Preparation And Performance Of Oil-water Separation Membrane For Ship Bilge Water

Ships play an important role in the development of international trade as a major maritime conveyance.At the same time,ships cause marine pollution.Ships will produce oily sewage during operation.Bilge water is the main source of oily sewage from ships,which causes serious harm to the flora and fauna by damaging the ecological balance of the sea environment.Moreover,it has a long term detrimental effect on human life and health.The membrane separation system is a promising treatment process to address the bilge oily sewage from the ships and vessels.Extraordinary features like no phase change,secondary pollution and easy operational steps for the treatment of bilge oily sewage made the membrane separation system acceptable for the large scale application.The super-hydrophobic membrane is widely used as a filter material for oil-water separation because of its excellent hydrophobic and lipophilic properties.The superhydrophobic membrane can selectively filter oil components from water without causing secondary contamination.Non-woven fabrics have the advantages of low cost and recyclability,it is a good choice for the preparation of superhydrophobic membranes.In this work,PET-SiO2-NOEO superhydrophobic membrane and PET-PDA-SiO2-NOEO superhydrophobic membrane were prepared based on PET.Their contact angle were tested,their morphologies,structures and thermal stability were characterized.Their chemical stability were analyzed.Their oil-water separation performance of the superhydrophobic membrane under different conditions was evaluated.1.Development and optimization of PET-SiO2-NOEO superhydrophobic membrane for the evaluation of oil-water separation performancePET-SiO2-NOEO superhydrophobic membrane was prepared in one step by growing hydrophobic SiO2 particles on the PET non-woven fabric surface via sol-gel method.Optimize the design by response surface methodology,taking the water contact angle as the index,the optimal preparation process was determined as follows:pH at 10,NOEO:TEOS at 1.5,amount of ammonia water at 6 mL,temperature at 25?.The water contact angle of the PET-SiO2-NOEO superhydrophobic membrane was 161.90°.Moreover,the water contact angle was above 150° after soaking in the different pH and salt concentration for 24 hours.The PET-SiO2-NOEO superhydrophobic membrane was used to conduct oil-water separation experiments for mixture with different oil content,salt concentration and pH,the oil-water separation efficiency was above 95.3%.After 30 cycle times,the oil-water separation efficiency was 96.7%.2.Optimization of PET-PDA-SiO2-NOEO superhydrophobic membrane and evaluation of oil-water separation performanceIn order to improve the bonding strength between hydrophobic SiO2 particles and PET non-woven fabric,PET non-woven fabric was pre-treated with PDA solution,and then hydrophobic SiO2 particles were grown on the surface of PET non-woven fabric.Optimize the design by response surface methodology,taking the water contact angle as the index,the optimal preparation process was determined as follows:amount of ammonia water at 0.2 mL,dopamine hydrochloride concentration at 2.5 g/L,NOEO:TEOS at 1.5,reaction time at 4 h.The water contact angle of the PET-PDA-SiO2-NOEO superhydrophobic membrane was 164.62°.Moreover,the water contact angle was above 158° after soaking in solution with different pH and salt concentration for 24 hours.The PET-PDA-SiO2-NOEO superhydrophobic membrane was used to conduct oil-water separation experiments for mixture with different oil content,salt concentration and pH,the oil-water separation efficiency was above 97.6%.After 30 cycle times,the oil-water separation efficiency was 97.7%.The oil-water separation performance of PET-PDA-SiO2-NOEO superhydrophobic membrane is more stable.