Bioinspired Hybrid Micro/Nanostructure Composited Membrane with Intensified Mass Transfer and Antifouling for High Saline Water Membrane Distillation

Abstract

Membrane distillation (MD) holds great promise for high-saline solution treatment, but it is typically impeded by the trade-off between the high mass transfer and antifouling properties of the membrane. Herein, a new MD utilized membrane with bioinspired micro/nanostructure (lotus leaf and fish gill) was constructed on commercial PP membrane, which can simultaneously enhance the permeation flux and antifouling in the hypersaline MD operation. On the basis of the classic nucleation theory and hydrodynamics simulation, the nanoscale structure can intensify the interfacial nanoscale turbulent flow and hinder the crystal deposition, which works like the fish gill. In addition, the optimized nanoscale feature size renders the membrane with the heterogeneous nucleation barrier very similar to the homogeneous system, which works like the lotus leaf and hinders the induced nucleation effectively. The microscale structure as the supporting platform of nanostructure can additionally enlarge the effective evaporative surface with superior hydrophobicity and then promote the permeation transfer through the membrane. The hybrid micro/nanostructures render the fabricated membrane with excellent high-permeation flux and significantly prolonged fouling induction time, which sheds light on a new approach for the development of ideal MD utilized membrane.

In Situ Three-Dimensional Welded Nanofibrous Membranes for Robust Membrane Distillation of Concentrated Seawater

“…To date, the modification of interconnected porous membranes for desalinating hypersaline water stream has mainly focused on constructing superhydrophobic surfaces. − Roughening of membrane surfaces by attaching inorganic nanoparticles followed by low-surface-energy chemical modification is a typical strategy for making the membranes superhydrophobic. − However, this biomimetic method is complicated and expensive. In addition, excellent hydrophobicity does not equate to the long-term durability of hydrophobicity of membranes.…”

All-Polymer and Self-Roughened Superhydrophobic PVDF Fibrous Membranes for Stably Concentrating Seawater by Membrane Distillation

“…Interestingly, the membrane flux was significantly increased to 42.73 L m –2 h –1 after F-POSS was added to the PVDF FM. This reason was attributed to the fact that the increased membrane roughness led to a larger contact point for saline water evaporation, as shown in Figure S4. , Nevertheless, the membrane flux was decreased to 35.99 L m –2 h –1 after the F-POSS/PVDF FM was sandwiched between the two glass panels. This reason was attributed to the fact that the increased pressure applied to the membrane surface obviously improved the membrane density, while decreasing the membrane porosity (Figure F).…”

Biomimetic on-chip filtration enabled by direct micro-3D printing on membrane

“…Currently, anti-fouling/clogging strategies are mainly focused on novel membrane material development 16 , 17 and membrane surface modification 9 , 18 – 20 . Membrane surface chemistry and wettability, highly affects surface-foulant interaction and fouling tendency: membrane surface with super-hydrophobicity and underwater oleophobicity is desired to mitigate foulant adhesion 17 , 21 , 22 .…”