A Comprehensive Overview of Forward Osmosis Membrane: Composition, Grades, and Industrial Implementation

Types of Forward Osmosis Membranes

Forward osmosis (FO) is an advanced membrane separation technology that leverages natural osmotic pressure to draw water through a semipermeable membrane from a low-concentration feed solution to a high-concentration draw solution. Unlike reverse osmosis (RO), which requires external hydraulic pressure, FO operates with significantly lower energy input, making it an attractive option for sustainable water treatment, desalination, wastewater reclamation, and food processing.

The forward osmosis membrane is the core component of any FO system. It must exhibit high water permeability, excellent solute rejection, minimal internal concentration polarization, and long-term chemical and mechanical stability. Four primary types of FO membranes are widely used in industrial and research applications, each offering distinct structural, performance, and operational characteristics.

Rigid Membranes

Constructed from robust, inflexible polymers like polyethersulfone (PES) and polysulfone (PSf), rigid FO membranes are engineered for durability and high selectivity in demanding environments.

Advantages

• High permselectivity and osmotic efficiency
• Excellent chemical and thermal stability
• Long operational lifespan in industrial settings
• Available in asymmetric and composite configurations for tailored performance

Limitations

• Heavier and bulkier than flexible alternatives
• Limited scalability in compact systems
• Higher manufacturing complexity

Best for: High-pressure industrial applications, research labs, and systems requiring maximum solute rejection

Spiral-Wound Membranes

These membranes consist of flat sheet FO material spirally wrapped around a central permeate collection tube, separated by spacer layers to maintain flow channels.

Advantages

• High surface area-to-volume ratio
• Efficient permeate collection and modular design
• Easily scalable for large-scale operations
• Compatible with backflush cleaning (e.g., torpedo-shaped methods)

Limitations

• Prone to fouling in spacer-filled channels
• Difficult to clean thoroughly in highly contaminated feeds
• Higher pressure drop across the module

Best for: Municipal water treatment, desalination plants, and large-scale industrial systems

Hollow Fiber Membranes

Composed of thousands of thin, tubular fibers bundled together, hollow fiber FO membranes offer a compact and efficient design with exceptional surface area density.

Advantages

• Extremely high surface area per unit volume
• Lightweight and space-efficient
• Up to 20% greater surface area and 25% higher water flux with polyketone variants
• Excellent mass transfer and low energy consumption

Limitations

• More fragile and susceptible to mechanical damage
• Challenging to clean and regenerate
• Potential for fiber breakage under high flow conditions

Best for: Portable water purification, space-constrained installations, and high-flux applications

Thin-Film Composite (TFC) Membranes

A specialized subset of rigid membranes, TFC membranes feature a thin polyamide (PA) selective layer on a porous polysulfone support, offering superior water-solute separation.

Advantages

• Exceptional water permeability and solute rejection
• Tunable surface chemistry for specific applications
• Reduced internal concentration polarization
• Widely used in hybrid FO-RO systems

Limitations

• Sensitive to chlorine and oxidative agents
• Higher cost compared to standard PES/PSf membranes
• Requires careful pH and temperature control

Best for: High-purity water production, food and beverage concentration, and pharmaceutical applications

Type	Surface Area Efficiency	Durability	Water Flux	Best Application
Rigid Membranes	Medium	Excellent	Good	Industrial processing, high-stability environments
Spiral-Wound	High	Very Good	Very Good	Large-scale water treatment, desalination
Hollow Fiber	Excellent	Fair	Excellent	Compact systems, high-flux needs
Thin-Film Composite	Good	Good	Excellent	Precision separation, sensitive applications

Expert Tip: For optimal performance in FO systems, ensure proper selection of the draw solution and regular monitoring of membrane fouling. Pre-treatment of feed water can significantly extend membrane life and maintain high water flux over time.

In summary, the choice of forward osmosis membrane depends on the specific requirements of the application, including desired water flux, system footprint, fouling potential, and operational conditions. By understanding the strengths and trade-offs of each membrane type—rigid, spiral-wound, hollow fiber, and thin-film composite—engineers and operators can design more efficient, cost-effective, and sustainable water treatment solutions.

