Preparation Of Nitrogen-doped Biomass Carbon Composites And The Study For Removal Of Ofloxacin In Water

With the rapid development of science and technology,scientists have discovered nearly ten thousand kinds of antibiotics,which have played a huge role in modern human health and social progress.But antibiotics entering the environment can affect ecosystems.Due to the complex molecular structure of antibiotics and the difficulty of being degraded,antibiotics contained in the environment cannot often be completely removed.In this paper,an experimental study on the removal of ofloxacin by biomass carbon composite materials was carried out.Wheat straw was selected as the substrate and a nitrogen-doped biomass carbon composite material was prepared by the dipping method.This paper uses transmission electron microscopy(TEM)to characterize the microstructure and morphology of this biomass carbon composite;the prepared composite is applied to the removal of ofloxacin in simulated wastewater.Adsorption amount or removal rate is used to measure the removal effect of ofloxacin by the prepared material,and reveals the removal mechanism of ofloxacin by biomass carbon composite materials.The following results and conclusions are drawn:1.Preparation of massive porous biomass carbon composite material with wheat straw as precursorIn this paper,we use wheat straw as a precursor to biomass carbon,activated with potassium carbonate,and doped with urea to prepare a low-cost block pore structure of nitrogen-doped biomass carbon composite material,as an adsorbent to remove ofloxacin in water effectively,at the same time as a catalyst to activate persulfate to degrade ofloxacin.2.Study on removal of ofloxacin by nitrogen-doped biomass carbon composite material as adsorbentIn this paper,the adsorption kinetics experiment and adsorption isotherm experiment of nitrogen-doped and undoped biomass carbon composites calcined at different temperatures were studied.Experimental results of adsorption kinetics show that the higher the calcination temperature,the faster the adsorption rate of the material.The adsorption rate of nitrogen-doped biomass carbon composites calcined at 700℃ is better than that of undoped biomass carbon composites calcined at the same temperature.The results of adsorption isotherm experiments show that the higher the calcination temperature,the greater the equilibrium adsorption capacity of the material.The equilibrium adsorption capacity of the undoped biomass carbon composite at 700℃ calcination temperature is 268.82mg/g,while the nitrogen adsorption temperature at 700℃ The equilibrium adsorption capacity of the doped biomass carbon composite material is 459.67mg/g.The equilibrium adsorption capacity of the nitrogen-doped biomass carbon composite material calcined at 700℃ is better than that of the undoped biomass carbon composite material calcined at the same temperature.3.Study on degradation of ofloxacin by nitrogen-doped biomass carbon composite material as a catalystIn this paper,the catalytic properties of biomass carbon composites with different calcination temperatures,with and without nitrogen doping and different amounts of nitrogen doping are compared.The results show that the catalytic properties of nitrogen-doped biomass carbon composites calcined at 700℃ are excellent and different.The difference in catalytic effect of nitrogen-doped biomass carbon composites is not significant.4.Research on the factors influencing the degradation of ofloxacin by using nitrogen-doped biomass carbon composite as a catalystIn this paper,the effects of different oxidant doses,different catalyst doses,different initial pH and different oxidant types on the degradation of ofloxacin by nitrogen-doped biomass carbon composites were studied.The results show that with the increase of oxidant dose and catalyst dose,the removal rate of ofloxacin also increases.Acidic and weakly acidic experimental conditions are more conducive to the removal of ofloxacin.Persulfate and persulfate as oxidizing agents are more effective in removing ofloxacin than hydrogen peroxide.5.Study on the mechanism of degradation of ofloxacin by nitrogen-doped biomass carbon compositesIn this paper,the mechanism of catalytic degradation of ofloxacin by nitrogen-doped biomass carbon composites was studied by quenching experiments.The experimental results show that singlet oxygen(1O2)as a non-free radical in the process of degradation of ofloxacin by nitrogen-doped biomass carbon composites As far as the leading role is concerned,sulfate radicals(SO4·-)play a role in the removal of ofloxacin,and hydroxyl radicals(·OH)have little effect on the removal of ofloxacin.