Technology trends in membrane filtration use

A significant amount of resources are allocated in the research and development of membrane filtration technology. However, it remains unclear how closely research goals align with solving industry needs. Sepideh Jankhah, Ph.D, P.Eng. examines the history, evolution and R&D trends in this area.

Since 2001, a significant amount of resources have been allocated each year to the research and development (R&D) of membrane filtration technology. However, it remains unclear how closely research goals align with solving industry needs. This article examines the history and evolution of membrane filtration technology applications and investigates R&D trends in this area based on peer-reviewed literature. Interestingly, it appears that research and industry needs are converging at a similar pace, though the leading party varies by area of application.

Membrane filtration history

Membrane filtration technology is widely utilized across various industries: water and wastewater treatment, food and beverage processes, pharmaceutical and medical applications, chemical processing, and other industrial separation or purification applications. The history of membrane separation goes back to the early 1700's, when the word osmosis was first used to describe the permeation of water through a diaphragm.

Filtration technology has evolved from osmosis to electrodialysis, gas filtration, and membrane distillation, contributing to the invention and improvement of countless industrial products, processes and applications. Membrane filtration is now commonly used to concentrate fruit juices, remove contaminants from water and wastewater, and harvest cells for antibiotic production.

Membrane filtration technology has several advantages over conventional separation technologies (i.e. coagulation and sedimentation, sand filtration, dissolved air floatation, etc.). These advantages include improved product quality, increased separation capacity, lower risk factor, smaller footprint and generally lower chemical usage.

The global demand for membranes is expected to grow 8.5% annually, reaching $26.3 billion in 2019.2 The US market alone is expected to grow 7.9% annually, reaching $6.2 billion in 2018. Growth may be intensified due to global water shortages, increasingly stringent guidelines for drinking water and wastewater discharge quality, a drop in the cost of membrane production and operation, and recent advancements in the membrane technology.

Major membrane applications

Water and wastewater treatment account for more than 50% of industrial membrane usage, followed by food and beverage processes (21%) and pharmaceutical and medical applications (9%). Over the next five years, pharmaceutical and medical applications are expected to be the fastest growing markets. This trend is driven by increasing purity standards and expanding medical applications for this technology. Water treatment (including desalination) and food and beverage processing are expected to maintain steady growth.3

R&D data trends were derived from the number of peer reviewed journal articles published between 2001-2016 and sorted by primary application area, as mined from the Engineering Village Database. During the last decade, trends in research application observed closely align with industrial applications. Water and wastewater R&D represents 40%, followed again by food and beverage at 34%.

For industry, emphasis has been placed on the development of gas separation processes and desalination. Meanwhile, R&D has focused on pushing the boundaries of technology. Additional resources have been allocated to conduct research on such topics as membrane distillation, forward osmosis, pervaporation, electrodialysis, graphene oxides and biomimetic membranes for water and wastewater.

Use of these technologies has focused on development of new membrane product or processes, as well as optimizing existing membrane products and processes in terms of performance and associated ­operating/capital costs. There are some advances in the industrial pipeline, but most are still in the preliminary stages of development and require additional research before they prevail in the market.

Membrane classifications

Membranes are classified into four categories based on separation capacity: microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF) and Reverse/Forward Osmosis (RO/FO). MF membranes exhibit the largest pore size distribution (on the micron scale), followed by UF membranes in the submicron range, down to the ­theoretical 0.001 micron pore size of NF, and finally the non-porous RO and FO membranes.

Currently, MF membranes account for the majority demand in the industry (44%). RO/FO (28%) and UF (25%) hold similar shares of the market, leaving NF membranes with a small fraction. By 2019, the market size for RO systems are expected to reach $8.8 billion with a compound annual growth rate (CAGR) of 10.5%. This growth is expected to be primarily driven by municipal water desalination applications, along with process water treatment and reuse.7

Similar trends are observed between research and industry when it comes to membrane classification. This repeats the mimicking observed between these two sectors in regards to application. However, the prevalence of RO research compared to the MF research does not reflect the slightly larger industry share for MF membranes.

This discrepancy may be due to the large amount of academic work focused on low-energy RO and membrane surface modification. The increasing need for desalination, water reuse, removal of emerging contaminants, and high purity output streams contribute to the urgency of expanded research in RO and FO areas.

Meanwhile, MF and UF are the most mature technologies in the filtration industry, with relatively low prices compared to other membrane types. MF and UF are widely used as a primary filtration method or as a pre-treatment step for membranes with finer pores.

Future technology

Our research indicates that research goals (as represented by the number of published peer reviewed literature) have closely followed industry demands for the last decade. Industry has benefited from the developments achieved by research initiatives, and the observed positive correlation between industry and R&D goals is expected to continue as we face new challenges. This symbiosis should result in more efficient processes and new products or applications that will address the shortcoming of current industry solutions.

This study was limited in its analysis due to the uncertainty about the research information from within industry, and may be biased due to the time gap between conducted research and peer-reviewed literature published by institutions.

The synergy between technology development and industry adoption is an intriguing avenue for further research. Understanding this synergy would enable us to better predict when or if developing technologies based on membrane surface modifications, engineered osmosis, graphene oxides, and biomimetic membrane will be prevalent in the market.