Specifications and Maintenance of Forward Osmosis Membranes

Forward osmosis (FO) membranes are advanced semi-permeable barriers that play a critical role in water purification, desalination, wastewater reclamation, and even food processing. Unlike reverse osmosis, FO relies on natural osmotic pressure differences to draw water through the membrane, offering energy-efficient separation with reduced fouling potential. Understanding the key specifications and proper maintenance practices is essential for maximizing performance, longevity, and system efficiency.

Key Specifications of Forward Osmosis Membranes

Membrane Materials

Forward osmosis membranes are typically constructed from high-performance polymeric materials designed to balance permeability, selectivity, and durability. Common materials include:

• Cellulose Acetate (CA): Known for good fouling resistance and chlorine tolerance, CA is widely used in industrial applications despite moderate flux levels.
• Thin-Film Composite (TFC) Polyamide: Offers high water flux and excellent salt rejection but is more sensitive to chlorine and extreme pH conditions.
• Polymer Blends with Amphiphilic Additives: Engineered to enhance surface hydrophilicity and reduce fouling by repelling organic and biological contaminants.

Material selection depends on feedwater quality, draw solution compatibility, and operational environment.

Pore Size and Selectivity

The effective pore size in FO membranes typically ranges from 0.1 to 10 nanometers, classifying them as ultrafiltration to nanofiltration-grade barriers. While FO does not rely solely on size exclusion, pore structure influences:

• Rejection of ions, macromolecules, and microorganisms
• Internal concentration polarization (ICP), which affects overall water flux
• Resistance to fouling and scaling

Membranes are engineered with asymmetric structures—dense selective layers on porous supports—to optimize both rejection and permeability.

Water Flux Performance

Water flux measures the volume of water passing through a unit area of membrane per unit time, commonly expressed in liters per square meter per hour (LMH) or gallons per square foot per day (GFD). Typical FO flux ranges from 5–20 LMH, depending on several factors:

• Osmotic pressure gradient: Higher draw solution concentration increases flux.
• Temperature: Elevated temperatures enhance diffusion rates and water mobility.
• Membrane orientation: Active layer facing feed solution (AL-FS) vs. active layer facing draw solution (AL-DS) impacts fouling and ICP.
• Fouling and scaling: Accumulation of contaminants reduces effective flux over time.

Rejection Rate

The rejection rate quantifies the membrane’s ability to retain contaminants such as salts, organic matter, pathogens, and micropollutants. FO membranes can achieve:

• 95–99% salt rejection for NaCl using TFC membranes
• Over 99% rejection of bacteria, viruses, and colloidal particles
• Variable organic rejection based on molecular weight and hydrophobicity

Rejection is influenced by membrane chemistry, pore size, and interactions between solutes and the membrane surface. It is critical for ensuring product water quality in potable and process water applications.

Operating Temperature Range

FO membranes operate effectively within a specific temperature window, typically between 5°C and 45°C (41°F to 113°F). Operating outside this range can lead to:

• Low temperatures: Reduced water flux due to increased viscosity and slower diffusion.
• High temperatures: Risk of polymer degradation, loss of mechanical strength, and accelerated biological growth.

Some specialty membranes are designed for extended thermal stability in industrial or waste heat recovery applications.

Chemical and pH Stability

FO membranes vary in their resistance to chemical exposure:

• Cellulose acetate: Stable in pH 3–8, resistant to chlorine but hydrolyzes at high pH.
• Polyamide: Stable in pH 4–11, but degrades in the presence of free chlorine.

Understanding chemical compatibility is essential during cleaning and system shutdown procedures to prevent irreversible damage.

Specification	Typical Range	Impact on Performance
Water Flux	5–20 LMH	Affected by osmotic gradient, temperature, and fouling
Salt Rejection	90–99.5%	Determines product water purity; varies by membrane type
Pore Size	0.1–10 nm	Influences selectivity and fouling resistance
Operating pH	3–11 (varies by material)	Must match cleaning agents and feedwater chemistry
Temperature Range	5–45°C	Extreme temps reduce flux or damage membrane

Essential Maintenance Practices

Proper Storage: When not in use, FO membranes should be stored in a protective solution (e.g., 1% sodium metabisulfite) in a cool, dark environment (4–10°C) to prevent microbial growth and oxidative damage. Always follow manufacturer guidelines for long-term preservation.

