Study On Using Photocatalyst Loaded On Marine Shellfish/Coral Carrier To Degrade Oil Pollutant Suspened Upon The Ocean

In recent years, due to oil field leakage, ship sewage and other reasons, themarine oil pollution issue has aggravated, which damages the ecological balance ofthe ocean. The problem not only causes massive deaths of marine organisms, but alsothreats to the health of human beings. Therefore, the prevention and control of marineoil pollution has become one of the current focus of attention from all the society.TiO₂photocatalytic technology is a new environmental technology with theadvantages of good stability, high activity and non-toxic, which can be used to dealwith the floating oil without recycling value.In this paper, tetrabutyl titanate is used as the titanium source; sol-gel method isused to prepare TiO₂catalyst precursor; the methods of impregnation and calcinationare used to load the catalyst thin film on the marine shellfish and coral carriers; aseries of studies to oil as the object of degradation are conducted.First of all, marine shellfish is used as the carrier to load Fe³⁺-TiO₂photocatalystand Ce³⁺-TiO₂photocatalyst. Effects of metal ion doping amount, calcinationtemperature, water quality and other factors on the degradation rate of oil areinvestigated, drawing the conclusions as follows. Fe³⁺-TiO₂photocatalyst has the bestcatalytic activity when iron ion doping amount is0.7%and calcination temperature is450℃; The Ce³⁺-TiO₂photocatalyst has the best catalytic activity when cerium iondoping amount is1.3%and calcination temperature is450℃. The oil degradationrates are61%and65%after16hours in view of the above two kinds of circumstances.Photocatalyst degradation effect on oil is better in distilled water environment thanthat in sea water environment.Preliminary practical simulation is carried out with Fe³⁺-TiO₂photocatalystloaded on coral carrier, investigating the effects of light, temperature and other factors on the reaction. Macro-dynamics analysis is conducted for the reaction, drawing theconclusions as follows. The oil degradation rate can reach56%under natural lightirradiation for8hours, however, the oil degradation rate is only30%under thehomemade solar light irradiation. The photocatalytic efficiency increases with the risein water temperature; the degradation rates are respectively50%and60%when thewater temperature is respectively10℃and30℃. Photocatalytic degradation of oilcan be divided into two stages, and the second stage responses characteristics of thefirst order reaction. According to Arrhenius formula, the reaction activation energyis equal to26.79kJ/mol by calculating.Field experiment is conducted at the beach. The shellfish/coral carrier loadingFe³⁺-TiO₂photocatalyst is placed in the real marine environment to degradate thefloating oil, drawing the conclusions as follows. When the Fe³⁺-TiO₂photocatalyst isloaded on the coral carrier, the oil degradation rate can reach46%under natural lightirradiation for8hours. The rate drops to33%when the Fe³⁺-TiO₂photocatalyst isloaded on the shellfish carrier. The experiment shows that the supported photocatalystcan indeed play the role of degradation of floating oil, however, for the purpose ofimproving catalytic efficiency and large-scale practical application, the preparationprocess and loading process of photocatalyst should be ameliorated.