Study On The Preparation Of Fe³⁺-doped TiO₂Nanoparticles Mixed With Shell Support And Photocatalytic Degradation Of Oil Pollutant Suspension Upon The Ocean

With the continuous development and utilization of Marine resources, petroleumpollution has become one of the main culprits for marine pollution. According to thestatistics, around10million tons of crude oil spills into the ocean every year in theworld, which cause heavy pollution to the water and Marine systerm.Therefore, thegovernance of petroleum pollution in the ocean was regarded as an urgent topic forthe whole society.In this paper wasted sea shells were choosen as the main raw material; gypsumand cement were used as binder. By forcing molding and ambient moisturizingmaintenance, The sea shell supporter with certain bending strength is prepared.Tetrabutyl titanate was selected as Ti precursor and the nano-scale photocatalystFe³⁺-TiO₂composite was manufactured through the sol-gel method. Thephotocatalytic properties of the supporter were investigated by the degradation offossil oil in the sea water. The XRD、SEM-EDS、UV-Vis and XPS were employed inCharacterization. The reaults and conclusions corresponding the properties andstructures that may significantly affect the catalytic activities were arived in thefollowing graph:（1）XRD analysis shows that: The main ingredients of the Shell supporter beforeand after calcining at450℃is CaCO₃and the crystal is not changed. The differencesof shell powder content, shell powder particle size and maintenance time haveinfluence on the Shell supporter’s flexural strength. Flexural strength of the Shellsupporter is lower with the shell powder has higher content and greater size,maintenance time becomes shorter. In order to meet the requirements of the strenth ofthe grumliu of photocatalys, shell powder quality percentage content is60%, particlesize for100-200mesh and adsorption body maintenance time more than28days. （2）Through the experiment the catalyst of calcining temperature, Fe³⁺dopingquantity and coating rate on the influence of the oil removal rate in sea water werediscussed. The results show that: With the experimental conditions of calciningtemperature of450℃, Fe³⁺doping content is0.7%and coating number keeps fourtimes, the catalyst has the highest light catalytic activity. It was investigated that thedifferent water, oil pollutant initial concentration and illumination time influences onthe catalytic reaction activity. The results exhibit that: The activity of the catalyst ishigher in distilled water than in sea water. At the same reaction time, the higher ofinitial concentration of oil, the lower of degradation rate. With the extension ofphotocatalytic reactions time, the degradation rate of oil is increasing. For theconcentration of50mg/L oil, degradation rate can reach76%with thephotodegradation of16h.（3）The particle of TiO₂on the Fe³⁺-TiO₂/Shell supporter’s surface increases withthe increasing of calcining temperature and the rutile mineral crystal generated at thecalcining temperature of550℃. TiO₂particle size of pure powder is smaller than TiO₂on the Fe³⁺-TiO₂/Shell supporter’s surface at the same calcining temperature.Compared with the catalyst without doping Fe³⁺, Fe³⁺-TiO₂/Shell supporter’sabsorption of light appears clear to happen to red shifted. TiO₂formed a layermembrane at the TiO₂/supporter’s surface and the the particle size is about25nm.Part of TiO₂appears enrichment in the membrane’s surface. XPS analysis shows thatFe and Ti are exist at Fe³⁺and Ti⁴⁺respectively.（4）The catalytic reaction is divided into two stages.The degradation rate of oil isfaster in the first four hours. The second stage of the oil degradation reaction showsfirst-order reaction and the k of reaction rate constant is3.52mg/（L·h）, the K ofadsorption equilibrium constant is0.0239L/mg, Ea of reaction activation energy is23.551kJ/mol.