The Versatile Efficacy of Chitosan for Microplastic Removal: A Sustainable Solution

This visual representation of plastic breakdown underscores the concern of microplastics entering our water and, subsequently, our bodies.

The proliferation of microplastics (MPs) in the environment has become an escalating global crisis, demanding urgent and effective remediation strategies. Defined as plastic particles smaller than five millimetres, these ubiquitous contaminants are detected across diverse ecosystems, from the deepest ocean trenches to terrestrial soils and even the atmosphere (Prasetyo et al., 2025, Sun et al., 2020). This widespread dispersion is a direct consequence of the extensive production and subsequent mismanagement of plastic waste over several decades (Prasetyo et al., 2025).

The enduring nature of these synthetic polymers means they persist in the environment for extended periods, fragmenting into progressively smaller particles, thereby increasing their potential for ecological harm (Sinha et al., 2025). Furthermore, microplastics exhibit a propensity to adsorb various pollutants, including heavy metals and persistent organic compounds, acting as vectors for these toxins into the food web, ultimately posing risks to human health (Fu et al., 2021). The sheer scale of microplastic pollution and its potential ramifications underscore the critical need for innovative and sustainable removal technologies.

Limitations of Conventional Microplastic Removal Technologies

While conventional wastewater treatment plants (WWTPs) can achieve significant removal rates of microplastics, often exceeding 90%, a substantial volume still escapes into the marine environment (An et al., 2020). Certain types and sizes of microplastics present particular challenges for existing technologies. Microplastics smaller than 600 micrometres, including nano plastics, and specific polymer types such as polyethylene (PE), polyamide (PA), and polystyrene (PS), are not efficiently captured by traditional treatment processes (Zhao & You, 2022). Moreover, established filtration methods can be associated with high costs, operational inefficiencies, or sustainability concerns.

Traditional coagulation methods, which utilise inorganic salts like aluminium sulphate, demonstrate limitations in their effectiveness, particularly for the removal of smaller microplastic particles, and can also generate non-biodegradable sludge, creating secondary environmental issues (Ma et al., 2019). These limitations in current technologies highlight a critical gap in our ability to comprehensively address microplastic pollution, paving the way for the exploration of novel and more efficient solutions.

Chitosan: A Promising Biopolymer for Microplastic Remediation

Derived from chitin, the second most abundant polysaccharide in nature, Chitosan is recognised for its biodegradability and biocompatibility. Its unique chemical properties, notably its cationic nature, make it highly effective in interacting with the predominantly negatively charged surfaces of microplastics. Numerous studies have documented its efficacy in wastewater treatment and pollution control, positioning Chitosan as a frontrunner in microplastic removal.

The Role of Chitosan's Properties in Microplastic Removal

Electrostatic Interactions and Charge Neutralisation

The effectiveness of Chitosan in microplastic removal is fundamentally linked to its intrinsic chemical and physical properties. Microplastics present in aquatic environments frequently exhibit a negative surface charge. Chitosan's positive charge, arising from protonated amine groups in acidic to neutral conditions, enables effective microplastic removal. Due to the negative surface charge of most microplastics, Chitosan neutralises these charges, causing destabilisation and flocculation. These larger flocs are then easily removed via sedimentation or filtration. Studies show optimal removal efficiency around pH 6.0, confirming charge neutralisation as the primary removal mechanism (Prasetyo et al., 2025).

Hydrophilic Nature and Adsorption Capacity

Diagram showing the chemical structure of chitin and the process of its conversion to chitosan through deacetylation.

In addition to electrostatic interactions, the hydrophilic nature of Chitosan significantly enhances its adsorption capacity. Its numerous hydroxyl (–OH) and amino (–NH₂) groups engage in chemical interactions with microplastic surfaces. Although microplastics are inherently hydrophobic, modifications to the Chitosan structure, such as the incorporation of aldehyde groups, can further optimise these interactions, thereby improving overall capture efficiency (Risch & Adlhart, 2021).

Hydrogen Bonding Interactions

Chitosan’s molecular structure also allows it to form hydrogen bonds with various polymeric substances. These bonds add an extra layer of adhesion, particularly with polymers like polyethylene (PE) and polypropylene (PP), which are common in microplastic pollution (Sun et al., 2020). The combined effect of electrostatic forces and hydrogen bonding enables Chitosan to target a broad spectrum of microplastics, making it a versatile adsorbent.

Enhancing Microplastic Removal with Chitosan Composites

To further enhance the microplastic removal efficiency and broaden the applicability of Chitosan, researchers have explored its integration with various composite materials, leveraging the synergistic effects arising from the combination of their unique properties.

Chitosan-Graphene Oxide Composites

Graphene oxide (GO) offers an exceptionally large surface area and strong π-π interactions that complement Chitosan’s properties. When combined, the resulting Chitosan–GO composite exhibits a significantly improved adsorption capacity and mechanical stability. Studies have shown that these composites can achieve removal efficiencies exceeding 90%, effectively capturing various forms of microplastics from water (Sun et al., 2020).

