Related Experiment Video
Updated: Aug 5, 2026
Aqueous Droplets Used as Enzymatic Microreactors and Their Electromagnetic Actuation
Published on: August 28, 2017
Balancing interaction energy and collision frequency for engineering-efficient algal removal by covalently
Lili Li1, Liangjun Yang2, Zimin Wang3
1Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; Key Laboratory of Environmental Aquatic Chemistry, State Key Laboratory of Regional Environment and Sustainability, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China.
Micrometer-scale magnetic particles (MPs) functionalized with polyethyleneimine (PEI) offer a cost-effective solution for rapid algal removal. This study demonstrates their efficiency and reusability, presenting a practical alternative to expensive nanoparticles for water treatment.
Area of Science:
- Environmental Science
- Materials Science
- Chemical Engineering
Background:
- Magnetic separation is a promising method for algal removal without chemical coagulants.
- Current methods often rely on expensive magnetic nanoparticles, limiting practical application.
- Developing cost-effective and efficient magnetic materials for algal removal is crucial.
Purpose of the Study:
- To investigate the efficacy of micrometer-scale magnetic particles (MPs) for algal removal.
- To explore the influence of particle size on algal removal efficiency and kinetics.
- To develop a stable and cost-effective functionalization strategy for MPs.
Main Methods:
- Grafting polyethyleneimine (PEI) onto MPs using a silane-coupling strategy.
- Systematic investigation of MPs with sizes ranging from 90 nm to 32 μm.
- Performance evaluation based on removal efficiency, separation time, and reusability.
- Mechanistic analysis using DLVO theory, Smoluchowski collision theory, and separation kinetics.
Main Results:
- PEI-functionalized MPs effectively removed algae via electrostatic attraction.
- Optimal algal removal was achieved with 5 μm MPs, reaching 90% removal in 1 minute.
- Micrometer-scale MPs demonstrated comparable or superior performance to nanoparticles, with faster kinetics and lower cost.
- The 5 μm MPs maintained high removal efficiency over four reuse cycles and in pond water.
Conclusions:
- Covalently functionalized micrometer-scale MPs represent a practical and cost-effective strategy for algal removal.
- A specific particle size window (around 5 μm) is optimal for algal removal efficiency and kinetics.
- This approach offers a sustainable alternative for water treatment applications.
