High-throughput Durable Distillation Membranes With Internal Bonding Structure For Desalination

With the rapid development of modern industry and the dramatic increase in the global population,the demand for water resources in countries around the world is also increasing.However,due to the uneven distribution of water resources in time and space and water pollution,there is a serious shortage of freshwater resources.Membrane distillation technology can effectively solve the current lack of water resources,it is a combination of membrane separation and thermal distillation to effectively seawater desalination technology.The key to this technology lies in the study of distillation membranes.Distillation membrane membranes require sufficient hydrophobic stability,high thermal stability,high resistance to fouling,and good membrane flux.This is also a feature of the membrane distillation process.Large-scale application constraints.The purpose of this paper is to develop a membrane material with high stability,good hydrophobicity,and high membrane flux.The traditional membrane manufacturing process has the problem of low flux,while the through-hole fiber membrane prepared by electrospinning process has membrane fibers.Uniform,high porosity,large flux advantages.Through-hole PVDF nanofiber membranes prepared by electrospinning technology were combined with later superhydrophobic modification to prepare super-hydrophobic PVDF membranes and used for direct contact membrane distillation tests to study membrane flux and conductivity changes.First prepare the PVDF membrane and then modify it on the membrane surface.In this paper,we introduce a non-fluorinated hydrophobic PDMS and Si O2 nanoparticle combination method to build a superhydrophobic structure in one step,in which the PDMS polymer can effectively reduce the surface of the membrane,and the Si O2 nanoparticles can A multi-level rough structure(mimicking the leaf surface of nature)was constructed to make the PVDF membrane superhydrophobic(159.8°).In order to explore th e versatility of one-step construction of super-hydrophobic structures,we used paper sheets,non-woven fabrics,and steel meshes as the hydrophilic materials for surface modification.The surface of the modified materials reached a superhydrophobic state,illustrating PDMS/ The SNP one-step modification method can be used as a new method for constructing superhydrophobic surfaces.Comparing the PVDF membrane before and after modification with commercial PVDF membrane and PTFE membrane for membrane distillation,it can be seen that the modified PVDF@PDMS/SNP membrane has high flux,good hydrophobic stability,and can meet the long-term requirements of membrane distillation.run.In order to test the contamination resistance of PVDF@PDMS/SNP membranes,the fe ed fluid used brines containing various contaminants.The contaminants included dyes,humic acid(HA),lubricating oil,surfactant(SDBS),etc.PVDF@PDMS/SNP membranes have excellent anti-pollution properties.In order to test the distillation effect of PVDF@PDMS/SNP membrane in real seawater,the feed fluid was configured with salt water according to seawater composition and tested for 50 hours.The experimental results indicated that the membrane could meet the desalination requirement.In order to verify the consistency of the high flux and durability of the prepared distillate film,the film was tested for a long time of 300 hours.It was found that the flux of the film remained almost stable and the conductivity did not increase,indicating that the film meets the long-term application requirements.