| Fuel ethanol refers to absolute ethanol with a volume concentration of more than99.5%and burns clean high octane fuel.Osmotic vaporization separation technology is especially suitable for the separation of organic mixture solution at near boiling point and constant boiling point,as well as the advantages of small energy consumption and product purity that are high required for separation.Polyvinyl alcohol（PVA）is a kind of hydrophilic organic polymer,low price,easy to obtain raw materials and has superior water permeability performance.Because PVA is easy to swell in water,this paper mainly adopts the way of mixing hydrophilic nanomaterials and crosslinkers to modify PVA film.With MAX phase ceramic material（Ti3Al C2）,natural scale graphite（C）as raw materials.Preparation of hydrophilic nanoparticles MXene and Graphene oxide（GO）,and separately with Sulfonysuccinate（SSA）,Diacylglycerol（DAG）,glutaraldehyde（GA）was supplemented with a PVA solution,PVA/MXene,PVA/GO composite membranes were prepared by spin coating,intended to develop a new permeable vaporization film with good separation properties.And with the help of SEM,FTIR,XRD,XPS,TGA,DCS,Roman,contact angle,nano indentation and nano scratch test instruments and measurement methods,study the mixed matrix membrane microscopic morphology,chemical structure,thermal stability,mechanical strength,etc.,and the membrane water flux,separation performance,long time test physical and chemical indexes,the main conclusions are as follows:（1）During TGA,DCS and swelling testing,the weight retention rate（WRP）of PVA and PVA/SSA membranes was about 5.0%and 2.1%,respectively,which were lower than that of PVA/SSA/MXene and PVA/SSA/GO membranes（22.9%）,（6.7%）,and the glass transition temperature（Tg）was gradually increased.At the same time,PVA,PVA and PVA/SSA membranes were（258%）,（77%）,much higher than PVA/SSA/MXene（43%）and PVA/SSA/GO membranes（51%）.This indicated that the thermal and chemical stability of PVA/SSA/MXene and PVA/SSA/GO membranes were higher than those of PVA and PVA/SSA membranes.（2）By SEM,XPS and Roman characterization,the results showed that under the action of super gravity,the two-dimensional nanosheets MXene and GO migrated downward in the PVA substrate and were stacked layer by layer at the bottom of the PVA membrane separation layer,and the hydrophilic permeable nanochannel was constructed by layer by layer stacking structure for rapid alcohol/water osmotic evaporation.Among them,the water flux and separation factors of PVA/SSA/MXene composite membrane reached 1.22 kg·m-2·h-1and 1577,the water flux and separation factors of PVA/SSA/GO composite membrane reached 1.12kg·m-2·h-1and 1178,respectively.Nanoindentation and scratch tests indicate strong binding forces between the separation layer and the carrier due to the high modulus and hardness of the PVA/SSA/MXene composite film,which are 0.2822 GPa and 0.019 GPa,respectively.（3）When investigating the influence of the type and amount of crosslinker on the vaporization performance of PVA mixed matrix membrane,it was found that PVA/SSA/MXene,PVA/SSA/GO were higher than that of PVA/GA/MXene(0.76kg·m-2·h-1,814.3)and PVA/GA/GO(kg·m-2·h-1,917.5).In addition,the addition of hydrophilic nanoparticles MXene and GO has the best effect at 3wt%.Excessive MXene and GO will reunite in the separation membrane,leading to the production of defects and reducing the separation factor of the membrane.（4）When examining the relationship between the osmotic vaporization performance and the ethanol concentration at different temperatures,it was found that the separation factor reached the highest level when the material liquid temperature was 50℃,and the presence of MXene and GO material helped to reduce the energy required for the components to permeate across the membrane.During the PV test of up to 300 hours,the water flux and water content of PVA/SSA/MXene composite membrane and PVA/SSA/GO composite membrane were relatively stable at temperatures of 30℃and 60℃,with excellent long-term stable separation ability. |
