Study On Photo Degradation Of Nonylphenol By Titanium Dioxide Composite Catalyst And Sulfate Fenton-like System

Nonylphenol is a typical representative of environmental hormones,which is also an industrial raw material for the synthesis of nonylphenol polyoxyethylene ether surfactants.As persistent organic pollutants,NP which have endocrine disrupting and toxic effects on organisms,are found widely consist in natural water,soil and sediment.In this paper,we choose NP as subject investigated.The adsorption property of modified TiO₂ and its catalytic performance for NP degradation were discussed.Two kinds of titanium dioxide catalysts were prepared by the"sol-gel"method,Two catalysts,TiO₂ doped Co and TiO₂ loaded Ag,were prepared,and the photocatalytic degradation of NP was carried out through two catalysts.The effects of doping amount,load,initial concentration of the solution and the input of catalyst on the catalytic performance were analyzed.At the same time,two kinds of composite catalysts were studied in light dark reaction and photocatalytic degradation of NP in the free base Fenton system of sulfate radical.The major conclusions of this paper was as following:（1）The initial concentration of NP solution had no obvious effect on the degradation efficiency;the degradation rate of NP increases with the increase of the dosage of catalyst TiO₂,and the maximum degradation rate was 76.7%when TiO₂dosage was 0.10g;the effect of initial concentration of NP on photocatalytic activity was the best when the initial concentration of NP solution was 30mg/L.The adsorption capacity of NP was not obvious,and the maximum adsorption rate was 9.4%.（2）Taking 1%Co-TiO₂ as an example,the results of XRD characterization showed that the doping of Co helped to transform TiO₂ into anatase crystal and enhanced the photocatalytic performance.The SEM characterization results showed that the Co-TiO₂ catalyst powder had a partial unity and the appearance of the ellipsoidal shape was basically the same.The particle size of the Co-TiO₂ catalyst was about 495nm.The results of UV-Visible DRS showed that the forbidden band width of Co-TiO₂ was smaller than that of TiO₂ theoretically.This allows long wavelength photons to be absorbed,which improveed the utilization of TiO₂ to sunlight.When the Co doping amount was 1.5%（mole percentage）,the degradation rate of NP in the solution reacheed 82.9%.When the load of Ag was 1%（mole percentage）,the photocatalytic performance was the best and the degradation rate was up to 85.5%.（3）Effect of Co-TiO₂ Catalyst Dosage on NP Degradation:When the dosage of0.5%Co-TiO₂,1.0%Co-TiO₂ and 1.5%Co-TiO₂ was 0.01g,the degradation rate of NP solution was the best,and the degradation rate was 79.8%,74.4%and 82.9%respectively.（4）Effect of Ag/TiO₂ Catalyst Dosage on NP Degradation:When the dosage of0.5%Ag/TiO₂ was 0.03g,the degradation rate of NP was the largest and the degradation rate was 83.8%.When the dosage of 1%Ag/TiO₂ and 1.5%Ag/TiO₂ was0.01g,the degradation rate of NP was the largest and the degradation rate was 85.5%and 70.1%.（5）Analysis of decomposition properties of PMS by composite catalyst:Under the condition of no light,the whole system showed high degradation rate for NP solution.The degradation rates of the three kinds of Co-TiO₂ catalysts for NP were75.5%,80.2%and 83.4%,respectively,and the degradation rates of the three Ag/TiO₂catalysts for NP were 63.3%,56.8%and 53.8%respectively.That composite catalysts had strong catalytic decomposition on SO₄?^-Fenton-like system.（6）Analysis of photocatalytic degradation of NP by composite catalyst and Fenton-like system:In the presence of light,when the reaction was carried out to300min,the NP in solution almost completely degraded.At this time,the degradation rate of the Co-TiO₂ catalyst for the three kinds of doping reached 93%,90.3%and93.9%,respectively.The degradation rate of the three Ag/TiO₂ catalysts for the NP was 86.4%,88.8%and 87.1%respectively.It is indicated that the composite catalyst can not only catalyze the decomposition of PMS to produce more radical radical of sulfate radical,but also have good photocatalytic properties,and can absorb visible light to degrade NP by absorbing visible light in the system of PMS.（7）Analysis of catalytic activity of composite catalyst:After three repeated experiments,the degradation rate of 1.5Co-TiO₂ to NP was only reduced by 5.2%,and the degradation rate of 1%Ag/TiO₂ to NP was only 5.7%lower.These two composite catalysts still have high catalytic activity after washing,drying and grinding.