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Reinforced Low Energy Membrane and Module for Pressure Driven Water Purification Processes

Technology Overview

This technology relates to a reinvention of the structure of spiral wound membrane module to increase productivity and to simplify the membrane fabrication process. Despite undergoing a long history of development, the structure of the spiral wound membrane modules remained the same. Each module is made up of several leaf sets, with each leaf set consisting of feed spacers, flat sheet membranes and a permeate carrier wrapped around the permeate collecting tube.

The technology here involves combining the 3 layers in a leaf set into 2 layers on an industrial-scale casting line such that more membrane can fit into a standard specific volume. By combining the permeate carrier and the membrane into a single sheet, we were able to eliminate the need for the typical non-woven backing for the membrane. As such, the leaf set thickness can be significantly reduced by approximately 10-20%, and hence the theoretical surface area and productivity of the membrane modules can be increased by 30-50%.

The material cost can potentially be reduced by 10-20% and the internal ion concentration polarization (ICP) is expected to be reduced due to less bulky structure. This design also lessen the work required to roll an element due to less sheets per leaf-set. The technology provider is currently seeking joint-venture partners for technology evaluation licensing with research collaboration agreement (RCA) to scale-up and commercialize the technology.

Technology Features & Specifications

  • The reinforced flat sheet membrane combines both the membrane layer and the permeate carrier layer into a single sheet resulting in 2 sheets (reinforced membrane and feed spacer) wounding instead of 3 sheets (membrane, permeate carrier and feed spacer).
  • With the elimination of non-woven polyester backing, the leaf set thickness is significantly reduced; hence, the theoretical surface area and productivity of the membrane modules could be increased.
  • Potential reduction in membrane material cost by 10-20% and internal ion concentration polarization (ICP).
  • Membrane support with sufficient permeate channels on the backside of the membrane for efficient permeate flow. This feature has been evaluated at high-pressure spiral wound element module.

 

Potential Applications

The membrane may be used for pressure driven water purification processes, e.g. Ultraflltration (UF), Forward Osmosis (FO), Reverse Osmosis (RO), Nanofiltration (NF), Pressure Retarded Osmosis (PRO), Microfiltration (MF).

Market Trends and Opportunities

Overall leaf set thickness in spiral wound membrane module is the key factor affecting performance in terms of pressure driven product throughput. In the reinvented design, the permeate carrier and the membrane combine into a single sheet which eliminated the typical non-woven support layer. As such, the leaf set thickness was significantly reduced and the productivity of the module can be improved as more membranes could be rolled within the same standard housing.  Membrane SWM modules using the reinforced membranes have the potential to be the next low energy workhorse of the water industry

Customer Benefits

  • A low energy reinforced spiral wound module and membrane, which has overall leaf set thickness reduced by approximately 10-20%, theoretical surface area (productivity) of the membrane modules increased by 30-50%, and potential material cost reduction by 10-20%.
  • Proven method of translating reinforced membrane fabrication from lab-scale to industrial scale phase inversion (PI) casting line and interfacial polymerization (IP) coating line.
  • Readily available industrial-scale process settings to fabricate reinforced membrane with permeate channels of one meter in width and several hundreds of meter in length.

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