Microplastics exhibit a propensity to adsorb various pollutants, including heavy metals and persistent organic compounds, acting as vectors for these toxins into the food web, ultimately posing risks to human health

Chitosan-Cellulose Composites

Blending Chitosan with cellulose forms a robust network through hydrogen bonding, yielding a fibrous material known as Ct-Cel. This composite is highly efficient in adsorbing a diverse range of microplastic particles, including PS, PMMA, PP, and PET, with removal rates reaching 98%–99.9% in real-world water samples (Sayadi & Nowrouzi, 2025). In addition to its filtration efficiency, Ct-Cel demonstrates strong resistance to pollutants such as heavy metals, ensuring longevity and reusability.

Magnetic Chitosan Nanoparticles

The integration of magnetic nanoparticles like iron oxide (Fe₃O₄) into Chitosan matrices introduces the benefit of magnetic responsiveness. This innovation allows the easy separation of the microplastic-loaded adsorbent from water using an external magnet, a method that has achieved removal efficiencies over 95% (Vohl et al., 2024). Such magnetic composites combine high performance with the convenience of recyclability.

Chitosan-Bentonite Clay Composites

Bentonite clay, with its layered structure, can be modified with Chitosan to enhance its adsorption capabilities. The Chitosan–bentonite hybrid shows improved performance in removing both organic pollutants and larger microplastic particles, leveraging the natural binding properties of both materials (Biswas et al., 2021). This composite’s strength lies in its ability to combine the mechanical stability of clay with the binding affinity of Chitosan.

Versatility of Chitosan Composites

The diversity of Chitosan composites from GO-based materials to magnetic nanoparticles demonstrates its adaptability for various water conditions and microplastic types. Scientific research supports the efficacy of these composites, with reported removal rates varying depending on the formulation and environmental conditions.

Key Findings from Scientific Studies

Multiple studies have confirmed that Chitosan can achieve removal rates of approximately 68.3% in some scenarios (Prasetyo et al., 2025). However, when used in specific applications such as pre-treatment for microfibers in laundry wastewater or within advanced composite systems, the efficiency can exceed 90% (Šaravanja et al., 2022). For instance, Chitosan-based hydrogels and surface-modified composites have demonstrated rapid removal of sub-micrometre particles, with some experiments reporting over 90% efficiency within minutes (Yang et al., 2021). Optimisation studies indicate that an ideal Chitosan concentration of around 30 parts per million (ppm) and a pH near 6.0 are crucial for maximising performance (Putranto et al., 2023).

Though visually pure, water can carry microplastics, posing a risk to our health. [Image by Adobe Stock]

Factors Influencing Removal Efficiency

The success of Chitosan-based remediation depends on several variables:

• Particle Size and Type: Smaller microplastics and nano plastics pose challenges but can be effectively targeted using modified Chitosan.

• Composite Formulation: The integration of complementary materials (e.g., GO, cellulose) can significantly enhance adsorption capacity.

• Environmental Conditions: pH, water salinity, and the presence of other contaminants influence the interaction dynamics between Chitosan and microplastics.

• Process Parameters: Optimal dosages and contact times are essential to ensure that the adsorption process is both effective and efficient.

Entoplast: Leading the Way in Sustainable Chitin and Chitosan Production

At Entoplast, we are dedicated to transforming the future of biopolymer production. Our innovative approach harnesses the potential of insect biomass, specifically from the Black Soldier Fly, to produce high-quality chitin and chitosan. Our proprietary green extraction process not only minimises environmental impact compared to traditional crustacean sources, but it also delivers biopolymers with superior mechanical strength, flexibility, and consistency.

We pride ourselves on offering a diverse range of tailored products designed to meet the specific needs of various industries, from environmental remediation to advanced material applications. At Entoplast, sustainability is at the core of our mission. We are committed to driving positive change and providing cutting-edge solutions for a cleaner, greener future. Join us as we lead the way in sustainable innovation.

Conclusion: A Call to Action for a Microplastic-Free Future

The extensive body of scientific evidence demonstrates that Chitosan, with its unique electrostatic, hydrophilic, and hydrogen bonding properties, is highly effective at capturing and removing microplastics from water. Its versatility is further enhanced through composite formulations that integrate materials such as graphene oxide, cellulose, magnetic nanoparticles, and bentonite clay, resulting in advanced remediation solutions adaptable to diverse environmental conditions.

As the global demand for sustainable and effective microplastic removal technologies grows, the time to act is now. We invite academics, environmental scientists, and investors to join us in exploring innovative strategies for cleaner water. For further information or to discuss partnership and investment opportunities, please contact us at hello@entoplast.com or by filling the form below. Together, we can make significant strides toward a microplastic-free future.