The Study Of Using Upconversion Luminescence Compound With TiO₂ To Decrease Marine Oil Pollution In UV-Visible Light

With the development of technology, marine oils are explored and utilized increasingly by human beings, thus the pollution events of marine oil are occured unavoidably. Photocatalytic technique receives much attention in dealing with the marine oil pollutions. In this study, the materials, such as fluoride and oxide, which can change the visible light into ultraviolet light, are modified by Ti O2 through combustion and co-precipitation. The composite photocatalysts of Ca F2(Er3+)/Ti O2 and Zr O2(Er3+)/Ti O2 are utilized in decreasing marine oil pollution The results are as follows.(1) The up-conversion luminescent materials Ca F2(Er3+) which is fabricated through combustion method are modified by Ti O2, and the compound is characterized by XRD and SEM techniques and the crystal form, morphology and size of the particles are determined. The photocatalytic ability of sample is evaluated through the experiments of diesel pollutants removing using a homemade reactor. The relevant factors which influence the efficiency of decreasing the oil are studied as well. Composite photocatalyst particle size in the range of 10 to 50 nm.The results show that the compound is well-distributed and formed in the shape of ball; the best reaction condition, which is determined through orthogonal experiment, is as follows: photocatalyst dosage is 0.8g/L, diesel initial concentration 10mg/L, Ca F2(Er3+) loading in photocatalyst is 15%, p H value 7.0 and reaction time 2.5h; Under such condition, the best removal rate of photocatalytic degradation diesel can reach 88.85%. The orthogonal experiments show that the influence of each factor on removing diesel can be arranged in decreasing order: initial concentration of diesel > dosage of photocatalyst> p H value > reaction time > loading ratio.(2) The photocatalyst of Zr O2(Er3+)/Ti O2 samples with different doping ratio(10%, 20%, 30%, 40%, 50%) are synthesized through co-precipitation method. All the samples are well-distributed and well-crystallized. According to the pictures of XRD, the Zr O2(Er3+) is compounded into photocatalyst in a certain form. The ability of diesel degradation through Zr O2(Er3+)/Ti O2 photocatalyst is more efficient than the pure Ti O2 under visible light. Appropriate Zr O2(Er3+) doping can improve the sensitiveness of photocatalyst in different p H; over-loading of Zr O2(Er3+) might wake the ability of photocatalyst in removing oil experiment. The Zr O2(Er3+) doping ratio, initial concentration of oil, photocatalyst dosage, p H value and reaction time effect the removal rate of eliminating diesel experiments. The orthogonal experiment under visible light shows that the best reaction condition is: initial concentration of diesel is 0.20g/L, the reaction time is 2.5h, Zr O2(Er3+) doping ratio is 40%, the photocatalyst dosage is 0.8g/L and the p H value is 7. In such condition, the best removal rate of photocatalytic degradation diesel can nearly reach 87.74%. The influence of each factor on removing diesel, utilizing range analysis, can be arranged in decreasing order: raction time > initial concentration of diesel > p H value > photocatalyst dosage > doping ratio. The factors, doping ratio and photocatalyst dosage, show no significant difference in degrading diesel experiments.(3) Zr O2(Er3+)/Ti O2 photocatalyst is prepared through co-precipitation, photocatalyst dosage, diesel initial concentration, doping ratio and p H value are considered in kinetic study. Matching the data with first order reaction, and it is deemed that the experiment fits the first order reaction.(4) Photocatalyst/polypropylene ball which can float on the water is prepared through coupling agent method, and the photocatalyst is the Zr O2(Er3+)/Ti O2 which is fabricated by co-precipitation. The diesel and crude oil degrading experiments are made with the floating photocatalyst and powder photocatalyst. After 8 hours illuminating in visible light, the removal rate of diesel in float experiment can reach 98%, however the rate in Zr O2(Er3+)/Ti O2 powder experiment is 68%. The removal rate of crude oil in float experiment is more than 96%, which is much higher than the removal rate of 39% of crude oil in Zr O2(Er3+)/Ti O2 powder experiment.