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Superlyophobic Materials for Immiscible Liquids Separation

Technology Overview

Separation of oil/water mixture using wetting materials has been extensively investigated. However, the wastes released in industrial processes such as multi-phase liquids extraction, food industries or chemical reaction contain more complicated liquids components. The technology presents a novel strategy to prepare a broad range of superlyophobic materials based on polydopamine (PDA) mediated coating. The results demonstrate that the deposition of PDA nanoparticles enhances the growth of silicone microsheets (SMS), which increases trapped air fraction and results in superlyophobicity towards high surface tension liquids and superlyophilicity to liquids with surface tension smaller than 30 mN/m.

Superlyophobic sorbents generated from melamine foam and polyurethane foam can absorb various oils with capacity from 53 g/g to 120 g/g (melamine foam) and from 26.5 g/g to 52.5 g/g (polyurethane foam), depending on the oil type and density. High absorption capacity of porous foams towards oils makes them possible to remove low surface tension liquids from a batch of high surface tension immiscible organic liquids such as formamide or diethylene glycol. On the other hand, superlyophobic membranes fabricated from stainless steel mesh, cotton fabric and filter papers can filter chloroform and carbon tetrachloride from water and formamide with efficiency higher than 96%. All as-prepared superlyphobic materials show excellent regeneration. The preparation of superlyophobic materials introduced in this work opens a general strategy for separation of immicible liquids by both static and continuous methods.

The technology provider is seeking partner for research collaboration, scale-up testing/test-bedding, product co-development, technology licencing or manufacturing.  

 

Technology Features & Specifications

The technology features and specifications are as follows:

  • The technology relates to composite membranes and absorbents and a method of fabricating the composite membrane and absorbents.
  • Polydopamine (PDA) is used as the template to grow silicone microsheets on various solid substrates. As a result, the substrates after silanization process exhibit superlyophobicity. In contrast, the substrates without PDA coating only exhibit superhydrophobicity after silanization. Superhydrophobic surface only has superrepellency to water, while superlyophobic (non-wetting surface) has superrepellency to other high surface tension organic liquids.
  • Polydopamine (PDA) is applied for the pretreatment step so that the substrate materials can be very versatile because of the universal, strong adhesion of PDA on almost any solid substrates, regardless of shapes and initial wettability.
  • The composite membrane can separate a broad range of immiscible liquids, in particular immiscible liquids with distinct surface tension values (high and low surface tensions) by both continuous filtration and absorption that the commercial hydrophobic materials cannot.
  • The mesh membrane allows repeated regeneration for the continuous separation process. The sorbents allow repeated regeneration for the absorption capacity.

 

Potential Applications

This technology is applicable in the following industries:

  • Liquid-liquid extraction, including water/oil separation, which is necessary in food industry, chemical engineering or environmental industry.
  • The liquid repellency properties of the materials can be used to fabricate anti-corrosion surface, anti-icing materials, self-cleaning surfaces or anti-fogging materials, which are very important for manufacturing the protective coatings.

Market Trends and Opportunities

Separation of liquid mixtures, especially organic liquid mixtures, is widely used in industrial processes but still faces challenges with respect to separation in a high-efficiency, low-energy mode. Oil/water separation membranes with different wettability towards water are attractive for their economic efficiency and convenience. The key factor for the separation process is the roughness-enhanced wettability of membranes based on the intrinsic wetting threshold (IWT) of water, that is, the limitation of the wettability caused by hydrophobicity and hydrophilicity. However, the separation of organic liquids (OLs) remains a challenge. The present invention provides a general strategy to separate any immiscible liquids efficiently, and may lead to the development of membranes with a large capacity, high flux, and high selectivity for organic reactions or liquid extraction in chemical engineering.

Customer Benefits

  • On-demand separation of both water/oil and immiscible organic liquids. Regeneration is available.
  • Be able to scale up, the products can be applied to oil spills or organic liquids spill incidents.

 

 

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