Preparation Of Modified Microtubule Carbon Nitride And Its Magnetic Composites And Study On Photodegradation Of Antibiotics

Aimed at the pollution situation of antibiotic in water,the conventional water treatment process is difficult to completely remove,in recent years,semiconductor photocatalysis technology because of its high efficiency,low cost,pollution-free advantages,shows great application prospect,including the preparation of graphite phase(g-C₃N₄),modified and how effectively for powder catalyst recycle become the hotspot research,based on the ordinary carbon nitride and traditional centrifugal recycle method shortcomings,this research mainly includes the following aspects:(1)In this study,melamine and solid phosphite H₃PO₃were used as raw materials to prepare hexagonal microtubule carbon nitnitide(MTCN-x)with different mass ratios of phosphorus doping and layered stacked porous structure by hydrothermal calcination method.X is the mass ratio of solid phosphite to melamine.By using XRD,FT-IR,XPS,SEM,TEM and UV-vis DRS to characterize the catalyst morphology structure and optical properties,the results show that the structure of tubular porous increases the specific surface area,increase the light reaction activity sites,P doping at the same time,the band width is reduced,the range of visible light response and absorptive capacity are enhanced,effectively inhibit the photoproduction electronic-hole composite,significantly enhanced the photocatalytic performance.The degradation rates of ciprofloxacin(CIP)and tetracycline(TCL)were 99.7%and 97.8%,respectively,and the reaction rate constant of MTCN-1.2 was 10.5 times and 6.8 times of BCN,respectively,under visible light irradiation(?>420nm)for 10min.(2)It was prepared by chemical coprecipitation Fe₃O₄magnetic nanoparticles,and then through the way of blending-calcination,according to the Fe₃O₄/MTCN-1.2quality ratio of 1:4,1:3,1:2,and 1:1,combines Fe₃O₄and MTCN-1.2 effectively,through a series of characterization methods of magnetic composite materials were characterized and the results show that the Fe₃O₄success and MTCN 1.2 together,in the condition of visible light(?>420 nm)lambda illuminate 30 min,Optimal proportion of FMT(1:4)to the antibiotic ciprofloxacin(CIP)and tetracycline(TCL)the degradation rate of 95.42%and 91.83%,very good to keep the MTCN-1.2 the degradation of superior performance,at the same time in magnetic materials recovery and recycling performance experiment,the results showed that after five cycles,magnetic magnetic composite material with 90.61%recovery rate,and five times the target pollutants photodegradation efficiency can reach 92.43%and 90.16%,still shows that magnetic composites have good magnetic recycling performance and light degradation of performance,It has the value of practical engineering application.(3)The effects of p H value of solution,dosage of catalyst and concentration of humic acid(HA)on photocatalytic degradation of antibiotics were investigated in this study.The results showed that MTCN-1.2 had the highest degradation efficiency on CIP and TCL when p H was 5 and 9.The high concentration of catalyst and the increase of humic acid concentration will decrease the catalytic efficiency of both.The calcination temperature in the range of 350?⁴50?has little effect on the degradation efficiency of FMT(1:4).At the same time,the free radical capture experiment showed that the superoxide free radical(·O^2-)and hole(H⁺)played a dominant role in the degradation process of the catalytic system.