Fixed-bed column study of phosphate adsorption using immobilized phosphate-binding protein

Area of Science:

• Environmental Science
• Biotechnology
• Chemical Engineering

Background:

• Phosphate removal and recovery are critical for water quality management.
• Batch-scale bio-adsorption using phosphate-binding proteins (PBP) shows promise.
• Scaling up PBP-based systems requires fixed-bed column optimization.

Purpose of the Study:

• Investigate continuous-flow fixed-bed column performance of PBP-NHS resin for phosphate adsorption.
• Evaluate phosphate removal to ultra-low levels and recovery.
• Assess resin selectivity, capacity, and reusability.

Main Methods:

• Continuous-flow fixed-bed column experiments were conducted.
• Phosphate-binding proteins immobilized on resin (PBP-NHS) were used.
• Breakthrough models (Thomas and Yoon-Nelson) were applied to analyze performance.
• Comparison with a commercial ion exchange resin (LayneRT™) was performed.
• Wastewater effluent treatment and multi-cycle operation were tested.

Main Results:

• Breakthrough time was influenced by influent concentration, bed volume, and flow rate.
• Thomas and Yoon-Nelson models accurately described PBP-NHS resin performance (R² > 0.95).
• PBP-NHS resin exhibited selective phosphate separation, outperforming LayneRT™.
• PBP-NHS capacity was unaffected by competing anions, unlike LayneRT™ (20% capacity drop).
• Successful phosphate removal from tertiary wastewater effluent was achieved.
• PBP-NHS resin demonstrated reusability over multiple cycles without performance decline.

Conclusions:

• Continuous-flow fixed-bed columns with PBP-NHS resin are effective for ultra-low level phosphate removal and recovery.
• The PBP-NHS resin offers superior selectivity and anion interference resistance compared to commercial ion exchange resins.
• The resin's reusability and stable performance support its application in scalable water treatment systems.