Regular Cleaning: Scheduled cleaning is crucial to remove accumulated foulants. Use membrane-compatible agents:

• Acidic cleaners (pH 2–4): Remove inorganic scaling (e.g., CaCO₃, CaSO₄)
• Alkaline cleaners (pH 10–12): Dissolve organic fouling and biofilms
• Enzymatic or low-foam detergents: Target biological and protein-based deposits

Fouling Prevention: Implement robust pre-treatment strategies such as:

• Media filtration and ultrafiltration for particle removal
• pH adjustment and antiscalants to prevent scaling
• Biocides or UV treatment to control microbial growth

Performance Monitoring: Track key parameters (flux, rejection, pressure drop) regularly to detect early signs of fouling, scaling, or membrane degradation. Sudden drops in flux or rejection indicate the need for intervention.

Timely Replacement: FO membranes have a service life of 3–7 years depending on operating conditions. Replace membranes when cleaning no longer restores performance or when integrity is compromised to maintain system efficiency and water quality standards.

Important: Always consult the membrane manufacturer’s technical manual before performing cleaning, storage, or replacement procedures. Using incompatible chemicals or improper methods can permanently damage the membrane. Regular maintenance not only extends membrane life but also ensures consistent water quality and system reliability.

Applications of Forward Osmosis Membranes Across Industries

Forward osmosis (FO) membrane technology has emerged as a highly efficient, low-energy separation process with transformative applications across a wide range of industries. By leveraging natural osmotic pressure to draw water through a semi-permeable membrane, FO systems concentrate solutions and purify water with minimal energy input. While waste management was among the first sectors to adopt this innovation—and remains its largest user—numerous other industries are now harnessing its benefits for improved efficiency, sustainability, and product quality.

Food & Beverage Processing

Forward osmosis is revolutionizing food and beverage production by enabling gentle concentration of sensitive liquids without compromising flavor, aroma, or nutritional content.

• Dairy Industry: Cheese manufacturers use FO to pre-concentrate milk before cheese production, reducing thermal load and preserving protein structure for improved yield and texture.
• Juice & Extract Concentration: Fruit juices are concentrated at low temperatures, maintaining volatile compounds responsible for taste and fragrance—ideal for premium extracts and natural flavorings.
• Wine & Spirits: Emerging applications include alcohol adjustment and aroma recovery during fermentation and aging processes.

Advantage: Energy savings of up to 50% compared to thermal evaporation methods.

Water Desalination & Reuse

FO technology offers a sustainable alternative to reverse osmosis in desalination and wastewater reclamation, particularly in energy-constrained environments.

• Seawater Desalination: FO membranes extract fresh water using a draw solution, requiring significantly less energy than high-pressure RO systems.
• Hybrid Systems: Often integrated with reverse osmosis (FO-RO), where FO concentrates seawater before final purification, improving overall efficiency.
• Brine Management: FO can further concentrate RO brine, reducing disposal volume and enabling resource recovery.

Sustainability benefit: Lower carbon footprint and reduced fouling due to absence of hydraulic pressure.

Pharmaceutical & Medical Applications

Precision and sterility are paramount in healthcare, making FO an ideal technology for sensitive fluid processing.

• IV Fluid Production: Medical professionals use FO to safely dilute and purify intravenous solutions, ensuring precise osmolarity and sterility.
• Drug Formulation: Used to concentrate active pharmaceutical ingredients (APIs) without exposing them to heat or shear stress.
• Vaccine & Antibiotic Concentration: Enables concentration of biologicals while preserving efficacy and stability.

Key benefit: Maintains integrity of heat-sensitive biomolecules, improving product quality and shelf life.

Essential Oils & Natural Extracts

The extraction of aromatic compounds from herbs and plants demands methods that preserve delicate chemical profiles.

• FO gently concentrates plant extracts, retaining volatile terpenes and esters responsible for scent and therapeutic properties.
• Ideal for organic and natural product manufacturers seeking clean-label processing methods.
• Reduces oxidation and degradation compared to thermal distillation or solvent-based extraction.

Quality advantage: Higher fidelity of flavor and aroma in final products.

Pharmaceutical Manufacturing

Forward osmosis supports green chemistry initiatives in drug development and production.

• Concentrates complex drug formulations while removing impurities and endotoxins.
• Used in buffer preparation and purification steps during biologics manufacturing.
• Enables water recycling in clean-in-place (CIP) systems, reducing facility water consumption.

Environmental impact: Reduces wastewater volume and chemical usage, contributing to a smaller carbon footprint.

