Preparation And Oil-water Separation Property Of Chitosan Compound Materials

The oil as one of the world’s fossil fuels are widely used, however,oil spill happens in the process of extraction, transportation, storage, and development,harming the soil, water and economy. Therefore, to explore efficient oil-water separation technology is an important measure to deal with oil spills effectively,reducing property damage and environmental hazards.In this article, a series of modified mesh were prepared by dipping coated and etching method with chitosan, alumina, nano-silica and titanium dioxide as raw material and stainless steel mesh as substrate. The surface morphology of modified mesh were characterized by scanning electron microscopy(SEM). The static contact angle of the modified mesh were tested by OCA20 machine. And the separation efficiency, the repeatability and resistance of alkali and salt solution was tested. The relations of different preparation conditions and wettability of material was discussed,results of which are following:(1)In the system of chitosan/alumina, the underwater oil contact angle(OCA)and separation efficiency increase with etching time and then reduce, when the etching time was 60 min, the underwater OCA was as high as 146°, the separation efficiency was 94.28%. The underwater OCA and separation efficiency increase with concentration of chitosan and then reduce, when the concentration of chitosan was0.4wt%, the underwater OCA was as high as 146°, the separation efficiency was93.28%. The underwater OCA and separation efficiency increase with the concentration of alumina and then reduce, when the concentration of alumina was10wt%, the underwater OCA was as high as 146°, the separation efficiency was93.44%. The mesh has stable oleophobicity underwater and excellent repeatability,showing high separation efficiency.(2)In the system of chitosan/nano-silica, first coated silica sol, and then coated with chitosan, to ensure the mesh unblocked control concentration of chitosan less than0.36wt%, concentration of nano-silica less than 2wt%.The results shows that the underwater OCA and separation efficiency increase with concentration of chitosan,when the concentration of chitosan was 0.36wt%, the underwater OCA was as high as134°, the separation efficiency was 98.91%. Changing the dipping order, the underwater OCA and separation efficiency increase with concentration of nano-silica,when the concentration of nano-silica was 2wt%, the underwater OCA was as high as142°, the separation efficiency was 99.24%. The underwater OCA and separation efficiency increase with dipping time and then reduce, when dipping three times, the underwater OCA was as high as 143°, the separation efficiency was 99.43%.The coated mesh show oleophobic property.(3) In the system of chitosan/titanium dioxide, first coated titanium dioxide sol,and then coated chitosan, to ensure the mesh unblocked, control concentration of chitosan less than 0.36wt%, concentration of titanium dioxide less than 2wt%. The results shows that the underwater OCA and separation efficiency increase with concentration of chitosan, when the concentration of chitosan was 0.36wt%, the underwater OCA was as high as 134°, the separation efficiency was 98.91%. Changing the dipping order, the underwater OCA and separation efficiency increase with concentration of titanium dioxide, when the concentration of titanium dioxide was2wt%, the underwater OCA was as high as 135°, the separation efficiency was99.02%.When blends 0.09wt% chitosan with 2wt% titanium dioxide to coat on the mesh, to test its OCA and separation, which are 138° and 99.13%.(4)In the system of chitosan/nano-silica/titanium dioxide, the coated mesh has micro-nano structure. When 0.36wt% chitosan and 2wt% titanium dioxide were dipped inside, then we coated nano-silica outside, control concentration of nano-silica less than 2wt%. The underwater OCA and separation efficiency increase with concentration of nano-silica, when the concentration of nano-silica was 2wt%, the underwater OCA was as high as 132°, the separation efficiency was 98.72%. When nano-silica were dipped inside, then we coated 0.36wt% chitosan and 2wt% titanium dioxide outside. The results shows underwater OCA was 139° and the separation efficiency was 99.37%.