Preparation Of Porous Polystyrene Materials Via HIPEs Method And Study On Oil Adsorption Performance

Oil spills leakage and massive discharge of industrial oily wastewater are common and terrible phenomena,which has catastrophic effect on the aquatic ecosystems and even threatens the living environment of human.And among various methods for oil spillage remediation,the measure of adsorption is considered to be ecologically friendly,economical and one of the most efficient technique.As a result,the development of cheap and reliable oil adsorbents is desirable and urgent both in the fields of fundamental research and practical application.High internal phase emulsions(HIPEs)consist of external continuous monomer phase and internal droplet phase exceeding 74%of the total volume and is stabilized with emulsifier.It is a template method to fabricate porous polymers(defined as PolyHIPEs)with controllable pore structures after the removal of the internal water phase.Because of high porosity and interconnected pores,PolyHIPEs have great potential in the field of separation.Porous polystyrene material was fabricated through the HIPEs technique and was used in the field of oil/water separation.And specific research contents were as follows:At first,high internal phase emulsions(HIPEs)technique to fabricate porous monolithic S20-Fe3O4/PS composite material was described.A novel co-stabilizer system of Span 20 and Fe3O4 solid particles were adopted to prepare the W/O type styrene-based emulsion and the maximum internal water phase ratio achieved 94.1 wt%.The influence of the addition of Span 20 and Fe3O4 particles on the microstructures of the PolyHIPEs was investigated and the optimal experimental scheme was determined finally.Field emission scanning electron microscopy(FE-SEM),mercury pressure meter,X-ray powder diffraction(XRD),thermogravimetric analysis(TG),vibrating sample magnetometer(VSM)and contact angle measuring instrument were adopted to characterize the composite foam materials.Results showed that the resulting composite polymer material exhibited excellent thermal stability with the thermal decomposition temperature over 280?.Besides,the water contact angle(WCA)of the material achieved 147° and oil contact angle approached 0° exhibiting oleophilicity and hydrophobicity.Take light petroleum product diesel as typical target pollutant,and the adsorption capacity of the solid foam toward it was 8.9 times its own mass even after 10 cycles of oil/water separation.Ethanol was adopted to regenerate the composite material and the deoiling rate reached nearly 100%.As a result,S20-Fe3O4/PS composite material showed excellent reusability as oil adsorbent.Secondly,carbonyl iron powders(CIPs)were introduced into the HIPEs template stabilized with Span 80.And S80-CIPs/PS composite foam materials with high porosity and interconnected pore structures were fabricated successfully.The internal water phase ratio reached 97.6 wt%at most.Physical and chemical properties of the composite material were characterized by XRD?SEM?fourier transform infrared spectroscopy(FTIR)?TG?VSM?universal tensile test machine and mercury pressure meter.The influence of internal water phase ratio and proportion of crosslinker DVB on the microstructure were also investigated.Results found that the improvement of the internal water phase ratio was beneficial for the enlargement of the pore size of the PolyHIPEs,while higher ratio of crosslinker led to smaller pore size of the polymer material.A porosity of 98.1%and density of 0.032 g/cm3 were achieved with the technique of HIPEs.The porous monolith possessed hydrophobicity with a water contact angle of 1420 and adsorbed oils from water selectively with diesel intake capacity of 22.7 times its own mass.Importantly,high porosity,interconnected porous structures as well as strong mechanical strength made it possible for the composite material saturated with oils could be regenerated by simple centrifugation with deoiling rate around 90%,and the tests showed that the oil intake capacities were not impaired after 10 absorption/regeneration cycles.Thirdly,4 kinds of Fe3O4 particles with varied particle sizes and morphology was modified with Span 80 and were used to prepare the W/0 type Pickering template.The materials fabricated with different types of Fe3O4 particles had varied hierarchical pore structures.And the influence of Fe3O4 solid particles on the microstructure was also investigated.Characterization such as XRD,SEM,FTIR,TG,VSM,universal tensile test machine and mercury pressure meter was adopted.The materials exhibited superhydrophobicity and excellent oleophilicity,with the WCA even exceeding 150° and oil contact angle approaching 0°.And the adsorption capacity of the monolithic foam towards diesel was as high as 32.2 g/g.Importantly,the materials soaked with oil could be regenerated effectively by means of centrifugation with oil recovery rate reaching 90%.More importantly,the monolithic PolyHIPEs were subjected to 20 adsorption-centrifugation cycles and superior reusability was demonstrated.Through the analysis of adsorption isotherm model and dynamics,the adsorption process of diesel satisfied thte Freundlich isotheram model and the pseudo-second-order kinetic model well.Finally,a novel low dense polystyrene sponge with superhydrophobicity and compressibility was prepared successfully by a dual-templating method,including HIPEs processing and the introduction of organic template species.And the polystyrene material with compressibility was obtained with the modulation of the internal water phase ratio in extensive ranges.For the first time stearic acid or calcium stearate was introduced into the HIPEs system to enhance micro roughness and impart the PolyHIPEs with superhydrophobicity.Besides,owing to the low density,high porosity,interconnected network structure and ultra large void size,the sponge exhibited fast oil adsorption rate and superior oil adsorption capacity of 66.2 g/g toward diesel.After adsorption saturation,the sponge was regenerated by simple squeezing with the deoiling rate around 85%.Importantly,the sponge showed swellable property and 78.1%of the first oil adsorption capacity was recorded after 10 adsorption-compression circles.The adsorption of diesel onto polystyrene composite material satisfied Freundlich isotherm model.Besides,it behaved as a pseudo-second?order kinetic model rather than the pseudo-first-order kinetic model.Low cost,high adsorption rate,excellent oil adsorption capacity,compressibility and renewability,all these favourable properties make it an ideal and practical oil adsorbent.