Horticulture & Agricultural Irrigation

FO is transforming sustainable agriculture through advanced water recycling and nutrient management.

• Treats and recycles wastewater from greenhouses for safe irrigation, reducing freshwater demand.
• Concentrates nutrient solutions for precision fertigation, minimizing runoff and environmental impact.
• Some systems integrate with evaporation suppression technologies to reduce water loss in arid climates.

Innovation highlight: Closed-loop irrigation systems powered by FO improve water use efficiency by up to 70%.

Industry Insight: Forward osmosis is not just a filtration method—it's a platform technology enabling resource recovery, energy efficiency, and product enhancement. As membrane materials and draw solutions continue to improve, FO is poised to expand into new markets including space life support systems, emergency water purification, and zero-liquid-discharge (ZLD) industrial facilities.

Industry	Primary Application	Key Benefit	Energy Efficiency vs. Traditional Methods
Food & Beverage	Milk and juice concentration	Preserves flavor and nutrients	40–60% reduction
Desalination	Seawater to potable water	Lower fouling, scalable	30–50% reduction
Pharmaceuticals	API and vaccine concentration	Maintains bioactivity	50–70% reduction
Horticulture	Wastewater reuse for irrigation	Water conservation	60–75% reduction
Essential Oils	Plant extract concentration	Retains aromatic compounds	55–65% reduction

Emerging Trends and Future Outlook

• Smart Membranes: Development of fouling-resistant and self-cleaning FO membranes to extend operational life.
• Draw Solution Innovation: Advances in recoverable draw solutes (e.g., magnetic nanoparticles, thermolytic salts) improving process efficiency.
• Modular Systems: Compact, containerized FO units enabling decentralized water treatment in remote areas.
• Circular Economy Integration: FO used in resource recovery from industrial effluents, including lithium and rare earth elements.
• Regulatory Support: Growing recognition in environmental standards for low-impact water treatment technologies.

How to Choose Forward Osmosis Membranes: A Comprehensive Guide for Industrial Buyers

Forward osmosis (FO) technology, while promising for its energy efficiency and low fouling potential, is still in its developmental phase compared to the well-established reverse osmosis (RO) systems. As a result, selecting the right FO membrane presents unique challenges for business and industrial buyers. Unlike RO, where standardized membranes dominate the market, FO membranes require a more application-specific approach due to variations in feed solutions, draw solutions, and operational conditions. This guide provides a structured framework to help decision-makers evaluate and select the most suitable forward osmosis membranes for their specific needs.

Critical Note: FO performance is highly dependent on the interaction between the membrane, feed solution, and draw solution. A membrane that performs well in one application may underperform in another. Always consider the complete system dynamics, not just the membrane alone.

Step 1: Define the Application and Target Use Case

The first and most crucial step in membrane selection is clearly identifying the intended application. The performance requirements, chemical compatibility, and operating conditions vary significantly across industries. Key application categories include:

• Food and Beverage Dewatering: Concentrating juices, dairy products, or liquid foods without thermal degradation. Requires food-grade materials and resistance to organic fouling.
• Wastewater Treatment and Reuse: Treating industrial effluents, landfill leachate, or municipal wastewater. Demands high fouling resistance and durability against complex contaminant mixtures.
• Desalination and Water Reclamation: Using FO as a pretreatment or hybrid system with RO. Needs high salt rejection and compatibility with saline environments.
• Emergency Water Purification: Portable systems for disaster relief. Prioritizes robustness, ease of use, and rapid deployment.
• Resource Recovery: Extracting valuable compounds from industrial streams (e.g., lithium, organics). Requires selective permeability tailored to target molecules.

Once the application is defined, focus narrows to membranes engineered for that specific use case. Material compatibility with the primary feed stream—whether acidic, alkaline, high in organics, or containing particulates—becomes a critical selection criterion.

Step 2: Evaluate Membrane Flux and Efficiency

Membrane flux—the rate at which water passes through the membrane—is a key performance indicator that directly impacts operational costs and system sizing. While FO typically operates at lower flux than RO, even small differences in flux can have a significant economic impact at industrial scale.

