Polydopamine-interlayer-mediated defective Ce-ATA-25PA@Chitosan biomass microspheres for efficient phosphate removal in aquaculture wastewater

PDA interlayer enables uniform in situ growth of defective Ce-MOF on chitosan. • Ce-ATA-25PA@PDA@CS achieves a phosphate capacity of 126.6 mg P g −1 . • Phosphate removal reaches 98.6% in real aquaculture wastewater within 60 min. • Synergistic ligand exchange, electrostatic attraction, and H-bonding drive uptake. • The microspheres retain over 68% phosphate removal after five regeneration cycles. The excessive accumulation of phosphate in water bodies can disrupt the ecological balance and pose a threat to human health, highlighting the urgent need for efficient and economically viable adsorbents to treat waters with high phosphorus content. The defective cerium-based metal–organic framework (Ce-MOF) has shown considerable potential for phosphate removal due to its abundant coordinatively unsaturated Ce active sites. However, the high cost of pure Ce-MOF limits its practical application in the large-scale treatment of phosphorus-containing wastewater. In this study, the composite microspheres (Ce-ATA-25PA@PDA@CS) as phosphorus adsorbents were successfully prepared by in situ growth strategy when the new defective Ce-MOF (Ce-ATA-25PA) grew on the surface of the polydopamine coated chitosan microspheres (PDA@CS). The PDA interlayer promoted a denser and more uniform distribution of Ce-ATA-25PA on the chitosan support, and the resulting composite microspheres exhibited an increased specific surface area and a maximum phosphate adsorption capacity of 126.6 mg P/g under the optimized conditions. Mechanistic investigations have shown that phosphate uptake is influenced by the synergistic coupling of multiple interactions: the phosphate uptake involved Ce–O–P interactions at Ce sites together with contributions from the –NH₂ and –OH groups of the PDA@CS support through electrostatic attraction and hydrogen bonding. This work provides presents an environmentally friendly, and efficient MOF/biomass composite adsorbent, which can be used for treating phosphorus-containing wastewater treatment and offers a useful strategy for designing advanced MOF/biopolymer materials for aquatic environmental remediation. Download: Download high-res image (164KB) Download: Download full-size image