Reparation Of TiO₂Phtocatalysis Floating Ball For The Degredation Of Metronidazole

PPCPs is short for pharmacecuticals and personal care products. In recent years,It has raised people’s deep concern about the pollution in our envionment due to the potential threat to the environment. In secondary treatment effluent, more and more PPCPs has been found. How to solve this serious problem through adavenced water treatment is not only about the water quality but also the safety of human.Semiconductor photocatalysts have many advantages, high efficiency, low selectivity, no secondary pollution, etc. In all kinds of semiconductor materials, TiO2nanoparticles show excellent ability in degradation of many environmental pollutants. Compared to other photocatalysts, they are low-cost, high stability, high activity. However, they are still limited in water and wastewater treatment field, mainly due to the difficult separation and reclaiming of TiO2nanoparticles from treated water.A Light weight ceramsite distinguished-out of other kinds of carrier-by a relativitbely low volumetric density at maintained high strength and large surface area, whcin was mainly made from excess activated sludge and baked in a kin. The composite photocatalyst has both the excellent photocatalytic activity of powder photocatalyst and the characteristic of recyclable. As a recyclable material, light weight ceramsite an practicable way to solve the difiiculties of sluge treatment due to the high expense and technology limited in sewage treatment plant. In this study, the light weight caramsite loaded the nano TiO2film which made by a sol-gel method, showing a good catalytic activity. The morphology and structure of the samples were characterized using analytical techniques of XRD, SEM, EDS etc. Some conclusions were made as follows:The SEM results indicated that the TiO2films are loaded on light weight ceramsite. The Photocatalysis floating balls were used in degradation experiments of methyl orange, it indicated that the five layers TiO2films which doped the mass ratio of1:20Degussal P25, annealed at500℃exhibit a good repeatability for photocatalytic activity. The result of experiments showed that photocatalysis floating ball contibuted to metronidazole degradation. Dagration rate reaches55.08%after200min with17floating balls, initial concentration of metronidazole is l0mg/L. Light intensity and pH effect the metronidazole degradation. Higher light intensity enhances the degration rate. Effect of pH value on metronidazole is investigated in the range from2.0to11.0, when pH<7, the rate is found increased with pH decreased, and when pH>7, the rate is decraesed with pH value. The highest rate reaches at the value of pH=7. HCO3-inhibits the efftct on degradation and enhances with HCO3-concentration increase. H2O2improves the degadation efficiency, resodual rate reaches4.34%after200min with the H2O2dosage75mg/L.