| Today, oil spills occur frequently. Through a series of physical and chemical reactions,petroleum hydrocarbons was dissolved into seawater to form sewater-soluble petroleum hydrocarbons, which may cause harm to marine life. In this study, the sol-gel method was used to prepare Fe3+/TiO2 coated on hollow glass microspheres catalyst. The orthogonal test and single factor experiment were used to determine the optiaml preparative conditions of catalyst. The best catalysts were characterized by X-ray diffraction analysis （XRD）, Scanning electron microscopy（SEM）, BET and TG-DSC analysis. The optimum dosage of catalyst and the optimal sampling time were also determined by experiment. The absorption spectrum of catalyst was broaden by doping Fe3+which was verified by experiment. Kinetic parameters were obtained by studing of degradation kinetics equation of petroleum hydrocarbons. Conclusions were as follows;The optimum preparation conditions:volume ratio of precursor, V（butyl titanate）:V（ethanol）:V（nitrate）:V（deionized water） was 5:20:0.4:1, atomic ratio of Fe-Ti was 5%, the calcination temperature 500℃, calcination time 2 h. The specific surface area of the best catalyst was increased to 147.909 cm3·g-1, while its particle size was reduced to 16.96 nm, whch greatly improving the photocatalytic efficiency. Under optimum conditions, the best catalyst for degradation of oil content and TOC of seawater solubled crude oil fractions were up to 84% and 45.7%. Both under the visible light and sun light, the degradation of TOC was increased by 23% and 8%, respectively. Thus it is verified that Fe3+ has been broaden the absorption spectrum of the catalyst, compare with unmodified catalyst. There were two stages in process of photocatalytic degradation. The degradation rate was fast in the first phase, the second stage was accord with the kinetic model of Langmuir-Hinshelwood. With the intial concentration of TOC increased, degradation rate of seawater-solubled oil increased rapidly and later slowly, after 24 h of the reaction, the greater intial concentration of TOC was, the smaller the degradation rate of TOC was. For the second stage, degardation of TOC was correspond better with kinetic equation of Langmuir-Hinshelwood, rate constant k was 12.47 mg·L-1 day-1. the adsorption equilibrium constant K was 0.029 mg·L-1. the half-life of different intial concentration of TOC was prolonged with the intial concentration of TOC increased. |
