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

Abstract

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 (PANAF-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 PANAF-FeOOH prepared with 0.3 mol L−1 Fe(OH)3 colloid had the best performance for OP degradation. The PANAF-FeOOH efficiently activated peroxydisulfate (PDS) for the degradation of PPOA with a removal efficiency of 99%. Moreover, the PANAF-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 PANAF-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•− and •OH generated by PDS activation. Furthermore, the PANAF-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 PANAF-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 PANAF-FeOOH. In conclusion, this study provides evidence for PANAF-FeOOH as a potential material for the degradation of OP and simultaneous recovery of phosphate.

Polypyrrole-Modified Nanocellulose Exhibits Superior Performance for Hg(II) Adsorption

“…It was found that the adsorption reached the equilibrium status within 60 min for CNC@PPy. According to the fitting of adsorption kinetics model in Figure 3 b, all adsorbent materials met the pseudo-second-order model [ 14 , 17 , 18 , 19 ]. The adsorption speed was the fastest, within 40 min, and the adsorption equilibrium could be reached.…”

“…According to the fitted experimental data, the adsorption of Hg(II) by this product was consistent with the Freundlich adsorption isotherm model. This indicates that the adsorption of Hg(II) by CNC/PPy adsorbent is a single molecular layer adsorption process and a surface adsorption process [ 17 , 18 , 19 ]. The pseudo-second-order model with R 2 = 0.948 ( Figure 3 d) better represented the adsorption process.…”

“…The pseudo-second-order model with R 2 = 0.948 ( Figure 3 d) better represented the adsorption process. This indicates that the rate controlling step of the adsorption is a chemical interaction process involving theCNC@ppy’s chelating function [ 19 ]. The parameters for the adsorption kinetic models are listed in Figure 3 a–d.…”

“…The result demonstrated that CNC@PPy possesses a high selectivity for Hg(II) in a complex competitive system. The property of cyclic adsorption behavior for a certain adsorbent is important for its underlying adaptability in wastewater remediation [ 14 , 19 ]. The reusability of the CNC@PPy for the adsorption of Hg(II) was investigated.…”

“…There are many strategies which have been used for removing pollutants in wastewater, including ion exchange, Polymers 2023, 15, 2735 2 of 10 photo/electrochemical reduction, coagulation, chemical precipitation, adsorption, or membrane separation [15,16]. Among these approaches, the adsorption method, as a promising technology for environmental remediation, has attracted widespread attention with a series advantages, such as being eco-friendly, reusable, low cost, and easy to operate [17][18][19]. Thus, the adsorbents play a significant role during the adsorption process.…”