The Study On Removal Of Antibiotics In Water Based On Three-dimensional Graphene

In recent years,the current situation of antibiotic contamination caused by the problem of antibiotic abuse has become increasingly serious.Conventional water treatment processes are not yet removed them completely,resulting in significant damage to the entire ecosystem.Therefore,the research on antibiotics in water has important practical significance.Among various methods,the adsorption method has unique technical advantages in water treatment because of its high efficiency,low cost and recyclability.However,the selective preparation of adsorbent materials is one of its key technologies.As a new type of adsorbent,three-dimensional graphene has a large specific surface area and a high porosity,and has better adsorption performance than other adsorbent materials.In this study,a new type of three-dimensional graphene(3DG)was used as the adsorbent.Firstly,a standard method for liquid chromatography which can rapidly detect and separate three antibiotics of tetracycline,oxytetracycline and chlortetracycline was established.Then the adsorption method was used to explore the adsorption effect and mechanism of methylene blue(MB)and tetracycline(TC)solutions from adsorption kinetics,adsorption thermodynamics,adsorption isotherms and adsorption influencing factors.On the one hand,the liquid phase separation conditions of each target were optimized by investigating different mobile phase compositions,gradient elution procedures and sample solvent ratios.At the same time,the instrument precision was investigated and the standard deviation of each drug detection was found to be between 2.8 and 5.6 with good reproducibility.In addition,the three antibiotics had a good linear correlation in the concentration range of 0.2-1.0 g/m L,with a wide linear range,regression coefficients above 0.98,detection limits between 0.05 g/m L and 0.13 g/m L,and quantitative limits between 0.18 g/m L and 0.44 g/m L.Therefore,the establishment of this method can meet the quantitative analysis requirements of three kinds of micro-antibiotics,and lay a good foundation for the subsequent research on the status of antibiotic pollution in the environment and environmental behavior analysis.On the other hand,from the adsorption kinetics,temperature,p H value,the initial concentration of the solution on the adsorption and the reproducibility of the adsorbent,it is known that the adsorption process of 3 DG to MB conforms to pseudo-secondary kinetics and is endothermic.The optimum adsorption performance was the best when the alkaline(p H = 12)and the initial concentration was 25 mg/L,and the 3DG still had high adsorption efficiency after repeated 5 adsorption processes.In addition,from the adsorption kinetics,adsorption thermodynamics,adsorption isotherms,the effect of p H on adsorption and the reproducibility of adsorbents,it is known that the adsorption process of 3DG on TC accords with pseudo-secondary kinetics and Langmuir adsorption isotherm model.The acid-or alkaline environment will reduce the adsorption efficiency of 3 DG to TC.Similarly,the adsorption efficiency of 3DG after 5 repeated adsorptions is still high,It indicates that the 3D graphene material prepared in this study is a good adsorbent with broad prospects and can be reused many times,which can be applied to the adsorption and removal of antibiotics and achieve a good adsorption effect.