Consider the following when assessing flux:

• Feed Water Characteristics: Is the feed water city water, industrial wastewater, or a high-solids slurry? High fouling potential may reduce effective flux over time.
• Draw Solution Compatibility: The choice of draw solution (e.g., NaCl, NH₄HCO₃, or proprietary solutions) affects osmotic pressure and thus water flux. Ensure the membrane is compatible with your intended draw solute.
• Long-Term Performance: Request flux data under sustained operation, not just initial lab results. Look for information on flux decline due to fouling or internal concentration polarization (ICP).
• Energy Efficiency: Higher flux reduces the required membrane area and footprint, lowering capital and pumping costs in hybrid systems.

Step 3: Analyze Membrane Structure and Support Layer Design

The support layer in an FO membrane plays a far more critical role than in RO due to the phenomenon of internal concentration polarization (ICP). ICP occurs when solutes accumulate within the porous support layer, reducing the effective osmotic driving force and lowering water flux.

When evaluating support layers, consider:

• Porosity and Tortuosity: A highly porous, low-tortuosity support layer minimizes ICP and enhances permeability.
• Thickness: Thinner support layers reduce diffusion resistance but must maintain mechanical strength.
• Material: Common materials include polysulfone (PSf), polyethersulfone (PES), and polyacrylonitrile (PAN). Each offers different chemical and mechanical properties.
• Configuration: Choose between hollow fiber (high surface-area-to-volume ratio, ideal for compact modules) and flat sheet (easier to clean, suitable for plate-and-frame systems).

Step 4: Select the Appropriate Module and Housing Configuration

The membrane module design significantly influences system performance, scalability, and maintenance. Your choice should align with existing infrastructure and operational goals:

Module Type	Advantages	Limitations	Best Suited For
Hollow Fiber (Cartridge)	High packing density, compact footprint, scalable	Prone to fouling, difficult to clean, sensitive to particulates	Desalination, large-scale water treatment
Flat Sheet (Plate-and-Frame)	Easy to clean, robust, handles high-fouling feeds	Larger footprint, lower packing density	Food processing, wastewater with solids
Spiral Wound	Moderate density, widely available	Limited to low-fouling applications, prone to ICP	Hybrid FO-RO systems

Additionally, evaluate the housing material—options include stainless steel, PVC, or advanced ceramics like alumina. Ceramic housings offer superior chemical and thermal resistance but at a higher cost, making them ideal for aggressive industrial environments.

Step 5: Conduct Lab-Scale Testing and Validation

Before committing to a full-scale purchase, it is essential to conduct pilot or lab-scale testing using your actual feed and draw solutions. This step allows you to:

• Validate claimed flux and rejection rates under real-world conditions
• Assess fouling propensity and cleaning requirements
• Evaluate long-term stability and degradation
• Compare multiple membrane candidates side-by-side
• Optimize operating parameters (flow rates, crossflow velocity, etc.)

Many membrane suppliers offer testing services or sample kits to support this evaluation phase.

Expert Tip: Engage with membrane manufacturers early in the selection process. Reputable suppliers can provide application-specific data, technical support, and customized solutions based on your feed water analysis and performance goals.

Additional Considerations for Long-Term Success

• Chemical Cleaning Compatibility: Ensure the membrane can withstand routine cleaning with common agents (e.g., citric acid, sodium hypochlorite) without degradation.
• Temperature and pH Range: Confirm the membrane’s operational limits align with your process conditions.
• Warranty and Lifespan: Inquire about expected membrane life and warranty terms based on application type.
• Total Cost of Ownership (TCO): Factor in replacement frequency, cleaning costs, energy use, and downtime when comparing options.
• Sustainability: Consider recyclability, chemical usage, and environmental impact of both membrane and draw solution.

Selecting the right forward osmosis membrane requires a holistic approach that balances technical performance, application requirements, and economic factors. By systematically evaluating application needs, membrane properties, module design, and real-world performance through testing, industrial buyers can make informed decisions that maximize efficiency, reliability, and return on investment in their FO systems.

Frequently Asked Questions About Forward Osmosis (FO) Membranes in Water Purification

Q1: What are the advantages of using FO membranes in water purification compared to traditional membrane processes?

