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Phosphorus removal and recovery from water with macroporous bead adsorbent constituted of alginate-Zr4+ and PNIPAM-interpenetrated networks

Luo, Huayong, Zeng, Xueyang, Liao, Peng, Rong, Hongwei, Zhang, Tian C., Jason Zhang, Z., Meng, Xiangchao
International journal of biological macromolecules 2019 v.126 pp. 1133-1144
Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, adsorbents, adsorption, alginates, biocompatible materials, desorption, effluents, electrostatic interactions, gels, ligands, moieties, phosphorus, polyethylene glycol, porous media, scanning electron microscopy, strength (mechanics), surface area, thermodynamics, wastewater, zeta potential
Currently, there is a growing trend in employing natural biomaterials (e.g., alginate) to prepare a novel bead adsorbent for phosphorus (P) elimination. However, the utilization of alginate beads to remove and recover P from effluents possesses limitations associated with its physical characteristics such as a dense gel layer, poor mechanical strength and low stability. To overcome the limitations and improve the adsorption performances, we synthesized a novel alginate-derived bead constituted of PNIPAM network interpenetrated in alginate-Zr4+ network (PNIPAM/SA-Zr) decorated with polyethylene glycol as a pore-forming agent, and then investigated its ability to remove and recover P from effluents. The morphology, functional groups, surface area, and mechanical strength of the beads were evaluated by SEM, FTIR, BET, and swelling analysis. The adsorption of P was investigated by varying various factors. The adsorption kinetics, isotherms, and thermodynamics were studied. Particularly, the P-loaded beads exhibited a faster desorption rate under thermal stimulus, and remained good desorption efficiency and reusability within five consecutive cycles. Zeta-potential and XPS results revealed that the adsorption mechanisms were related to electrostatic interactions, ligand exchange, and the formation of inner-sphere complexes. The beads possessed favorable fixed-bed column operation performances for P removal and recovery from real wastewater.