Electrospining Machine: Luxiang Wang, Xinjiang University & Hong Meng, Beijing University of Chemical Technology: A Robust, Scalable, Adaptive Wettability Candle Soot-Modified Nanofiber Membrane for Controlled Oil-Water Mixture/Emulsion Separation

Background

Separation membranes with super-wettability are ideal for treating various oil/water contaminants. However, Nanofiber Membrane suffers from single selectivity, poor stability, and inappropriate pore structure, which makes it difficult to modify it to improve the separation performance in practical applications. In view of this, researcher Wang Luxiang from Xinjiang University and Prof. Meng Hong from Beijing University of Chemical Technology proposed a novel submerged superhydrophobic Nanofiber Membrane, which has very high separability and can be used for oil-water separation and emulsion purification. The related research results are summarized as “A robust, scalable and adaptive wettability candle soot-modified fiber membrane for controllable oil-water A robust, scalable and adaptive wettability candle soot-modified fiber membrane for controllable oil-water mixtures/emulsion separation” was published in the journal ‘Separation and Purification Technology’.

The main point of this paper

1. An under-liquid superhydrophobic Nanofiber Membrane was prepared using a two-step process, in which candle soot was sprayed on the Nanofiber Membrane to form a rough structure, followed by heat treatment to improve stability. The prepared USFM-15 exhibited super amphiphilicity in air and submerged superhydrophobicity after pre-wetting with water and oil.

2. With the synergistic effect of suitable porosity and high selective wettability, the obtained membranes possessed permeate fluxes as high as 22,000 and 56,000 L m-2 h - 1, with separation efficiencies in excess of 99.5 % for immiscible light/heavy oil/water mixtures.

3. USFM-15 has a permeate flux of 4,000 and 20,000 L m-2 h-1 for oil-in-water and water-in-oil emulsions, respectively, and the separation efficiency of USFM-15 for emulsions is still greater than 99.2 % after 25 cycles. In addition, USFM-15 has excellent reusability, high chemical stability and mechanical durability.

How are superhydrophobic Nanofiber Membranes prepared under liquids?

In this study, submerged superhydrophobic Nanofiber Membrane was prepared by a two-step process.

1. First, candle soot was sprayed on the surface of Nanofiber Membrane to form a rough structure;

2. Then, a heat treatment step was performed to improve the USFM stability. The resulting USFM-15 exhibited superhydrophilicity in air and superhydrophobicity under liquid after being pre-wetted with water and oil.

This membrane, with proper pore structure and high selective wettability, exhibited permeate fluxes of up to 22,000 and 56,000 L m-2 h-1 with separation efficiencies in excess of 99.5% for immiscible light/heavy oil-water mixtures.

What are the main advantages of USFM-15 membranes over Nanofiber Membrane for oil-water separation?

1.Ultra-high separation efficiency:

USFM-15 membranes exhibit over 99.5% separation efficiency for immiscible light/heavy oil/water mixtures.

2.Ultra-high permeate flux: 

USFM-15 membranes have a permeate flux of 22,000 to 56,000 liters per hour per square meter, much higher than Nanofiber Membrane.

3. Excellent stability: 

USFM-15 membranes have excellent reusability, high chemical stability and mechanical durability for long-term stable oil-water separation applications.

Originallink: https://doi.org/10.1016/j.seppur.2023.125794