Carbon nanotubes and silver nanoparticles modification of PVDF membranes for improved seawater desalination in direct contact membrane distillation

Abstract

Membrane distillation (MD) has emerged as a novel technology capable of recovering fresh water from brackish, saline, and wastewater. However, its industrial application is limited to various challenges including membrane properties. In this work, the polyvinylidene fluoride (PVDF) membranes were modified to improve their performance towards desalination of simulated seawater particularly, acid treated carbon nanotubes (f-CNTs) and cellulose nanocrystals-capped silver nanoparticles (CNC-AgNPs) were incorporated into the PVDF matrix prior to casting. Simulated seawater (33.59 g/L) was used as the feed during DCMD tests. The modified membrane displayed improved tensile strength, surface roughness, and hydrophobicity. Interestingly, minimal leaching of AgNPs (0.378 ± 0.0628 ppm) was recorded within 72 h. Although water flux (0.179 ± 0.0303 kg/m2/hr) remained relatively low, salt rejection (99.8%) improved upon incorporation of NPs. This provides a one-step solution towards better performance in MD for recovery of freshwater from high saline seawater.

Effects of Poly(Vinylidene Fluoride-co-Hexafluoropropylene) Nanocomposite Membrane on Reduction in Microbial Load and Heavy Metals in Surface Water Samples

“…Functionalised CNTs and dendritic multi-walled carbon nanotubes were prepared using a method reported in the literature [25]. A PVDF-HFP membrane blended with Agdoped MWCNTs (i.e., 2.5 wt.% AgCNT) was prepared via the phase inversion technique, as described in the literature, to form the AgCNT/PVDF-HFP nanocomposite membrane [27].…”

Microbial Biopolymers: From Production to Environmental Applications—A Review

“…As with all membrane filtration processes, the main downside that limits their large-scale applications is membrane fouling, which occurs due to contaminants that adhere to the membrane's surface or get trapped within its pores over time, forming a layer that hinders the flow of desired components through the membrane. This phenomenon reduces filtration efficiency as well as the membranes' lifespan and increases energy consumption [352,353]. Recently, biopolymer nanocomposite membranes have gained popularity as a promising solution for mitigating membrane fouling.…”