Electrospun nanofiber membranes incorporating fluorosilane-coated TiO2 nanocomposite for direct contact membrane distillation

Abstract

The electrospinning technique as a method for fabricating hydrophobic membranes for membrane distillation (MD) has received much attention in recent times. In this study, TiO 2 functionalized with 1H,1H,2H,2H-perfluorooctyltriethoxysilane was added directly to the dope solution for electrospinning in order to increase the hydrophobicity of the resulting MD membranes. Three concentrations (10%, 15% and 20%) of polyvinylidene fluoride-cohexafluoropropylene (PH) dope solution were used for electrospinning with various amounts of TiO 2 (1%, 5% and 10%) to generate nanofibers. The electrospun nanofiber membrane (ENM) of 20% PH with 10% TiO 2 exhibited the highest surface hydrophobicity (contact angle = 149°) resulting from good dispersion of the TiO 2 particles, while the highest liquid entry pressure of 194.5 kPa was observed for the ENM comprising 10% PH with 10% TiO 2 due to its reduced pore sizes. Furthermore, the ENMs containing 10% TiO 2 exhibited better flux and stable salt rejection than commercial and ENMs without TiO 2. Notably, there was no severe wetting in the 20% PH ENM with 10% TiO 2 over seven days of operation, despite the high salt concentration (7.0 wt% NaCl) of the feed water.

Modelling of air gap membrane distillation and its application in heavy metals removal

“…Heat transfer from the feed side membrane interface through the membrane pores and air gap to the condensate interface is given by equation (11) [30,34]:…”

“…By combining equations (1), (10), (11), (15) and (17) and re-arranging, the following expressions for and can be obtained:…”

“…It is well documented in the literature that many parameters play a crucial role in hindering commercialization of membrane distillation, such as high energy consumption, shortage of high effectiveness membrane cells, low productivity and shortage of membranes with high hydrophobicity [9]. In terms of membrane hydrophobicity, many attempts have been made to overcome this problem, such as fluorosilanization of PVDF-SiO2 blended membranes [10] and TiO2 nanocomposite membranes [11], incorporation of carbon nanotubes (CNT) [12], use of PVDF-clay nanocomposites [13] and surface modification using a CF4 plasma to increase membrane hydrophobicity [14]. However, the majority of these methods involve using silane and fluorinated groups which have potential environmental consequences [15].…”

PDMS/PVDF hybrid electrospun membrane with superhydrophobic property and drop impact dynamics for dyeing wastewater treatment using membrane distillation

“…However, the complexity of chemical methods has been somewhat of deterrence for practical application. As an alternative method, electrospinning has been noted as a simple and versatile method that can enhance the properties of the membrane by direct application of nanomaterials, allowing a greater control over the structure of resultant membranes by changing the dope solution viscosity, voltage, flowrate, and hybrid combination of materials [11]. This reliable technique also enables to constructing controllable interfacial surface with inorganic nanomaterials and polymer matrix [12].…”

Luminescence performance of poly(aryl ether)s membranes with different morphologies

“…Electrospinning is facile and high‐throughput technique to directly prepare nano/micro‐scale with defined morphologies such as nanowires, nanorods, nanotubes, and microbelts . This method is based on the strong electrostatic force by applied a high static voltage to a homogeneous spinning solution.…”