Forward osmosis (FO) membranes offer several key advantages over conventional membrane technologies such as reverse osmosis (RO), microfiltration (MF), and ultrafiltration (UF). These benefits make FO a promising option for a variety of water treatment applications:

• Higher Permeate Flux: FO membranes often achieve greater water flux under optimal conditions due to the natural osmotic pressure gradient, which drives water through the membrane without requiring high external pressure. This results in faster purification rates and improved system efficiency.
• Reduced Membrane Fouling: Because FO operates at lower hydraulic pressures than RO, foulants such as organic matter, colloids, and biological materials are less likely to adhere to the membrane surface. This leads to less frequent cleaning, longer operational cycles, and extended membrane lifespan.
• Broad Contaminant Removal: FO membranes effectively reject a wide spectrum of contaminants, including dissolved salts (e.g., sodium, chloride), heavy metals, pharmaceuticals, endocrine disruptors, and organic pollutants, making them suitable for treating complex feedwaters like industrial effluents and seawater.
• Lower Energy Consumption: The osmotic-driven process eliminates or significantly reduces the need for energy-intensive high-pressure pumps used in RO systems. When integrated with renewable energy sources or low-grade heat, FO can be a highly energy-efficient solution, particularly in remote or off-grid locations.
• Compatibility with Osmotic Dilution: In hybrid systems such as FO-RO, the draw solution can be diluted during the FO stage and then reconcentrated using low-energy methods, enhancing overall process sustainability.

These advantages position forward osmosis as a sustainable, cost-effective alternative for next-generation water purification systems, especially where energy efficiency and fouling resistance are critical.

Q2: How does the performance of FO membranes degrade over time in water treatment applications?

While forward osmosis membranes exhibit superior fouling resistance compared to traditional pressure-driven membranes, their performance still declines gradually due to several interrelated factors:

• Membrane Fouling: Although reduced, fouling can still occur from the accumulation of organic matter, biofilms, or inorganic scaling on the membrane surface or within pores. This creates a barrier that reduces water flux and increases mass transfer resistance.
• Concentration Polarization: A major challenge in FO systems, this phenomenon occurs when solutes accumulate near the membrane surface (either on the feed side or draw side), reducing the effective osmotic pressure difference. Internal concentration polarization (ICP) within the porous support layer is particularly detrimental and can significantly lower net water flux over time.
• Oxidative Degradation: Exposure to chlorine or other oxidizing agents during cleaning or in feedwater can damage the polyamide active layer of FO membranes, leading to loss of selectivity and mechanical integrity.
• Draw Solution Carryover: Over time, small amounts of the draw solute may pass through the membrane into the purified water stream, contaminating the permeate and reducing process efficiency—especially if not properly managed in closed-loop systems.
• Physical and Chemical Aging: Long-term exposure to varying pH levels, temperature fluctuations, and mechanical stress can alter membrane morphology and performance characteristics.

To mitigate these issues, regular monitoring of flux, salt rejection, and pressure differentials is essential. Implementing optimized cleaning protocols, using fouling-resistant membrane coatings, and selecting compatible draw solutions can help maintain long-term performance and extend membrane life.

Q3: In which water treatment industries are Forward Osmosis (FO) membranes currently being used or explored?

Forward osmosis technology is gaining traction across multiple water treatment sectors due to its unique advantages in energy efficiency, fouling resistance, and versatility. Key industries adopting or researching FO membranes include:

Industry	Application	Status & Examples
Desalination	Seawater and brackish water purification	Being piloted with solar or waste heat integration to reduce energy costs; FO-RO hybrid systems improve overall recovery and reduce pretreatment needs.
Wastewater Treatment	Concentration of municipal and industrial wastewater	Used to pre-concentrate effluents before anaerobic digestion or zero-liquid discharge (ZLD) systems, reducing volume and energy for downstream processing.
Aquaculture	Water recycling and quality maintenance in fish farms	FO systems help maintain stable water conditions by removing waste metabolites and pathogens while conserving water resources.
Landfill Leachate Treatment	Concentration and detoxification of leachate	FO effectively handles highly contaminated leachate with minimal fouling, enabling safer disposal or further treatment.
Brine Management	Volume reduction in desalination plant discharges	FO is used to concentrate brine streams, improving the efficiency of crystallizers and reducing environmental impact.
Municipal Water Reuse	Advanced treatment for potable and non-potable reuse	Explored for indirect potable reuse (IPR) due to high contaminant rejection and compatibility with advanced oxidation processes.
Food & Beverage	Product concentration (e.g., juices, dairy)	Emerging use in gentle concentration without heat, preserving flavor and nutrients.

As FO membrane materials and system designs continue to improve, commercial adoption is expected to grow, particularly in niche applications where traditional methods face limitations in energy use, fouling, or water quality requirements.