Synthesis of FeOOH-Loaded Aminated Polyacrylonitrile Fiber for Simultaneous Removal of Phenylphosphonic Acid and Phosphate from Aqueous Solution

Phosphorus is one of the important metabolic elements for living organisms, but excess phosphorus in water can lead to eutrophication. At present, the removal of phosphorus in water bodies mainly focuses on inorganic phosphorus, while there is still a lack of research on the removal of organic phosphorus (OP). Therefore, the degradation of OP and synchronous recovery of the produced inorganic phosphorus has important significance for the reuse of OP resources and the prevention of water eutrophication. Herein, a novel FeOOH-loaded aminated polyacrylonitrile fiber (PAN(A)F-FeOOH) was constructed to enhance the removal of OP and phosphate. Taking phenylphosphonic acid (PPOA) as an example, the results indicated that modification of the aminated fiber was beneficial to FeOOH fixation, and the PAN(A)F-FeOOH prepared with 0.3 mol L-1 Fe(OH)(3) colloid had the best performance for OP degradation. The PAN(A)F-FeOOH efficiently activated peroxydisulfate (PDS) for the degradation of PPOA with a removal efficiency of 99%. Moreover, the PAN(A)F-FeOOH maintained high removal capacity for OP over five cycles as well as strong anti-interference in a coexisting ion system. In addition, the removal mechanism of PPOA by the PAN(A)F-FeOOH was mainly attributed to the enrichment effect of PPOA adsorption on the fiber surface's special microenvironment, which was more conducive to contact with SO4 center dot(-) and center dot OH generated by PDS activation. Furthermore, the PAN(A)F-FeOOH prepared with 0.2 mol L-1 Fe(OH)(3) colloid possessed excellent phosphate removal capacity with a maximal adsorption quantity of 9.92 mg P g(-1). The adsorption kinetics and isotherms of the PAN(A)F-FeOOH for phosphate were best depicted by pseudo-quadratic kinetics and a Langmuir isotherm model, showing a monolayer chemisorption procedure. Additionally, the phosphate removal mechanism was mainly due to the strong binding force of iron and the electrostatic force of protonated amine on the PAN(A)F-FeOOH. In conclusion, this study provides evidence for PAN(A)F-FeOOH as a potential material for the degradation of OP and simultaneous recovery of phosphate.

Automated summary

Phosphorus is an important metabolic element for living organisms, but excessive phosphorus in water can cause eutrophication. Current research on phosphorus removal focuses on inorganic phosphorus, while there is a lack of research on organic phosphorus (OP) removal. This study constructed a novel FeOOH-loaded aminated polyacrylonitrile fiber (PAN(A)F-FeOOH) to enhance OP and phosphate removal. The results showed that PAN(A)F-FeOOH efficiently degraded phenylphosphonic acid (PPOA) with a removal efficiency of 99% and had high removal capacity for OP over multiple cycles. Additionally, PAN(A)F-FeOOH demonstrated excellent phosphate removal capacity with a maximal adsorption quantity of 9.92 mg P g(-1).