Study On The Performance Of NiO/gC₃N₄ Supported Photocatalysis Coupled With Microbial Degradation Of Ciprofloxacin In Wate

Organic pollutants(antibiotics,dyes,pesticides,etc.)are persistent in the environment,and water pollution has been the subject of numerous studies due to their potential impacts on the environment and human health.Ciprofloxacin(CIP)is a fluoroquinolone antibiotic widely used in the treatment of bacterial infections.Large-scale production and widespread application of CIP have caused potential harm to the ecosystem,but conventional wastewater treatment processes are difficult to remove CIP.The main reasons why CIP is difficult to be removed by conventional wastewater treatment process are as follows:CIP is an organic compound,its molecular structure contains tetrad structure and fluorine element,which makes CIP difficult to be degraded by microorganisms;CIP has high stability in water and is difficult to be removed by physical treatment such as precipitation and filtration.CIP molecular structure contains many chemical functional groups,which makes it difficult to remove by chemical methods.CIP is a widely used antibiotic,and the high concentration of CIP in sewage makes it difficult to effectively remove by sewage treatment process.Therefore,new CIP wastewater treatment technologies need to be developed to achieve better treatment results.Researchers have been trying to use sustainable strategies to rapidly degrade CIP,and it is particularly important to find an effective and convenient CIP treatment method in sewage.Therefore,this paper proposes a method to treat CIP in sewage,i.e.photocatalyst coupled microbial membrane system.The prepared NiO/g-C3N4 photocatalyst was loaded onto the pretreated polyurethane foam(PUF),and the polyurethane foam supported by the photocatalyst was put into the microbial reaction tank.After inoculation,culture and domestication,microbial film will grow on the surface of foam to form a photocatalytic coupled microbial film system.This study explores the theoretical significance and practical value of CIP removal,which is mainly di vided into the following two aspects:(1)NiO/g-C3N4 nanosheets were prepared.Using urea as a precursor,ultra-thin g-C3N4 was prepared by calcination method.Ultra-thin g-C3N4 has the characteristics of high crystallization and large specific surface area,which makes it have more active sites,which can enhance its photocatalytic activity.NiO and NiO/g-C3N4 were prepared by using Ni(NO3)2·6H2O and urea as precursors,and the bulb structure of NiO improved the light efficiency.The successful composite of samples was proved by analysis,and then the morphology and structure of NiO/g-C3N4 were studied.Finally,the performance of CIP wastewater degradation by NiO/g-C3N4 was studied,and the optimal process parameters of photocatalytic degradation system were determined.(2)The NiO/g-C3N4-PUF coupled microbial system was prepared.Pretreatment of PUF enables it to better load NiO/g-C3N4 and inoculate microorganisms.The NiO/g-C3N4 was evenly dispersed onto PUF by impregnation method and then put into microbial reactor.Through inoculation,culture and domestication of microorganisms,the PUF loaded with NiO/g-C3N4 was able to grow microbial membrane.Subsequently,the degradation performance of CIP wastewater by NiO/g-C3N4 was studied,and the CIP solution degradation by photocatalyst was compared to determine the advantages of the photocatalytic coupled biofilm system.Then variable control method was used to determine the optimal process parameters of the photocatalytic degradation system.