How Biodegradable Dendritic Colloids are Changing the Future of Microplastic Removal

By Muhammad OsamaReviewed by Laura ThomsonApr 1 2025

In a recent article published in Advanced Functional Materials, researchers proposed a new method to address microplastic pollution in aquatic environments by developing self-dispersing soft dendritic colloids (SDCs) made from biodegradable materials. These systems are designed to efficiently capture and remove microplastics, providing a sustainable solution for water cleanup. The goal was to highlight the potential of eco-friendly materials while addressing the health risks associated with microplastic contamination.

Microplastic Pollution and Remediation Technologies

Microplastic accumulation in aquatic ecosystems poses significant risks to marine life and human health. Defined as plastic particles smaller than 5 mm, microplastic primarily originates from the degradation of larger plastic waste and resists natural decomposition.

Traditional removal methods, such as filtration and centrifugation, are often impractical for large-scale use, underscoring the need for better technologies.

Existing approaches have focused on self-propelling micromotors and active microcleaners that enhance dispersion for microplastic capture. However, many of these solutions rely on chemical fuels, limiting their application in open environments. This highlights the necessity for biodegradable and sustainable materials capable of efficiently capturing microplastics from water.

About this Research: Introducing a Novel SDC Mechanism

In this paper, the authors introduced a comprehensive multistage process for microplastic capture and recovery using biodegradable SDCs. Derived from chitosan, a biodegradable polymer sourced from shellfish waste, these fibrillar particles feature a hierarchical branching structure that enhances adhesion to microplastics through van der Waals interactions, similar to the gecko leg effect.

The system operates through multiple stages. First, SDCs are assembled into supraparticle pellets and infused with surface-active compounds, such as oleic acid and eugenol, to enable self-propulsion via the Marangoni effect.

As these supraparticles move across water surfaces, they gradually release individual SDCs, disperse, sink, and capture microplastics, forming dense aggregates. A secondary propulsion mechanism, driven by hydrogen bubbles generated from magnesium hydrolysis, facilitates the timed flotation of these aggregates, allowing for easy retrieval at the water surface.

The SDCs are fabricated using a liquid shear precipitation method to create highly branched structures, which are then agglomerated into supraparticles using maltodextrin (MD) as a stabilizing agent and vacuum-dried into pellets. This innovative approach provides an environmentally friendly and effective solution for large-scale microplastic remediation without introducing harmful byproducts.

Key Findings: Impacts of Implementing New System

The study demonstrated the effectiveness of SDCs in capturing microplastics under various conditions. SDCs treated with MD achieved over 60% capture efficiency, compared to 30-50% for untreated ones.

Eugenol-infused supraparticles enabled self-propulsion, traveling up to 470 mm at velocities of 15-50 mm/s, ensuring widespread dispersion. The timed flotation mechanism, attained through gelatin-coated magnesium particles, facilitated controlled retrieval of SDC-MP aggregates.

Tests in saline water and with diverse microplastic types confirmed the robustness of SDCs, which successfully captured real-world microplastics from Kamilo Beach, Hawaii. In controlled environments, they exhibited over 85% efficiency. The incorporation of MD improved redispersibility, enhancing microcleaner performance.

Propulsion studies showed that surface-active oils influenced movement. Oleic acid provided rapid initial propulsion but shorter travel distances due to monolayer saturation, while eugenol dissolved in water, sustaining longer propulsion. A novel vertical motion mechanism using gelatin-coated magnesium particles generated hydrogen bubbles, enabling microplastic aggregates to float for easy collection.

The Marangoni effect, induced by the release of surface-active compounds, allowed SDCs to self-disperse across large water volumes, improving capture rates. The supraparticle design maintained structural integrity, ensuring efficient aggregation and retrieval.

SDCs effectively captured various microplastics across different concentrations and conditions, including polystyrene and polyethylene. Their hierarchical branching enhanced aggregation, forming dense, easily collectable clusters. Actively moving supraparticles ensured uniform distribution, leading to higher capture rates.

Potential Applications of the Microcleaning System

This research has significant implications for sustainable water remediation technologies. Using biodegradable materials like chitosan and plant-derived oils ensures environmental safety and scalability. The ability of SDCs to disperse over large water volumes and retrieve captured microplastics makes them particularly suitable for open aquatic environments, including oceans, rivers, and lakes. Their modular design allows customization based on specific environmental conditions and microplastic types.

The SDCs’ capacity to capture microplastics of all sizes, including those coated with biofilms, enhances their versatility for environmental agencies and marine conservation efforts. The findings suggest that this technology could be scaled up for applications in treating polluted water bodies, wastewater effluents, and marine environments.

Conclusion and Future Directions

The novel SDC-based system proved effective for capturing and recovering microplastics by integrating biodegradable materials with active propulsion mechanisms, addressing the limitations of existing technologies. The findings highlight its potential for large-scale application, offering a sustainable solution to a global environmental challenge.

Future work should focus on scaling fabrication, optimizing performance across diverse environmental conditions, and assessing long-term ecological impacts. Integrating life cycle analyses and evaluating real-world feasibility will be crucial for its successful implementation. With further refinement, this technology could revolutionize water remediation efforts, contributing to healthier aquatic ecosystems and improved public health outcomes.

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