Application And Development Trends Of Membrane Separation Technology in Emerging Pollutant Control

With the acceleration of industrialization and urbanization, an increasing number of emerging pollutants have been detected in the environment. These pollutants are often characterized by complex structures, persistence, and high potential toxicity, making them difficult to remove with conventional treatment methods. In recent years, membrane separation technology has emerged as a key solution, owing to its high efficiency, selectivity, operational simplicity, and sustainability, and it shows broad application prospects in environmental protection

Emerging pollutants mainly include persistent organic pollutants (POPs), endocrine-disrupting chemicals (EDCs), antibiotics, and microplastics. They are widely present in water, soil, and air, with significant persistence and bioaccumulation potential. For instance, bisphenol A (BPA) and phthalates, commonly used plasticizers, can disrupt endocrine systems, affecting reproduction and immunity; perfluorinated compounds (PFCs) are highly resistant to degradation and accumulate in ecosystems, posing long-term risks to human health.As monitoring technologies advance, the scope of emerging pollutants continues to expand, creating urgent demand for efficient removal strategies.

Membrane separation technology utilizes the selective permeability of semi-permeable membranes to separate, purify, or concentrate mixtures. Based on pore size and separation mechanism, it can be categorized as follows:

• Microfiltration (MF): pore size 0.1–10 μm, removes suspended particles and bacteria;
• Ultrafiltration (UF): pore size 0.01–0.1 μm, intercepts viruses and macromolecules;
• Nanofiltration (NF): pore size 1–10 nm, removes divalent ions and small organic molecules;
• Reverse Osmosis (RO): pore size <1 nm, capable of removing almost all dissolved salts and organic contaminants.

Among these, NF and RO are especially effective in removing trace organic pollutants, heavy metals, and microplastics.

1) Water Treatment

Membrane separation is widely applied in drinking water purification, industrial wastewater treatment, and water reuse. For example, membrane bioreactors (MBRs) integrate membranes with biological processes, enhancing wastewater treatment efficiency while effectively removing pharmaceutical residues and microplastics.

2) Air Purification

In air purification, membrane technology addresses volatile organic compounds (VOCs), fine particulate matter (PM2.5/PM10), and toxic gases. Nanofiber and functionalized membranes have shown excellent performance in capturing VOCs and particulates, providing new solutions for industrial emission control and indoor air purification.

3) Soil Remediation

Membrane separation removes pollutants from soil through physical separation and chemical adsorption. NF membranes are effective in eliminating heavy metals, while UF membranes are suitable for separating organic pollutants, making them valuable in soil remediation projects

Advantages:

High efficiency: Effectively removes trace and persistent pollutants;

Eco-friendly & energy-saving: Operates under mild conditions with low secondary pollution;

Flexibility: Modular design fits different treatment scales;

Material diversity: Various membranes tailored for specific contaminants.

Challenges:

Membrane fouling: Reduced flux, higher costs, and shorter lifespan;

Material limitations: Current membranes still face constraints in chemical resistance and fouling resistance;

Energy demand: High-pressure processes consume significant energy, requiring further optimization

1. Advanced Membrane Materials: Nanomaterials, 2D materials (e.g., graphene), and composite membranes are research hotspots, offering higher selectivity and fouling resistance.
2. Hybrid Processes: Combining membrane separation with biodegradation, advanced oxidation, and adsorption enables synergistic pollutant removal.
3. Green and Intelligent Solutions: Future membranes will emphasize self-cleaning, low-energy operation, and sustainable designs.
4. Policy and Market Drivers: Policies such as China's Action Plan for Emerging Pollutant Control and the EU's Water Framework Directive are accelerating large-scale adoption of membrane technologies

Membrane separation technology is becoming a key tool in emerging pollutant control. It has demonstrated remarkable effectiveness in water, air, and soil applications, particularly in removing trace and persistent contaminants. Looking forward, innovations in materials, hybrid systems, and energy efficiency will drive the next stage of development. With stricter global environmental standards and growing public awareness, membrane separation is expected to play an increasingly central role in the environmental industry.