Engineering Research Center of Comprehensive Utilization and Clean Processing of Phosphorus Resources of Ministry of Education, School of Chemical Engineering, Sichuan University, No. 24 South Section 1, Yihuan Road, Chengdu, 610065, PR China.
Material and Chemical Engineering College, Yibin University, No. 24 Wuliangye Avenue, Yibin, 644000, PR China.
Chemosphere. 2022 Nov;307(Pt 2):135901. doi: 10.1016/j.chemosphere.2022.135901. Epub 2022 Aug 6.
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 (P). 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 P and pyrophosphate (P) on goethite was investigated by molecular dynamics (MD) simulation. The more Fe 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 P and P in APP were mainly adsorbed by goethite via mainly forming bidentate complexes. The goethite preferentially adsorbed P 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 P pre-adsorbed on goethite could be replaced by P at high P concentration. The results develop new insights regarding the selective adsorption of various P species coexistence in goethite-rich environments.
聚磷酸盐（poly-Ps）的地球化学过程对于磷（P）管理和环境保护至关重要。含有各种 P 形态的水溶性铵聚磷酸盐（APP）已越来越多地被用作替代 P 肥料。与单一正磷酸盐（P）相比，各种 P 形态的共存和 poly-Ps 与金属的螯合作用会引发 P 的竞争吸附，并影响 APP 在针铁矿上的吸附强度。通过批量实验研究了两种 P 形态的 APP1 和七种 P 形态的 APP2 在针铁矿上的 P 吸附行为，并与传统的 P 肥料磷酸一铵（MAP）进行了比较。通过分子动力学（MD）模拟研究了 P 和焦磷酸盐（P）在针铁矿上的共吸附。由于 APP 中 poly-Ps 的螯合作用，更多的 Fe 从针铁矿中溶解出来充当桥梁，从而导致 APP 对针铁矿的吸附强度强于 MAP。离子色谱和光谱分析表明，APP 中的 P 和 P 主要通过形成双齿配合物被针铁矿吸附。当 APP 浓度较低时，针铁矿优先吸附 P，但当 APP 浓度较高时，针铁矿增加了 poly-Ps 的吸附。MD 模拟表明，静电相互作用和氢键在水-磷酸盐-针铁矿体系中起着关键作用。在高 P 浓度下，预吸附在针铁矿上的 P 可以被 P 取代。研究结果为针铁矿富磷环境中各种 P 形态共存的选择性吸附提供了新的认识。
