Selective adsorption of various phosphorus species coexistence in water-soluble ammonium polyphosphate on goethite: Experimental investigation and molecular dynamics simulation. (November 2022)

• Record Type: Journal Article
• Authors: Ji, Lingmei; Ren, GenKuan; Xu, Dehua; Fan, Bingqian; Zhang, Zhiye; Yuan, Taiyan; Yan, Zhengjuan; Wang, Xinlong
• Is Part Of: Chemosphere. Volume 307:Part 2(2022)
• Publication Date: 2022-11
• Subjects: Goethite -- Ammonium polyphosphate -- Selective adsorption -- Ion chromatography -- Molecular dynamics simulation; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.135901
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The geochemical processes of polyphosphates (poly-Ps) are important for phosphorus (P) management and environmental protection. Water-soluble ammonium polyphosphate (APP) containing various P species has been increasingly used as an alternative P-fertilizer. The various P species coexistence and the chelation of poly-Ps with mental would trigger the P's competitive adsorption and affect the APP's adsorption intensity on goethite, compared to single orthophosphate (P1 ). P adsorption behaviors of APP1 with two P species and APP2 with seven P species on goethite were investigated via batch experiments in comparison to the traditional P-fertilizer of mono-ammonium phosphate (MAP). Coadsorption of P1 and pyrophosphate (P2 ) on goethite was investigated by molecular dynamics (MD) simulation. The more Fe 3+ dissolved from goethite as a bridge due to the chelation of poly-Ps in APP and contributed to the stronger APP adsorption on goethite compared with MAP. Ion chromatography and spectral analysis showed P1 and P2 in APP were mainly adsorbed by goethite via mainly forming bidentate complexes. The goethite preferentially adsorbed P1 at lower APP concentration but increased the poly-Ps' adsorption at higher APP concentration. MD simulation showed that electrostatic interaction and hydrogen bonds played a key role in water-phosphates-goethite systems. The P1 pre-adsorbed on goethite could be replaced by P2 at high P2 concentration. The results develop new insights regarding the selective adsorption of various P species coexistence in goethite-rich environments. Graphical abstract: Image 1 Highlights: APP adsorption on goethite (Gt) increased with an increasing number of P species. Gt co-adsorbed P species with low molecular weight (MW) in APP at low P concentration. P species with high MW contributed to adsorption of APP on Gt at high P concentration. Pyrophosphate (P2 ) could replace orthophosphate (P1 ) pre-adsorbed on Gt. Hydrogen bonds played a key role in the water-phosphates-goethite adsorption systems.