China's new membrane tech offers 97% oil separation with 99.9% purity

Zhejiang University researchers have developed a new membrane-based technology called the Janus Channel of Membranes (JCM) to tackle this issue. 

“Our JCM achieves exceptional oil and water recoveries of up to 97 and 75%, respectively, with near 99.9% purities,” the researchers wrote in the study paper. 

The recycling tech

As per the study paper, this new JCM technology uses a pair of semipermeable membranes: one hydrophilic and one hydrophobic. 

The membranes are separated by a channel that can adjust in width from 4 to 125 millimeters, optimizing the separation process.

The confined space between the membranes amplifies the separation process, leading to high recovery rates of up to 97% for oil and 75% for water, with minimal impurities.

“Guo et al. stacked a hydrophilic and a hydrophobic membrane one in front of the other to form a square channel between them, with a size that can be varied between 4 and 125 millimeters,” noted the study paper. 

A small amount of pressure is applied to pump the oil-water mixture into the chamber. The membranes work simultaneously to recover both oil and water. 

Small oil droplets collide and merge, forming larger droplets that can easily pass through the hydrophobic membrane and end up in an external tank.

Simultaneously, water molecules slip through the hydrophilic membrane and fall into another tank.

“As an emulsion of oil and water is forced to circulate through the slit, water passes through the hydrophilic membrane, and the increased concentration of oil in the emulsion creates increases the rate of oil permeation through the hydrophobic membrane,” the authors explained in the study paper.

Separation of both oil and water

While conventional separation technologies typically isolate oil or water from an emulsion, this innovative method enables the recovery of both components.

This simple yet ingenious approach has shown remarkable results. In lab tests, the technique recovered nearly 97% of the oil and 75% of the water from the mixture.

The recovered oil and water exhibit exceptionally high purity levels, approaching 99.9% purity.

According to the  South China Morning Post (SCMP) , the Janus Channel of Membranes (JCM) is aptly named after the ancient Roman god Janus, who was known for his two faces. The name symbolizes the technology’s ability to simultaneously process oil and water.

Interestingly, these membrane pairs have the potential to be scaled up for larger-scale operations.

Industries like petrochemicals, metallurgy, food, and pharmaceuticals produce large volumes of challenging oily wastewater. 

This innovative technology has the potential to improve the sustainability of wastewater treatment significantly. 

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Taxonomy

• Source Separation
• Oil Water Separation
• Oil Spill Treatments
• Filtration Separation
• Filtration Separation