DVB Modified Fibrous Membranes And Their Applications In Membrane Distillation

Membrane distillation is a desalination technology combined with thermal and membrane processes.This article is aimed to apply hydrophobically modified electrospun fibers to membrane distillation,and to exploit the high porosity and low mass transfer resistance of electrospun fiber membranes.The research work of this paper is to use electrospinning technology to prepare polyacrylonitrile(PAN)nanofiber membranes with different fiber diameters,different fiber morphologies,and different membrane layers.Initiation chemical vapor deposition(iCVD)is used for hydrophobic modification.An environmentally friendly material divinylbenzene(DVB)is used as the monomer,tert-Butyl peroxide is used as initiation,the hydrophobic polymer film is coated on nanofibers by iCVD.The DVB modified fibers are treated with SEM,water contact angle measuring,liquid entry pressure measuring,atomic force microscope,and so on.The fiber morphologies,wettability,LEP and the thickness variation of the fiber membrane before and after iCVD were characterized,and the DVB modified fibers were tested with an air gap membrane distillation.Explore the mass and heat differences in transmembrane transference of different fibers.This article was discussed in the following aspects:(1)The fibrous membranes with different fiber diameters,fiber morphologies,and structures were preparated using electrospinning technology.Characterized by SEM,water contact angle measuring,liquid entry pressure measuring,atomic force microscope,etc.The characterization of the fibrous membranes like surface energy,internal structure,fiber morphology,wettability,LEP,etc.were determined to study the relationship between fiber characteristics,structural characteristics,and the characteristics of the fibrous membranes.(2)The super-hydrophobic modification treatment of the fibrous membrane was carried out by initiation chemical vapor deposition(iCVD),and the modified fibrous membrane was subjected to MD to study the effects of various thermodynamic parameters on the MD.(3)Combined with specific experimental data of membrane distillation and related theory on microscale transference,the MD properties of fibrous membranes of different fiber morphologies and structures were studied,and the differences in the transmembrane transfer mass and heat in MD were investigated.The relationship and the mechanism analysis between the different membrane structures in the MD were summarized.(4)The composite fibrous membranes were prepared.Based on the experimental results and theoretical analyses,the differences in the transmembrane transference between the fibrous membrane of the single structure and the composite fibrous membrane in the MD were analyzed.