| In recent years,antibiotics have been widely used in the treatment of human and animal diseases,but they are considered to be one of the world's organic pollutants because they cannot be completely absorbed and degraded,which seriously threatens food safety.Residues of antibiotics in the environment can be accumulated in the organism through the enrichment of the food chain,leading to the spread of disease resistance genes.With the widespread use and abuse of antibiotics,more and more antibiotic resistance occurs in various pathogens around the world.Residues of water-soluble antibiotics such as tetracycline hydrochloride?TC-HCl?are mainly present in soil and groundwater,causing serious water pollution problems.At present,the methods for antibiotics removal mainly include membrane filtration,catalytic degradation,biological treatment,chemical oxidation and adsorption,among which adsorption is considered to be the simplest and most cost-effective method.Compared with traditional adsorbents,two-dimensional porous carbon nanomaterials have excellent characteristics such as strong adsorption capacity,simple preparation process,non-toxic and harmless,and large-scale production,which have attracted wide attention.Based on these,a tetracycline hydrochloride adsorbent based on a novel Co/N co-doped mesoporous carbon nanosheet?Co/N-MCs?was prepared by a two-step method,and the structure of the adsorbent and its adsorption performance for tetracycline hydrochloride were evaluated.The main research contents and results are as follows:1.Co/N-MCs were prepared by solvothermal method and then high temperature thermal cracking.Field emission scanning electron microscopy?SEM?and transmission electron microscopy?TEM?showed that the Co/N-MCs were a lamellar structure with a large number of well-distributed mesoporous structures on the surface.X-ray diffraction?XRD?,energy dispersive X-ray?EDX?,Fourier transform infrared spectroscopy?FT-IR?and X-ray photoelectron spectroscopy?XPS?characterization results confirmed the successful preparation of Co/N-MCs.2.Study on the adsorption performance of Co/N-MCs adsorbent on tetracycline hydrochloride.The adsorption kinetics and adsorption thermodynamics experimental data of Co/N-MCs adsorbed tetracycline hydrochloride were fitted.The results show that the adsorption process is more consistent with the pseudo-second-order kinetic model and the Langmuir isotherm model,indicating that the adsorption reaction belongs to the chemical adsorption on the monolayer,and the maximum adsorption capacity is 344.83 mg g-1,which is superior to the reported carbon-based tetracycline hydrochloride adsorbents.Studies on the adsorption mechanism shows that the main mechanism of action of Co/N-MCs on the adsorption of tetracycline hydrochloride is?-?electron donor-receptor interaction,cation exchange,surface complexation and electrostatic attraction,and the higher specific surface area and unique mesoporous structure of Co/N-MCs adsorbent provide a large number of adsorption sites for the adsorption of tetracycline hydrochloride.3.Feasibility study of Co/N-MCs adsorbent in practical applications.Salt-resistant ion interference test and recyclability study showed that various ions in the test did not have a great influence on the adsorption performance of the adsorbent reflecting that the Co/N-MCs adsorbent has strong resistance to salt ion interference.Moreover,the removal efficiency of Co/N-MCs adsorbent for tetracycline hydrochloride after five recycle times can still over 86%.Therefore,Co/N-MCs adsorbent has a good application prospect in the field of antibiotic pollution control because of its low cost,excellent adsorption performance and good recyclability for tetracycline hydrochloride removal. |
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