PBA shows the record high adsorption capacity toward target CAPs.The adsorption capacity for CAP,FF and TAP was measured to be 786.1,751.5 and 691.9 mg/g at 298 K,respectively.The Langmuir-Freundlich isotherm model can better describe the adsorption isotherm data.Specifically,2 mg/L CAPs can be completely removed within 10 min,and over 90%CAPs can be removed within 10 min even when the initial concentration was as high as 40 mg/L.Adsorption mechanism of CAPs on 3D-PBA was fully determined using XPS and FTIR.As a result,the pore-filling effect,π-π/n-πEDA interaction and electrostatic interaction played a crucial role,and it also accompany with hydrogen bonding interaction.Furthermore,the synergistic action of hydrophobic interaction also acts as indispensable role during the adsorption process.Overall,the 3D-PBA can act as an efficient candidate for ultrafast CAPs removal（Chapter 2）.（2）Tetracycline antibiotics are among the most widely used human and veterinary antibiotics in the world and are frequently detected in wastewater.In this chapter,Cu/N-carbon nanocomposites（Cu-NC）was successfully prepared by calcining that copper onto carbon material substrate.After simple PMS degradation,35.5%tetracycline hydrochloride（TC-H,20 mg/L）can be removed within 40 min.Further,after Cu-NC simple activation,the effect increased to 94.8%.In the analysis of XRD and XPS,there is a large proportion of Cu⁰ in the material.The proportion of cuprite increases rapidly after the degradation reaction,and Cu⁰ changes to positive monovalent copper.After Cu⁰ reacts with its adsorbed PMS,Cu⁰ is oxidized to Cu（I）.Cu⁺is produced in solution,and dissolved Cu⁺participates in the activation of PMS to produce sulfate radical(SO₄^·?).Such as Fe⁰,Cu⁰ can be used as an electron intermediate to accelerate electron transfer between PMS and catalyst,promote the generation of hydroxyl radical（HO^·）.And HO^·also be generated under alkaline conditions.According to the treatment results of various quenchers,SO₄^·?,HO^·,singlet oxygen（¹O₂）and superoxide anion radicals(O₂^·-)exist in the system.These reactive oxygen species have certain effects on the degradation of TC-H.However,the inhibitory effect of excess tert-butanol（TBA）and ethanol（EtOH）is almost identical to that of PMS alone.Therefore,SO₄^·?and HO^·play the most important role in the TC-H degradation progress（Chapter 3）.