The Preparation Of Hollow Titanium Dioxide And Intimate Coupling Of Photocatalysis And Biodegradation For The Degradation Of Tricyclazole

The hollow nano TiO2 was successfully synthesized by hard template method.The cavity size was 350 nm and the thickness of TiO2 was precisely controlled by controlling the amount of tetrabutyl titanate(TBOT),around 10-30 nm.And the crystal morphology and crystallinity of TiO2 were effectively controlled by changing calcination temperature.SEM and XRD showed that as the amount of TBOT increases,the thickness of TiO2 increases first and then decreases.With the increase of calcination temperature(500-900 ℃),the crystallinity increased,and the Ti02 was anatase crystal.Photocurrent test and methylene blue(MB)and tricyclazole degradation experiments showed that hollow TiO2 nanoparticles exhibited excellent photocatalytic activity and exhibited good adsorption for MBPesticide wastewater was characterized by complex components,high concentration,high toxicity and difficult to be biodegraded.In this paper,a set of photocatalytic-biological coupling system was established,and a new reactor was developed.Tricyclazole was used as the target pollutant,and the efficient treatment of tricyclazole pesticide wastewater was achieved.The degradation mineralization effects of three degradation models were compared:photocatalytic oxidation alone(P),biodegradation alone(B),intimate coupling of photocatalysis and biodegradation(P&B).The results showed that the photocatalytic oxidation of tricyclazole had some effect,biodegradation alone can’t make the tricyclazole degraded,especially to high concentration of tricyclazole.The single degradation mode had no effect on the degradation of TOC.However the effect of intimate coupling of photocatalysis and biodegradation is much better than that of a single one.20 mg/L of triazole was degraded completely in 5 h and the removal rate of TOC was higher than 50%.With the increase of triazole concentration,the time needed for degradation was prolonged.The reactor continuous flow experiment showed that the degradation efficiency of tricyclazole was 15%when only biodegradation was existed in the reactor.The concentration of triazole decreased obviously and remained stable after a hydraulic cycle,and the degradation rate was 100%.